Adjuvant Radiation Therapy May Improve Stage III Melanoma Outcomes

Research suggests that adjuvant radiation may reduce melanoma recurrences in stage III patients at risk of local relapse

by Dr. C.H. Weaver M.D. updated 2/2019

Adjuvant radiation therapy improves local control of melanoma following therapeutic lymph node dissection for lymph node-metastatic disease and may improve disease-specific survival.

Historically, surgery has been the primary treatment for patients with melanoma; however, high recurrence rates have led to the search for new and more effective approaches. Researchers from the M. D. Anderson Cancer Center conducted a study that included 615 patients with Stage III melanoma. These patients underwent therapeutic lymphadenectomy. All patients were considered to be at high risk for regional recurrence; 106 patients underwent surgery alone, and 509 patients underwent surgery plus radiation therapy.

After a median follow-up of five years, 10.2% of patients who underwent surgery plus radiation developed a regional recurrence compared with 40.6% of patients who received surgery alone. The rate of distant recurrence was 55.4% in the radiation group compared with 73.6% in the surgery-alone group. Table 1 shows the five-year regional control rate based on the area of lymph node treatment.

Table 1: Regional control rates in patients with Stage III melanoma who received surgery plus radiation vs. surgery alone

The researchers concluded that the addition of radiation therapy to therapeutic lymphadenectomy in patients with Stage III melanoma was associated with a significantly lower risk of regional recurrence. Furthermore, they observed that radiation therapy may improve survival from melanoma.

Adjuvant radiotherapy was also found to improve regional lymphatic control for high-risk patients after therapeutic lymphadenectomy for metastatic melanoma, according to the results of a study published in the Lancet Oncology.

Researchers conducted a randomized clinical trial in 16 hospitals in Australia, New Zealand, the Netherlands, and Brazil to evaluate the use of radiation therapy in melanoma. The study included 217 patients who had undergone therapeutic lymphadenectomy for metastatic melanoma in regional lymph nodes. All patients were at high risk of lymph-node field relapse. Patients were randomized to receive adjuvant radiotherapy of 48 Gy in 20 fractions (109 patients) or observation (108 patients).

After a median follow-up of 40 months, the researchers found that the risk of lymph-node field relapse was significantly reduced in the patients receiving adjuvant radiation therapy compared to their counterparts in the observation group. There were 20 relapses in the radiotherapy group, compared to 34 in the observation group. Although there was a significant improvement in the risk of local relapse within the affected nodal basins, there were no differences in relapse-free survival or overall survival. Side effects were generally mild. The most common grade 3 and 4 adverse events were seroma, radiation dermatitis, and wound infection.

The researchers concluded that adjuvant radiation therapy improves lymph-node field control in patients at high risk of lymph-node field relapse after therapeutic lymphadenectomy for metastatic melanoma. Risk stratification measures, such as the number and size of involved nodes and the presence of extracapsular disease, might be used to identify patients at high risk of regional lymphatic failure.

References:

Burmeister BH, Henderson MA, Ainslie J, et al. Adjuvant radiotherapy versus observation alone for patients at risk of lymph-node field relapse after therapeutic lymphadenectomy for melanoma: a randomised trial. The Lancet Oncology. 2012; 13(6): 589-597.

Agrawal S, Kane JM, Guadagnolo BA, et al. The benefits of adjuvant radiation therapy after therapeutic lymphadenectomy for clinically advanced, high-risk, lymph node-metastatic melanoma. Cancer [early online publication]. August 21, 2009.

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