CT abdomen only for active surveillance in patients with stage I germ cell tumor (GCT): A multi-institutional study.

Abstract

410 Background: Active surveillance (AS) for stage I germ cell tumor (GCT) typically includes periodic imaging of chest, abdomen and pelvis. Efforts to modify the surveillance protocols aim to minimize radiation exposure in this young patient population. We report our multi-institutional effort to assess the effect of omitting CT pelvis. Methods: Using data from three major referral centers for GCT (University of Southern California, University of Toronto, and University of Chicago), all patients with stage I GCT who experienced recurrence on AS were selected. Clinicodemographic information including recurrence pattern (tumor marker (TM), imaging, physical exam (PE), or a combination of these) were collected. Bifurcation of the common iliac arteries was defined as the anatomic landmark between CT abdomen and pelvis. The location of recurrent nodal disease was determined accordingly. Results: A total of 270 patients were included. 122(45%) patients had non-seminomatous GCT (NSGCT). 17(6%) patients had history of cryptorchidism and 38 (14%) had history of scrotal/inguinal surgery. The median time to recurrence for seminoma and NSGCT was 16 months (IQR 8–27) and 6 months (IQR 4–13), respectively. The most common method for detecting recurrence was imaging-only (49%) followed by combination of TM and imaging (43%). A total of 43/270(16%) patients had pelvic/inguinal nodal recurrence (PNR). Prior hernia repair was significantly higher in patients with pelvic/inguinal nodal disease compared to their counterparts (19%vs2.5%;p=0.01). PNR was detectable only by imaging in 16/270(6%) patients. However, in 11/16(69%) patients, PNRe was either visible on CT abdomen cuts or there was simultaneous retroperitoneal recurrence. Overall, only 5/270(1.8%) patients (4 seminoma, 1 NSGCT) had PNR only detectable on CT pelvis. Conclusions: CT abdomen only, chest imaging, TM and PE detect majority of recurrences in stage I GCT and CT pelvis could be safely omitted during AS. Future modification in AS protocols of stage I GCT may be warranted.[Table: see text]