Surgical Resection for Colorectal Liver Metastasis in Elderly Patients Aged ≥ 80: A Retrospective Nationwide Cohort Survey in Japan With Propensity Score Matching

ABSTRACT Background As the aging of the global population increases, the number of elderly patients with colorectal liver metastasis (CRLM) is expected to increase. The aim of this study was to clarify the long‐term oncological outcomes and treatment of CRLM in elderly patients aged ≥ 80. Methods Patients with CRLM were identified from the Japanese database of Liver Metastases Survey of Colorectal Cancer, collected from 145 centers. Two thousand four hundred nine patients with liver resection were eligible for analysis. This cohort was divided into two groups aged < 80 (group Y (younger); n = 2194) and ≥ 80 (group E (elderly); n = 215). We compared the long‐term outcomes after liver resection of patients with CRLM aged ≥ 80 and < 80 years after adjustment using propensity score matching (PSM), and we identified the reasons for differences in these outcomes. Results After PSM, group E showed a comparable recurrence‐free survival to that in group Y (hazard ratio (HR): 1.20, p = 0.16). However, group E had significantly worse cancer‐specific survival (CSS) (HR: 1.77, p = 0.002) and overall survival (OS) (HR: 1.80, p = 0.0004). Treatment for recurrence was given at a significantly lower rate in group E (80/130 (61.5%) vs. 1148/1329 (86.4%), p < 0.0001). Conclusions Surgical resection seems to be as effective in elderly patients aged ≥ 80 as in nonelderly patients. The significantly worse CSS and OS may have resulted from a lower rate of treatment for recurrence in elderly patients aged ≥ 80. Physicians should keep this finding in mind with regard to limitations of treatments for recurrence after initial liver resection in elderly patients aged ≥ 80 with CRLM.