Background and importance The increase in life expectancy, the higher incidence of cancer in elderly patients and the lack of clinical trials in these patients makes it necessary to carry out studies that allow us to know the effect and safety of the treatments.

Aim and objectives To analyse the effectiveness and safety of firstline treatment of metastatic colorectal cancer (CRCm) in the elderly treated in a third level hospital.

Material and methods This was an observational retrospective study including patients aged ≥75 years with CRCm, who received chemotherapy treatment in 2017. The main variables studied were type of treatment, clinical response, progression free survival (PFS), overall survival (OS), dose reductions and treatment delays due to adverse events.

Results 59 patients (71.2% men) with a median age of 76 years were enrolled, 27.1% were ≥80 years old. 41/59 patients presented with colon cancer, the left colon being the most frequent location. 26/59 metastases were hepatic, 11/59 pulmonary, 9/59 hepatic and pulmonary, and 13/59 in other locations. They were treated with nine different schemes: 50/59 in combination with two or more drugs and 9/59 as monotherapy with capecitabine. 36/59 patients were treated with target therapies. The median number of administered cycles was 10. The response was complete in 6/59 patients, partial in 29/59, stable disease in 17/59 and progression of disease in 7/59. Median PFS and OS were 12 and 30 months, respectively. We observed that patients with left colon tumours, no RAS mutation, tumours with a degree of differentiation 1 and 2 (well differentiated) and patients rescued by surgery had better OS (p<0.05). 23/59 patients started treatment with doses lower than recommended in clinical practice guidelines. In terms of safety, 34/59 patients had at least one dose reduction, and 30/59 had one treatment delay. Adverse events with frequency ≥50% were asthenia, peripheral neuropathy, diarrhoea and palmar–plantar erythrodysaesthesia.

Conclusion and relevance Our patients presented with baseline clinical characteristics similar to the general adult population, with no tumour characteristics associated with advanced age. Effectiveness and safety were similar to those in clinical trials, although our patients had more dose reductions. Considering the heterogeneity of patients and in the absence of clinical trials in the elderly, real life studies can be very useful.

References and/or acknowledgements None

Conflict of interest No conflict of interest