The optimum regimen of maintenance treatment after first-line chemotherapy in patients with metastatic colorectal cancer (mCRC) is unknown. This study was designed to determine the efficacy and safety of maintenance treatment with capecitabine metronomic chemotherapy versus conventional chemotherapy.

In this Prospective, open-label, randomised controlled trial, the investigators will recruit 250 mCRC patients who have finished 18 to 24 weeks first-line chemotherapy and disease evaluation is SD, PR or CR. Then, the patients will be randomised into two group. The experimental group, capecitabine metronomic chemotherapy versus capecitabine conventional chemotherapy as control group. These treatment regimens will be continued until progression, death, or an unacceptable adverse event.

The primary endpoint is progression-free survival (PFS). Secondary endpoints are overall survival (OS), quality of life (QOL) and toxic effects.

Inclusion Criteria:

• Histological proof of colorectal cancer (in case of a single metastasis, histological or cytological proof of this lesion should be obtained);
• Distant metastases (patients with only local recurrence are not eligible);
• Unidimensionally measurable disease (> 1 cm on spiral CT scan or > 2 cm on chest X-ray; liver ultrasound is not allowed). Serum CEA may not be used as a parameter for disease evaluation;
• In case of previous radiotherapy, at least one measurable lesion should be located outside the irradiated field.

Exclusion Criteria:

• Prior adjuvant treatment for stage II/III colorectal cancer ending within 6 months before the start of induction treatment;
• Any prior adjuvant treatment after resection of distant metastases;
• Previous systemic treatment for advanced disease.