Predicting response to initial chemotherapy in pediatric lymphoma using a semiquantitative contrast enhanced CT (CECT)-based abdomino-thoracic score: a pilot prospective observational study.

Abstract

Background: There is a lack of staging systems in pediatric lymphoma to quantify the burden of the disease based on the anatomical extent of lymph nodal distribution.

Purpose: To evaluate the utility of a CECT-based semiquantitative lymph nodal scoring system in predicting histopathological type of childhood lymphoma and response to initial chemotherapy.

Materials and methods: Pre-treatment CECT of abdomen and thorax was performed in children with lymphoma and a Checklist-based reporting template was used to report the lymph nodal involvement. Based on the distribution of lymph nodes, a semi-quantitative scoring system was developed to cover all the locations of thorax and abdomen. Anatomical semiquantitative scoring was done for thorax (score 0-10), abdomen (scores 0-10), and a combined thoraco-abdominal score (0-20) was calculated. Also, the mean scores were compared in patients with complete response(CR) and Non-complete response(NCR) to primary treatment. Decrease in size of all the pathological nodes to < 10 mm in short axis and < 15 mm in long axis was defined as CR.

Results: Fifty patients were included with 35 cases of Hodgkin Lymphoma(HL) and 15 cases of Non-Hodgkin Lymphoma(NHL). Mean abdominal, thoracic, and combined lymph nodal scores were significantly lower in the pre-treatment scan in children with HL (3.5 ± 2.3, 3.3 ± 1.75,and6.89 ± 3.54) compared to NHL (4.8 ± 2.1,5.2 ± 2.8,and10.0 ± 3.96). The mean abdominal, thoracic, and combined lymph nodal scores in the pre-treatment scan was significantly higher in NCR group.

Conclusion: The lymph nodal burden, estimated by semiquantitative abdominal and thoracic scores is significantly higher in lymphoma patients with non-complete response.