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BackgroundMultiparametric MRI may cause overdiagnosis of clinically significant prostate cancer (csPCa) with the Prostate Imaging Reporting and Data System version 2.1 (PI‐RADS v2.1).ObjectivesTo investigate the diagnostic performance of stiffness as a standalone and complementary marker to PI‐RADS v2.1 for diagnosing csPCa.Study TypeProspective.SubjectsOne hundred forty‐seven participants with pathologically confirmed prostate lesions (≥1 cm), including 71 with csPCa.Field Strength/SequenceT1‐weighted fast spin‐echo, T2‐weighted fast spin‐echo, single‐shot echo‐planar diffusion‐weighted imaging, fast 3D gradient‐echo T1‐weighted dynamic contrast‐enhanced imaging, and 3D single‐shot spin‐echo based echo‐planar MR elastography at 3.0 T.AssessmentThe PI‐RADS v2.1 score was assessed by three radiologists independently. Lesion shear stiffness (SS) values at 60 Hz and 90 Hz were measured. A modified PI‐RADS integrating stiffness with PI‐RADS v2.1 was developed. Diagnostic performance for csPCa was compared between stiffness, PI‐RADS v2.1 and the modified PI‐RADS.Statistical TestSpearman's correlation, Fleiss κ and intraclass correlation, Pearson correlation, one‐way analysis of variance, area under the receiver operating characteristic curve (AUC), and the Delong test. Significance level was P < 0.05.ResultsIn the peripheral zone, csPCa (N = 35) had significantly higher SS than non‐csPCa at 60 Hz (3.22 ± 0.66 kPa vs. 2.56 ± 0.56 kPa) and at 90 Hz (5.64 ± 1.30 kPa vs. 4.48 ± 0.84 kPa). PI‐RADS v2.1 showed 100% sensitivity, 58% specificity, and 0.79 AUC for detecting csPCa. SS achieved 97% sensitivity, 52% specificity, and 0.80 AUC at 60 Hz, while SS had 63% sensitivity, 87% specificity, and 0.78 AUC at 90 Hz. The modified PI‐RADS, combing SS at 60 Hz with PI‐RADS v2.1, resulted in a significantly increased AUC (0.86) compared to that of PI‐RADS v2.1, with a sensitivity of 97% and specificity of 75%.Data ConclusionStiffness can help identifying csPCa in the peripheral zone. Combining stiffness with the PI‐RADS v2.1 improved the diagnostic accuracy and specificity for csPCa.Evidence Level1Technical EfficacyStage 2

Background Standard first-line therapies for metastatic colorectal cancer (mCRC) include fluoropyrimidine-containing regimens with oxaliplatin and/or irinotecan and a biologic agent. Immunotherapy may enhance antitumor activity in combination with standard therapies in patients with mCRC. Here, we present phase 2 results of nivolumab plus standard-of-care therapy (SOC; 5-fluorouracil/leucovorin/oxaliplatin/bevacizumab) versus SOC in the first-line treatment of patients with mCRC (CheckMate 9X8). Methods CheckMate 9X8 was a multicenter, open-label, randomized, phase 2/3 trial. Eligible patients were at least 18 years of age with unresectable mCRC and no prior chemotherapy for metastatic disease. Patients were randomized 2:1 to receive nivolumab 240 mg plus SOC or SOC alone every 2 weeks. The primary endpoint was progression-free survival (PFS) by blinded independent central review (BICR) per Response Evaluation Criteria in Solid Tumors V.1.1. Secondary endpoints included PFS by investigator assessment; objective response rate (ORR), disease control rate, duration of response, and time to response, all by BICR and investigator assessments; overall survival; and safety. Preplanned exploratory biomarker analyses were also performed. Results From February 2018 through April 2019, 310 patients were enrolled, of which 195 patients were randomized to nivolumab plus SOC (n=127) or SOC (n=68). At 21.5-month minimum follow-up, PFS with nivolumab plus SOC versus SOC did not meet the prespecified threshold for statistical significance; median PFS by BICR was 11.9 months in both arms (HR, 0.81 (95% CI, 0.53 to 1.23); p=0.30). Higher PFS rates after 12 months (18 months: 28% vs 9%), higher ORR (60% vs 46%), and durable responses (median 12.9 vs 9.3 months) were observed with nivolumab plus SOC versus SOC. Grade 3–4 treatment-related adverse events were reported in 75% versus 48% of patients; no new safety signals were identified. Conclusions The CheckMate 9X8 trial investigating first-line nivolumab plus SOC versus SOC in patients with mCRC did not meet its primary endpoint of PFS by BICR. Nivolumab plus SOC showed numerically higher PFS rates after 12 months, a higher response rate, and more durable responses compared with SOC alone, with acceptable safety. Further investigation to identify subgroups of patients with mCRC that may benefit from nivolumab plus SOC versus SOC in the first-line setting is warranted. Trial registration number NCT03414983 .

Abstract Intraductal carcinoma of the prostate (IDC-P) is a lethal prostate cancer subtype that generally coexists with invasive high-grade prostate acinar adenocarcinoma (PAC) but exhibits distinct biological features compared with concomitant adenocarcinoma. In this study, we performed whole-exome, RNA, and DNA-methylation sequencing of IDC-P, concurrent invasive high-grade PAC lesions, and adjacent normal prostate tissues isolated from 22 radical prostatectomy specimens. Three evolutionary patterns of concurrent IDC-P and PAC were identified: early divergent, late divergent, and clonally distant. In contrast to those with a late divergent evolutionary pattern, tumors with clonally distant and early divergent evolutionary patterns showed higher genomic, epigenomic, transcriptional, and pathologic heterogeneity between IDC-P and PAC. Compared with coexisting PAC, IDC-P displayed increased expression of adverse prognosis–associated genes. Survival analysis based on an independent cohort of 505 patients with metastatic prostate cancer revealed that IDC-P carriers with lower risk International Society of Urological Pathology (ISUP) grade 1–4 adenocarcinoma displayed a castration-resistant free survival as poor as those with the highest risk ISUP grade 5 tumors that lacked concurrent IDC-P. Furthermore, IDC-P exhibited robust cell-cycle progression and androgen receptor activities, characterized by an enrichment of cellular proliferation–associated master regulators and genes involved in intratumoral androgen biosynthesis. Overall, this study provides a molecular groundwork for the aggressive behavior of IDC-P and could help identify potential strategies to improve treatment of IDC-P. Significance: The genomic, transcriptomic, and epigenomic characterization of concurrent intraductal carcinoma and adenocarcinoma of the prostate deepens the biological understanding of this lethal disease and provides a genetic basis for developing targeted therapies.

Abstract TFE3-translocation renal cell carcinoma (TFE3-tRCC) is a rare and heterogeneous subtype of kidney cancer that has no standard treatment for advanced disease. We described comprehensive molecular characteristics of 63 untreated primary TFE3-tRCCs based on whole-exome and RNA sequencing. TFE3-tRCC is highly heterogeneous, both clinicopathologically and genotypically. ASPSCR1-TFE3 fusion, certain fusion isoforms and high somatic copy number alteration burdens were associated with aggressive features and poor outcomes. Apart from tumors with MED15-TFE3 fusion, most TFE3-tRCCs exhibited low PD-L1 expression and low T-cell infiltration. Unsupervised transcriptomic analysis revealed five molecular clusters with distinct angiogenesis, stroma, proliferation and KRAS down signatures, which showed association with fusion patterns and prognosis. Specifically, the high angiogenesis/stroma/proliferation cluster exclusively consisted of tumors with ASPSCR1-TFE3 fusion, which was likely to benefit from combination of immune checkpoint and anti-angiogenesis inhibitors. Our findings reveal the genomic and transcriptomic features of TFE3-tRCC and provide insights into precision medicine for this disease.

203 Background: D2 gastrectomy followed by adjuvant S-1 is one of the standard therapy for the patients (pts) with stage III gastric cancer (GC) in Japan; however, the outcome is not satisfactory. We examined the efficacy of perioperative capecitabine and oxaliplatin (CapeOx) in pts with clinical SS/SE N1-3 M0 GC. Methods: The eligibility criteria included histopathologically confirmed clinical T3(SS)/T4a(SE) N1-3 M0 GC according to the Japanese Classification of GC (JCGC; 3rd English Edition). Three cycles of neoadjuvant CapeOx (NAC; capecitabine, 2,000 mg/m2 for 14 days; oxaliplatin, 130 mg/m2 on day 1, every 3 weeks) were administered, followed by five cycles of adjuvant CapeOx after D2 gastrectomy. The primary endpoint was the pathological response rate (pRR) according to JCGC ( ≥Grade 1b). Results: Thirty-seven pts were enrolled from April 2016 to May 2017, and fully evaluated for efficacy and toxicity. Thirty-three pts (89.2%) completed the planned three cycles of NAC and underwent gastrectomy, with an R0 resection rate of 78.4% (n = 29) and a pRR of 54.1% (n = 20, p = .058; 90% confidence interval [CI], 39.4–68.2) were demonstrated. The relative dose intensity (RDI) of capecitabine and oxaliplatin were 90.5% and 91.9%, respectively. Among 27 pts who initiated AC, 21 (63.6%) completed the treatment, and the RDI of capecitabine and oxaliplatin were 80.9% and 65.1%, respectively. Grade 3–4 toxicities during NAC included neutropenia (8%), thrombocytopenia (8%), and anorexia (8%) and during AC included neutropenia (37%), diarrhea (4%), and anorexia (4%), but no treatment-related death was reported. The overall survival (OS) rate and relapse free survival (RFS) rate at 3 years was 83.8% (95% CI, 72.7-96.5%) and 73.0% (95% CI, 60.0-88.8%), respectively. Subgroup analyses according to residual tumor after surgery (R status) showed a 3-year OS and RFS rate of 86.2% (95% CI, 74.5-99.7%) and 75.7% (95% CI, 63.0-90.8%) for R0. Conclusions: Perioperative CapeOx showed good feasibility and favorable prognosis with sufficient pathological response, although statistical significance at .058 did not reach the commonly accepted cutoff of .05. The data obtained using this novel approach warrant further investigations. Clinical trial information: 000021641.

AbstractPurpose:Fumarate hydratase–deficient renal cell carcinoma (FH-deficient RCC) is a rare but lethal subtype of RCC. Little is known about the genomic profile of FH-deficient RCC, and the therapeutic options for advanced disease are limited. To this end, we performed a comprehensive genomics study to characterize the genomic and epigenomic features of FH-deficient RCC.Experimental Design:Integrated genomic, epigenomic, and molecular analyses were performed on 25 untreated primary FH-deficient RCCs. Complete clinicopathologic and follow-up data of these patients were recorded.Results:We identified that FH-deficient RCC manifested low somatic mutation burden (median 0.58 mutations per megabase), but with frequent somatic copy-number alterations. The majority of FH-deficient RCCs were characterized by a CpG sites island methylator phenotype, displaying concerted hypermethylation at numerous CpG sites in genes of transcription factors, tumor suppressors, and tumor hallmark pathways. However, a few cases (20%) with low metastatic potential showed relatively low DNA methylation levels, indicating the heterogeneity of methylation pattern in FH-deficient RCC. Moreover, FH-deficient RCC is potentially highly immunogenic, characterized by increased tumor T-cell infiltration but high expression of immune checkpoint molecules in tumors. Clinical data further demonstrated that patients receiving immune checkpoint blockade–based treatment achieved improved progression-free survival over those treated with antiangiogenic monotherapy (median, 13.3 vs. 5.1 months; P = 0.03).Conclusions:These results reveal the genomic features and provide new insight into potential therapeutic strategies for FH-deficient RCC.

102 Background: This phase II study aimed to investigate the safety and efficacy of XP compared to SP in the first-line treatment of HER2 negative AGC. Methods: Patients were randomly assigned to receive either SP (S-1 at 40–60 mg twice daily for 21 days plus cisplatin at 60 mg/ m2 on day 8, every 5 weeks) or XP (capecitabine 1,000 mg/m2 twice daily for 14 days plus cisplatin 80 mg/m2 on day 1, every 3 weeks). Primary endpoint was response rate (RR), and secondary endpoints were progression-free survival (PFS), overall survival (OS), time to treatment failure (TTF), and adverse events. Results: 84 eligible patients were randomly assigned to receive SP ( N = 41) or XP ( N = 43). No statistical difference was observed in overall RR between the SP and XP groups [51.2% (95% CI, 35.1% to 67.1%) vs. 53.5% (95% CI, 37.7% to 68.8%), P = 1.000]. Despite not significant, however, SP vs. XP showed a trend toward better PFS [median, 5.9 months vs. 4.1 months; hazard ratio (HR), 0.763; 95% CI, 0.462 to 1.259; P = .284] and OS (median, 13.5 months vs. 10.0 months; HR, 0.776; 95% CI, 0.485 to 1.244; P = .290). This trend in the SP vs. XP comparison was more pronounced in TTF (median, 4.5 months vs. 3.1 months; HR, 0.651; 95% CI, 0.421 to 1.006; P = .052). Common grade 3 to 4 hematological toxicities were neutropenia and anemia (SP group, 23% and 23%; XP group, 35% and 28%). Grade 3-4 anorexia and hyponatremia were more frequently seen in the XP group (31% and 16%) compared to the SP group (13% and 5%). Treatment-related deaths occurred in one patient (2.3%) in the XP group. Conclusions: XP failed to demonstrate the superior efficacy over SP. Higher incidence of severe toxicities by XP suggests SP as the standard 1st line chemotherapy for HER2 negative AGC in Japan. Clinical trial information: UMIN000006755.