NEW YORK CITYIrinotecan (Camptosar), 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 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.