Peritoneal metastases in elderly patients with colorectal cancer

Background With the introduction of cytoreductive surgery with intraperitoneal chemotherapy and the development of new systemic anti-cancer agents, the treatment of colorectal cancer (CRC) patients with peritoneal metastases has changed. Real-world data on the treatment of elderly patients and their clinical outcomes is lacking. Methods All CRC patients diagnosed with synchronous peritoneal metastases (SPM) during 2008–2019 (n = 7,748) were identified from the Netherlands Cancer Registry. Trends in treatment and postoperative mortality were described by age category (<70, 70–74, 75–79, ≥80 years) and period of diagnosis (2008–2013, 2014–2019). Kaplan-Meier curves were constructed, and log-rank tests were performed to evaluate differences in overall survival (OS). Results With increasing age, less patients received multimodality treatment and systemic treatment. Of the patients aged <70 years, 38% underwent multimodality treatment and 35% palliative systemic therapy, declining to 4% and 12% in patients ≥80 years. A large and increasing proportion of elderly patients did not receive cancer-directed treatment, this increased from 32% in 2008–2013 to 41% in 2014–2019 in 75–79 years old patients and from 52% to 65% in ≥80 years old. Postoperative mortality decreased in all age categories over time, OS remained stable. The median OS of elderly patients ranged from 8 months in 70–74 years old to 3 months in patients aged ≥80 years. Discussion Age strongly affects treatment of patients with SPM, with a large and increasing proportion of elderly patients not receiving cancer-directed treatment. Their prognosis remains very poor. There is a need for therapeutic options that are well tolerable for elderly patients.