CHICAGO - High-risk melanoma patients who are treated with radiation therapy after surgery have a significantly lower risk of their cancer returning to their lymph nodes compared to patients who do not receive this treatment, according to a presentation this week at the American Society for Radiation Oncology (ASTRO) annual meeting.
In a Monday press conference, the study was heralded as the first real advance in the management of melanoma to be reported in the past 15 years, according to ASTRO president Dr. Tim Williams, chairman of radiation oncology at South Florida's Boca Raton Community Hospital. Prior to this study, the only data to support the use of adjuvant radiotherapy after lymphadenectomy for isolated lymph node relapse of melanoma came from retrospective and phase II clinical trials.
Sixteen cancer centers located in Australia, Brazil, the Netherlands, and New Zealand participated in the prospective randomized clinical trial, consisting of 217 patients who received treatment between March 2002 and September 2007. The patients were studied to assess the effect of radiation therapy on the subsequent risk of regional relapse and survival.
Patients recruited for the study had:
- One or more parotid, two or more cervical or axillary, or three or more groin positive nodes
- Extranodal spread of tumors, and/or
- Minimum metastatic node diameter of 3 cm for neck or axilla or 4 cm for groin
Only 19% of the patients who received radiation therapy treatment had a local recurrence, compared to 31% of patients who only had surgery, according to Dr. Bryan Burmeister, director of radiation oncology at the Princess Alexandra Hospital in Brisbane, Australia.
After lymphadenectomy, the patients were randomized to either receive radiotherapy of 48 Gy in 20 fractions within 12 weeks after surgery or be observed without radiotherapy treatment. However, relapsed patients with isolated disease in the observation group could be offered further surgery followed by radiation therapy.
One hundred nine patients from the radiation treatment group and 108 patients from the surgery-only group were followed for a median of 27 months. The researchers reported that 20 patients in the radiation therapy group and 34 patients in the observation group relapsed regionally.
The observation-only patient group had a median survival 16 months longer than the group receiving radiation therapy (47 months versus 31 months). Burmeister said that this was not clinically significant because the number of study participants was too small to statistically analyze, and for this reason, survival outcomes were not incorporated in the study. A larger number of patients had been enrolled in the study to assess this, but the dropout rate precluded planned survival outcome analysis.
Burmeister reported that the proper radiotherapy protocols were not followed for 21% of the group that received this treatment. The study did not analyze whether there was any difference in outcome between this subset and the 79% who received the correct protocols because the number in each group was too low to accurately statistically assess.
At the press conference, Williams said that from his perspective as a community oncologist working in a location where exposure to the sun was high, the findings of this study would affect the treatment he recommended to patients.
"Now I can tell my high-risk melanoma patients that a definitive study exists verifying that radiation therapy reduces the risk of recurring lymph node involvement," he said. "This is now a proven effective treatment, and an alternative to interferon, which has been proven to be helpful in preventing recurrence but is very toxic."
Williams also noted that the findings are not applicable to the 90% of patients he sees who are diagnosed with early-stage, low-risk melanoma.
When asked if radiation therapy was established standard treatment in Australia, Burmeister said his department, located in the "melanoma capital of the world," recommends radiotherapy to all patients who have had a lymphadenectomy. "But now we have facts to support our recommendation," he said.
By Cynthia E. Keen
AuntMinnie.com staff writer
November 3, 2009
Related Reading
US can predict survival of melanoma patients, September 25, 2009
Melanogenesis inhibition sensitizes melanoma cells to radiotherapy, October 6, 2008
Radioimmunotherapy targets metastatic melanoma lesions in phase I trial, July 2, 2008
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