Association between social background and implementation of postoperative adjuvant chemotherapy for older patients undergoing curative resection of colorectal cancers, sub-analysis of the HiSCO-04 study.

Purpose: Adjuvant chemotherapy is recommended following colorectal cancer resection based on risk of recurrence. In older patients, treatment decisions should consider recurrence rates and tolerability, as well as functional prognosis, residual disease, and social factors. This study aims to investigate factors, including social background, influencing implementation of postoperative adjuvant chemotherapy in older patients undergoing curative resection for colorectal cancer.

Methods: This multi-institutional prospective cohort study included 15 institutions belonging to the Hiroshima Surgical study group for Clinical Oncology. We analyzed 159 older patients aged ≥ 80 years, who underwent curative resection for stage III colorectal cancer between December 2013 and June 2018, as sub-analysis of the HiSCO-04 study.

Results: In total, 62 (39.0%) patients underwent postoperative adjuvant chemotherapy. Four factors were significantly associated with its implementation: performance status < 2, Charlson Comorbidity Index < 2, prognostic nutritional index ≥ 40, and presence of a spouse or siblings as lifestyle supporters. No significant difference was found in the backgrounds between complete and incomplete postoperative adjuvant chemotherapy patients.

Conclusion: Performance status, Charlson Comorbidity Index, nutritional status, and presence of a spouse or siblings as lifestyle supporters are possible factors influencing the implementation of postoperative adjuvant chemotherapy in older patients. To select appropriate treatment options, including postoperative adjuvant chemotherapy, it is essential to consider physical condition and comorbidities of older patients, thoroughly explain the situation to their families, and establish a support system to enhance understanding of the available treatment options.