ESTRO 2024 - Abstract Book

S1145

Clinical - Haematology

ESTRO 2024

the skin and another received treatment to the thyroid gland. The mean latency time between the diagnosis and the administration of RT was 4.8 months.

Four of the patients with gastric MALT lymphoma received H.pylori eradicating treatment with antibiotics, they required RT for the lack of response; also, two of the patients had involvement of contiguous lymph nodes.

Out of the five patients with orbital affection, two received systemic treatment previous to RT with little to no response. The patient with a lesion on the skin did not receive any form of systemic treatment.

The patient diagnosed with primary thyroid lymphoma underwent surgery (isthmusectomy and right thyroidectomy) with a suspected diagnosis of diffuse large B-cell lymphoma (DLBCL), however the anatomopathological result confirmed EMZL. Given the persistence of fluorodeoxyglucose (FDG-18) uptake in the surgical bed and left thyroid lobe in control positron emission tomography (PET-CT), the patient required consolidation RT. The standard dose used was 30 Gy to the involved field fractionated in 17 sessions, dose was delivered with modulated technique (IMRT vs. VMAT). Few patients (n = 2) were treated with 20-25 Gy in 12 - 14 fractions to reduce toxicity. The treatment was tolerated in most of the patients, however grade 1 (G1) RT - toxicities were observed in 4 of 12 patients. G1 RT-toxicities were recorded as fatigue (n=1), pyrosis (n=2) and nausea (n=1). One of the patients required surgery for cataract removal. Initial local control was evaluated with gastric endoscopy monitoring in those with gastric affection, cranial CT scan in patients with orbital disease, PET-CT to evaluate the thyroid and physical examination to the skin. 67% of the patients were at complete response three months after receiving radiotherapy, the remaining (n=4) experienced a partial response; one of them with orbital affection, two of them with persistence of gastric MALT disease and focal uptake suggesting partial response to the thyroid. After a median follow-up of 28.6 months (range 4 to 190) all patients are alive, 83% (n=10) with stable disease. One of the patients presented new lesions in different locations, requiring systemic treatment, in partial response at the moment. Another patient progressed to a IVa stage three years after receiving RT and required systemic treatment reaching complete response; four years later (September 2021) this patient was diagnosed with an angiommunoblastic T-cell lymphoma, currently in a stable situation.

Conclusion:

The results from this review on 12 patients suggest that radiotherapy might be an effective treatment for the local control of EMZL, specially in localized gastric MALT lymphomas resistant to H. pylori eradication, primary orbital and ocular adnexal lymphoma, primary thyroid location and single lesions on the skin. However, it warrants further investigation and a larger number of patients.

Keywords: marginal zone lymphoma, radiotherapy

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