Germline DNA damage response (DDR) mutations in an East Asian (EA) cohort with prostate cancer (PCa)

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Background: Aberrations of the DDR pathway have been shown to be prognostic of survival and predictive of PARP inhibition in PCa. Additionally, germline mutations in DDR genes are linked to PCa susceptibility. Here, we report the germline DDR mutation frequencies in an EA PCa cohort, and their associations with clinicopathological indices and outcomes. Methods: We utilized a prospectively recruited cohort of 891 EA patients, with centrally assessed Gleason’s score (GS) by an expert pathologist. Germline mutation profiling was performed by whole exome sequencing (100X) using the Illumina Novaseq (CA). Following joint genotyping, common variants of ≥1% were filtered, and only variants defined as pathogenic (P)/likely pathogenic (LP) in ClinVar or predicted to be P by CADD or REVEL were retained. We used a 32 DDR gene-set for tests of association with clinicopathological indices, biochemical relapse-free rate (bRFR), and distant metastasis-free survival (DMFS). Results: Median follow up was 54 (33-83) mo; median age at diagnosis was 70 (64-74) y. 741 (84%) men had localized PCa, 65 (7%) had N+M0, and 80 (9%) had M1 disease. Among those with localized PCa, 417 (56%) were stratified as NCCN high/very high. 5-year DMFS was 100%, 96%, 86%, and 74% for NCCN low, intermediate, high/very high, and N+M0 PCa, respectively. 31 (3.5%) men in our cohort harbored a P/LP variant in at least one of the 32 DDR genes; P/LP variants were most frequently observed for BRCA2 (N=11[1.2%]), ATM (N=6[0.7%]), and RAD50 (N=5[0.6%]). P/LP variants were more frequent in men with N+M0/M1 compared with those with localized PCa (29% vs 16%, P=0.05), and in men with GS 9-10 vs 6-8 tumors (43% vs 20%, P=0.002). Presence of P/LP DDR variants were significantly associated with bRFR (HR 2.44 [95% CI:1.0-6.1], P=0.049) in M0 patients treated with RT+/-hormonal therapy on univariable and multivariable analyses. Conclusions: Herein, we observed lower frequencies of germline DDR P/LP mutations in our EA PCa cohort than other published Chinese cohorts (Wei, et al. 2018; Wei, et al. 2020). Nonetheless, there was a strong trend for increased incidence of DDR mutations with more advanced PCa. Men with DDR mutations were more likely to fail treatment than men without. [Table: see text]

Adjuvant Capecitabine Following Concurrent Chemoradiotherapy in Locoregionally Advanced Nasopharyngeal Carcinoma: A Randomized Clinical Trial

Importance

Induction or adjuvant chemotherapy with concurrent chemoradiotherapy (CCRT) are first-line treatment options for treatment of locoregionally advanced nasopharyngeal carcinoma (LA-NPC). Adjuvant platinum regimens are, however, poorly tolerated, highlighting the unmet need for an efficacious, tolerable adjuvant regimen.

Objective

To investigate the efficacy and safety of adjuvant capecitabine with CCRT for the treatment of patients with LA-NPC.

Design, Setting, and Participants

This open-label randomized clinical trial recruited patients from March 31, 2014, to July 27, 2018, at 3 institutions in China, with at least 3 years of follow-up. The data collection cutoff date was February 9, 2022. Eligibility included stage III-IVb nasopharyngeal carcinoma and at least 1 of the following: T3-4N2 or T1-4N3; plasma Epstein-Barr virus DNA titer higher than 20 000 copies/mL; primary gross tumor volume larger than 30.0 cm3; fluorodeoxyglucose F 18 positron emission tomography/computed tomography maximum standard uptake value of the primary gross tumor volume larger than 10.0; or multiple nodal metastases and any larger than 4.0 cm.

Interventions

Patients were randomly assigned 1:1 to receive either capecitabine (1000 mg/m2 twice daily for 14 days every 3 weeks for 8 cycles) or observation following CCRT (100 mg/m2 cisplatin every 3 weeks for 2 to 3 cycles, depending on duration of radiotherapy).

Main Outcomes and Measures

Failure-free survival in the intention-to-treat cohort was assessed using Kaplan-Meier survival curves compared with the log-rank test. Unstratified Cox proportional hazards regression models were used to estimate hazard ratios, with corresponding 95% CIs based on the Wald test.

Results

There were 180 patients enrolled (median [IQR] age, 47 [40-55] years; 143 [79.4%] men). Among 90 patients in the capecitabine group, 76 (84.4%) had at least 2 high-risk factors; among 90 patients in the control group, 80 (88.9%) had at least 2 high-risk factors. All patients completed CCRT, except 1 patient in the capecitabine group who received 1 cycle of cisplatin. Of the 90 patients in the capecitabine group, 85 (94.4%) received capecitabine, with 71 (78.9%) completing 8 cycles. With a median (IQR) follow-up of 58.0 (49.5-80.1) months, 18 events were recorded in the capecitabine group vs 31 events in the control group. Failure-free survival was improved with adjuvant capecitabine (3 years, 83.3% vs 72.2%; 5 years, 78.5% vs 65.9%; hazard ratio, 0.53 [95% CI, 0.30-0.94]; P = .03). The incidence of grade 3 treatment-related adverse events (TRAEs) was higher in the capecitabine group than in the control group (54 of 90 patients [60.0%] vs 46 of 90 patients [51.1%]). Treatment-related adverse events included xerostomia (17 [18.9%] vs 9 [10.0%] patients), mucositis (21 [23.3%] vs 15 [16.7%] patients), and anorexia (8 [8.9%] vs 4 [4.4%] patients). The incidence of grade 3 delayed treatment-related adverse events was comparable in both groups (9 of 83 [10.8%] vs 7 of 81 [8.6%] patients).

Conclusions and Relevance

In this randomized clinical trial, adjuvant capecitabine at the full dose following CCRT was well tolerated and improved failure-free survival among patients with LA-NPC and high-risk factors. Further investigations assessing optimal dose and duration are warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT02143388.

Prognostic Model for Stratification of Radioresistant Nasopharynx Carcinoma to Curative Salvage Radiotherapy

Purpose

To investigate for a prognostic index (PI) to personalize recommendations for salvage intensity-modulated radiotherapy (IMRT) in patients with locally recurrent nasopharyngeal carcinoma (lrNPC).

Methods

Patients with lrNPC from two academic institutions (Sun Yat-Sen University Cancer Center [SYSUCC-A; n = 251 (training cohort)] and National Cancer Centre Singapore [NCCS; n = 114] and SYSUCC-B [n = 193 (validation cohorts)]) underwent salvage treatment with IMRT from 2001 to 2015. Primary and secondary clinical end points were overall survival (OS) and grade 5 toxicity-free rate (G5-TFR), respectively. Covariate inclusion to the PIs was qualified by a multivariable two-sided P < .05. Discrimination and calibration of the PIs were assessed.

Results

The primary PI comprised covariates that were adversely associated with OS in the training cohort (gross tumor volumerecurrence hazard ratio [HR], 1.01/mL increase [ P < .001], agerecurrence HR, 1.02/year increase [ P = .008]; repeat IMRT equivalent dose in 2-Gy fractions [EQD2] ≥ 68 Gy HR, 1.42 [ P = .03]; prior radiotherapy-induced grade ≥ 3 toxicities HR, 1.90 [ P = .001]; recurrent tumor [rT]-category 3 to 4 HR, 1.96 [ P = .005]), in ascending order of weight. Discrimination of the PI for OS was comparable between training and both validation cohorts (Harrell’s C = 0.71 [SYSUCC-A], 0.72 [NCCS], and 0.69 [SYSUCC-B]); discretization by using a fixed PI score cutoff of 252 determined from the training data set yielded low- and high-risk subgroups with disparate OS in the validation cohorts (NCCS HR, 3.09 [95% CI, 1.95 to 4.89]; SYSUCC-B HR, 3.80 [95% CI, 2.55 to 5.66]). Our five-factor PI predicted OS and G5-TFR (predicted v observed 36-month OS and G5-TFR, 22% v 15% and 38% v 44% for high-risk NCCS and 26% v 31% and 45% v 46% for high-risk SYSUCC-B).

Conclusion

We present a validated PI for robust clinical stratification of radioresistant NPC. Low-risk patients represent ideal candidates for curative repeat IMRT, whereas novel clinical trials are needed in the unfavorable high-risk subgroup.

Compensatory caspase activation in MPP+-induced cell death in dopaminergic neurons

Many have hypothesized that cell death in Parkinson's disease is via apoptosis and, specifically, by the mitochondrial-mediated apoptotic pathway. We tested this hypothesis using a mouse dopaminergic cell line of mesencephalic origin, MN9D, challenged with the Parkinsonism-causing neurotoxin MPP+ (1-methyl-4-phenylpyridinium ion). Apoptosis was the main mode of cell death when the cells were subjected to MPP+ treatment under serum-free conditions for 24 h. Caspase-3 and caspase-9, however, were not activated, thus indicating the existence of alternate or compensatory cell death pathway(s) in dopaminergic neuronal cells. Using caspase inhibitors, we demonstrated that these pathways involve caspase-2, -8, -6 and -7. A time-course study indicated that activation of caspase-2 and -8 occurred upstream of caspase-6 and caspase-7. Upon MPP+ challenge, the apoptosis-inducing factor was translocated from the mitochondria into the MN9D cytosol and nucleus. These results suggest the existence of alternative apoptotic pathways in dopaminergic neurons.