Results of Chemoradiotherapy for Nodal Follicular Lymphoma of the Abdominal Cavity and Pelvis. Report I. Immediate Effect, Local Progression-Free Survival and Progression-Free Survival

Relevance: The effectiveness of adjuvant radiation therapy used to consolidate the effect of chemotherapy in patients with malignant lymphomas remains a subject of debate and intensive study. The usefulness of chemoradiotherapy has been proven for certain lymphoma sites (mediastinum, central nervous system, bone, gonads), but its role in follicular lymphoma with primary involvement of the abdominal and/or pelvic lymph nodes has been insufficiently studied.

Purpose: Determination of the effectiveness of chemoradiotherapy in primary patients with abdominal and pelvic nodal follicular lymphoma.

Materials and methods: We studied the immediate effect of treatment, 10-year local progression-free survival (LPFS) and progression-free survival (PFS) of 77 primary patients with follicular lymphoma of the abdominal and pelvic lymph nodes treated in 1985–2024 at the Russian Scientific Center of Roentgenology and Radiology. Chemoresistant patients were not included in the study. The main group (43 patients) underwent chemoradiation therapy (CRT) with adjuvant irradiation of initially massive conglomerates of abdominal and/or pelvic lymph nodes, while the control group (34 patients) received chemotherapy alone. Identical chemotherapy regimens ± rituximab immunotherapy were used in both groups. The differences between the groups were statistically insignificant in terms of the main parameters that are potentially important for treatment outcomes.

Results: Upon completion of radiation therapy in the main group, the rate of complete remissions statistically significantly increased from 23 % to 49 % (p = 0.014). The 10-year LPFS rate was statistically significantly higher in the CRT group as a whole (80 % vs 30 %, p = 0.00006), as well as in all analyzed subgroups, except for the subgroups of patients with a lesion size of 7 cm or less and patients with complete remission after chemotherapy. The 10-year PFS rate was statistically significantly higher in the CRT group as a whole (49.6 % vs 14.2 %, p = 0.0017), as well as in most compared subgroups and did not reach statistical significance in men, patients over 60 years of age, at local stages of the disease, in the high-risk group, patients treated without rituximab and patients with complete remission after chemotherapy.

Conclusions: In primary patients with nodal follicular lymphoma of the abdominal and pelvic localization who are sensitive to chemotherapy, chemoradiotherapy significantly compensates for the low efficacy of chemoimmunotherapy in relation to massive tumor foci, which is expressed in a statistically significant increase in the proportion of complete remissions, a decrease in the initially high risk of subdiaphragmatic progression, and the achievement of a 10-year period free from disease progression in half of the patients.

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