NRG-CC008: A nonrandomized prospective clinical trial comparing the non-inferiority of salpingectomy to salpingo-oophorectomy to reduce the risk of ovarian cancer among BRCA1 carriers [SOROCk]

TPS10615

Background: Studies of ovarian cancer screening in the general population have not demonstrated a reduction in ovarian cancer mortality. High-grade pelvic serous carcinomas (HGSCs) have traditionally been thought to originate from the ovarian surface epithelium. However, more recent data strongly suggests that most HGSCs originate from precursor lesions found in the distal fallopian tube. Serous tubal intra-epithelial carcinoma (STIC) lesions are found in association with HGSCs in 50-60% of cases and other early serous precursor lesions can be identified in an additional 25% of cases. The Society of Gynecologic Oncology has recently issued recommendations that salpingectomy can be considered at the completion of childbearing in indiviuals at increased genetic risk of ovarian cancer who do not agree to salpingo-oophorectomy. They also indicated that approximately 30% of BRCA1 mutation carriers choose not to remove their ovaries, and the mean age at RRSO for those who do is in the late 40s, much later than recommended age per guidelines. The purpose of this study is to compare risk-reducing approaches in high-risk women with deleterious germline BRCA1mutations; specifically, to demonstrate the non-inferiority of bilateral salpingectomy compared to bilateral salpingo-oophorectomy to reduce the incidence of ovarian cancer among deleterious germline BRCA1mutation carriers. Methods: This is a non-randomized prospective trial to determine if bilateral salpingectomy is non-inferior to bilateral salpingo-oophorectomy in terms ovarian, primary peritoneal, and fallopian tube cancer risk among gBRCA1m carriers between 35 and 50 years old. Individuals choose the treatment they want to receive in collaboration with their physician(s). The primary endpoint is the time to development of incident HGSC, specifically ovarian, primary peritoneal, or fallopian tube cancers. Secondary endpoints include measurement of health-related quality of life, estrogen deprivation symptoms, sexual function, menopausal symptoms, cancer distress, Medical Decision Making, and adverse events. Results: As of 1/31/2022, 116 individuals have been enrolled into this trial. A recent amendment was put forward to allow the following individuals to also participate in this trial: 1) Individuals who are receiving hormonal therapy for maintenance therapy (eg, tamoxifen, AIs, etc), 2) Individuals with a history of any prior cancer and have completed chemotherapy, at least 30 days ago, and 3) Individuals who are considering Assisted Reproductive Technologies (eg, IVF). Furthermore, there is ongoing consideration of allowing general Ob/Gyn providers to recruit patients to this trial and perform procedures, with proper pathology training and sign off at their hospitals. NCI grant UG1CA189867. Clinical trial information: NCT04251052.

Impact of lymph node yield at prostatectomy on outcomes in NRG/RTOG 9601

265

Background: A recent study ( Fossati et al, 2018) found that higher lymph node count at radical prostatectomy was associated with improved outcomes in patients treated with salvage radiation for elevated prostate-specific antigen (PSA) after surgery. We sought to validate these results in NRG/RTOG 9601, a randomized controlled trial of men with pT2/T3 disease who underwent either radiation (RT) alone or RT+antiandrogen (bicalutamide) therapy for PSA elevation following radical prostatectomy from 1998-2003. Methods: We reviewed available pathology reports for all patients in NRG/RTOG 9601 to determine the nodal count at radical prostatectomy. Clinical data was as of 11/5/2015, same as the primary endpoint for the trial. Cox proportional hazards models were used to assess the effect of number of positive lymph nodes, treatment arm (RT alone or RT+bicalutamide), Gleason score, positive margins, and seminal vesicle invasion on the following endpoints: times to local and distant failure and overall and disease specific survival. Results: Out of the 760 patients originally eligible in the trial, 552 (73%, 276 in each arm) had complete data available. Median node count in the entire cohort was 6 (range 0-33, Q1-Q3 3-9). There were no significant differences between treatment arms in terms of patient demographic or clinical characteristics, including total lymph nodes removed in either arm (RT alone vs RT+bicalutamide median 5 vs 6, p = 0.11). There was no significant association between total lymph nodes and overall survival with both arms combined (HR = 1.00, 95% CI:0.97-1.03, p = 0.87) or in the individual arms alone (RT+Casodex: HR = 1.01, 95% CI:0.97-1.05, p = 0.65; RT+Placebo: HR = 0.98, 95% CI: 0.94-1.03, p = 0.45). There was also no significant association between total lymph nodes and disease-specific survival with both arms combined (HR = 1.00, 95% CI:0.95-1.04, p = 0.84) and in the arms alone (RT+Casodex: HR = 1.00, 95% CI:0.95-1.05, p = 0.92; RT+Placebo: HR = 0.99, 95% CI: 0.92-1.07, p = 0.86). In multivariable analysis performed on the two arms, Gleason score was the only feature associated with worse overall and disease-specific survival, seen only in the RT alone arm. Similar findings were seen when evaluating times to local and distant failure. Conclusions: Lymph node yield in NRG/RTOG 9601 did not show any association with adverse outcomes in the entire cohort, or in either treatment arm alone. The therapeutic benefit of an extensive lymph node dissection in this population remains uncertain. Clinical trial information: NCT00002874.

Longitudinal predictive ability of mapping algorithms: Secondary analysis of NRG Oncology/RTOG 0415

60

Background: Mapping algorithms informing economic evaluations are often derived using baseline data from clinical trials. It is unclear if these algorithms can predict health utilities accurately in post-intervention data. Thus, this study examines the longitudinal predictive ability of mapping algorithms derived from baseline trial data and explores the factors associated with prediction errors. Methods: This methodological study utilized data from an international, multicenter, randomized controlled trial of patients with low-risk prostate cancer (PC), conducted by NRG Oncology (NCT00331773). In addition to patient demographic and clinical data, this study utilized PRO data collected at baseline and 6, 12 and 24 months post-intervention. The Expanded Prostate Cancer Index Composite (EPIC) questionnaire measures health-related quality-of-life (HRQoL) and has four domains (urinary, sexual, hormonal, and bowel) and two subdomains per domain (function and bother); EuroQOL-5D-3L (EQ5D) captures health utilities. Ordinary Least Squares (OLS) regression models were used to map EPIC scores to EQ5D utilities in the baseline data through 5-fold cross-validation. Predictive performance was tested in the post-intervention data; predicted and reported utilities were compared using t-tests, and the absolute prediction error was modeled using fixed effects, as a function of baseline demographic and clinical covariates, as well as observed and predicted EQ5D utilities. Results: A total of 267 (199) patients had complete EQ5D and EPIC domain (or subdomain) data at baseline and all subsequent assessments. In the EPIC domain sample, mean ± standard deviation observed EQ5D utility was 0.90±0.13 at baseline, 0.92±0.11 at 6 months, 0.90±0.13 at 12 months and 0.89±0.14 at 24 months. Mean absolute differences (MDs) between reported and predicted were lower for models using EPIC subdomain data compared to EPIC domain data, and generally decreased as the time of assessment increased. The mapping functions over-predicted utilities for patients in perfect health while the prediction errors were increasingly negative for lower reported EQ5D scores. According to the fixed effects model for EPIC domain data, lower observed and predicted baseline EQ5D scores, and time of assessment were significant predictors of the absolute prediction error; for EPIC subdomain data, lower observed and predicted baseline EQ5D scores, hormonal bother and function, and bowel function significantly predicted the absolute prediction error. Conclusions: This study is the first to demonstrate the longitudinal validity of EPIC questionnaire, and builds upon existing research on longitudinal validity of mapping functions. The low MDs in prediction errors in post-intervention data indicate that the mapping functions are sensitive to treatment effect, thereby increasing confidence in their use in economic evaluations in PC.

18 FDG PET/CT prediction of treatment outcomes in patients with p16-positive, non-smoking associated, locoregionally advanced oropharyngeal cancer (LA-OPC) receiving deintensified therapy: Results from NRG-HN002

6563

Background: To determine the negative predictive value (NPV) of 12-14 week post-treatment PET/CT for 2-year progression-free survival (PFS) and 2-year locoregional control (LRC) in NRG-HN002, which is a two-arm phase II trial for patients with low-risk, non-smoking associated p16-positive LA-OPC randomized in a 1:1 ratio to reduced-dose IMRT with or without cisplatin. Methods: PET/CT scans were reviewed both centrally and locally by participating institutions. Tumor response evaluations for primary site, right neck, and left neck were carried out using a 5-point ordinal scale (‘Hopkins Criteria’). Overall scores were then assigned as ‘Negative,’ Positive,’ or ‘Indeterminate.’ Patients who had a ‘Negative’ score for all three evaluation sites were given an overall score of ‘Negative.’ The endpoints were NPV for LRC and PFS at 2 years testing NPV ≤ 90% vs > 90% (1-sided alpha 0.10 and 76% power). Results: There were 316 patients enrolled, of whom 306 were randomized and eligible. Of these, 131 (42.8%) patients consented to a post-therapy PET/CT, and 117 (89.3%) patients were eligible for PET/CT analysis. The median time from end of treatment to PET/CT scan was 94 days (range 52-139). The rates of 2-yr PFS and LRC in the analysis subgroup were 91.3% and 93.8%, respectively. Based on central review, post-treatment scans were negative for residual tumor for 115 patients (98.3%) and positive for 2 patients (1.7%). The NPV for 2-year LRC was 94.5% (90% lower confidence bound [LCB] 90.6%; p = 0.07). NPV for 2-year PFS was 92.0% (90% LCB 87.7%; p = 0.30). Similar NPV results were obtained based on analysis of local reviews. Conclusion: Within the context of deintensification with reduced-dose radiation, the NPV of a 12-14 week post-therapy PET/CT for 2-year LRC is statistically > 90%, similar to that reported for patients receiving standard chemoradiation. However, in this study, there was not enough evidence to conclude that the NPV of a 12-14 week post-therapy PET/CT for 2-year PFS is > 90%. Grant acknowledgement: This project was supported by grants U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), U24CA180803 (IROC), UG1CA189867 (NRG Oncology NCORP) from the National Cancer Institute (NCI). This project is funded, in part, under a Grant with the Pennsylvania Department of Health. The Department specifically disclaims responsibility for any analyses, interpretations or conclusions. Clinical trial information: NCT02254278 .

Breast conservation versus mastectomy in patients with T3 breast cancers (> 5 cm): an analysis of 37,268 patients from the National Cancer Database

PURPOSE

Breast conservation therapy (BCT) is standard for T1-T2 tumors, but early trials excluded breast cancers > 5 cm. This study was performed to assess patterns and outcomes of BCT for T3 tumors.

METHODS

We reviewed the National Cancer Database (NCDB) for noninflammatory breast cancers > 5 cm, between 2004 and 2011 who underwent BCT or mastectomy (Mtx) with nodal evaluation. Patients with skin or chest wall involvement were excluded. Patients having clinical T3 tumors were analyzed to determine outcomes based upon presentation, with those having pathologic T3 tumors, subsequently assessed, irrespective of presentation. Overall survival (OS) was analyzed using multivariable Cox proportional hazards models, with adjusted survival curves estimated using inverse probability weighting.

RESULTS

After exclusions, 37,268 patients remained. Median age and tumor size for BCT versus Mtx were 53 versus 54 years (p < 0.001) and 6.0 versus 6.7 cm (p < 0.001), respectively. Predictors of BCT included age, race, location, facility type, year of diagnosis, tumor size, grade, histology, nodes examined and positive, and administration of chemotherapy and radiotherapy. OS was similar between Mtx and BCT (p = 0.36). This held true when neoadjuvant chemotherapy patients were excluded (p = 0.39). BCT percentages declined over time (p < 0.001), while tumor sizes remained the same (p = 0.77). Median follow-up was 51.4 months.

CONCLUSIONS

OS for patients with T3 breast cancers is similar whether patients received Mtx or BCT, confirming that tumor size should not be an absolute BCT exclusion. Declining use of BCT for tumors > 5 cm in younger patients may be accounted for by recent trends toward mastectomy.