Impact of imaging modality on clinical outcome in Hodgkin lymphoma in a resource constraint setting

Treatment of Hodgkin lymphoma (HL) has evolved with risk-stratified therapy based on PET-CT scan at multiple timepoints. In a resource constraint setting even a single PET-CT scan ($400) is inaccessible to many patients, who are re-assessed with only clinical examination, abdominal ultrasonogram and/or x-ray (C/U/X) ($10). To compare clinical outcomes in patients with HL who have had suboptimal imaging after completion of chemotherapy for HL, with those who had a CT or PET-CT, 283 patients were treated for HL from 2011 to 2015, and 268 patients completed six cycles of ABVD therapy with response assessment modality by CT/PET in 185 patients and by C/U/X in 83. There was no difference in the number of patients with advanced (64·1% vs. 61·1%; P = 0·650) or bulk disease (8·1% vs. 7·2%). A significantly higher number of patients in the CT/PET group received IFRT (25·4% vs. 7·7%; P = 0·0005). The three-year overall survival and progression-free survival of all treated patients (n = 283) was 83·5 ± 2·3% and 76·7 ± 2·6% respectively median follow-up 36 months (range 2–93)]. At three years, the overall relapse-free survival (RFS) was 80·1 ± 2·5%, with RFS of 77 ± 3·2% vs. 85 ± 4·0% in the CT/PET group and C/U/X groups respectively (P = 0·349). There was no difference in RFS between the two groups either in early-stage disease (88·1 ± 4·6% vs. 91·8 ± 5·6%; P = 0·671) or late-stage disease (73·9 ± 4·8% vs. 81·3 ± 6·0%; P = 0·747). The only significant factor adversely affecting RFS was advanced disease (P = 0·004). Factors not affecting RFS were age (P = 0·763), sex (P = 0·925), bulk disease (P = 0·889) and imaging modality (P = 0·352). There was no difference in relapse rates between patients who had suboptimal imaging compared to those who had a PET/CT. It is possible to use these basic imaging modalities when resources are a constraint, with acceptable outcomes.