Comprehensive genomic profiling (CGP) in patients with relapsed/refractory germ cell tumors (GCT).

388 Background: Understanding the genetic alterations in patients with relapsed/refractory GCT (rrGCT) could delineate the pathogenesis of cisplatin resistance. Our study uses CGP to characterize genomic alterations (GA) in refractory GCT and correlate with clinical outcomes. Methods: 432 patients with rrGCT were seen at Indiana University between Jan 2016 to Sep 2019 of whom 52 patients underwent CGP using a hybrid-capture based commercial assay to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and reported as mutations/Mb and microsatellite instability (MSI) was determined on 114 loci. PDL1 expression was determined by IHC (DAKO 22C3 antibody). Results: All patients relapsed after first-line cisplatin-based combination chemotherapy. Median age at diagnosis was 33 (range 15-68). Primary site of GCT was testicular in 85% and mediastinum in 8%. 6 patients had pure seminoma and 46 had non-seminoma. Platinum refractory disease, defined as serologic or radiographic progression within 4 weeks of first-line chemotherapy comprised 23% of patients. The primary tumor was used for sequencing in 6 cases (12%) and non-primary tumor metastatic site (lymph node, lung, liver, brain, omentum) in 46 cases (88%). The most common GA in the entire cohort were FGF6 (27%), FGF23 (27%), KDM5A (27%), CCND2 (27%), KRAS (18%), TP53 (14%), KIT (8%), APC (8%), ZNF217 (6%), MUTYH (6%), AURKA (6%), NRAS (6%), EGFR (6%), CTNNB1 (6%), GNAS (6%). Most common alterations for testicular primary tumors were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, KIT. For non-testicular primary GCT, most common GA were APC, TP53, EGFR. Most common GA for non-seminoma were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, APC. Most common GA for pure seminoma was KIT. Potentially targetable genomic alterations were found in 17 patients (33%). 10 of 17 patients (59%) tested had PDL1 score ≥1% and 3 patients had PDL1 ≥50%. Median TMB was 3.5 mutations/MB. There were 4 patients (8%) with TMB ≥ 10 mutations/Mb and 2 patients (4%) with TMB ≥ 20 mutations/Mb. 1 of 48 patients (2%) evaluated for MSI had MSI-High status. Isochromosome 12p was detected in the majority of samples where it was tested. Outcomes with GA-directed therapy will be presented at the conference. Conclusions: CGP can reveal potential therapeutic targets in patients with rrGCT including EGFR, ERBB3, KIT, and MET. Consistent with reported clinical trials in rrGCT, biomarkers predicting response to immune checkpoint blockade are uncommon with most patients having low TMB, absence of MSI-H status, and low expression of PDL1.

Testicular Cancer - An Unexpected Course of the Disease

There are two major histologic types of testicular cancer: pure seminoma and nonseminomatous germ cell tumours which include embryonic carcinoma, choriocarcinoma, yolc sac tumours and teratomas. Rarely, in 2% of cases, teratomas may contain elements of somatic cancer, such as sarcoma or adenocarcinoma and it is then referred to as a ''teratoma with somatic type malignancy''. The histology of somatic malignant elements most commonly includes adenocarcinoma and various types of sarcomas; however, so far as the primitive neuroectodermal tumors (PNETs) are concerned the experience is quite limited. Here we report an unusual case of a testicular seminoma that relapsed 6 months after surgery as a teratoma with somatic neuroendocrine differentiation situated in retroperitoneal lymph nodes.

Primary Mediastinal Germ Cell Tumors—The University of Western Ontario Experience

Extragonadal germ cell tumors account for 2–5.7% of germ cell tumors (GCTs). Of these, primary mediastinal GCTs (PMGCTs) are responsible for 16–36% of cases. Given the rarity of these tumors, specific treatment strategies have not been well defined. We report our experience in treating these complex patients. In total, 318 men treated at our institution with chemotherapy for GCTs between 1980 and 2016 were reviewed. PMGCT was defined as clinically diagnosed mediastinal GCT with no evidence of testicular GCT (physical exam/ultrasound). We identified nine patients diagnosed with PMGCT. All patients presented with an anterior mediastinal mass and no gonadal lesion; four patients also had metastatic disease. Median age at diagnosis was 30 years (range, 14–56) and median mass size at diagnosis was 9 cm (range, 3.4–19). Eight patients had non-seminoma and one had pure seminoma. All patients received cisplatin-based chemotherapy initially. Surgical resection was performed in four patients; three patients had a complete resection and one patient was found to have an unresectable tumor. At a median follow-up of 2 years (range, 3 months–28 years) six patients had progressed. Progression-free survival was short with a median of 4.1 months from diagnosis (range 1.5–122.2 months). Five patients died at a median of 4.4 months from diagnosis. One and 5-year overall survivals were 50% and 38%, respectively. PMGCT are rare and aggressive. Our real-life Canadian experience is consistent with current literature suggesting that non-seminoma PMGCT has a poor prognosis despite prompt cisplatin-based chemotherapy followed by aggressive thoracic surgery.

Unusual case of classic testicular seminoma in a 90-year-old patient: a case report

Background Seminoma is the most common subtype of testicular cancer and occurs most commonly in patients aged 30–49 years, but decreases to a very low level in men in their 60s or older. Case presentation A 90-year-old Syrian man with a 6-year history of an increase in size of his right scrotum, presented to the urological clinic and, on clinical examination, the findings suggested testicular tumor. After orchiectomy and histology results based on microscopic and immunohistochemical examinations, a pure seminoma was diagnosed, so we describe in this case report the second-oldest patient with classical seminoma in the medical literature. Conclusion This case report has been written to focus on the probability of any type of testicular tumor occurring at any age or decade; urologists should consider seminoma as a differential diagnosis with any testicular swelling even in elderly patients.

Comprehensive genomic profiling (CGP) in patients with relapsed/refractory germ cell tumors (GCT).

e17053 Background: Understanding the genetic alterations in patients with relapsed/refractory GCT (rrGCT) could delineate the pathogenesis of cisplatin resistance. Our study uses CGP to characterize genomic alterations (GA) in refractory GCT and correlate with clinical outcomes. Methods: 432 patients with rrGCT were seen at Indiana University between Jan 2016 to Sep 2019 of whom 52 patients underwent CGP using a hybrid-capture based commercial assay to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and reported as mutations/Mb and microsatellite instability (MSI) was determined on 114 loci. PDL1 expression was determined by IHC (DAKO 22C3 antibody). Results: All patients relapsed after first-line cisplatin-based combination chemotherapy. Median age at diagnosis was 33 (range 15-68). Primary site of GCT was testicular in 85% and mediastinum in 8%. 6 patients had pure seminoma and 46 had non-seminoma. Platinum refractory disease, defined as serologic or radiographic progression within 4 weeks of first-line chemotherapy comprised 23% of patients. The primary tumor was used for sequencing in 6 cases (12%) and non-primary tumor metastatic site (lymph node, lung, liver, brain, omentum) in 46 cases (88%). The most common GA in the entire cohort were FGF6 (27%), FGF23 (27%), KDM5A (27%), CCND2 (27%), KRAS (18%), TP53 (14%), KIT (8%), APC (8%), ZNF217 (6%), MUTYH (6%), AURKA (6%), NRAS (6%), EGFR (6%), CTNNB1 (6%), GNAS (6%). Most common alterations for testicular primary tumors were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, KIT. For non-testicular primary GCT, most common GA were APC, TP53, EGFR. Most common GA for non-seminoma were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, APC. Most common GA for pure seminoma was KIT. Potentially targetable genomic alterations were found in 17 patients (33%). 10 of 17 patients (59%) tested had PDL1 score ≥1% and 3 patients had PDL1 ≥50%. Median TMB was 3.5 mutations/MB. There were 4 patients (8%) with TMB ≥ 10 mutations/Mb and 2 patients (4%) with TMB ≥ 20 mutations/Mb. 1 of 48 patients (2%) evaluated for MSI had MSI-High status. Isochromosome 12p was detected in the majority of samples where it was tested. Outcomes with GA-directed therapy will be presented at the conference. Conclusions: CGP can reveal potential therapeutic targets in patients with rrGCT including EGFR, ERBB3, KIT, and MET. Consistent with reported clinical trials in rrGCT, biomarkers predicting response to immune checkpoint blockade are uncommon with most patients having low TMB, absence of MSI-H status, and low expression of PDL1.

Semi-ResMass Study: Residual masses after salvage chemotherapy in men with pure seminoma—A multicenter retrospective analysis.

420 Background: Only scarce data exist on the management of residual masses in men who have received two lines of chemotherapy for advanced seminoma. Due to the lack of data, the role of PET scanning, surgery and other additional treatments is controversial in these men. Methods: Data from men with pure seminoma and residual masses after salvage chemotherapy were retrospectively collected from 10 high-volume centers in 3 European countries. We analyzed the clinical management of residual masses (imaging, surgery, pathological data, and additional treatment modalities) and long-term outcomes. Residual mass was defined as a lesion of ≥1 cm after two lines of platin-based chemotherapy. Results: To date, data from 48 patients (pts) with non-progressing residual masses after second line (salvage) chemotherapy have been collected and are included in this analysis. Median age at diagnosis was 36 years (range 31; 42). A post-chemotherapy PET-FDG was performed in 32 (67%) pts. Surgery was performed in 20/48 (41%) pts irrespectively of FDG uptake (no, n=8; yes, n=5). Complete necrosis was found in 16 (80%), viable seminoma in 3 (15%), and teratoma in 1 pt, respectively. All pts with a negative PET (PET-) who underwent surgery (8/8) had complete necrosis. 5/11 pts with a positive PET (PET+) underwent surgery: 3 had a complete necrosis while 2 had viable seminoma. Among those with a PET+, 3 pts (28%) experienced either viable seminoma in residual masses or a subsequent relapse. The absence of FDG uptake correlated with absence of viable cancer (p=0.04). A second relapse occurred in 5/48 pts (10%). Only 2/20 pts who had residual masses resected post 1st salvage chemotherapy subsequently relapsed (one had viable seminoma in the residuals). At a median follow up of 4 years (IC95% [3.5-5.5]), 41/48 pts (87%) were alive. 7/48 patients died of cancer progression. Conclusions: Most men with residual masses after 1st salvage chemotherapy for advanced seminoma may achieve a cure. Pending validation with more pts in this rare situation, PET-FDG may help guide who should be selected for post-chemotherapy resection. Updated results will be presented at the congress.

Metastatic seminoma with isolated gastric metastases: a case report

Gastric metastases are a rare occurrence in patients with malignancy. In case reports of these arising from germ cell tumours, the majority were non-seminomatous germ cell tumours and had evidence of retroperitoneal involvement. We present a unique case of a 67-year-old man with metastatic testicular pure seminoma. He presented with dyspepsia and investigation found isolated metastases to the gastric mucosa and sub-mucosa from a right testicular primary. No lymph node involvement was identified. The patient was managed with curative intent with total gastrectomy and inguinal orchidectomy. To date, there is no evidence of disease recurrence.

Playing the long surveillance ball game: Metachronous testicular tumor developing after treatment and remission of extragonadal germ cell tumor

A 32-year-old man with vague abdominal pain was found to have enlarged para-aortic and mediastinal lymph nodes on computed tomography. He was diagnosed with retroperitoneal mixed germ cell tumor as confirmed on percutaneous biopsy. At the time of diagnosis, lactic dehydrogenase, human beta-chorionic gonadotropin, and alpha-fetoprotein were elevated. He completed four cycles of platinum-based chemotherapy with excellent response and no clinical disease progression. Three years later, he presented to the Urology clinic with a right testicular mass. His tumor markers remained negative. He was taken for a right radical orchiectomy with the pathology resulting in pure seminoma (pT1Nx).