SOX Versus XELOX for Patients With Peritoneal Metastasis of Colorectal Cancer

A Randomized Phase II Study of Oxaliplatin and S-1 (SOX) Versus Oxaliplatin and Capecitabine (XELOX) in Patients With Peritoneal Metastasis of Colorectal Cancer

The aim of this study is to compare the activity and safety of Oxaliplatin and S-1 (SOX) and Oxaliplatin and Capecitabine (XELOX) in patients with peritoneal metastasis of colorectal cancer.

Peritoneal dissemination from colorectal cancer is common, and it has been traditionally regarded as end-stage disease only amenable to palliation by systemic chemotherapy (sCT), or supportive care .Oxaliplatin and oral fluoropyrimidines (capecitabine or S-1) are active agents for colorectal cancer. Recent a phase II trial of combination chemotherapy of oxaliplatin with S-1 (OS) and several phase II trial of combination chemotherapy of oxaliplatin with capecitabine (XELOX) demonstrated good activity and mild toxicity in advanced colorectal cancer. Oxaliplatin and S-1 or capecitabine have distinct mechanisms of action and no overlap of key toxicities. Furthermore, oxaliplatin and fluorouracil were shown to be highly synergistic, not only in preclinical models but also in subsequent clinical trials.

Inclusion Criteria:

Histologically confirmed colorectal adenocarcinoma, initially diagnosed or recurred

Peritoneal metastasis of colorectal cancer

At least one uni-dimensional measurable lesion by RECIST criteria

Age 18 to 80 years old

Estimated life expectancy ≥3 months

ECOG performance status ≤2

Adequate bone marrow function (WBCs ≥ 4,000/µL or absolute neutrophil count ≥ 1,500/µL, platelets ≥ 100,000/µL)

Adequate kidney function (creatinine < 1.5 mg/dL)

Adequate liver function (bilirubin < 2.0 mg/dL, transaminase levels <2.5 times the upper normal limit)

Written informed consent

Exclusion Criteria:

Other tumor type than adenocarcinoma

Previous history of chemotherapy (exception : neoadjuvant or adjuvant chemotherapy without oxaliplatin)

Presence of CNS metastasis, psychosis, or seizure

Obvious bowel obstruction

Evidence of serious gastrointestinal bleeding

Past or concurrent history of neoplasm other than colorectal adenocarcinoma, except for curatively treated non-melanoma skin cancer or in situ carcinoma of the cervix uteri

Pregnant or lactating women, women of childbearing potential not employing adequate contraception

Other serious illness or medical conditions