Assessment of the Prognostic Significance of Positron Emission Tomography Combined With Computed Tomography at Different Stages of Treatment in Patients With Non-Hodgkin Lymphomas: A Cohort Study

BACKGROUND: The Russian Federation is experiencing an increase in the incidence of tumors of lymphoid and hematopoietic tissues; however, no unified diagnostic or treatment algorithm has been developed for these conditions.

AIM: To determine effective diagnostic and therapeutic approaches, as well as criteria for early treatment adaptation, in patients with non-Hodgkin lymphomas.

METHODS: The medical records of 439 patients with two histological types of non-Hodgkin lymphomas who received inpatient treatment and follow-up at the Republican Clinical Oncology Dispensary of the Ministry of Health of the Republic of Tatarstan over a 10-year period were retrospectively reviewed: 386 patients with aggressive lymphoma (diffuse large B-cell lymphoma) and 53 patients with indolent lymphoma (follicular lymphoma). There were 237 patients (54.0%) aged over 60 years and 89 (20.2%) aged over 70 years. A total of 259 patients underwent three positron emission tomography combined with computed tomography (PET/CT) scans (primary, interim, and final). Inclusion criteria were: age ≥18 years; no prior treatment for non-Hodgkin lymphoma; and a histologically and immunohistochemically confirmed diagnosis. Exclusion criteria were: acute somatic or infectious diseases (including HIV infection) ; severe cognitive impairment; refusal to participate in the study; and residence outside the region. Statistical analysis was performed using IBM SPSS Statistics and Statistica 10 software. Normality of distribution was tested using the Kolmogorov–Smirnov test. Survival was assessed using the Kaplan–Meier method. Differences were considered statistically significant at р < 0.05.

RESULTS: Changes in the maximum standardized uptake value (SUVmax) on interim PET/CT were shown to be associated with the risk of progression and with overall survival rates, which decreased significantly with increasing disease stage. Assessment of the metabolic response at the interim stage using the Deauville scale demonstrated high prognostic significance: scores of 1–3 identified a group of patients with complete metabolic remission. However, even when a pronounced tumor response was achieved, some patients developed severe cumulative toxicity. Specifically, in a group of 120 patients who continued treatment after the fourth cycle, high-grade febrile neutropenia was recorded in 11 patients (9.2%), and in 10 of these cases (8.3%) it was accompanied by fatal complications due to multiple organ failure.

CONCLUSION: These findings underscore that in patients who achieve a complete metabolic response but have signs of severe cumulative toxicity, reducing the planned volume of chemotherapy should be considered to improve treatment safety.