Surveillance of postchemotherapy subcentimeter residual retroperitoneal mass in metastatic nonseminomatous germ cell tumor: Does how you measure matter?

BACKGROUND

Approximately 70% to 80% of patients with metastatic nonseminomatous germ cell tumor (NSGCT) treated with cisplatin-based chemotherapy achieve a complete response, defined as normalization of serum tumor markers and either no residual retroperitoneal mass (RRM) or an RRM <1.0 cm. While there is universal agreement that patients with an RRM ≥1.0 cm should undergo retroperitoneal lymph node dissection (RPLND), many institutions including ours recommend surveillance for patients who achieve a complete response. However, studies have not defined which axis of the RRM should be considered when deciding between surveillance and RPLND.

PATIENTS AND METHODS

Good-risk metastatic NSGCT patients treated with cisplatin-based chemotherapy who achieved a complete response and underwent surveillance were identified using our institution's electronic medical records. A post-hoc review was performed by a blinded radiologist. The RRM dimensions in the transaxial short axis (TSA), transaxial long axis (TLA), and craniocaudal axis (CCA) were recorded. Differences in the frequency of recurrence between groups with an RRM <1.0 cm and ≥1.0 cm in the TLA and CCA were assessed using the Fisher exact test.

RESULTS

Thirty-nine patients who met study criteria were included. At a median follow-up of 63.8 months, 2 patients (5.1%) recurred. Both were successfully treated with salvage chemotherapy and RPLND. Thirteen (33%) and 27 (69%) patients had an RRM ≥1.0 cm in the TLA and CCA, respectively. There were no statistically significant differences in the risk of recurrence between patients with an RRM <1.0 cm and ≥1.0 cm in the TLA (P = 0.54) or CCA (P = 0.53).

CONCLUSIONS

Surveillance is an effective strategy in good-risk NSGCT patients with a postchemotherapy RRM <1.0 cm in the TSA. Our study suggests referencing the TSA and not the TLA or CCA may avoid unnecessary postchemotherapy RPLNDs.