Assessment of Survival Outcomes of Histopatho-Logical Subtypes of Colorectal Adenocarcinoma in Ugandan Patients

Background: In the West, high grade mucinous adenocarcinomas are more common in younger patients and are associated with a poor prognosis. The survival outcomes of the various histopathologic subtypes of colorectal adenocarcinoma (CRC) and lymphovascular invasion (LVI) are unknown in Uganda. We looked at the survival rates of various histopathologic subtypes of CRC and LVI in Ugandan patients.

Methods: The Kampala Cancer Registry and hospital medical records were used to conduct a retrospective cohort study on patients diagnosed with CRC from 2008 to 2018. The data obtained included the date of diagnosis, demographics, stage, grade, and location of the CRC. The main predictor variables for our outcome were histopathologic subtype, stage, grade, and LVI. We used Kaplan-Meier survival curves to determine factors associated with survival, log-rank tests to test survival equality, and multivariable Cox regression to determine factors associated with survival.

Results: 12.4 percent of patients had mucinous adenocarcinoma/signet ring colorectal carcinoma (MAC/SRCC), while 87.6 percent had classical adenocarcinoma (AC). The median age (SD) at diagnosis of MAC/SRCC was 47.8 (16.6) years and 53.8 (15.9) years for AC. SRCC/MAC was significantly associated with more LVI than AC (p=0.002). In multivariate analysis, factors associated with increased mortality included stage III (aHR=2.56; p=0.009) and stage IV (aHR=6.64; p <0.001). After adjusting for lymph node involvement and metastasis, SRCC/MAC patients had a shorter survival than AC patients; however, this difference was not statistically significant (p=0.229).

Conclusions: The proportion of MAC in Uganda is comparable to that found in the Western world. LVI was associated with SRCC/MAC more than AC. Overall survival was lower in patients with SRCC/MAC. Because more patients in Uganda present with advanced-stage CRC, which is associated with poor survival, national screening guidelines are required to improve survival.