MP81-15 GENETIC BASIS FOR CISPLATIN RESISTANCE IN PATIENTS WITH ADVANCED GERM CELL TUMORS (GCT)

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Source of Funding: None.

MP81-13 ROLE OF 18F-FDG PET/CT IN IDENTIFYING INGUINAL NODAL METASTASIS IN PATIENTS ON SURVEILLANCE AFTER PRIMARY TREATMENT OF PENILE SQUAMOUS CELL CARCINOMA- SINGLE CENTRE PROSPECTIVE STUDY Yuvaraja Thyavihally*, Santosh Waigaonkar, Abhinav Pednekar, Nikhil Dharmadhikari, Harshvardhan Rao, Nikhil Gulavani, Tirathram Kaushik, Mrunal Parab, Kalyan Chakradhar, Amit Patil, Mumbai, India INTRODUCTION AND OBJECTIVES: The extent of lymph node involvement is the most relevant prognostic factor in patients with penile cancer. Management of clinically normal groin nodes (N0 groin) in patients with carcinoma of penis is controversial. Aim of our prospective study was to assess the role of 2-18 fluro-2-deoxy-D-glucose positron emission tomographye computerized tomography (PET-CT) in detecting lymph node metastasis in carcinoma penis with clinically N0 groin during follow up. METHODS: Nineteen patients (38 groins) who had clinically N0 groin and PET scan negative chose close observation of groin after primary treatment of penile cancer. 14 patients were low risk and 5 were high risk for metastasis based on primary tumor histopathology. Follow up protocol included clinical examination, ultrasonographhy of groin every three months and PET scan at 3, 6, 12, 18,24,36,48 months in high risk group and 6, 12, 24,36,48 months in low risk group. Data was collected prospectively and analysed. Follow up period ranged from 12 -48 months (median 22). RESULTS: Six out of 19 patients had PET uptake during follow up. 3 /5 patients of high risk were PET positive. One was positive at 6 months (bilateral, palpable), second was positive at 12 months and 18 months (rt epalpable and left), other at 24 months (unilateral) and in total 5/10 groins of high risk were positive for PET. 3/14 patients with low risk were PET positive. One developed PET uptake at 12 months (Unilateral), other at 12 and 24 months (bilateral), third one at 28 months (unilateral- had palpable disease) and in total 4/28 groins of low risk were positive for PET. All 9 groins which had PET uptake underwent groin node dissection (GND) out of which one was negative for metastasis. One patient had clinical node enlargement but PET was negative. Our test showed sensitivity of 88%, specificity of 96%, positive predictive value of 88% and negative predictive value of 96% in detecting groin node metastasis during follow up. CONCLUSIONS: 18F-FDG-PET/CT is a promising staging tool in assessing the inguinal lymph node involvement of patients with penile carcinoma. Our results show that PET CT is useful in following up groin of patients with ca penis after primary treatment. It is a promising investigation which can identify early metastases. Limitation of this study was less number of patients, not confirming negative groins by histopathology and was based on clinical examination. However further follow up of these patients is required to identify late recurrences. Source of Funding: None

MP81-14 WHEN IS IT APPROPRIATE TO CONSIDER TESTIS-SPARING SURGERY FOR UNILATERAL TESTICULAR TUMORS? Michael Maccini*, Brian Caldwell, Paul Maroni, Nicholas Cost, Aurora, CO INTRODUCTION AND OBJECTIVES: Testis-sparing surgery (TSS) has been proposed as an alternative therapy to radical orchiectomy for select patients with testicular masses, particularly in cases of synchronous bilateral tumors and subsequent metachronous tumor following prior contralateral orchiectomy. Additionally, it may be an option in patients with a small, unifocal, unilateral testicular mass. Criteria of tumor size < 2cm, normal germ cell serum tumor markers,

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and non-metastatic disease have been proposed previously. Our objective was to review patients who had undergone surgical treatment for testicular masses at our institution and evaluate characteristics associated with appropriateness for TSS. METHODS: We reviewed the medical records of 99 patients undergoing radical orchiectomy or TSS for testicular masses between July 2003 and July 2015. Demographic and clinical information were extracted, including presenting symptoms, tumor size, frozen section results (if performed), final pathology results, tumor marker levels, and stage. Post-hoc, patients were considered appropriate for TSS if AFP and beta-HCG were normal pre-operatively and there was no radiographic evidence of metastatic disease. Additionally, patients who were found to have active germ cell tumor elements (seminoma, yolk sac, embryonal carcinoma or choriocarcinoma) on final histology were categorized as not appropriate for TSS. RESULTS: 48 patients with negative initial AFP and beta-HCG were further analyzed. 18 (37.5%) of these patients were retrospectively found to be appropriate for TSS. In general, the median tumor size was less in the TSS-appropriate group (11 mm vs 27 mm on imaging, p ¼ 0.001). Tumor size <2 cm was associated with increased likelihood of appropriateness for TSS (p ¼ 0.003) with 61.9% of those with these smaller tumors having final pathology appropriate for TSS. No germ cell tumors were missed on intra-operative frozen section. An ROC curve analysis demonstrated a maximum sensitivity and specificity for selecting masses with normal tumor markers as appropriate for TSS at a size cutoff of 18 mm on testicular ultrasound. CONCLUSIONS: It appears reasonable and safe to perform TSS in patients with localized small testicular masses (<2 cm) and non-elevated tumor markers, but these procedures should be performed with intra-operative frozen section to ensure negative margins, complete resection and adequate cancer control. Source of Funding: None

MP81-15 GENETIC BASIS FOR CISPLATIN RESISTANCE IN PATIENTS WITH ADVANCED GERM CELL TUMORS (GCT) Aditya Bagrodia*, Byron Lee, William Lee, Eugene Cha, John Sfakianos, Paul Gao, Emily Zabor, Irina Ostrovnaya, Samuel Kaffenberger, Jana Eng, Michael Berger, Dean Bajorin, Nikolaus Schultz, Joel Sheinfeld, George Bosl, Hikmat Al-Ahmadie, David Solit, Darren Feldman, New York, NY INTRODUCTION AND OBJECTIVES: Salvage chemotherapy or desperation surgery is required in 20-30% of patients with advanced GCT (aGCT) that have cisplatin-resistant (CR) disease. We sought to delineate genomic markers of CR in aGCT patients. METHODS: Cisplatin-sensitivity (CS) was defined as complete response to chemotherapy alone or  2 year partial response with negative markers including patients who had post-chemo surgery with pathology showing necrosis or teratoma. Patients with viable GCT at post-chemo surgery were considered CR. Exploratory whole exome sequencing of 19 samples (10 CR, 9 CS) with aGCT was performed. Five of ten patients with CR disease had alterations within the TP53/ MDM2 pathway compared to none of the patients with CS disease (p¼0.033). To further explore this finding, we performed targeted sequencing on a panel of 341 cancer-associated on a validation cohort of 101 patients with aGCT. Our final analysis included 120 patients. We explored the relationship of mutation profile with clinical outcomes. RESULTS: Patient characteristics are presented in Table 1. In the validation cohort, we identified 10 mutations and 1 deletion of TP53. We also identified 4 additional tumors with MDM2 amplifications. The TP53 mutations and MDM2 amplifications were mutually exclusive and only identified in patients within the CR group (23% TP53/MDM2 alteration in CR vs 0% TP53/MDM2 alteration in CS, P¼0.001). In the combined group, there was a strong association between CR and TP53/MDM2 alteration (CR 26.3% vs CS 0%, p<0.001). TP53/MDM2 alteration was more frequent among patients with IGCCCG poor-risk disease compared to those with intermediate- and good-risk disease

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(31% vs 11% vs 7%; p¼0.005). Patients with an altered TP53/MDM2 pathway had significantly shorter progression-free survival. TP53/MDM2 alteration was an independent predictor of progression (HR 2.89, 95% CI 1.66 to 5.02, p< 0.001) in a multivariable analysis that included IGCCCG risk group. CONCLUSIONS: The increased frequency of TP53 pathway alterations amongst patients with IGCCCG poor-risk disease and the association of these alterations with shorter progression free survival independent of IGCCCG risk, support routine genomic profiling of patients with aGCTs to enhance risk stratification and possibly identify patients for novel treatment strategies. Table 1 Patient Characteristics (Discovery and Validation Cohorts)

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primary RA-RPLND compared to 33 (32%) patients who received previous chemotherapy. Mean operative time was 339 min (SD 108). Estimated blood loss was 244.1 ml (SD 486). Length of postoperative hospital stay was 2.1 days (SD 1.5). There were six conversions (5.8%) to open RPLND. Postoperatively, there were 28 total complications (Grade I¼22, II¼5, IIIB¼1). From oncological point of view, mean lymph node (LN) yield was 24.1 LNs (SD 10.8) with positive LN identified in 35 patients (33.9%). Among the primary RARPLND, adjuvant chemotherapy was given to 21.4% (3/14) of pIIA, 50% (3/6) of pIIB and 50% of pIIC patients. There were five lung recurrences (4.8%) identified at a mean follow up of 26.9 months (SD 22.4). No in field recurrences were identified CONCLUSIONS: To our knowledge this study represents the largest study of RA-RPLND outcomes in testicular cancer patients. It demonstrates that this procedure is safe and reproducible.

Variable

All Patients (n¼120)

Sensitive (n¼44)

Resistant (n¼76)

Median Age (Range)

29.7 (16.0 e 65.1)

31.0 (16.0 e 65.1)

29.4 (18.2 e 58.3)

NSGCT

92 (76.7%)

28 (63.6%)

64 (84.2%)

Seminoma

28 (23.3%)

16 (36.4%)

12 (15.8%)

Testis

106 (88.3%)

42 (95.5%)

64 (84.2%)

MP81-17

Mediastinum

14 (11.7%)

2 (4.5%)

12 (15.8%)

ORCHIECTOMY FOLLOWING MICROSURGICAL DENERVATION OF THE SPERMATIC CORD: SINGLE INSTITUTION REVIEW

Good

56(46.7%)

30 (68.2%)

26 (34.2%)

Kathryn Lipscomb*, Daniel Williams IV, Madison, WI

Intermediate

19 (15.8%)

9 (20.5%)

10 (13.2%)

Poor

45 (37.5%)

5 (11.4%)

40 (52.6%)

39 (51.3%)

Histology

Source of Funding: None

Primary site

IGCCCG

Initial Chemo BEP

50 (41.7%)

11 (25%)

EP

44 (36.7%)

25 (56.8%)

19 (25%)

TIP or VIP

26 (21.7%)

8 (18.2%)

18 (23.7%)

Primary

50 (41.7)

40 (90.9)

30 (39.5)

Metastasis

70 (58.3)

4 (9.1)

46 (60.5)

Sample Type

Sample collection Pre-chemotherapy

70 (58.3%)

44(100%)

26 (34.2%)

Postchemotherapy

50 (41.7%)

0 (0%)

50 (65.8%)

Died of Disease

17 (14.2%)

0 (0%)

17 (22.3%)

Source of Funding: Urology Care Foundation Research Scholars Program

MP81-16 PERIOPERATIVE AND EARLY ONCOLOGICAL OUTCOMES FOLLOWING ROBOT ASSISTED RETROPERITONEAL LYMPH NODE DISSECTION FOR TESTICULAR CANCER: A MULTI-INSTITUTIONAL STUDY Haidar Abdul-Muhsin*, Phoenix, AZ; Michael Marshall, Sean Stroup, James L’esperance, San Diego, CA; Michael Woods, Chapel Hill, NC; James Porter, Seattle, WA; Erik Castle, Phoenix, AZ INTRODUCTION AND OBJECTIVES: To evaluate the perioperative outcomes and postoperative complication rates for robot assisted retroperitoneal lymph node dissection (RA-RPLND) in a large multi-Institutional cohort. METHODS: After individual institutional review board approval in four participating institutions, the data of all testicular cancer patients treated with RA-RPLND at these tertiary institutions were collected and retrospectively analyzed. The procedures were performed by a single robotic surgeon at each participating institution. All demographic, Intraoperative variables, post-operative pathological outcomes and complications were reported. Additionally, Recurrence rates were reported at then end of follow up. RESULTS: There were 103 patients who underwent RA-RPLND. The mean patients age was 29.6 years (SD 9.7), mean BMI was 26.4 Kg/m2 (SD 5.1). Bilateral Full template dissection was performed in 65 (63.1%) patients compared to 36 patients (35%) who had modified templates of dissection. Nerve sparing was attempted in 68 (66%) patients. There were 70 (68%) patients who underwent

INTRODUCTION AND OBJECTIVES: Chronic scrotal content pain can be a debilitating condition for patients and a challenge for urologists to treat. In the absence of physical findings to explain scrotal content pain, microsurgical denervation of the spermatic cord (MDSC) can be an effective testis-sparing treatment when symptoms are refractory to medical therapy. Success rates for MDSC have been reported when performed after other attempted surgical treatments. However, no data exists on the rate and efficacy of orchiectomy following MDSC for recurrent or persistent pain. METHODS: A retrospective chart review was performed. Data collected included basic demographics, side(s) denervated, symptomatic improvement, time to follow up, current symptomatology, and any ongoing treatments. Charts of patients undergoing subsequent orchiectomy were further examined for symptomatic improvement following orchiectomy. RESULTS: We identified 124 patients with 134 testes treated with MDSC. Median age at time of presentation was 45. Follow-up ranged from 3 to 88 months with mean of 37.7 months. 10 radical inguinal orchiectomies (8% of patients, 7.4% sides treated) were performed for recurrent or persistent scrotal content pain following MDSC. Time to orchiectomy ranged from 1 to 32 months with an average of 13.8 months. 11 of 124 patients (8%) underwent bilateral MDSC, and 4 of these patients ultimately underwent unilateral orchiectomy. One patient is pending completion of bilateral orchiectomy. Of the 10 orchiectomies, 7 patients reported complete resolution of pain, 2 patients remain on narcotics for pain control, and 1 patient remains on gabapentin. CONCLUSIONS: Following MDSC, 8% of our patients underwent orchiectomy for recurrent or persistent scrotal content pain, and two-thirds of them reported complete resolution of their pain following orchiectomy. Men with bilateral scrotal content pain were at a greater risk of progressing to orchiectomy following MDSC. Knowing the rate of, time to, and efficacy of orchiectomy after MDSC can help providers counsel patients about and set expectations for the outcomes of these procedures. Source of Funding: NONE