P-13 Management of metastatic colorectal cancer in patients ≥70 years: A single-center experience

Age-standardized mortality rates for metastatic colorectal cancer (mCRC) are highest among patients ≥70 years. Elderly mCRC patients are underrepresented in clinical trials and one out of four elderly mCRC patients does not receive chemotherapy-based palliative systemic therapy due to comorbidities, chronological age or poor performance status. In current clinical guidelines, treatment recommendations for this patient population are based on a limited number of clinical trials. Patients aged ≥70 years at mCRC diagnosis undergoing systemic therapy for mCRC at our tertiary cancer center were included in this monocentric, retrospective analysis. The primary aim of this analysis was to evaluate the therapeutic management of elderly mCRC patients and clinical outcome in a real-world setting. Furthermore, this analysis aimed at investigating the frequency, feasibility and efficacy of metastasectomy and/or local ablative treatment with putative curative intent in this elderly population. We included 117 unselected, consecutive mCRC patients aged ≥70 years undergoing systemic therapy for mCRC between February 2009 and July 2022. After a median follow-up of 38.4 months (95% CI: 29.3-47), the median OS was 25.6 months (95% CI: 21.8-29.4). The median age was 78 years (range: 70-90) and 21%, 48%, 26% and 5% had an ECOG performance score of 0, 1, 2, and 3, respectively. The median number of systemic therapy lines was 2 (range: 1-5). The likelihood of applying a doublet or triplet chemotherapy backbone in first line declined with increasing age (p < 0.001) and with a worse ECOG performance score (p=0.007). The choice of the first-line chemotherapy backbone (doublet or triplet versus mono) did not impact OS (HR: 0.83, p=0.50), nor the probability of receiving subsequent therapy lines (p=0.697). Metastasectomy and/or local ablative treatment in the liver, lung, peritoneum and/or other organs were applied in 26 patients (22%) with curative intent. First-line anti-EGFR-based therapy showed a trend towards longer OS compared to anti-VEGF-based therapy or chemotherapy alone in left-sided mCRC (anti-EGFR: 39.3 months versus anti-VEGF: 27.3 months versus chemotherapy alone: 13.8 months, p=0.105). In multivariable analysis, metastasectomy and/or local ablative treatment with curative intent (yes versus no, HR: 0.22, p < 0.001), the ECOG performance score (2 versus 0, HR: 3.07, p=0.007; 3 versus 0, HR: 3.66, p=0.053) and the presence of liver metastases (yes versus no, HR: 1.79, p=0.049) were independently associated with OS. Clinical outcome among real-world elderly mCRC patients was comparable to the results of first-line elderly mCRC landmark trials. Our findings corroborate front-line monochemotherapy in combination with targeted therapy as the treatment of choice for elderly mCRC patients with palliative treatment intent. Metastasectomy and/or local ablative treatment with curative intent are feasible and may improve OS in selected elderly mCRC patients.