NEW YORK CITYIrinotecan (Camptosar), oxaliplatin(Drug information on oxaliplatin), and other new agents have shown promising activity in rectal cancer and are now being tested in combination regimens with 5-fluorouracil (5-FU) and in new chemoradiotherapy regimens, according to Bruce Minsky, MD.
"The addition of irinotecan(Drug information on irinotecan) to 5-FU/leucovorin has improved overall survival for patients with metastatic rectal cancer. In the adjuvant setting, in the preoperative setting, and in the neoadjuvant setting, irinotecan is an active agent, and we are actively pursuing it," Dr. Minsky said.
"Whether irinotecan will be better than some of the other agents such as oxaliplatin is unknown, but certainly this drug’s activity in advanced disease provides a very good rationale for incorporating it into preoperative regimens and perhaps into postoperative regimens as well," he continued. Dr. Minsky is professor and vice chairman of the Department of Radiation Oncology at Memorial Sloan-Kettering Cancer Center in New York City.
With irinotecan-based programs Dr. Minsky recommended conventional radiation rather than the twice-daily schedule used in some European studies. "The available phase I/phase II data also suggest that irinotecan should be combined with 5-FU based therapy and not used as a single agent in treating rectal cancer," he said.
Investigators in the Scandinavian countries as well as in England and some other European countries favor short, intensive, preoperative courses of radiation without chemotherapy. "In general, patients receive 5 Gy times five. That’s 500 cGy for 5 days in a row, followed 1 week later by surgery," Dr. Minsky said. He pointed out that the European studies include patients with T1 through T3 disease, which complicates comparison to US studies, which include only patients with T3 or node-positive disease.
Dr. Minsky said that the Dutch CVKO 95-04 study will report that total mesorectal resection followed by radiation reduced local failure rates but had no effect on survival. "These data suggest that even with the best of operations we still need adjuvant treatment for local control improvement," he said.