Limited utility of routine surveillance imaging for classical Hodgkin lymphoma patients in first complete remission.

BACKGROUND: The objective of this study was to compare the outcomes of patients with classical Hodgkin lymphoma (cHL) who achieved complete remission with frontline therapy and then underwent either clinical surveillance or routine surveillance imaging. METHODS: In total, 241 patients who were newly diagnosed with cHL between January 2000 and December 2010 at 3 participating tertiary care centers and achieved complete remission after first-line therapy were retrospectively analyzed. Of these, there were 174 patients in the routine surveillance imaging group and 67 patients in the clinical surveillance group, based on the intended mode of surveillance. In the routine surveillance imaging group, the intended plan of surveillance included computed tomography and/or positron emission tomography scans; whereas, in the clinical surveillance group, the intended plan of surveillance was clinical examination and laboratory studies, and scans were obtained only to evaluate concerning signs or symptoms. Baseline patient characteristics, prognostic features, treatment records, and outcomes were collected. The primary objective was to compare overall survival for patients in both groups. For secondary objectives, we compared the success of second-line therapy and estimated the costs of imaging for each group. RESULTS: After 5 years of follow-up, the overall survival rate was 97% (95% confidence interval, 92%-99%) in the routine surveillance imaging group and 96% (95% confidence interval, 87%-99%) in the clinical surveillance group (P = .41). There were few relapses in each group, and all patients who relapsed in both groups achieved complete remission with second-line therapy. The charges associated with routine surveillance imaging were significantly higher than those for the clinical surveillance strategy, with no apparent clinical benefit. CONCLUSIONS: Clinical surveillance was not inferior to routine surveillance imaging in patients with cHL who achieved complete remission with frontline therapy. Routine surveillance imaging was associated with significantly increased estimated imaging charges.

Assessment of cellular proliferation in tumors by PET using 18F-ISO-1.

UNLABELLED: This first study in humans was designed to evaluate the safety and dosimetry of a cellular proliferative marker, N-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-2-(2-(18)F-fluoroethoxy)-5-methylbenzamide ((18)F-ISO-1), and evaluate the feasibility of imaging tumor proliferation by PET in patients with newly diagnosed malignant neoplasms. METHODS: Patients with biopsy-proven lymphoma, breast cancer, or head and neck cancer underwent (18)F-ISO-1 PET. Tumor (18)F-ISO-1 uptake was assessed semiquantitatively by maximum standardized uptake value, ratios of tumor to normal tissue and tumor to muscle, and relative distribution volume ratio. The PET results were correlated with tumor Ki-67 and mitotic index, from in vitro assays of the tumor tissue. The biodistribution of (18)F-ISO-1 and human dosimetry were evaluated. RESULTS: Thirty patients with primary breast cancer (n = 13), head and neck cancer (n = 10), and lymphoma (n = 7) were evaluated. In the entire group, tumor maximum standardized uptake value and tumor-to-muscle ratio correlated significantly with Ki-67 (τ = 0.27, P = 0.04, and τ = 0.38, P = 0.003, respectively), but no significant correlation was observed between Ki-67 and tumor-to-normal-tissue ratio (τ = 0.07, P = 0.56) or distribution volume ratio (τ = 0.26, P = 0.14). On the basis of whole-body PET data, the gallbladder is the dose-limiting organ, with an average radiation dose of 0.091 mGy/MBq. The whole-body and effective doses were 0.012 mGy/MBq and 0.016 mSv/MBq, respectively. No adverse effects of (18)F-ISO-1 were encountered. CONCLUSION: The presence of a significant correlation between (18)F-ISO-1 and Ki-67 makes this agent promising for evaluation of the proliferative status of solid tumors. The relatively small absorbed doses to normal organs allow for the safe administration of up to 550 MBq, which is sufficient for PET imaging in clinical trials.

Role of routine imaging in lymphoma.

Patients with lymphoma commonly undergo routine imaging studies after treatment completion, yet the appropriate interval, duration, and modality of follow-up, and the overall efficacy of various approaches is unclear. Existing guidelines are vague and not evidence-based, and consequently, practice patterns are varied. Most surveillance approaches in lymphoma have focused on early detection of recurrence, with the hope of prolonged survival and potential cure. Concerns regarding the prognostic value of frequent scanning, cost-effectiveness, and long-term risks associated with prolonged radiation exposure have led many to question the role of routine imaging in this setting. Given the multiple lymphoma subtypes and the clinical heterogeneity of these entities, a single approach to follow-up may not be reasonable. Much of the available literature focuses on Hodgkin lymphoma, and may not be generalizable. Retrospective series show that most relapses are detected by signs and symptoms regardless of the imaging schedule. In summary, clinicians are still left with "expert opinion" to guide them. This article examines the available data outlining the role of surveillance imaging in lymphoma.