Impact of Age on Multimodality Treatment and Survival in Locally Advanced Rectal Cancer Patients

SIMPLE SUMMARY: The median age for diagnosing rectal cancer is 70 years. Older patients represent a heterogeneous group with varying comorbidities and have potentially higher postoperative complication risk. Intensified multimodal treatment is necessary for locally advanced rectal cancer. This is not always offered to older patients with locally advanced rectal cancer. The aim of our population-based study was to assess the association between age and treatment differences and its effect on outcomes. Treatment regimens varied between patients aged <70 years and ≥70 years. Older patients were less frequently guideline-based treated than younger patients. Patients ≥70 years received neoadjuvant radiation more often than chemoradiation, were less often referred to higher volume hospitals for resection and surgical resection was conducted more often in low volume hospitals. Despite less referral and undertreatment, survival was in both younger and older patients was good. Treatment decisions should be based on the combination of age, comorbidity and performance. ABSTRACT: Background: Optimal treatment for locally advanced rectal cancer is neoadjuvant (chemo)radiation followed by radical surgery. This is challenging in the aging population because of frequently concomitant comorbidity. We analyzed whether age below and above 70 years is associated with differences in treatment strategy and outcome in this population-based study. Methods: Data between 2008 and 2016 were extracted from the Netherlands Cancer Registry with follow-up until 2021. Differences in therapy, referral and outcome were analyzed using χ(2) tests, multivariable logistic regression and relative survival analysis. Results: In total, 6524 locally advanced rectal cancer patients were included. A greater proportion of patients <70 years underwent resection compared to older patients (89% vs. 71%). Patients ≥70 years were more likely treated with neoadjuvant radiotherapy (OR 3.4, 95% CI 2.61–4.52), than with chemoradiation (OR 0.3, 95% CI 0.23–0.37) and less often referred to higher volume hospitals for resection (OR 0.7, 95% CI 0.51–0.87). Five-year relative survival after resection following neoadjuvant therapy was comparable and higher for both patients <70 years and ≥70 years (82% and 77%) than after resection only. Resection only was associated with worse survival in the elderly compared to younger patients (56% vs. 75%). Conclusion: Elderly patients with locally advanced rectal cancer received less intensive treatment and were less often referred to higher volume hospitals for surgery. Relative survival was good and comparable after optimal treatment in both age groups. Effort is necessary to improve guideline adherence, and multimodal strategies should be tailored to age, comorbidity and performance status.