Main Session
Sep
30
PQA 09 - Hematologic Malignancies, Health Services Research, Digital Health Innovation and Informatics
3654 - The Influence of Dose on Response Duration of Total Skin Electron Beam Therapy (TSEBT) for Mycosis Fungoides in the Modern Era of TSEBT Dose Reduction
Presenter(s)
Kaitlyn Lapen, MD - Memorial Sloan Kettering Cancer Center, New York, NY
K. Lapen1, B. S. Imber2, V. Liao3, B. Fregonese2, N. P. Mankuzhy2, R. R. Patel2, A. Dreyfuss2, G. Cederquist2, Z. R. Moore2, P. Ghione4, R. Stuver4, A. J. Moskowitz4, S. Horwitz4, S. Geller3, and J. Yahalom2; 1Memorial Sloan Kettering Cancer Center, New York, NY, 2Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, 3Dermatology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 4Lymphoma Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY
Purpose/Objective(s):
Total skin electron beam therapy (TSEBT) has long been effective for patients with mycosis fungoides (MF) and other cutaneous malignancies. More recent studies suggest that the original dose of 30-36 Gy could be reduced to 12 Gy or lower. In the last decade, we adopted the use of lower dose TSEBT and sought to evaluate response and factors that influence response using a large cohort at a single institution.Materials/Methods:
We retrospectively analyzed patients who received TSEBT between 2012-2023. Patient demographic and clinical characteristics, treatment details, and disease outcomes were collected. Response to TSEBT was determined by clinical documentation review and photo review by an expert dermatologist. Logistic regression evaluated for characteristics associated with response to TSEBT. Kaplan-Meier was used to evaluate cutaneous freedom from progression (FFP).Results:
We identified 124 patients who received TSEBT with median age of 61 years (IQR 48-73). 86% (n=117) had a diagnosis of MF. Among MF patients, 20% (n=23) and 28% (n=33) had folliculotropic morphology or large cell transformation of their disease, respectively. Among MF patients, 25% (n=29) had stage IV disease. The most common TSEBT dose regimens were 16 Gy in 8 fractions (n=22, 18%) and 12 Gy in 6 fractions (n=18, 15%) delivered twice weekly. Response to TSEBT was determined for 110 patients of which 79% (n=87) responded to TSEBT, 12% (n=13) had stable disease, and 9% (n=10) progressed. Photos taken before and after TSEBT were available for 32% (n=40) of all patients; rate of agreement between documented response and photographic response was 83%. Among MF patients, on unadjusted logistic regression, there were no demographic or clinical factors associated with response compared to lack of response. Median follow-up was 28.2 months (IQR 9.5-52.4). Among MF responders (n=77), 6-month and 1-year FFP was 62% (95% CI 52-74%) and 40% (95% CI 30-53%), respectively. Among MF responders who received 12 Gy or less (n=18, 23%), median time to cutaneous progression was 6.5 months (95% CI 4.1-16.1) compared to 11.2 months (95% CI 6.6-14.7) for those who received more than 12 Gy (n=59, 77%). This difference was statistically significant (p=0.043). Overall, 26% (n=23) had subsequent focal radiation therapy (RT) to an area covered by TSEBT. Median time to subsequent focal RT was 15.1 months (IQR 8.0-24.4). 17% (n=15) had subsequent TSEBT. Median time to subsequent TSEBT was 18.2 months (IQR 10.7-23.1).Conclusion:
TSEBT is an effective treatment option for MF and other cutaneous malignancies, particularly for chemorefractory and advanced stage disease. Duration of response is limited but appears more durable among patients who receive higher dose regimens. Further work is warranted to determine the effect of TSEBT on patients’ symptom burden and quality of life.