Main Session
Sep
28
PQA 04 - Breast Cancer, Patient Reported Outcomes/QoL/Survivorship, Functional Radiation Medicine, Hematologic Malignancies, Palliative Care, and International/Global Oncology
Presenter(s)
Penny Fang, MD, MBA - MD Anderson Cancer Center, Houston, TX
P. Patel1, J. R. Gunther1, S. Y. Wu1, D. Chihara2, P. Strati2, T. A. Lin1, O. Saifi1, C. C. Nze2, F. Furqan2, A. Lionel2, R. Nair2, M. Hamilton2, L. Fayad2, S. S. Neelapu2, C. Flowers2, J. Westin2, S. Ahmed2, B. Dabaja1, C. C. Pinnix1, and P. Fang1; 1Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 2Department of Lymphoma-Myeloma, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
Purpose/Objective(s):
The role of radiotherapy (RT) in patients with follicular lymphoma (FL) with limited-site relapse after prior treatment is unclear. We hypothesized that focal RT to relapsed sites could provide durable disease control and possibly lengthen the time to subsequent next systemic therapy.Materials/Methods:
We performed an IRB-approved retrospective review of consecutive patients with biopsy-proven FL treated with RT for limited-site relapse between 2014 and 2025 at a single institution. Limited-site relapse was defined as PET-CT–confirmed involvement of 1–2 Ann Arbor sites that could be encompassed by a single radiation field. Time-to-event outcomes were calculated from completion of RT. Endpoints included local control, freedom from distant progression, time to next systemic therapy (TTNST), and progression-free survival (PFS). Univariate Cox proportional hazards regression models were used to evaluate the association between relevant covariates and time to distant relapse.Results:
Among 108 eligible patients, median age was 61.5 years [IQR: 51.3 – 68.7], and 58 (54%) patients were male. Eighty-one (75%) patients had advanced-stage disease at initial diagnosis. Most patients had grade 1-2 (88, 81%) FL. Patients relapsed after prior systemic therapy completion (82, 76%) or had persistent or progressive disease while on systemic therapy (26, 24%) before RT. Patients received 1 median line of prior systemic therapy (range 1-7). 19 (18%) received prior RT, 12 (11%) specifically for FL. Median time from initial diagnosis to RT for limited disease relapse was 5.6 years (range 0.16-31.4). The most common RT regimen was 4Gy in 2 fractions (80, 74%), followed by 20-30 Gy (20, 19%). 20 patients (19%) experienced grade 1 toxicity, most commonly fatigue. With median follow-up of 2.4 years [95% CI: 1.9 – 4.0], the local control rate was 84% (91/108), and freedom from distant progression was 56% (60/108). Thirty-five patients (32%) initiated systemic therapy after RT, with median TTNST of 0.97 years. Median distant and overall PFS were 3.4 years [95% CI 1.9 – NR] and 2.1 years [95% CI 1.4 – NR], respectively. On univariate regression, factors such as advanced stage, > 1 line of prior systemic therapy, systemic therapy refractory disease, and advanced stage were not associated with time to distant relapse, though advanced stage disease at diagnosis trended towards significance (HR 2.12, 95% CI 0.94 – 4.77, p = 0.0694).Conclusion:
Patients with limited-site relapse of FL after prior therapy for FL experience durable disease control following RT, with outcomes approaching those observed in de novo limited-stage FL. These findings support consideration of RT as single modality treatment for limited site relapse, which has the potential to prolong systemic therapy–free survival.