In this retrospective observational study, the case series of patients undergoing first-line treatment for metastatic colorectal adenocarcinoma with doublet fixed-dose and reduced-dose chemotherapy in combination with full-dose monoclonal antibody in patients aged 70 years or older is collected.

Treatment in the elderly first-line patient of metastatic colorectal cancer is often conditioned by the age and general condition of the patient.

Such treatment involves the combination of chemotherapy and biological therapy targeted on the basis of the site and genetic mutations of the colorectal tumour, in particular RAS and BRAF.

With regard to targeted biologic therapy, the choice of monoclonal antibody is determined by tumour site and mutations. In particular, for right-sided and/or RAS/BRAF mutated tumours anti-VEGF therapy with Bevacizumab is the best option, whereas for left-sided and RAS/BRAF WT tumours monoclonal antibodies Panitumunab or Cetuximab are the choice.

In the elderly patient, the intensity of chemotherapy to be combined with targeted biologic therapy varies according to the patient's age, general condition and treatment goals. In particular for patients aged 70 years or older, a valid option is the combination of monochemotherapy with fluorodrugs in combination with bevacizumab. In addition, an Italian randomised trial tested monochemotherapy with 5-Fluorouracil in combination with Panitumumab in RAS WT/BRAF WT tumours and obtained the same efficacy as a doublet of chemotherapy with FOLFOX also in combination with Panitumumab.

Full-dose doublet chemotherapy is hardly feasible in the elderly patient because of the frailty of these patients and the high risk of toxicity.

In this retrospective observational study, we report on the case series of patients undergoing first-line treatment for metastatic colorectal adenocarcinoma with doublet of fixed-dose and reduced-dose chemotherapy in combination with full-dose monoclonal antibody in patients 70 years of age and older.

Inclusion Criteria:

1. Patients with metastatic colorectal adenocarcinoma not treated with any therapy in the metastatic phase. Previous (neo)-adjuvant treatment with fluoroderivatives with or without Oxaliplatin is permitted.
2. Age ≥ 70 years
3. G8 score ≥ 12
4. Patients with colorectal adenocarcinoma MSS
5. Patients with BRAF WT colorectal adenocarcinoma
6. Ability to understand and sign the informed consent form.

Exclusion Criteria:

1. Patients with MSI tumours
2. Patients with BRAF V600E mutated tumours
3. Patients not eligible for doublet chemotherapy by clinical decision

The study population includes patients aged 70 years and older, with metastatic colorectal adenocarcinoma, MSS, BRAF WT, with a G8 score greater than or equal to 12, candidates for metastatic first-line treatment