De-escalated radiotherapy for indolent primary cutaneous B-cell lymphoma
PO-0922
Abstract
De-escalated radiotherapy for indolent primary cutaneous B-cell lymphoma
Authors: OERTEL|, Michael(1)*[mail@michael-oertel.net];Elsayad|, Khaled(1);Weishaupt|, Carsten(2);Steinbrink|, Kerstin(2);Eich|, Hans Theodor(1);
(1)University Hospital Muenster, Department of Radiation Oncology, Muenster, Germany;(2)University Hospital Muenster, Department of Dermatology, Muenster, Germany;
Show Affiliations
Hide Affiliations
Purpose or Objective
Radiotherapy (RT) has an established role in the curative treatment of indolent primary cutaneous B-cell lymphoma. With the role of low-dose regimens as 2*2 Gy being uncertain, we compared conventional-dose RT to a low-dose approach and investigated outcome and toxicities.
Material and Methods
We retrospectively reviewed the medical records of 26 patients with 44 cutaneous lesions treated at our institution between 2007 and 2017, comprising 22 marginal zone lymphoma (PCMZL) lesions and 22 follicle center lymphoma (PCFCL) lesions. Seven lesions (16%) were treated with low-dose RT (4 Gy) and 37 (84%) with conventional-dose (≥24 Gy, median 40 Gy). Median follow-up duration was 76 months.
Results
The overall response rate (ORR) was 91% (complete response rate (CRR): 75%). The 5-year local control rate (LCR) was 88% and the 10-year LCR was 84%. The response rates were significantly higher following conventional-RT dose (ORR: 92% vs. 86%; CRR: 84% vs. 29%, P=.007). In terms of radiation dose, the rate of infield relapses (14% vs. 11%, P=.4) and the 5-year LCR (86% vs. 90%, P=.4) were comparable in the low-dose RT and conventional-dose group. During RT courses, about two-thirds of patients experienced mild toxicities with grade 1 and 2 acute toxicity rates of 61% and 9%, respectively, with lower incidences of grade 1 (14% vs. 70%) and grade 2 (0% vs. 8%, P=.004) toxicities following low-dose RT.
Conclusion
This long-term analysis confirmed the excellent outcome of RT in the management of indolent primary skin lymphoma. The low-dose RT concept with 4 Gy was associated with a comparable LCR and reduced rates of acute toxicity. However, the response rates were significantly lower for this group and low-dose RT may therefore not be recommended as standard treatment.