Surgical under-treatment of older adult patients with cancer: A systematic review and meta-analysis

Older patients with cancer often have lower surgery rates and survival than younger patients, but this may reflect surgical contraindications of advanced disease, comorbidities, and frailty - and not necessarily under-treatment. This review describes variations in surgery rates and observed or net survival among younger (<75) and older (≥75) patients with lung, breast, and colorectal cancer, while taking account of pre-existing health factors, in order to understand how under-treatment is defined and estimated in the literature. MEDLINE, Embase, Web of Science and PubMed databases were searched. Thirty relatively high-quality studies of patients with breast (230,200; 71.9%), lung (77,573; 24.2%), and colorectal (12,407; 3.9%) cancers were identified. Compared to younger patients, older patients were less likely to receive surgical treatment for 1) breast cancer after adjusting for comorbidity, performance status (PS), functional status and patient choice, 2) lung cancer after accounting for stage, comorbidity, PS, and 3) colorectal cancer after adjusting for stage, comorbidity, and gender. The pooled unadjusted analyses showed lower surgery receipt in older patients in breast (odds ratio [OR] 0.31, 95% confidence interval [CI] 0.13-0.78), lung (OR 0.54, 95% CI 0.39-0.75), and colorectal (OR 0.59, 95% CI 0.51-0.68) cancers. Lower surgery rates in older patients may contribute to their poorer survival compared to younger patients. Future research quantifying under-treatment should include necessary clinical factors, patient choice, patient's quality of life and a statistically-robust approach, which will demonstrate how much of the survival deficit in older patients is due to their receiving lower surgery rates.