ESTRO 2024 - Abstract Book

S1154

Clinical - Haematology

ESTRO 2024

p=0.01). At MVA, RP was associated with disease stage and location: patients with stage II disease or with disease location outside the stomach or breast were more prone to develop disease relapse (respectively HR 2.18, p=0.015 and HR 1.30, p=0.006). On the other hand, the association of systemic therapy did not significantly impact on relapse probability (p=0.678). At 5 years, the risk of RP was lower for patients treated with RT doses ³24 compared to LDRT (21% vs 45%, p=0.03). In orbital lymphoma, however, the use of a LDRT regimen of 4 Gy guaranteed similar rates of RP at the median follow-up time compared to ³24 Gy (19% vs 21%, respectively p=0.52). Moreover, the impact of RT dose on RP was not confirmed at the MVA. No significant differences in RP where identified when comparing 24 Gy with higher doses of radiation (p=0.66).

Conclusion:

Radiation therapy is an effective treatment strategy for stage IE and IIE extranodal indolent lymphomas, guaranteeing good PFS and local and systemic control rates. Moreover, the association with systemic therapy did not significantly impact on the risk of relapse and progression, which further supports the role of exclusive radiotherapy in the first line setting. Standard doses of ³24 Gy are associated with lower relapse rates when compared to low-dose (4 Gy in 2 fractions) regimens, with the exception of orbital lymphoma. Dose-escalation >24 Gy did not result in improved outcomes and is therefore not supported in this setting.