A clinical pilot study combining surgery with intraoperative pelvic hyperthermochemotherapy to prevent the local recurrence of rectal cancer. Intraoperative pelvic hyperthermochemotherapy (IOPHC) with mitomycin C (MMC) was prescribed for 14 patients with resectable advanced rectal cancer in an attempt to prevent a postoperative local recurrence. Immediately after rectal amputation and extended lymphadenectomy, IOPHC was performed using physiologic saline containing 40 micrograms/mL of MMC at 45.5 +/- 0.6 C for 90 minutes, with an apparatus devised for IOPHC. At the end of IOPHC, the esophageal temperature was 37.2 +/- 0.8 C and cooling was not required. Antitumor efficacy and complications in the IOPHC group were compared with findings in 12 rectal cancer patients who underwent surgery only within the same period of time. Operation time was not prolonged with IOPHC treatment. In cytologic examinations of the pelvic lavage just before IOPHC treatment, viable cancer cells were detected in 6 of the 14 patients but were never detected in the postoperative exudate drained from the pelvic cavity. Of the 12 patients in the control group, 2 had a local recurrence, while in the IOPHC group there was no local recurrence for 16.9 +/- 9.7 months at this writing. Postoperative complications did not differ between the groups. This IOPHC treatment is a favorable method in eradicating cancer cells for postoperative local recurrence of rectal cancer. 