Cancer Resources > Cancer News > 2002 > October

Radiation reduces risk of recurrence in node-positive mastectomy patients

Emma Hitt, PhD

Last Updated: 2002-10-08 16:02:54 -0400 (Reuters Health)

NEW ORLEANS (Reuters Health) - In breast cancer patients with positive lymph nodes or positive surgical margins after mastectomy, or both, subsequent radiation therapy lowers the risk of local-regional recurrence, a new study shows.

Dr. Wendy A. Woodward, with the department of radiation oncology, at the MD Anderson Cancer Center, Houston, Texas, presented the findings Tuesday at the American Society for Therapeutic Radiology and Oncology 44th Annual Meeting here.

"At our institution, we do not currently treat patients with one to three positive nodes with radiation therapy," Dr. Woodward told Reuters Health, "but our findings suggest that radiation therapy may be used on a case-by-case basis and that these patients could be entered into clinical trials for radiation therapy," she said.

The study patients had been treated in five prospective clinical trials with mastectomy followed by doxorubicin-based chemotherapy. Included in the analysis were 469 breast cancer patients treated with post-mastectomy radiation and 1031 patients who did not receive radiation. Median follow-up was 10 years.

The researchers found that post-mastectomy radiation reduced local-regional recurrence (LRR) rates for all patients regardless of the number of nodes involved.

Specifically, LRR in patients with 20% or more positive lymph nodes was 27% for patients who did not receive radiation compared with 11% for those treated with radiation. For patients with fewer than 20% involved lymph nodes, LRR was 12% in those who received radiation compared with 4.2% in those who did not.

Likewise, in patients with close or positive margins, LRR was 13.3% in those who received radiation therapy and 45% in those who did not (p = 0.01).

Chest wall recurrences were reduced from 68% to 6.4% with the addition of radiation, and supraclavicular recurrences were reduced from 41% to 3.4%.

In patients treated with radiation, pathologic size of the largest involved node, estrogen receptor status, and lymph-vascular space invasion were significant predictors of LRR.

Dr. Woodward pointed out that, compared with patients who did not receive radiation therapy, patients in the radiation therapy group started out with significantly less favorable prognostic factors, including a higher number of positive nodes and larger tumor size, yet they saw a benefit in this group nonetheless.

"This is one of the first studies to demonstrate reduction of LRR with radiation in patients with adequate axillary dissection and doxorubicin-based therapy," she said. "But a randomized trial is needed to see whether stage T1/2 patients with 1 to 3 positive lymph nodes would benefit from post-mastectomy radiation."

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