Predictors of viable germ cell tumor in postchemotherapeutic residual retroperitoneal masses

Testicular Radiomics To Predict Pathology At Time of Postchemotherapy Retroperitoneal Lymph Node Dissection for Nonseminomatous Germ Cell Tumor

INTRODUCTION

Testicular germ cell tumors are the most common malignancy in young adult males. Patients with metastatic disease receive standard of care chemotherapy followed by retroperitoneal lymph node dissection for residual masses >1cm. However, there is a need for better preoperative tools to discern which patients will have persistent disease after chemotherapy given low rates of metastatic germ cell tumor after chemotherapy. The purpose of this study was to use radiomics to predict which patients would have viable germ cell tumor or teratoma after chemotherapy at time of retroperitoneal lymph node dissection.

PATIENTS AND METHODS

Patients with nonseminomatous germ cell tumor undergoing postchemotherapy retroperitoneal lymph node dissection (PC-RPLND) between 2008 and 2019 were queried from our institutional database. Patients were included if prechemotherapy computed tomography (CT) scan and postchemotherapy imaging were available. Semiqualitative and quantitative features of residual masses and nodal regions of interest and radiomic feature extractions were performed by 2 board certified radiologists. Radiomic feature analysis was used to extract first order, shape, and second order statistics from each region of interest. Post-RPLND pathology was compared to the radiomic analysis using multiple t-tests.

RESULTS

45 patients underwent PC-RPLND at our institution, with the majority (28 patients) having stage III disease. 24 (53%) patients had teratoma on RPLND pathology, while 2 (4%) had viable germ cell tumor. After chemotherapy, 78%, 53%, and 33% of patients had cystic regions, fat stranding, and local infiltration present on imaging. After radiomic analysis, first order statistics mean, median, 90th percentile, and root mean squares were significant. Strong correlations were observed between these 4 features;a lower signal was associated with positive pathology at RPND.

CONCLUSIONS

Testicular radiomics is an emerging tool that may help predict persistent disease after chemotherapy.

Clinico-pathological outcomes of post- primary and salvage chemotherapy retroperitoneal lymph node dissection for mixed germ cell tumors, King Hussein Cancer Center experience

OBJECTIVE

We sought to characterize clinical and pathologic outcomes of advanced mixed germ cell tumors after retroperitoneal lymph node dissection for post-chemotherapy residual masses.

MATERIAL AND METHODS

Between January 2006 and November 2015, 56 patients underwent retroperitoneal lymph node dissection (RPLND) for residual masses of greater than 1 cm after receiving either primary chemotherapy or salvage chemotherapy. Retrospective review of the patients' characteristics, clinical, pathological, and treatment outcomes were performed after institutional review board (IRB) and ethics committee approval.

RESULTS

The mean age at diagnosis was 30 years. Ninety percent of the patients received 3-4 cycles of BEP (bleomycin/etoposide/cisplatin) as primary chemotherapy, and 29% of them salvage chemotherapy prior to lymph node dissection. The mean size of the residual masses after chemotherapy was 6 cm. The histological findings were necrosis in 30%, viable tumor in 34% and teratoma in 36% of the retroperitoneal masses. The mean time to relapse after RPLND was 11 months, out of 9 relapses, 6 were in the retroperitoneum, 1 in the lung and 1 in the kidney and 1 in the contralateral testicle.

CONCLUSION

Our results indicated higher incidence of viable germ cell tumor in the retroperitoneal residual masses after primary and salvage chemotherapy when compared with previously reported global incidence rates.