Some Necessary Additional Points
The authors provided an excellent review of the options for using positron emission tomography in combination with computed tomography (PET/CT) (1).
The authors wrote: “The HD15 study conducted by the German Hodgkin Study Group (GHSG) investigated whether radiotherapy could be restricted to patients with PET-positive residual findings following the completion of chemotherapy. Even without subsequent radiotherapy, patients with PET-negative residual lymphomas had a similar prognosis to patients that achieved complete remission on CT.”
Some additional comments are needed in this context. The HD15 Study (2) investigated patients with advanced cancers, whose prognosis is notably worse and whose default treatment is six to eight courses of polychemotherapy (BEACOPP). The patients who still have PET-positive residual findings after completing this treatment have a significantly worse progression-free survival period compared with PET-negative patients (86.2% versus 92.6% after four years), which justifies the use of radiotherapy.
For all other stages, the standard therapy is consolidating radiotherapy after chemotherapy, which, in accordance with the results of the HD10 and HD11 studies of the GHSG, is administered to the most restricted irradiation field and at the lowest possible dose without endangering the success of the treatment. Studies that waived radiotherapy in favor of intensified chemotherapy—such as the UK RAPID trial (3, 4)—observed substantially more disease progression after such experimental methods, which prompted early termination of the respective study arms.
The most recent studies of the GSHG (HD16–17) evaluated again the importance of PET in the early stages for the purpose of treatment stratification, by not providing for subsequent radiotherapy in the respective experimental arm in PET negative findings after completed chemotherapy (2*ABVD or 2*BEACOPP escalated/2*ABVD). Forgoing radiotherapy is admissible only in clinical trials or at advanced stages (in analogy to the HD15 Study).
Dr. med. Michael Oertel
Prof. Dr. med. Hans-Theodor Eich
Klinik für Strahlentherapie –
Radioonkologie, Universitätsklinikum Münster
Conflict of interest statement
The authors declare that no conflict of interest exists.
|1.||Derlin T, Grünwald V, Steinbach J, Wester HJ, Ross TL: Molecular imaging in oncology using positron emission tomography (PET). Dtsch Arztebl Int 2018; 115: 175–81 VOLLTEXT|
|2.||Engert A, Haverkamp H, Kobe C, et al.: Reduced-intensity chemotherapy and PET-guided radiotherapy in patients with advanced stage Hodgkin‘s lymphoma (HD15 trial): a randomised, open-label, phase 3 non-inferiority trial. Lancet 2012; 379: 1791–9 CrossRef|
|3.||Radford J, Illidge T, Counsell N, et al.: Results of a trial of PET-directed therapy for early-stage Hodgkin‘s lymphoma. N Engl J Med 2015; 372: 1598–607 CrossRef MEDLINE|
|4.||Raemaekers JM, André MP, Federico M, et al.:Omitting radiotherapy in early positron emission tomography-negative stage I/II Hodgkin lymphoma is associated with an increased risk of early relapse: clinical results of the preplanned interim analysis of the randomized EORTC/LYSA/FIL H10 trial. J Clin Oncol 2014; 32: 1188–94 CrossRef MEDLINE|