Gravida and birth outcomes prior to and after diagnosis of early age onset colorectal cancer among female patients: Population-based epidemiologic studies.

Background: Early age-onset colorectal cancer (EAO-CRC) strikes during the reproductive years, yet pregnancies before and after diagnosis have not been thoroughly studied. Our objective was to comprehensively examine: 1) the relationship between gravida and EAO-CRC; and 2) the relationship between EAO-CRC and births post cancer diagnosis.

Methods: We conducted a case-control and a cohort study using administrative health data from British Columbia, Canada, of females diagnosed with EAO-CRC from 2005 to 2017, and age and sex matched cancer-free controls. Multivariable logistic regression models were used to evaluate: 1) the association between gravida assessed over the 5-year prodrome period before cancer diagnosis and EAO-CRC; and 2) the association between EAO-CRC and births assessed over a 5-year period following cancer diagnosis.

Results: The study sample consisted of 865 females (age at EAO-CRC diagnosis 42.5 +/- 6.1 years) with EAO-CRC and 8,291 controls (42.4 +/- 6.3 years). Females with a gravida of ≥2 in the 5-year prodrome period had 1.82 times the odds of EAO-CRC compared to those with gravida of 0 (odds ratio [OR] 1.82; 95% confidence interval (CI) 1.19, 2.78). Post cancer diagnosis, females with EAO-CRC had significantly lower odds of giving birth within five years (OR 0.23; 95% CI 0.15, 0.37). Older age, lower income, rural residence, and greater healthcare utilization were associated with lower odds of post-diagnosis births.

Conclusions: Our study highlights the complex relationship between reproductive health and EAO-CRC.

Impact: Findings indicate a need for comprehensive psychosocial support addressing family planning for female EAO-CRC patients.