Benefit of intensive chemotherapy for elderly patients aged 80 years or older with metastatic colorectal cancer: a state-wide multicenter cohort study.

Background: It remains unclear whether intensive chemotherapy for Stage IV colorectal cancer (CRC) patients aged 80 years or older is beneficial prognostically. This study aimed to investigate the overall survival of Stage IV CRC patients aged ≥ 80 years receiving intensive chemotherapy.

Methods: The study design was a population-based, multicenter, historical cohort study. The extracted participants' data were consecutive patients diagnosed as Stage IV CRC between January 2008 and May 2015 in nine hospitals in Japan. Patients were classified into two groups according to age: aged group (≥ 80 years) and younger group (< 80 years old). Intensive chemotherapy was defined as at least two courses of doublet chemotherapy with oxaliplatin-or irinotecan-based regimens. The primary outcome was the adjusted hazard ratio (HR) of age ≥ 80 years in patients who undergoing intensive chemotherapy.

Results: During the study period, 1259 patients were treated for Stage IV CRC in the participating hospitals. In total, 231 patients (18.3%) were in the aged group, and 1028 (81.7%) were in the younger group, and 788 (62.6%) underwent intensive chemotherapy. The median overall survival for the aged and younger group patients was 21.0 months (interquartile range (IQR), 10.6-34.1 months) and 24.3 months (IQR 12.6-39.3 months), respectively. The adjusted HR of age ≥ 80 years was 1.29 (confidence intervals 0.84-2.00).

Conclusion: Stage IV CRC patients aged 80 years or older receiving intensive chemotherapy had a similar prognosis to those aged < 80 years. Avoiding intensive chemotherapy for mCRC patients simply because they are ≥ 80 years old is not recommended.