Prognostic factors and hazard ratios in colorectal cancer patients over 80 years of age: a retrospective, 20-year, single institution review

Background: An aging population and a high incidence of colorectal cancer (CRC) in patients over the age of 80 make it important to understand survival times, hazard ratios and prognostic factors in this group. A better understanding of these factors will help clinicians determine appropriate therapeutic strategies for such patients, including when more aggressive treatment strategies may be preferred to palliative treatment. Methods: A retrospective analysis of 619 CRC patients of >= 80 years of age from 1991-2010 at Baylor Scott & White Hospital in Temple, Texas. Twelve variables were analyzed through statistical analysis as potential prognostic factors for survival. Univariate and multivariate Cox proportional hazard models were used to determine hazard ratios. The elderly population was further stratified by age subgroup (80-84, 85-89, >= 90). Results: Median survival time was 53.6, 30.0, and 11.3 months for age groups of 80-84, 85-89, and >= 90, respectively. Median survival time for stage 0/I, II, III, and IV patients was 72.4, 53.5, 28.0, and 5.9 months, respectively. Patients not receiving surgery had significantly higher mortality (hazard ratio 2.605; 95% CI, 1.826-3.694). For stage III CRC patients, those not receiving chemotherapy had significantly higher mortality (hazard ratio 1.808; 95% CI, 1.018-1.827). Conclusions: Our study provides evidence to support the benefits of surgery and chemotherapy (for stage III) patients over 80, potentially contributing to improved clinical decisions in treating elderly CRC patients. Such patients are sometimes undertreated due to their underrepresentation in clinical trials. Additional prospective studies with a higher proportion of patients over 80 are needed.