Background: With concerns of long-term complications due to radiotherapy (RT), recent studies have evaluated ABVD alone in patients (pts) with bulky classic Hodgkin lymphoma (cHL) with an end of treatment (EOT) PET-negative (neg) scan. However, variable definitions of bulky disease are used, and long-term follow-up remains limited. Since 2005, advanced stage (stage 2B/3/4, bulky (≥10cm) stage 1/2) cHL pts in British Columbia (BC) have been managed with PET-guided consolidative RT.
Methods: The BC Cancer Lymphoid Cancer Database was screened to identify all pts >16 years (y) with bulky (≥10cm) cHL treated with 6 cycles of ABVD chemotherapy. Pts with progressive disease on interim scan or at EOT were excluded. Pts with an EOT PET-positive (pos) scan received consolidative RT. PET scans assessed by the IHP criteria were re-reviewed to assign a Deauville (D) score (PET-neg=D1-3, DX; PET-pos=D4-5). Freedom from treatment failure (FFTF) was measured from diagnosis to relapse/ progression of HL, or death due to HL or treatment toxicity.
Results: From 2005-2020, 215 patients (115M, 100F) were identified. Median age was 29 years (y) (17-72y), median mass size was 11cm (10-21cm), 94% had bulky mediastinal mass, and 2%, 65%, 8%, and 25% had stage 1, 2, 3 and 4 disease, respectively. At EOT, 176 (82%) had a PET-neg scan (none received RT), and 39 (18%) had a PET-pos scan (34 received RT to residual mass; 5 were observed: false pos n=3, refused n=1, not radioencompassable n=1). With a median follow-up of 6.75y (0.8-15.75y), pts with a PET-neg scan had 5y FFTF of 94% (stage 1/2-94%, stage 3/4-96%) vs 65% with a PET-pos scan (p<0.001). Overall survival (OS) was similar in PET-neg and pos (97% vs 90%, p=0.191). The 5y FFTF was similar by D score in PET-neg cases (DX-100%; D1-90.5%; D2-97%; D3-100%, p=0.213) but inferior in D4 (58%) and D5 (42%) (p<0.001). The 5y OS was similar between PET-neg and D4 (DX-93%, D1-97%, D2-100%, D3-100%, D4-94%), but inferior in D5 cases, with 5y OS 60% (p=0.015). There were 23 relapses: 10 PET-neg (7 in what would have been the RT field (residual mass), 3 inside and outside field); 13 PET-pos (5 in field, 8 included sites outside the RT field).
Conclusion: With a median follow-up of almost 7y, bulky cHL with an EOT PET-neg scan have excellent outcomes, regardless of initial stage. A large proportion of D4 PET-pos cases are salvaged with RT and maintain an excellent OS. Both FFTF and OS are inferior in those with an EOT D5 scan.
Jowon Laura Kim, Diego Villa, R. Petter Tonseth, Alina S. Gerrie, Don Wilson, Francois Benard, Chris Venner, Brian Skinnider, Pedro Farinha, Graham W. Slack, David W. Scott, Joseph M. Connors, Laurie H. Sehn, Kerry J. Savage