Postoperative Irradiation for

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John Han-Chih Chang, MD
OncoLink Assistant Editor
Last Modified: November 1, 2001

Presenter: Christopher Willett, MD
Affiliation: Massachusetts General Hospital, Boston, MA and Roswell Park Cancer Institute, Buffalo, NY

Background:
Postoperative systemic therapy is the standard of care for intermediate to advanced colon cancer. Radiation therapy (RT) has been utilized far less due to the technical considerations such as not being able to localize the target. In T4 disease, by definition, there has been invasion into adjacent structures, which are usually more "fixed" in location and more easily targeted. Hence, the authors investigated their long term experience with this patient population receiving postoperative RT.

Materials and Methods:

• One hundred and fifty-two patients having undergone a resection of a colon cancer were irradiated to 50 Gy to the tumor bed with or without 5-Flurouracil chemotherapy.
• A majority of the patients had no evidence of either gross or microscopic residual disease.

• Seventy-nine patients who had N0 or one lymph node positive disease had 10 year local control of 88%. Relapse free survival was 58% at 10 years.
• Even patients who had T4 tumors complicated by perforations or fistulas had a nearly similar local control and relapse free survival rate.
• Those with gross residual disease were not well controlled, and relapse free survival was 19% at 10 years.

1. In selected stage T4 colon cancers, postoperative RT may improve local control and relapse free survival.
2. As with any retrospective review, patient selection biases may be a factor. However, the data presented in this series are compelling.
3. Prospective trials should be pursued in the locally advanced colon cancer patients with established guidelines regarding systemic therapy, which has demonstrated its positive impact on this disease entity.

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