Routine Imaging Identifies a Group of Patients with More Favorable Aggressive NHL at Relapse: A Retrospective Study of a Uniformly Treated Patient Population.
Authors: Liedtke Michaela , Moskowitz Craig H. , Hamlin Paul A. , Zelenetz Andrew D. 
Published: October 2019

INTRODUCTION: Forty to sixty percent of patients (pts) with aggressive non-Hodgkin’s lymphoma relapse after achieving a complete remission with initial therapy. Approximately one third of those pts can still be cured with second line therapy. We have previously reported that the age-adjusted international prognostic index (sAAIPI) determined at the start of second-line chemotherapy predicts outcome (Hamlin, Blood102:19892003) in DLBCL, suggesting that early detection of recurrent disease might be important in determining outcome. Routine follow-up imaging is common practice in most centers using a combination of CXR, CT scans and functional imaging evaluation with gallium or FDG PET. During the first two years, these studies are performed every 3 to 6 months, then less frequently thereafter (8–12 months). Routine imaging is a source of pt anxiety as well as a significant cost in the post treatment setting and limited studies are available to evaluate its utility. We sought to define the role of routine imaging in a well defined group of pts with relapsed NHL.

METHODS: We retrospectively identified 118 pts with relapsed aggressive non-Hodgkin’s lymphoma treated on sequential trials with ICE-based second-line chemotherapy between 1993 and 2000. Nineteen pts were excluded because we did not have complete information regarding the imaging studies.

RESULTS: The median age was 49 (22–71) years and the median duration of follow-up for surviving pts is 5 years. Patients underwent a median of 3 to 4 imaging studies before recurrence was diagnosed. Of the 99 pts, 20 relapses (20.2%) were detected by routine imaging at a time when the pts had no symptoms and an unremarkable physical exam (group 1). In contrast, 79 pts underwent unscheduled imaging to evaluate abnormal findings on exam or reported symptoms at the time of relapse (group 2); of these, recurrent disease was detected by imaging in 66 cases. 74 pts (74.8%) self-reported symptoms or new physical findings and five pts (5.1%) were found to have abnormal findings on routine exam. The most common patient-reported symptoms leading to the diagnosis of recurrent disease were: lymphadenopathy (36.4%) and pain (34.3%), followed by B-symptoms (4%).

The breakdown of the sAAIPI for group 1 pts was low risk (sAAIPI=0/1) 70% and high risk (sAAIPI=2/3) 30%, compared to group 2 in which the sAAIPI was low risk 39% and high risk 61% (p=0.014 by χ2). Pts were 3.6 times (95% CI:1.3–10.4) more likely to have high risk disease if relapse was diagnosed by symptoms or physical findings (group 2) compared with routine imaging (group 1). Median overall survival at 5 years for group 1 versus group 2 was 52% and 43% respectively (p=0.28).

CONCLUSIONS: Routine imaging has a limited impact on the detection of recurrent disease; however, it does identify a population of pts with a more favorable outcome based on the sAAIPI. Additional prospective imaging studies will need to be conducted to determine if the relapse identified by routine imaging represents early detection of disease at a more favorable timepoint or identification of a group of patients with a more favorable underlying biology.