Treatment of Metastatic Colorectal Cancer Patients ≥75 Years Old in Clinical Practice: A Multicenter Analysis.

Background: Colorectal cancer patients have a median age of incidence >65years although they are largely under-represented in phase-III trials. This large population contains patients unfit for treatment, those suitable for monotherapy or for doublets and the impact of chemotherapy outside clinical trial is unclear. The aim of the study was to retrospectively analyse Overall Survival(OS) of elderly metastatic colorectal cancer(mCRC) patients treated with chemotherapy in daily practice.

Methods: Kaplan-Meir method was used for OS, the log-rank or Tarone-Ware test for differences between subgroups, Cox's proportional hazard model to assess the impact of known prognostic factors and treatment.

Results: 751 patients with mCRC observed between January 2000 and January 2013 were collected. Median age was 79 year(75-93); Male/Female 61/39%, ECOG-PS 0-1/2 85/15%; colon/rectum 74/26%; multiple metastatic sites 34%, only liver metastasis in 41% of patients. KRAS status was studied in 35% of patients: 44% of them showed gene mutation. 20.5% of patients did not received any kind of treatment including surgery. Comorbidities observed: cardiovascular 34%, diabetes 14%, hypertension 50%. Primary tumor was resected in 80.6%; surgery of liver metastasis was done in 19% of patients (2.3% of patients >80years). 78% of patients underwent chemotherapy. Median follow up was 12 months(range 1-124). Median OS was 17 months (CI 95%15-19);median OS in no-treated patients was 5 months (4-6); mOS of patients with at least one treatment was 20 months (18-22). In KRAS mutated group median OS was 19months (15-23) while in KRAS wild type patients median OS was 25 months (20-30). At multivariate analysis sex(Female), age(<80y), performance status(0-1), chemotherapy, Surgery of metastasis, Surgery of primary tumor and Site of metastasis(liver) were prognostic factors for OS.

Conclusion: The results of our study show that in clinical practice treatment has a positive impact on OS of elderly patients, confirmed at multivariate analysis, included patients with age >80 years old or with a poor performance status (respectively p<0.0001 and p<0.0001). KRAS analysis deserve further evaluation.