560 Background: The AJCC TNM Staging System for Testicular Cancer (TC) does not set a minimal diameter to define positive lymph nodes (LN) on computed tomography scan. It is common to refer to LN ≥ 1 cm in diameter as positive, even though benign LN in the borderline size of 1-1.5cm are common. Our goal is to describe the outcome of TC patients with borderline size retroperitoneal LN of undetermined significance managed initially with surveillance. Methods: We retrospectively reviewed the medical records of all TC patients treated at our institution during 2006-2016. Demographic, clinical, laboratory, imaging, pathological, treatment and surveillance data were obtained. Results: Of a total of 109 TC patients, 25 patients (22.7%) with borderline size LN were assigned to an active surveillance protocol by our tumor board. Median age at the time of orchiectomy was 37.2 years (IQR, 23.9-40.3). With a median follow-up of 3.9 years (IQR 1.7-6.5), overall survival rate in the group was 100%. Nine of 25 patients (36%) relapsed and were treated within a median of 4.9 months (IQR 2.2-5.5). Median follow-up for 16 patients who did not relapse was 3.4 years (IQR 1.5-5.4). Relapse-free survival was 71% (95% CI 48-85), and 61% (95% CI 38-77) at one and two years, respectively. Orchiectomy pathology included pure seminoma in 18/25 (72%), and a nonseminomatous tumor in 7/25 (28%). Tumor type was not associated with likelihood of relapse (p = 0.66). The median LN diameter at the time of diagnosis was 11 mm (IQR 9-12, mean 10.4). LN diameter was not associated with likelihood of relapse (p = 0.34). Patients who relapsed during follow-up were significantly younger at the time of TC diagnosis than patients who did not relapse (Median age 23.9 years [IQR 19.6-35.2] and 39.2 years [IQR 34.3-47.9] respectively, p = 0.0056). Conclusions: Surveillance alone for TC patients with borderline size LN of undetermined significance at diagnosis is a possible option and may help avoid overtreatment in 60% of these patients.
MP37-06 IS SURVEILLANCE WITHOUT IMMEDIATE TREATMENT AN OPTION FOR NEWLY DIAGNOSED TESTICULAR GERM-CELL CANCER PATIENTS WITH BORDERLINE SIZE RETROPERITONEAL LYMPH NODES ON COMPUTED TOMOGRAPHY SCAN?
