Treatment of primary colon cancer with peritoneal carcinomatosis - Comparison of concomitant vs. delayed management

PURPOSE: The initial dissemination of colon cancer occurs through three rou tes: the lymphatics, the portal blood, and the peritoneal surfaces. Althoug h lymphatic and hematogenous metastases indicate an aggressive disease proc ess, it is possible that dissemination to peritoneal surfaces may be only s uperficial contamination of the parietal and visceral peritoneum that may b e treatable for cure. Unfortunately, surgery may have an adverse impact on peritoneal surface dissemination. Surgical interventions may convert a supe rficial process into an invasive condition with a greatly reduced prognosis . This study was conducted to test this hypothesis by the use of data prosp ectively recorded from patients treated for peritoneal carcinomatosis conco mitant with resection of the primary colon cancer or treated for carcinomat osis after disease recurrence prompted referral. METHODS: Our first group o f patients had definitive treatment of carcinomatosis simultaneous with res ection of the primary colon cancer. They had cytoreductive surgery includin g peritonectomy procedures followed by heated intraoperative intraperitonea l chemotherapy with mitomycin C plus early postoperative intraperitoneal 5- fluorouracil. The comparison group was treated with a colon resection at an outside hospital and then later referred to us with progressive disease fo r treatment. The major difference between the groups is the timing of the d efinitive treatment of carcinomatosis. These patients were also studied by use of the completeness of the cytoreduction score and the peritoneal cance r index as prognostic indicators. Survival was the end point for all the an alysis. RESULTS: Of 104 patients with peritoneal carcinomatosis from colon or rectal adenocarcinoma, five patients (4.8 percent) had definitive treatm ent of the peritoneal surface spread of the cancer concomitant with resecti on of the primary lesion. Median survival for these patients has not been r eached and their five-year survival rate is 100 percent. The remainder of t he patients (n = 99) were referred for local and regional recurrence after their primary cancer had been removed and there was progression of carcinom atosis. Forty-four patients (42.3 percent) had a complete cytoreduction res ulting in a 24-month median survival and a 30 percent five-year survival (P < 0.0001). The other 55 patients (52.9 percent) had an incomplete cytoredu ction resulting in a 12-month median survival and a 0 percent five-year sur vival (P < 0.0001). Patients with a peritoneal cancer index of 10 or less h ad a 48-month median survival and a 50 percent five-year survival rate. Pat ients with a peritoneal cancer index between 11 and 20 had a 24-month media n survival and a 20 percent five-year survival rate (P < 0.0001). Patients with a peritoneal cancer index of more than 20 had a 12-month median surviv al and a 0 percent five-year survival (P < 0.0001). CONCLUSIONS: In patient s with peritoneal seeding occurring at the time of resection of the primary malignancy, peritonectomy procedures and perioperative intraperitoneal che motherapy should be performed concomitantly. By use of a quantitative scori ng system, the mass of cancer present in the abdomen and pelvis at the rime of treatment of carcinomatosis correlated directly with survival. Aggressi ve treatment of patients with peritoneal carcinomatosis requires considerat ion in the management of colorectal cancer.