ABSTRACT

Objective:

To analyze the specific five-year survival of colorectal cancer (CRC) diagnosed between 2008 and 2013, according to sex and age group, of residents in Greater Cuiabá, state of Mato Grosso, Brazil.

Methods:

This is a retrospective cohort study. Specific survival of CRC was considered as the time between disease diagnosis and death from CRC, in months. Data from the Population-Based Cancer Registry and the Brazilian Mortality Information System were used. To estimate the probability of survival by sex and age group, the Kaplan-Meier estimator was used, and to estimate the effect of age group on the survival of participants, the Cox model stratified by sex was adjusted.

Results:

From 2008 to 2013, 683 new cases and 193 deaths from CRC were registered. The median time between diagnosis and death from CRC was 44.8 months (95%CI 42.4– 47.3) for women and 46.1 months (95%CI 43.4–48.6) for men, and the five-year survival probabilities of 83.5% (95%CI 79.9–87.2%) and 89.6% (95%CI 86.4–93.0%), respectively. Men aged 70–79 years (HR=2.97; 95%CI 1.11–3.87) and 80 years or older (HR=3.09; 95%CI 1.31–7.27) were at higher risk of mortality, and we verified no difference for women.

Conclusion:

Women had a shorter time between the diagnosis of CRC and death from the disease as well as a lower probability of survival. Conversely, men were at higher risk of mortality after 70 years of age.

Keywords:
Survival; Colorectal neoplasms; Demographic factors; Registries

INTRODUCTION

Chronic diseases and noncommunicable diseases account for more than half of the total number of deaths in Brazil, representing 54.7% of deaths registered in the country in 2019. Among the main groups of chronic diseases is cancer¹1. Brasil. Ministério da Saúde. Secretaria de Vigilância em Saúde. Departamento de Análise em Saúde e Vigilância de Doenças Não Transmissíveis. Plano de ações estratégicas para o enfrentamento das doenças crônicas e agravos não transmissíveis no Brasil 2021-2030 [Internet]. Brasília: Ministério da Saúde; 2021 [acessado em 29 nov. 2021]. Disponível em: https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/publicacoes-svs/doencas-cronicas-nao-transmissiveis-dcnt/09-plano-de-dant-2022_2030.pdf/view#:∼:text=O%20plano%20de%20A%C3%A7%C3%B5es%20Estrat%C3%A9gicas,a%20dirimir%20desigualdades%20em%20sa%C3%BAde
https://www.gov.br/saude/pt-br/centrais-... , whose mortality has been growing worldwide and already represents the second leading cause of death in most countries²2. World Health Organization. WHO report on cancer: setting priorities, investing wisely and providing care for all [Internet]. Geneva: World Health Organization; 2020 [acessado em 20 set. 2021]. Disponível em: https://www.who.int/publications/i/item/9789240001299
https://www.who.int/publications/i/item/... .

Cancer can affect several parts of the human body. Colorectal cancer (CRC) is a malignant neoplasm that affects the large intestine. Until 1950, it was relatively rare, but currently it is one of the cancers with the highest incidence and mortality worldwide³3. Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2021; 71(3): 209-49. https://doi.org/10.3322/caac.21660
https://doi.org/10.3322/caac.21660... . This increase has been partly related to the aging of the population, but also to factors related to lifestyle such as unhealthy eating habits, smoking, sedentary lifestyle, alcohol consumption, and obesity⁴4. Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2018; 68(6): 394-424. https://doi.org/10.3322/caac.21492
https://doi.org/10.3322/caac.21492... ,⁵5. World Cancer Research Fund. American Institute for Cancer Research. Continuous Update Project. Diet, nutrition, physical activity and colorectal cancer [Internet]. London: World Cancer Research Fund; 2018 [acessado em 2 mar. 2022]. Disponível em: https://www.wcrf.org/wp-content/uploads/2021/02/Colorectal-cancer-report.pdf
https://www.wcrf.org/wp-content/uploads/... .

For 2020, more than 1.9 million new cases and 935 thousand deaths from CRC were estimated worldwide, representing about 1 in 10 cases or deaths from cancer. Overall, CRC ranks third in terms of incidence, but second in terms of mortality. Incidence rates are lower in middle-income countries, but mortality rates are higher³3. Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, et al. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2021; 71(3): 209-49. https://doi.org/10.3322/caac.21660
https://doi.org/10.3322/caac.21660... .

Concerning Brazil, for each year of the triennium 2020–2022, 20,520 cases of CRC are estimated in men and 20,470 in women. These values correspond to an age-adjusted incidence of 18.80 new cases/100 thousand men and 13.36 new cases/100 thousand women. For Greater Cuiabá, state of Mato Grosso, 20 cases of CRC were estimated for men and 40 for women in the year 2020, with an age-adjusted incidence of 8.58 and 14.04/100 thousand inhabitants for men and women, respectively⁶6. Instituto Nacional de Câncer José Alencar Gomes da Silva. Estimativa 2020: incidência de câncer no Brasil [Internet]. Rio de Janeiro: INCA; 2019 [acessado em 7 mar. 2022]. Disponível em: https://www.inca.gov.br/sites/ufu.sti.inca.local/files//media/document//estimativa-2020-incidencia-de-cancer-no-brasil.pdf
https://www.inca.gov.br/sites/ufu.sti.in... .

In terms of mortality, in 2019, 10,191 deaths from the disease were registered for men and 10,385 for women in Brazil, corresponding to a mortality rate of 9.73 deaths/100 thousand men and 7.81 deaths/100 thousand women, respectively⁷7. Instituto Nacional de Câncer José Alencar Gomes da Silva. Atlas online de mortalidade [Internet] 2020 [acessado em 28 jan. 2022]. Disponível em: https://mortalidade.inca.gov.br/MortalidadeWeb
https://mortalidade.inca.gov.br/Mortalid... .

As for five-year net survival in the country, it was estimated at 44.5, 50.6, and 48.3% for patients diagnosed with colon cancer in the years 2000 to 2004, 2005 to 2009, and 2010 to 2014, respectively. For patients diagnosed with rectal cancer, for these same periods, the net survival was 37.7, 45.7, and 42.4%⁸8. Allemani C, Matsuda T, Di Carlo V, Harewood R, Matz M, Nikšić M, et al. Global surveillance of trends in cancer survival 2000-14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet 2018; 391(10125): 1023-75. https://doi.org/10.1016/S0140-6736(17)33326-3
https://doi.org/10.1016/S0140-6736(17)33... .

Hospital-based studies have shown greater and better survival for women, young people, and patients diagnosed early⁹9. Agüero F, Murta-Nascimento C, Gallén M, Andreu-García M, Pera M, Hernández C, et al. Colorectal cancer survival: results from a hospital-based cancer registry. Rev Esp Enferm Dig 2012; 104(11): 572-7. https://doi.org/10.4321/s1130-01082012001100004
https://doi.org/10.4321/s1130-0108201200... –¹²12. Morishima T, Matsumoto Y, Koeda N, Shimada H, Maruhama T, Matsuki D, et al. Impact of comorbidities on survival in gastric, colorectal, and lung cancer patients. J Epidemiol 2019; 29(3): 110-5. https://doi.org/10.2188/jea.JE20170241
https://doi.org/10.2188/jea.JE20170241... . The stage of CRC in diagnosis is one of the most important primary determinants of survival and one of the main predictors of mortality¹³13. Alexander DD, Waterbor J, Hughes T, Funkhouser E, Grizzle W, Manne U. African-American and Caucasian disparities in colorectal cancer mortality and survival by data source: an epidemiologic review. Cancer Biomark 2007; 3(6): 301-13. https://doi.org/10.3233/cbm-2007-3604
https://doi.org/10.3233/cbm-2007-3604... . Five-year survival rates may be higher than 90% if the diagnosis is made at an early stage; however, only 37% of cases are diagnosed at this stage¹⁴14. Mendes V. Prevenir o cancro do cólon e recto [Internet]. J Port Gastrenterol 2008; 15: 153-5. [acessado em 02 dez. 2021]. Disponível em: http://www.sped.pt/images/sped/GE/GE_2008/4setout2008/v15n4a02.pdf
http://www.sped.pt/images/sped/GE/GE_200... . CRC can be considered a condition with good prognosis, and survival can be better the more initial the stage of the lesion at diagnosis is⁸8. Allemani C, Matsuda T, Di Carlo V, Harewood R, Matz M, Nikšić M, et al. Global surveillance of trends in cancer survival 2000-14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet 2018; 391(10125): 1023-75. https://doi.org/10.1016/S0140-6736(17)33326-3
https://doi.org/10.1016/S0140-6736(17)33... .

Thus, the objective of this study is to analyze the specific five-year survival of CRC diagnosed between 2008 and 2013, according to sex and age group, of residents in Greater Cuiabá, state of Mato Grosso (MT), Brazil.

METHODS

This is a population-based retrospective cohort study of residents of Greater Cuiabá. The municipalities of Cuiabá and Várzea Grande compose the region called Greater Cuiabá. They are the most populous municipalities in the state and have a territorial extension of 4,015,975 km². According to data from the last demographic census (2010), Cuiabá recorded 4.5% of illiteracy rate, 20.0% of the population with income lower than half minimum wage, unemployment rate of people aged 16 years or older of 6.4%, and municipal human development index (MHDI) of 0.785. For Várzea Grande, these values were, respectively, 5.5; 27.3; 6.8; and 0.734%¹⁵15. Ministério da Saúde. Portal da Saúde. DATASUS. Informações de Saúde (TABNET). Demográficas e socioeconômicas [Internet]. 2010 [acessado em 29 nov. 2021]. Disponível em: https://datasus.saude.gov.br/informacoes-de-saude-tabnet/
https://datasus.saude.gov.br/informacoes... ,¹⁶16. Instituto Brasileiro de Geografia e Estatística. Cidades e Estados [Internet]. 2010 [acessado em 13 dez. 2021]. Disponível em: https://www.ibge.gov.br/cidades-e-estados.html?view=municipio
https://www.ibge.gov.br/cidades-e-estado... .

Information on new cases of the disease were retrieved from the Population-based Cancer Registry of Greater Cuiabá, namely PBCR-Cuiabá, and information on deaths were provided by the State Department of Health of Mato Grosso (Secretaria de Estado de Saúde de Mato Grosso – SES-MT) and later comprised the Brazilian Mortality Information System (Sistema de Informações sobre Mortalidade – SIM). Those who presented the following codes were identified as cases or deaths due to CRC, registered according to the 10th edition of the International Classification of Diseases (ICD-10): C18 (malignant neoplasm of colon), C19 (malignant neoplasm of rectosigmoid junction), C20 (malignant neoplasm of rectum), and C21 (malignant neoplasm of anus and anal canal), as considered by the Brazilian National Cancer Institute (INCA)⁶6. Instituto Nacional de Câncer José Alencar Gomes da Silva. Estimativa 2020: incidência de câncer no Brasil [Internet]. Rio de Janeiro: INCA; 2019 [acessado em 7 mar. 2022]. Disponível em: https://www.inca.gov.br/sites/ufu.sti.inca.local/files//media/document//estimativa-2020-incidencia-de-cancer-no-brasil.pdf
https://www.inca.gov.br/sites/ufu.sti.in... ,¹⁷17. Instituto Nacional de Câncer José Alencar Gomes da Silva. Coordenação de Prevenção e Vigilância. Estimativa 2016: incidência de câncer no Brasil [Internet]. Rio de Janeiro: INCA; 2015 [acessado em 29 set. 2021]. Disponível em: https://www.inca.gov.br/bvscontrolecancer/publicacoes/edicao/Estimativa_2016.pdf
https://www.inca.gov.br/bvscontrolecance... . All new cases diagnosed with other malignant neoplasms were excluded from the analysis, as well as cases with diagnosis of tumors with in situ behavior; in situations in which the same patient had more than one primary tumor, only the first diagnosis was preserved.

The specific five-year survival of CRC was considered as the time, in months, elapsed between the diagnosis of the disease (time of patients’ entry in the cohort, whose recruitment occurred in the period from 01/01/2008 to 12/31/2013, i.e., diagnosed in this period) and death from CRC or date of last information¹⁸18. Carvalho MS, Andreozzi VL, Codeço CT, Campos DP, Barbosa MTS, Shimakura SE. Análise de sobrevivência: teoria e aplicações em saúde. 2a ed. rev ampl. Rio de Janeiro: Editora Fiocruz; 2011.. The follow-up time occurred until 12/31/2018. The follow-up of new cases was passively performed, i.e., by cross-referencing the cases identified in the PBCR-Cuiabá with the deaths, regardless of the cause, identified in the SIM. Patients who were not found in death records (n=439; 64.3%) were assumed to be, in their vital status, alive and censored on 12/31/2018. Hence, there was no active follow-up of patients¹⁹19. Bustamante-Teixeira MT, Faerstein E, Latorre MR. Técnicas de análise de sobrevida. Cad Saúde Pública 2002; 18(3): 579-94. https://doi.org/10.1590/S0102-311X2002000300003
https://doi.org/10.1590/S0102-311X200200... . Patients who died from other types of cancer (n=21; 3.1%) and other causes (n=30; 4.4%) were assumed to be, in their vital status, as alive and censored on the date of death.

For the probabilistic linkage between the two databases (PBCR-Cuiabá and SIM), the record linkage technique was used, which aims to identify records related to the same unit (e.g., people) in two or more distinct databases²⁰20. Camargo Jr KR, Coeli CM. Reclink: aplicativo para o relacionamento de bases de dados, implementando o método probabilistic record linkage. Cad Saúde Pública 2000; 16(2): 439-47. https://doi.org/10.1590/S0102-311X2000000200014
https://doi.org/10.1590/S0102-311X200000... . To this end, three stages were performed: standardization of the common fields to be used in pairing; blocking, by the variable “sex”; and, finally, pairing, by developing concordance scores by the variables “patient’s name,” “mother’s name,” and “date of birth.” The soundex option was used, which reduces problems of spelling errors. A score was estimated for each pair of registries found. The higher the score, the greater the probability that the identified pair refers to the same person. A cutoff point of 7 was adopted, according to Queiroz et al.²¹21. Queiroz OV, Guerra Júnior AA, Machado CJ, Andrade EIG, Meira Júnior W, Acurcio FA, et al. Relacionamento de registros de grandes bases de dados: estimativa de parâmetros e validação dos resultados, aplicados ao relacionamento dos registros das autorizações de procedimentos ambulatórias de alta complexidade com os registros sistema de informações hospitalares. Cad Saúde Colet 2010; 18(2): 298-308.. The databases were paired by the RecLink III program. Figure 1 shows the flowchart of the probabilistic record linkage procedure between PBCR-Cuiabá and SIM databases for the CRC, for the period from 2008 to 2013.

To estimate the probability of the specific five-year survival, by sex and age group, the Kaplan-Meier¹⁹19. Bustamante-Teixeira MT, Faerstein E, Latorre MR. Técnicas de análise de sobrevida. Cad Saúde Pública 2002; 18(3): 579-94. https://doi.org/10.1590/S0102-311X2002000300003
https://doi.org/10.1590/S0102-311X200200... ,²²22. Colosimo EA, Giolo SR. Modelo de regressão de Cox. In: Colosimo EA, Giolo SR, ed. Análise de sobrevivência aplicada. São Paulo: Edgard Blücher; 2006. p. 155-200. estimator and the log-rank test were used, aiming at verifying whether there were statistical differences in the lifetime per groups. To estimate the effect of the age group on the participants’ survival, stratified by sex, the Cox model was adjusted, obtaining estimates of the hazard ratio (HR) and their respective 95% confidence intervals (95%CI) for each category of interest. A statistical significance level of 0.05 was adopted. To verify the proportionality of the failure rates, the Schoenfeld residual test was used according to the statistical significance level of 5%²³23. Schoenfeld D. Partial residuals for the proportional hazards regression model. Biometrika 1982; 69(1): 239-41. https://doi.org/10.1093/biomet/69.1.239
https://doi.org/10.1093/biomet/69.1.239... .

Statistical analyses were performed based on the results and graphs were obtained using the R software, version 4.0.2.

The project was approved by the Research Ethics Committee of Hospital Universitário Júlio Muller (Opinion No. 3.048.183, from 11/20/2018) and the Research Ethics Committee of Secretaria de Estado de Saúde de Mato Grosso (Opinion No. 3.263.744, from 04/12/2019).

RESULTS

In the analyzed cohort, 683 individuals diagnosed with CRC were included. Of these, 244 died, 193 of which from CRC (Figure 1). Among deaths from CRC, 57.5% were women, and there was a higher proportion in the age groups from 60 to 69 years (31.5%) and 50 to 59 years (22.5%) for women and 70 to 79 years (29.3%) and 50 to 59 years (24.4%) for men. The time elapsed from diagnosis to death ranged from 38.7 months (70 to 79 years) to 49.1 months (under 50 years of age) for women; and from 33.2 months (80 years or older) to 47.5 months (50 to 59 years) for men. Women had a median of 44.8 months (95%CI 42.4–47.3) and men, 46.1 months (95%CI 43.4–48.6) (Table 1).

The probability of specific five-year survival of CRC, considering both sexes, was 84.2% (95%CI 80.5–87.8%). For women, it was 83.5% (95%CI 79.9–87.2%), ranging from 79.4% (60 to 69 years) to 87.4% (under 50 years of age) and, for men, it ranged from 69.9% (80 years or older) to 87.7% (under 50 years of age), with survival of 89.6% (95%CI 86.4–93.0%) (Table 1).

We noticed that, for women, the lowest probabilities of survival occurred for age groups as from 60 years, especially for the age group from 60 to 69 years, which presented a value 10.3% lower than the same age group for men. Conversely, for men, the lowest probabilities of survival occurred as from 70 years, especially for those aged 80 years or older, who presented a value 16.3% lower than the same age group for women (Table 1).

In Figure 2 we show the specific five-year survival curve of CRC, according to sex and age group. For women, we noticed that those aged 60 to 69 years and those aged 70 to 79 years had lower probabilities of survival when compared with women of other age groups, while those under 50 years of age had the highest probabilities. Moreover, we observed lower changes in probabilities as from 30 months.

For men, we observed the lowest probabilities of survival for the age groups 70 to 79 years and 80 years or older, while the other age groups presented similar probabilities after 47 months. There was a greater discrepancy between the curves, with values with greater amplitude between the age groups for this group (Figure 2).

In the Cox model, men aged 70 to 79 years (HR=2.97; 95%CI 1.11–3.87) and 80 years or older (HR=3.09; 95%CI 1.31–7.27) presented higher risk of mortality than men of other age groups. For women, there was no difference between age groups (Table 2).

In Figure 3 we present the evaluation of the assumption of proportionality by Schoenfeld’s residual analysis. We can observed that there are no significant trends for the variables “sex” and “age.” It is noteworthy that the residuals do not have a random pattern around 0, thus suggesting a violation of the principle of proportionality of the risk function.

DISCUSSION

The results of the present study showed that women had a shorter time between the diagnosis of CRC and death from the disease when compared with men as well as a lower probability of survival. For women, the lowest probabilities of survival were as from 60 years, while for men, as from 70 years. Conversely, men were at greater risk of mortality after 70 years of age.

Worldwide, the survival of the several types of cancer has been analyzed and published by the CONCORD program, using population-based registries. Brazil also contributes data to the program, from six national registries. However, the employed methodology estimates net survival, a survival function derived from excess risk, an estimator used in the comparison of populations because it is independent of population mortality²⁴24. Perme MP, Stare J, Estève J. On estimation in relative survival. Biometrics 2012; 68(1): 113-20. https://doi.org/10.1111/j.1541-0420.2011.01640.x
https://doi.org/10.1111/j.1541-0420.2011... .

The latest data published by the program showed that for patients diagnosed with colon and rectal cancer from 2010 to 2014, five-year net survival has considerably varied, especially in Central and South America, Asia, and Europe. For this period, Brazil had a net survival of 48.3% for colon cancer and 42.4% for rectal cancer. The program highlights that most estimates were considered reliable, with the exception of some countries, including Brazil⁸8. Allemani C, Matsuda T, Di Carlo V, Harewood R, Matz M, Nikšić M, et al. Global surveillance of trends in cancer survival 2000-14 (CONCORD-3): analysis of individual records for 37 513 025 patients diagnosed with one of 18 cancers from 322 population-based registries in 71 countries. Lancet 2018; 391(10125): 1023-75. https://doi.org/10.1016/S0140-6736(17)33326-3
https://doi.org/10.1016/S0140-6736(17)33... .

A study that analyzed specific five-year survival of CRC, with data from 1980 to 2010 from major public hospitals in South Australia over three decades, showed that survival was 55.3% for men and 57.0% for women, but with no significant difference. Those aged 80 years or older had a lower probability of survival (49.0%) and a higher risk of death (HR=1.44; 95%CI 1.14–1.81)²⁵25. Roder D, Karapetis CS, Wattchow D, Moore J, Singhal N, Joshi R, et al. Colorectal cancer treatment and survival: the experience of major public hospitals in south Australia over three decades. Asian Pac J Cancer Prev 2015; 16(6): 2431-40. https://doi.org/10.7314/apjcp.2015.16.6.2431
https://doi.org/10.7314/apjcp.2015.16.6.... .

CRC survival data are scarce in Brazil, especially specific data and with analysis per five-year period. In a study by Aguiar Junior et al.²⁶26. Aguiar Junior S, Oliveira MM, Silva DRM, Mello CAL, Calsavara VF, Curado MP. Survival of patients with colorectal cancer in a cancer center. Arq Gastroenterol 2020; 57(2): 172-7. https://doi.org/10.1590/S0004-2803.202000000-32
https://doi.org/10.1590/S0004-2803.20200... , the authors did not analyze specific survival, but the overall survival (death from any cause), and did not consider anal canal cancer of patients with CRC treated in an oncology center in São Paulo (state of São Paulo), from 2000 to 2013, with follow-up until 2018. The results showed that five-year survival was 63.5%, with no difference between men and women, and higher in patients under 49 years (70.0%) and worse in those over 75 years (43.8%, p<0.001).

To date, only one study that evaluated survival in the same geographic region considered in the present study has been identified. In the study by Alves²⁷27. Alves CMM. Câncer colorretal – carga da doença no estado do Mato Grosso [tese de doutorado]. Juiz de Fora: Faculdade de Medicina da Universidade Federal de Juiz de Fora (UFJF); 2019., survival was analyzed considering patients diagnosed with CRC in the period from 2000 to 2009, and the follow-up period of five years. Nevertheless, anal canal cancer was not considered for the analyses. A total of 692 cases were analyzed, of which 347 were men and 344, women. The results of the study showed that specific survival was higher among women (62.8%; 95%CI 57–68%) than among men (57.2%; 95%CI 51.3–62.7%), and men had a 22% higher risk of death, but differences between the sexes were not significant.

Thus, we understand that the survival results in this study are, overall, higher than those previously presented. Information on the survival of cancer patients in a population allows comparing the efficacy of health systems, and the long-term surveillance of these results contributes to the evidence of the regional cancer control policy²⁸28. Coleman MP, Quaresma M, Berrino F, Lutz JM, De Angelis R, Capocaccia R, et al. Cancer survival in five continents: a worldwide population-based study (CONCORD). Lancet Oncol 2008; 9(8): 730-56. https://doi.org/10.1016/S1470-2045(08)70179-7
https://doi.org/10.1016/S1470-2045(08)70... .

Women in this study had lower survival than men, a result that is opposed to what has been verified in the literature²⁹29. Berger MD, Yang D, Sunakawa Y, Zhang W, Ning Y, Matsusaka S, et al. Impact of sex, age, and ethnicity/race on the survival of patients with rectal cancer in the United States from 1988 to 2012. Oncotarget 2016; 7(33): 53668-78. https://doi.org/10.18632/oncotarget.10696
https://doi.org/10.18632/oncotarget.1069... ,³⁰30. Kotake K, Asano M, Ozawa H, Kobayashi H, Sugihara K. Gender differences in colorectal cancer survival in Japan. Int J Clin Oncol 2016; 21(1): 194-203. https://doi.org/10.1007/s10147-015-0868-6
https://doi.org/10.1007/s10147-015-0868-... . Nonetheless, women have been screened for CRC at rates significantly lower than men³¹31. Paulson EC, Wirtalla C, Armstrong K, Mahmoud NN. Gender influences treatment and survival in colorectal cancer surgery. Dis Colon Rectum 2009; 52(12): 1982-91. https://doi.org/10.1007/DCR.0b013e3181beb42a
https://doi.org/10.1007/DCR.0b013e3181be... . Screening provides opportunities for early diagnosis of CRC; however, it often occurs when patients already present with signs and symptoms of the disease, a situation more frequent among men³²32. Kim SE, Paik HY, Yoon H, Lee JE, Kim N, Sung MK. Sex- and gender-specific disparities in colorectal cancer risk. World J Gastroenterol 2015; 21(17): 5167-75. https://doi.org/10.3748/wjg.v21.i17.5167
https://doi.org/10.3748/wjg.v21.i17.5167... , which can interfere with the probabilities of survival. In a meta-analysis study that verified the differences between sexes in the survival of CRC, the authors argue that this variable is rarely identified as an independent prognostic factor in clinical trials involving CRC patients, for example, as it has not been considered as a possible source of interaction between treatment and survival³³33. Yang Y, Wang G, He J, Ren S, Wu F, Zhang J, et al. Gender differences in colorectal cancer survival: a meta-analysis. Int J Cancer 2017; 141(10): 1942-9. https://doi.org/10.1002/ijc.30827
https://doi.org/10.1002/ijc.30827... .

Older men had a higher risk of death from CRC than younger men. Survival decreases with increasing age and this has been a predictive factor for death in cancer patients because it is more associated with a higher risk of comorbidities⁹9. Agüero F, Murta-Nascimento C, Gallén M, Andreu-García M, Pera M, Hernández C, et al. Colorectal cancer survival: results from a hospital-based cancer registry. Rev Esp Enferm Dig 2012; 104(11): 572-7. https://doi.org/10.4321/s1130-01082012001100004
https://doi.org/10.4321/s1130-0108201200... ,³⁴34. Zare-Bandamiri M, Khanjani N, Jahani Y, Mohammadianpanah M. Factors affecting survival in patients with colorectal cancer in Shiraz, Iran. Asian Pac J Cancer Prev 2016; 17(1): 159-63. https://doi.org/10.7314/apjcp.2016.17.1.159
https://doi.org/10.7314/apjcp.2016.17.1.... .

For CRC, despite being a type of cancer whose signs and symptoms take years to appear, being susceptible to early detection or secondary prevention, late diagnosis leads to more invasive and expensive treatments and, consequently, lower survival for the patient and greater chance of mortality from the disease³⁵35. Scandiuzzi MCP, Camargo EB, Elias FTS. Câncer colorretal no Brasil: perspectivas para detecção precoce. Brasília Med 2019; 56: 8-13. https://doi.org/10.5935/2236-5117.2019v56a02
https://doi.org/10.5935/2236-5117.2019v5... .

It is worth highlighting that survival expresses the natural history of the disease, as well as cancer control activities, including screening, organization, and quality of health services³⁶36. Black RJ, Sankaranarayanan R, Parkin DM. Interpretation of population-based cancer survival data. In: Sankaranarayanan R, Black RJ, Parkin DM, editors. Cancer Survival in Developing Countries. Lyon: International Agency for Research on Cancer; 1998. p. 13-7..

In Brazil, there is no population-based screening program for CRC. The Ministry of Health recommends that patients diagnosed or suspected of CRC or anal canal cancer should have preference in referral to the proctologist, and that the criteria should be readapted according to the needs of the local regulation. For those with family history or suspected Lynch Syndrome or familial adenomatous polyposis, screening should be done in a specialized genetics and gastroenterology service³⁷37. Brasil. Ministério da Saúde. Proctologia [Internet]. Brasília: Ministério da Saúde; 2016 [acessado em 27 mai. 2022]. Disponível em: https://bvsms.saude.gov.br/bvs/publicacoes/protocolos_atencao_basica_especializada_proctologia_v_VII.pdf
https://bvsms.saude.gov.br/bvs/publicaco... .

Despite the discussions on the cost-benefit of implementing a national screening program for the disease and the organization of health services for this routine, considering the conditions of providing definitive diagnosis and treatment for the screened condition³⁸38. Brasil. Ministério da Saúde. Secretaria de Atenção à Saúde. Departamento de Atenção Básica. Rastreamento [Internet]. Brasília: Ministério da Saúde; 2010 [acessado em 27 mai. 2022]. Disponível em: https://bvsms.saude.gov.br/bvs/publicacoes/caderno_atencao_primaria_29_rastreamento.pdf
https://bvsms.saude.gov.br/bvs/publicaco... , studies show a reduction in incidence and mortality from CRC with organized screening³⁹39. US Preventive Services Task Force, Davidson KW, Barry MJ, Mangione CM, Cabana M, Caughey AB, et al. Screening for colorectal cancer. US Preventive Services Task Force Recommendation Statement. JAMA 2021; 325(19): 1965-77. https://doi.org/10.1001/jama.2021.6238
https://doi.org/10.1001/jama.2021.6238... .

As limitations of this study, we can mention that, usually, population-based survival does not enable the evaluation of variables such as tumor staging, morphology, and treatment, which are important for understanding the clinical feature of the disease¹⁹19. Bustamante-Teixeira MT, Faerstein E, Latorre MR. Técnicas de análise de sobrevida. Cad Saúde Pública 2002; 18(3): 579-94. https://doi.org/10.1590/S0102-311X2002000300003
https://doi.org/10.1590/S0102-311X200200... . Clinical and demographic variables, for not being mandatory, still have limited completion, which makes it difficult to monitor variations in survival data⁴⁰40. Lima FCS, Souza BSN, Oliveira JFP, Galvão ND, Souza PCF. Sobrevida específica do câncer do colo do útero na Grande Cuiabá, Mato Grosso, Brasil. Rev Bras Epidemiol 2022; 25: e220017.supl.1. https://doi.org/10.1590/1980-549720220017.supl.1.1
https://doi.org/10.1590/1980-54972022001... . Moreover, limitations related to the passive follow-up of patients should be considered. Cases of patients who may have died, but which, due to failures in the death certificate (DC), were not registered and, consequently, not included in the analysis, may overestimate survival¹⁹19. Bustamante-Teixeira MT, Faerstein E, Latorre MR. Técnicas de análise de sobrevida. Cad Saúde Pública 2002; 18(3): 579-94. https://doi.org/10.1590/S0102-311X2002000300003
https://doi.org/10.1590/S0102-311X200200... . Another limitation is the lack of information on the life table of Greater Cuiabá, which made it impossible to estimate net survival²⁴24. Perme MP, Stare J, Estève J. On estimation in relative survival. Biometrics 2012; 68(1): 113-20. https://doi.org/10.1111/j.1541-0420.2011.01640.x
https://doi.org/10.1111/j.1541-0420.2011... .

Conversely, the Kaplan-Meier method eliminates the need to assume that the censoring of observations uniformly occurs during this interval. In addition, the use of population-based data decreases the probability of selection bias because it includes all incident cases in the coverage region, which facilitates international comparations, as clinical trials include selected groups of patients¹⁹19. Bustamante-Teixeira MT, Faerstein E, Latorre MR. Técnicas de análise de sobrevida. Cad Saúde Pública 2002; 18(3): 579-94. https://doi.org/10.1590/S0102-311X2002000300003
https://doi.org/10.1590/S0102-311X200200... . The PBCR-Cuiabá was implemented in 1999 by the State Department of Health of Mato Grosso and currently has 38 health facilities as notifying sources, namely: one federal hospital, ten municipal and four state health services, six philanthropic establishments, and seventeen private health institutions (diagnostic and treatment clinics and anatomic pathology laboratories)⁴¹41. Galvão ND, Souza RAG, Souza BSN, Melanda FN, Andrade ACS, Sousa NFS, et al. Cancer surveillance in Mato Grosso, Brazil: methodological and operational aspects of a university extension/research project. Rev Bras Epidemiol 2022; 25(Supl 1): e220002. https://doi.org/10.1590/1980-549720220002.supl.1.1
https://doi.org/10.1590/1980-54972022000... .

In 80% of countries, the increasing trend of premature cancer mortality is impacting the achievement of target 3.4 of the Sustainable Development Goals, which refers to reducing by one third premature mortality from chronic noncommunicable diseases by 2030². Thus, the importance of the implementation, maintenance, updating, and availability of population data from Cancer Registries is evident, for the best knowledge of the disease panorama. The contributions would add to the structuring and formulation of public policies aimed at improving the early diagnosis, treatment, and quality of life of the population.

ACKNOWLEDGMENTS

The authors would like to thank the Brazilian National Cancer Institute (INCA), for contributing to the training of cancer recorders; the Public Health Institute of Universidade Federal de Mato Grosso (UFMT), for the physical space; the Coordination for the Improvement of Higher Education Personnel (CAPES), for the graduate scholarship (PhD).

References

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