Maximum disease diameter is associated with outcomes in stage II follicular lymphoma treated with radiation therapy alone

Yi Xu; Belinda A Campbell; Matthew Chan; Jessica Chan; Pedro Farinha; Christopher P Venner; David W Scott; Alina S Gerrie; Diego Villa; Laurie H Sehn; Kerry J Savage; Andrea C Lo

doi:10.1016/j.ctro.2024.100869

Maximum disease diameter is associated with outcomes in stage II follicular lymphoma treated with radiation therapy alone

Clin Transl Radiat Oncol. 2024 Sep 29:49:100869. doi: 10.1016/j.ctro.2024.100869. eCollection 2024 Nov.

Authors

Yi Xu¹, Belinda A Campbell^{2

3

4}, Matthew Chan^{5

6}, Jessica Chan^{5

6}, Pedro Farinha⁷, Christopher P Venner^{1

8

9}, David W Scott^{1

8

9}, Alina S Gerrie^{1

8

9}, Diego Villa^{1

8

9}, Laurie H Sehn^{1

8

9}, Kerry J Savage^{1

8

9}, Andrea C Lo^{5

6

9}

Affiliations

¹ Department of Medicine, University of British Columbia, 2775 Laurel Street, Vancouver, British Columbia V5Z 1M9, Canada.
² Department of Radiation Oncology, Peter MacCallum Cancer Center, 305 Grattan Street, Melbourne, Victoria 3000, Australia.
³ The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia.
⁴ Department of Clinical Pathology, University of Melbourne, The University of Melbourne, Grattan Street, Parkville, Victoria 3010, Australia.
⁵ Department of Radiation Oncology, BC Cancer - Vancouver, 600 West 10th Avenue, Vancouver, British Columbia V5Z 4E6, Canada.
⁶ Department of Surgery, University of British Columbia, 2775 Laurel Street, Vancouver, British Columbia V5Z 1M9, Canada.
⁷ Department of Pathology and Laboratory Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver, British Columbia V6T 2B5, Canada.
⁸ Department of Medical Oncology, BC Cancer - Vancouver, 600 West 10th Avenue, Vancouver, British Columbia V5Z 4E6, Canada.
⁹ The Centre for Lymphoid Cancer, BC Cancer - Vancouver, 600 West 10th Avenue, Vancouver, British Columbia V5Z 4E6, Canada.

Abstract

Purpose: The optimal management of stage II follicular lymphoma (FL) is unclear. Radiation therapy (RT) alone has been the gold standard treatment, but a proportion of patients relapse. We sought to characterize outcomes and prognostic factors for stage II FL treated with RT alone to identify a high-risk subgroup of patients who may benefit from treatment intensification.

Methods: This was a population-based, province-wide, retrospective study. Included patients had grade 1-3A, non-mesenteric, stage IIA or IIAE FL diagnosed between 1986 and 2016 and treated with curative-intent (≥20 Gy) RT alone.

Results: 102 patients were included. Median follow-up was 10.4 years (range, 0.3-22.3). Median age was 59 years (range, 33-86). Median greatest disease diameter was 3.6 cm (range, 1.5-11.5). Freedom from progression (FFP) was 60.3% at 5 years and 40.7% at 10 years. Overall survival (OS) was 89.2% at 5 years and 81.8% at 10 years. Greatest disease diameter of >3.6 cm was associated with inferior FFP (10-year FFP 34% vs. 47%, p = 0.013) on univariable analysis and inferior FFP (hazard ratio [HR] 1.87, p = 0.019) and inferior OS (HR 2.12, p = 0.027) on multivariable analysis (MVA). Older age was associated with inferior OS (HR 1.08, unit = 1 year, p < 0.001) on MVA.

Conclusions: 40.7% of stage II FL patients treated with RT alone remained disease-free at 10 years. Greatest disease diameter >3.6 cm was associated with inferior FFP and OS, representing a novel prognostic indicator in this population that may help in the decision-making process on whether to complement RT with systemic therapy.

Keywords: Kaplan-Meier Estimate; Lymphoma, Follicular; Prognosis; Radiotherapy; Survival Analysis; Treatment Outcome.