Detection of Relapse in Diffuse Large B-Cell Lymphoma (DLBCL) and Hodgkin’s Lymphoma (HL): Observations and Implications for Post-Remission Radiologic Surveillance.

According to reports in the literature since 1991, 5–30% of relapses of DLBCL and HL were identified by surveillance X-rays and CT scans in the post-remission setting. Recently, a large series of DLBCL relapses were analyzed and suggested that surveillance imaging can identify early relapse in a population of patients with a more favorable outcome (Leidtke et al, Ann Oncol 17: 909–913, 2006). We retrospectively evaluated 40 patients with relapses of HL and DLBCL after complete remission from three referral lymphoma practices between 2000–2006 at the University of Pennsylvania. Relapsed disease was identified after primary therapy or after salvage chemotherapy and high-dose therapy with autologous stem cell transplantation. These relapsed patients underwent post-remission surveillance CT scans with or without PET scans roughly every 3–4 months for the first 1–2 years and every 6–12 months thereafter for at least 5 years. Seventeen patients had DLBCL and 23 had HL. Among relapses, 22 (55%) were detected with surveillance imaging and 18 (45%) were detected by clinical findings (10 complaints of lymphadenopathy, 2 with B-symptoms, 2 with both B-symptoms and lymphadenopathy, 3 with pain, 1 with cough, 1 with physician-detected lymphadenopathy, and none by laboratory results alone). Among the asymptomatic relapses detected by surveillance imaging, PET scanning detected 4 cases of DLBCL (36%) and 3 cases of HL (27%) relapses not identified by other techniques. In summary, compared to prior reports, our series reveals a much higher proportion of relapses detected by surveillance imaging in both diseases. We have adhered to a protocol similar to the NCCN 2006 guidelines; including CT scans as a part of follow-up evaluation. This schedule is more intensive than surveillance reported in prior studies, perhaps accounting for our higher rate of radiographic relapse detection. FDG-PET scans performed in combination with follow-up CT scans detected additional early relapses not seen by CT scanning alone. Prospective screening studies looking at the role of FDG-PET scans combined with CT scans to detect earlier relapses is warranted. Whether early detection of relapse provides a survival advantage should be evaluated in larger prospective studies in both HL and DLBCL.