Background
Retrospective single-institution analysis (MD Anderson Cancer Center) of adjuvant hypofractionated RT for melanoma with regional lymph node metastases. 154 patients with Stage III melanoma treated with CLND + adjuvant RT. Hypofractionated schedule: 30 Gy in 5 fractions (6 Gy/fx), 3 fractions/week.
Interventions and follow up
Arm A: CLND + adjuvant RT 30 Gy in 5 fractions (6 Gy/fx) to the lymph node basi
Arm B: N/A — single-arm retrospective series; historical comparison to surgery alone
Primary endpoint: Regional relapse, toxicity
mFollow up: Not specified
Arm B: N/A — single-arm retrospective series; historical comparison to surgery alone
Primary endpoint: Regional relapse, toxicity
mFollow up: Not specified
Results
Regional Relapse: ~10% with adjuvant RT (vs historical 30–50% without RT for high-risk disease)
10-Year Regional LC: ~90%
Late toxicity (lymphedema): ~20–25% with 30 Gy/5 fx; less than higher-dose schedules
Grade ≥3 late toxicity: Acceptable; no unexpected toxicities
10-Year Regional LC: ~90%
Late toxicity (lymphedema): ~20–25% with 30 Gy/5 fx; less than higher-dose schedules
Grade ≥3 late toxicity: Acceptable; no unexpected toxicities
Adverse events
Main adverse events: Lymphedema (grade 2–3): 20–25%, primarily in inguinal/iliac fields. Skin fibrosis at field edges. Radiation-induced lymphedema risk increases with inguinal vs. cervical/axillary fields. Fatigue during treatment course.
Conclusions
Adjuvant hypofractionated RT (30 Gy in 5 fractions) achieves ~90% regional lymph node control in high-risk Stage III melanoma with acceptable late toxicity. The 6 Gy/fraction hypofractionated schedule exploits melanoma's relative radioresistance with high alpha/beta ratio, shortens treatment course, and is well tolerated.
Key Limitations
Key Limitations: Retrospective, single-institution; no randomized comparison within study; heterogeneous patient population; pre-immunotherapy era — patients in this series did not receive modern adjuvant systemic therapy; limited to lymph node basin treatment.
Clinical Context
The MDACC 30/5 hypofractionated schedule has become the most widely used adjuvant RT regimen for melanoma lymph node basins in the U.S. The ANZNTG 01.02 trial used 48/20 (conventional fractionation), while MDACC uses 30/5 — both are acceptable. In the modern era of adjuvant immunotherapy (pembrolizumab), the additional role of RT is being re-evaluated.
References