- Colorectal cancer (CRC) is in increasing trend in Nepal.
- Significant burden of colorectal cancer is seen in younger age group.
- The most common site of colorectal cancer is rectum followed by colon.
CRC is the third most common malignancy and the second leading cause of death in the world1. According to GLOBOCAN 2018, CRC comprised of 10.2% of new cases of cancer2 and its incidence is rising globally, especially in developing countries3. The age-standardized incidence and mortality rates of CRC in Nepal were 5.8 and 4.8 per 100,000, respectively, in the year 20184. CRC is the seventh most common cancer in Nepal, and the fifth among the cancer deaths4. It is growing as a public health problem. Alcohol, tobacco, obesity, sedentary lifestyle, and excessive red meat consumption are the established risk factors for CRC. Genetic predisposition accounts for 6%–10% of all CRCs, and 20% of those are diagnosed before 50 years of age5. A study in Western Nepal among 800 participants showed that 20% of them had not heard of CRC and only a few knew about CRC screening6. Most of the CRC cancers in Nepal are presented in advanced stage7,8. The health-seeking behaviors of CRC patients is very poor, taking on an average of 5.6 months from the onset of the symptoms9. Screening of neoplasms such as cervical cancer and breast cancer are addressed in national public health programs. However, the CRC screening is not addressed effectively in the public health system of Nepal.
It is important to know the trend of CRC in a country to formulate prevention and control strategies. As B.P. Koirala Memorial Cancer Hospital (BPKMCH) is a national comprehensive cancer center in Nepal and receives overwhelmingly majority new cancer cases for treatment10, the data provided can be very insightful in the trend analysis of the CRC. This study will help the public health professionals, clinicians and policymakers on successful planning to address CRC. This study aims to analyze the trend of CRC incidence over a period of 5 years in BPKMCH.
Materials and methods
This was a cross-sectional study with secondary data analysis based on existing data, obtained from the cancer registry of BPKMCH. BPKMCH is the largest comprehensive government cancer center, centrally located in Nepal at Bharatpur Metropolitan city of Chitwan district. This study included all new CRC cases registered over a period of 5 years from January 2014 to December 2018. All patients diagnosed with CRC were identified using site-specific International Classification of Diseases 10th version (ICD-10) codes from C18 to C21. The cecum (C18.0), ascending colon (C18.2), and transverse colon (C18.4) were grouped as proximal colon cancer. The descending colon (C18.6) and sigmoid (C18.7) were grouped as distal colon cancer, and rectosigmoid junction (C19) and rectum (C20) were grouped as rectal cancer. Colon unspecified (colon NS) and appendix were analyzed separately.
The data was retrieved in Excel 2013, duplicate removed, and analyzed in Statistical Package for Social Sciences (SPSS) version 20 with graphs plotted with R 4.0.0. The number and percentage of cases were examined by gender, age, and tumor location. Male-to-female (MF) ratios were also calculated for different CRC sites. The average annual rise in incidence was calculated as the difference in incidence between 2018 and 2014, divided by incidence in the year 2014 and divided by 4. Approval for this study was obtained from the Institutional Review Committee of BPKMCH (Reference number: 1924/2076/077). This paper has been reported in line with the STROCSS criteria11.
A total of 24,344 new cancer cases were registered in BPKMCH from 2014 to 2018, out of which 45% were males and 55% were females with MF ratio of 0.81. Similarly, 1129 (4.6%) of the total cases were CRCs of which 644 (57.0%) were males and 485 (43.0%) were females with MF ratio of 1.4. Rectal cancers (50.0%) were the most common comprising half of the CRC cases followed by colon not specified (19.1%), and anus and anal canal (12.6%). However, the site-wise MF ratio was found to be different. The ratio was found to be more than one in all sites except for transverse colon cancer. This depicts that all CRCs except transverse colon cancer were more common among males. The highest MF ratio was found in appendix of 4.0 followed by colon of 2.0 (Table 1).
Table 1 -
Distribution of colorectal cancers by site and gender in B.P. Koirala Memorial cancer Hospital from 2014 to 2018.
||Anus and anal canal
|Total new cancer cases
|% CRC of total cancer cases
CRC indicates colorectal cancer.
CRC was most common in the age group of 45–59 years (31.9%) followed by 60–74 (25.9%) and 30–44 (24.6%). Similar results were observed in different sites of CRC. This study also observed a significant percentage of CRC (35.9%) in younger age group under 45 years. The highest incidence of CRC among all age groups was rectal cancer (Table 2).
Table 2 -
Distribution of colorectal cancers by site and age in B.P. Koirala memorial cancer hospital from 2014 to 2018.
|Anus and anal canal (C21)
CRC indicates colorectal cancer.
The trend of CRC according to the sites are shown in Figures 1–3. The figures show that, there was gradual rise in the trend of CRC cancer in both sexes (Fig. 1A). The rise in the incidence of CRC in older age group (45 y and above) was minimal from 2014 to 2015, however, rose steeply till 2016. Thereafter, the new cases dropped minimally in 2017 and then rose considerably till 2018 with an overall average annual increase of 6.7%. In younger age group (under 45 y), the incidence decreased in 2015 and then after the cases increased with an overall average annual increase of 1.7% each year (Fig. 1B).
In Figure 2, the number of new cases for all subsites of CRC except for rectal cancer dropped slightly till 2015. The number of cases for anal cancer and appendix cancer remained plateau throughout the years till 2018. There is significant fluctuation in the incidence of rectal cancer and distal colon cancer, whereas the cases of colon NS and proximal colon cancer were rising modestly till 2018. Likewise as depicted in Figure 3, there is a drastic difference in the trend of rectal cancer between males and females. The number of cases of rectal cancer in males rose steeply in 2015, whereas the female cases of rectal cancer dropped markedly. The cases of rectal cancer in females rose gradually between 2015 and 2018. In contrast, the cases of rectal cancer among males showed significant fluctuation. The cases of cancer of appendix remained plateau throughout the years in both the sexes. The number of cases of colon NS cancer almost doubled between 2014 and 2018 among males. Likewise, there was a remarkable growth in the incidence of colon NS among females till 2018. Subset analysis by gender showed steady rise in colon NS and rectal cancer cases after 2015 in females (Fig. 2). The incidence of anal cancer is decreasing from 2016 in males and increasing in females (Fig. 3).
CRC is an important public health issue with its rising global burden. Monitoring its trend is important in addressing its impact and making national guidelines for prevention, control, and treatment. In this study, CRC comprised of 4.6% of new cancer cases in the last 5 years which is lower than the GLOBOCAN 2018 estimates (10.2%). CRC incidence is rising globally especially in developing countries3, whereas in developed countries, the incidence is declining among 55 years and older. This decrease has been attributed to increasing screening practices. However, the incidence is rising in younger age groups for which screening is not routinely recommended12,13. American Cancer Society recommends screening only at the age of 45 years for individuals with average risk13. Our study showed an average annual increase by 1.7% in younger age group against 6.7% annual increase in older age group, which is strikingly different from developed countries where incidence in older age group is decreasing14. Obesity, sedentary lifestyle, processed food intake, red meat consumption, alcohol, and tobacco could attribute for this trend3. The major bulk of the increase in CRC cases is accounted for by increase in the number of colon cancer, unspecified cases. The peak incidence of CRC is in the seventh decade of life15, however most of our cases were in the sixth decade.
More than 90% of new CRC cases are diagnosed after 50 years16, interestingly in this study, almost 35% of new cases were diagnosed before 45 years. A study done in Patan in Nepal also had higher percentage (29%) of younger patients (under 40 y)17. CRC incidence rates are higher in men in the United States12, United Kingdom18 and worldwide19. Our study also showed more CRC in males (M/F=1.32, 57%) which is similar to age-adjusted incidence in SEER registry20 and a study in India21. Reasons for these differences are not clear but attributed to differences in risk factors exposure and sex hormones, and their complex relationship22. Left colon carcinomas are shown to be more common in females and right colon carcinomas in males23,24. In contrast to this, no such distinct pattern was seen in this study. Except for the transverse colon, males surpassed females at all sites with ratio >1, more so for appendix (ratio=4) and descending colon (ratio=2).
The proximal colon cancers are the most common followed by rectum25. But the most common site of CRC was rectum in our findings similar to other studies in Nepal9 and India21, followed by colon not specified (C18.9), anus and anal canal, proximal and distal colon. The decreasing order of site involvement was same in both males and females. The burden of proximal colon cancers was thus lesser than Western literature26. However, proximal colon cancer is increasing overall, the trend significantly contributed by males. This is in accordance to other studies27,28. Rectal cancer is increasing in overall and is quite apparent among females since 2015. Though anal cancer seems to increase in females after 2016, overall trend is static, similar to India29.
Due to the increasing trend in younger age groups, American College of Physicians has lowered the age of screening to 40 years in African Americans30. However, given the increasing trend in both the younger and older age groups in our setting, we need to focus more on secondary prevention in older age group and primary prevention in younger age group. And given the higher number of CRC cases in 45–59 years age group, screening at 45 years holds true in our setting. Although CRC is one of the important public health problems, it is not addressed effectively in the public health system of Nepal. Increased awareness regarding CRC is required among all the age groups with routine digital rectal examination in all patients with lower gastrointestinal symptoms. Colonoscopy services should also be expanded given the increase in cases of proximal colon cancer. It is equally important to improve the access of patients to CRC care.
There are some limitations to this study. As this is the record-based study, we cannot verify the quality of the data and we did not perform inferential statistics. Another limitation is that we considered the data from the cancer registry of only one hospital. However, BPKMCH is the largest and national cancer institute in Nepal, where the majority of the cases from all over the country are diagnosed and treated, and hence the finding can be valuable to highlight the trend of CRC at a national level.
CRC is increasing in Nepal, with significant burden borne by younger age groups. The most commonly involved site in CRC is the rectum. The increasing trend in younger age groups also suggests implementation of healthy lifestyle measures to reduce the CRC risk. Efforts should be made to increase awareness regarding CRC through nationwide public health campaigns, and screening should be launched effectively to decrease the burden of cancer.
The ethical approval for this study was obtained from Institutional Review Committee of B.P. Koirala Memorial Cancer Hospital (Reference number: 1924/2076/077). As the study is of retrospective nature, consent from the patients was not taken.
Sources of funding
G. Shrestha, S.K., and R.M. designed the study. G. Shrestha, S.K., R.M., and G. Sapkota were responsible for streamlining the research idea and finalizing the data collection form. G. Shrestha and R.M. collected the data. G. Shrestha, S.K., and R.M. were involved in data cleaning and statistical analysis, and contributed to the interpretation of the results. G. Shrestha and S.K. wrote the preliminary drafts. All authors have read and approved the final version of the manuscript.
Conflict of interest disclosures
The authors declare that they have no financial conflict of interest with regard to the content of this report.
Research registration unique identifying number (UIN)
Dr Gambhir Shrestha.
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