Inclusion Criteria:

1. Histologic (or cytologic) proof of colorectal carcinoma (CRC).

2. Age: between 18 and 80.

3. Sex: both sexes.

4. Previous treatment for metastatic disease is limited to FOLFIRI+ bevacizumab.

5. Prior adjuvant chemotherapy, with a fluoropyrimidine and/or Oxaliplatin, is allowed.

6. Prior radiotherapy, either as adjuvant treatment or palliation of metastatic sites is
allowed, provided that there are other non-irradiated foci of disease for evaluation.

7. Persistent remission, either complete, partial or minimal response (CR, PR or MR) or
stable disease (SD), one year+/-one month from initiation of first line treatment for
mCRC.

8. Asymptomatic patients at break from chemotherapy.

9. Intact organ function, including complete blood counts (CBC) showing normal values or
any toxicity limited to grade 1 and blood chemistry (SMA) showing liver and renal
functions < 1.5 upper normal limit (UNL).

10. Capability to understand and to sign the informed consent.

Exclusion Criteria:

1. Concurrent any other cancer (except BCC or squamous cell carcinoma of skin).

2. Inability to adhere to monthly visits to the oncology unit for evaluation.

3. Presence of brain metastases.

4. Any current or recent (within the last month) continuous treatment by steroids or by
NSAIDs, or with therapeutic doses of anticoagulants for any reason.

5. Previous radiotherapy to the only site of measurable disease.

6. Evidence of severe or uncontrolled systemic disease (e.g., unstable or uncompensated
respiratory, cardiac including arrhythmias, hepatic or renal disease), and/or
existence of active peptic ulcer (clinically and/or by gastroscopy).