Results
Baseline
A total of 396 were enrolled onto the study and 382 underwent ERA (186 PET-CT and 196 CECT). Based on the modality used at ERA, patients were divided into two groups (CECT and PET-CT). As shown in table 1, patients in CECT group had a lower mean age, lower hemoglobin value, more bulky disease and more B symptoms. Distribution in terms of early and advanced disease was similar in both groups. Of all the CECTs done, 75.5% of ERA were done at government hospitals, 5.1% at private and 19.4% at trust hospitals. PET-CT was the preferred modality at private and trust (36% + 37.6%=73.6%) hospitals as compared to the government hospitals (26.4%) (p<0.00001). This reflects that financial disparity, availability of scanning modality and institutional preference plays an imperative role in response evaluation.
Early response assessment
At ERA, more satisfactory response was observed in the PET-CT based assessment (151/186, 81.2%) as compared to CECT (126/196, 64.3%) (p value<0.001).
While analysing the significance of modality of scans at ERA, we also looked at its impact on patients with non-bulky disease. These were the patients who by the virtue of their disease did not merit RT unless their response was suboptimal. For the PET-CT arm 96/114 non-bulky patients achieved a satisfactory response (84.2%) as compared to 61/89 patients in the CECT arm (68.5%) with a p value=0.008. This showed that, by intention to treat analysis, children who undergo PET-CT at reassessment are significantly less likely to receive RT as compared to those who undergo CECT. RT was given (significantly) more in CECT arm, 98/196 (50%) as compared to 72/186 (38.7%) PET-CT patients (p value=0.017).