Hodgkin Lymphoma In First Remission: Routine PET/CT Imaging Is Not Superior To Clinical Follow-Up For Patients Without Residual Mass: Results Of a Bi-National Study Including 368 Patients

The optimal method of surveillance for patients with Hodgkin lymphoma (HL) in remission after chemotherapy or combined chemo- and radiation therapy remains debatable. Some trials have demonstrated high sensitivity of PET/CT in detecting disease progression; however, nowadays this approach is not recommended for routine surveillance.

The present study, conducted in two Israeli (N=291) and one New Zealand academic centers (N=77), compared a historical cohort of patients, followed-up with routine imaging every 6 months during the first 2 years after achieving remission and once in the third year, in whom additional dedicated PET/CT or CT scans were performed due to disease symptoms or physical findings (Group I), to a group of patients without residual masses who underwent clinically-based surveillance with dedicated imaging using CT or PET/CT only in case of suspected relapse (Group II).

Group I included 305 patients with a median age of 30 years. Thirty five percent of patients had early stage and 65% advanced stage disease. The chemotherapy regimens used were tailored BEACOPP (up to 6 cycles of escalated or standard BEACOPP depending on risk factors and interim PET/CT) and ABVD in 35% and 65% of patients, respectively. Radiation therapy was additionally given to 34% of patients. Group II included 63 patients with a median age of 34 years, 40% of whom had early stage and 60% advanced stage HL. Two percent of patients from this group received escalated BEACOPP and 98% - ABVD. Radiation therapy was given to 54% of patients. The 5-year overall survival (OS) was 94% and the median time to relapse was 8.6 months in both study groups (Table 1). Relapse rates in Groups I and II were 9% (N=28) and 13% (N=8), respectively. The 5-year progression free survival was 92% and 86%, respectively (p=NS). It is noteworthy that the number of relapses and the time to relapse diagnosis did not differ between the cohorts. However in Group II, 5/8 (63%) relapses within the first three years of surveillance were in the advanced disease stage patients, whereas in Group I the proportion was 12/25 (48%). During the 3-year follow-up, in Group I, 1188 scans (3.9/patient) were performed among 305 patients, of which 1084 scans were performed routinely in 302 patients, and 67 patients underwent 104 dedicated studies. In this group, 17 patients were diagnosed based on routine imaging and 8 patients due to clinical signs and symptoms. In contrast, 31 patients from Group II had 38 imaging studies performed based on clinical suspicion of relapse, and 8 relapses were diagnosed. Thus, in Groups I and II, 47.5 and 4.7 scans, respectively, were performed per single detected relapse.

The present study has demonstrated no benefit in either relapse rate, progression-free survival (PFS) or OS in HL patients followed by routine imaging compared to clinical surveillance. The cost of the former approach was 10 times higher. While it is likely that patients at high risk of HL relapse, e.g., those with positive interim PET/CT or a residual mass, may need a closer follow-up, the majority of patients does not benefit from routine imaging during follow-up and could be followed solely with regular clinic visits.

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No relevant conflicts of interest to declare.