NCCN: PET-Guided Therapy for Hodgkin Lymphoma Moving Into Clinical Practice
Interim positron emission tomography (PET) scan is being used to guide risk-adapted therapy in patients with early-stage and advanced-stage Hodgkin lymphoma for clinical research at academic centers, and experts predict that this will become standard of care in clinical practice. At the NCCN 8th Annual Congress on Hematologic Malignancies, Craig Moskowitz, MD, of Memorial Sloan-Kettering Cancer (MSKCC) in New York, updated attendees on use of PET-guided therapy in Hodgkin lymphoma.
An interim PET scan can be used to determine whether to escalate or deescalate therapy, based on whether a scan is positive or negative. A score of 1 to 5 based on Deauville criteria categorizes patients as PET-negative or PET-positive. When dose intensification is planned, a Deauville score of 1 to 3 is considered PET-negative and a score of 4 to 5 is considered PET-positive; those who are PET-negative will not require more intensive therapy. However, if dose deescalation is planned, scores of 1 to 2 are considered PET negative and 3 to 5 PET-positive. These shifts in score categories were designed to avoid overtreatment and undertreatment, Dr. Moskowitz explained.
Studies Confirm Predictive Value of Interim PET Scan
Several studies have shown that an interim PET scan is prognostic in early-stage Hodgkin lymphoma. According to the results of the RAPID study, patients with early-stage disease who are PET-negative on an interim scan can forego radiation. In this randomized trial, 602 treatment-naive patients with stage IA or IIA Hodgkin lymphoma with no B symptoms or bulky disease were treated with three cycles of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy and then assessed by an interim PET scan. Those who were PET-negative (Deauville score 1–2) were randomly assigned to receive either radiation or no further treatment. PET-positive patients (Deauville score 3–5) received another cycle of ABVD plus radiation.
Three-year progression-free survival was 97% for those who received radiation therapy and 91% for those who did not. Results have not yet been published, and follow-up was relatively short, but suggest that an interim PET scan can identify a population of patients with stage IA and IIA Hodgkin lymphoma who would have an excellent outcome with chemotherapy alone.
In advanced-stage Hodgkin lymphoma, data suggest that intensification of therapy in patients with a positive interim PET scan can improve progression-free survival. More than 90% of patients with a negative PET scan in these trials had good outcomes, compared with about one-third of those with a positive PET scan.
An international study confirmed the predictive value of an interim PET scan in advanced Hodgkin lymphoma. In this trial, 3-year progression-free survival was 95% in those with a negative PET scan vs 28% in those with a positive PET scan.
Other studies of PET-guided therapy in patients with stage III and IV disease have shown longer progression-free survival in patients managed with this strategy.
Interim PET scan is being used at MSKCC and other centers to determine transplant eligibility in relapsed/refractory disease, Dr. Moskowitz continued. There is no standard second-line chemotherapy regimen, but options include ICE (ifosfamide, carboplatin, and etoposide), DHAP (dexamethasone, high-dose cytarabine, and cisplatin), IGEV (ifosfamide, gemcitabine, and vinorelbine), and GND (gemcitabine, vinorelbine tartrate, and doxorubicin). Normalization of PET before high-dose chemotherapy and stem cell transplant should be the goal of second-line therapy, Dr. Moskowitz noted.
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