Background: Inadequate representation of elderly cancer patients in randomized clinical trials (RCTs) leading to a lack of external validity thereby an uncertainty regarding benefit-risk balance of cancer treatment in elderly, especially chemotherapy.

Hypothesis: The eligibility criteria explain only a part of the under-representation of elderly patients in trials. We make the assumptions that 1) Among the eligible, the invitation to participate in a trial and inclusion are inversely related to age, 2) Among the eligible, there are patients, practitioner, or organization factors that would explain the non inclusion of elderly patients.

Objectives:

1) To assess, in elderly patients with colorectal cancer, the proportions of patients:

1. eligible at least to one RCT
2. invited to participate
3. included 2)

a) Compare proportions among elderly patients to those of the comparator group of "young" subjects (age ≥ 18 and <65 years) (added by amendment n°3 accepted 18/02/2014) b)To identify factors associated with the non-invitation and the non-inclusion in RCT.

Material and methods:

Study design: A multicentric prospective cohort survey Population: all patients aged 18 years or more (added by amendment n°3 - 02/2014) with a colorectal cancer followed in one of the participating centers.

Data collection:

• At baseline: Patient characteristics (including SOCIO-demographic, oncologic and geriatric data) will be collected. Organization factors (e.g. clinical research team) will be collected.
• Follow-up: the patient will be followed for potential invitation and inclusion in one RCT. Reasons of non-invitation or non-inclusion will be assessed.

Number of subjects needed: 696 (553 elderly patients and 143 "young" patients) Number of centers : 7 (added by amendment n°3 - 02/2014)

Ethical aspects: each patient will give his oral informed consent. The International Review Board of Mondor Hospital (CPP Ile-de-France IX) gave its approval in December 2012.

Inclusion Criteria:

Patient aged of of 18 years and older (modified by amendment n°3 - 02/2014)

For a diagnosed colorectal cancer (CRC) irrespective of the stage

Exclusion Criteria:

None

Population: all patients aged 18 years or more with a colorectal cancer followed in one of the participating centers (amendment n°3 - 02/2014)