Relevance: In the Republic of Kazakhstan, colorectal cancer (CRC) ranks third in the structure of oncological pathology. In 2008-2019, the CRC incidence in the Republic was growing each year. There is an upward trend in CRC incidence among young people. Cohort studies show that, in young patients, CRC is characterized by distal localization of the tumor process, advanced stages of the disease, an aggressive course, and low tumor differentiation. The known association of phenotypic signs with clinical characteristics of the disease, such as the response to therapy and survival rates, urges addressing this problem. The phenotypic and molecular genetic aspects of CRC in young people have not been systematically studied in Kazakhstan.
The purpose of the study was to compare the phenotypic features of hereditary and sporadic colorectal cancer in young patients and patients over 65 years.
Results: The study involved 185 patients aged 17 to 50 years (Group 1) and 112 patients aged 65 to 85 (Group 2). In Group 1, a locally advanced process (stage III) was 14.8% more often than in Group 2; stage IV was 1.23 times more common in men; and multiple primary tumors were 3.1% more often, with a prevailing metachronous course. In Groups 1 & 2, most tumors were localized in the rectum; 84.8% and 78.6% of tumors, respectively, occurred in the left half of the colon. The frequency of right-sided tumors increased with age modified by gender (in Group 2). Hereditary burdened anamnesis was detected in 14.6% patients before 50 (6.57% more than in Group 2); family history of CRC – in 4.8% patients. The latter is consistent with published data. The studied syndromic variants met the diagnostic criteria for familial adenomatous polyposis, Lynch syndrome, Peutz-Jeghers syndrome, and familial type X colorectal cancer.
Conclusion: The increase in CRC incidence at the age of 50-70 years is explained by the effectiveness of screening. However, the upward trend for the age below 50 needs a detailed study of etiological (dietary, environmental, behavioral, hereditary) factors. Effective early diagnostics requires considering the phenotypic characteristics and hereditary history associated with a high risk of CRC onset.
Long-Term Outcome and Prognostic Factors of Sporadic Colorectal Cancer in Young Patients