627P - Racial disparities in synchronous and metachronous colorectal and prostate cancer: SEER based study 2000-2020

Background

The prevalence of multiple primary neoplasms has been increasing over time, with primary colorectal cancer and primary prostate cancer being a common coexistence. Notably, a primary prostatic cancer was discovered in approximately one-sixth of men who underwent prostate cancer screening prior to rectal cancer excision. Due to a lack of knowledge about the racial disparity factor in this multiple primary malignancy, our study aims to assess the risk of developing primary prostate cancer between African Americans and Caucasians in patients with colorectal cancer.

Methods

We extracted the data from cancer registries in the Surveillance, Epidemiology, and End Results (SEER) database for patients with primary colorectal cancer from 2000-2020. This allowed us to compare the risk of developing primary prostate cancer between African American and Caucasian individuals. We used MP-SIR session to estimate the SIR (standardized incidence ratios) as observed/expected (O/E), and excess absolute risk (EAR) per 10,000 patients using 95% Confidence intervals (CI), with significant result when p <0.05. The latency exclusion period was set at 0 month.

Results

Among 721,385 patients included in the study with primary colorectal cancer, only 8,943 (1.24%) developed primary prostate cancer (Expected= 8,938.87, O/E= 1.00, p >0.05, 95% CI: 0.98-1.02, EAR= 0.01). Out of these cases, approximately 7,340 (82.1%) were Caucasian individuals who developed primary prostate cancer (Expected= 7,633.79, O/E= 0.96, p <0.05, 95% CI: 0.94-0.98, EAR= -1.03), while only 1,603 (17.9%) were African American individuals who developed primary prostate cancer (Expected= 1,305.08, O/E= 1.23, P <0.05, 95% CI: 1.17-1.29, EAR= 7.82). Notably, at the age of 70-74 years, Caucasian individuals exhibited a significant decrease in the risk of developing primary prostate cancer (O/E= 0.91, P <0.05, EAR= -4.12), whereas African American individuals showed a significant increase in risk at this age (O/E= 1.27, P <0.05, EAR= 14.32).

Conclusions

Our results show a higher risk of developing primary prostate cancer in African American patients compared to Caucasian patients. Further research is needed to better understand the race variations on a genetic basis.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.