ADT Use and Nodal Irradiation in Men Receiving Post-Prostatectomy Salvage Radiotherapy within a Statewide Radiation Oncology Quality Consortium

PURPOSE/OBJECTIVE(S)

For men with biochemical recurrence after radical prostatectomy, salvage radiotherapy (SRT) is a standard of care. Outcomes are improved when SRT is delivered at lower PSA levels, and there has been increased emphasis on more timely treatment. With early SRT, however, there remains uncertainty as to the optimal use and duration of androgen deprivation therapy (ADT) and pelvic lymph node radiation (PLNRT). Moreover, PET imaging and genomic classifiers have emerged as tools to guide treatment decisions, but their uptake in routine practice is unknown. To address these questions, we analyzed a contemporary cohort treated with SRT within the Michigan Radiation Oncology Quality Consortium (MROQC). We hypothesized that ADT and PLNRT practices would reflect recent trial results in this setting.

MATERIALS/METHODS

Eligible patients receiving SRT at an MROQC center were enrolled from 06/09/20 to 11/04/22. Data was prospectively collected via patient-, physician-, and physicist-completed forms. Patients were matched to the Michigan Urological Surgery Improvement Collaborative (MUSIC) database for additional treatment- and patient-related data. Univariable (UVA) and multivariable analyses (MVA) were performed to test associations between patient/tumor factors and ADT or PLNRT use.

RESULTS

A total of 191 patients across 26 centers were enrolled in the MROQC database. Of these, 116 were matched to the MUSIC database. Median time from RP to SRT was 17 months (IQR 8 - 33 months). The median post-RP PSA prior to SRT was 0.25 (IQR 0.16 - 0.60). Early SRT was defined as pre-SRT PSA ≤0.5, and 27% (n = 31/116) had a pre-SRT PSA >0.5. Twenty-eight were pT3b/T4, 97% were pN0/NX, and 51% had positive surgical margins. Fractionation was conventional (>28 fractions) in 58% and moderate hypofractionation (20-28 fractions) in 38%. Table 1 describes the patients receiving ADT and/or PLNRT. Median ADT duration was 6 mo (IQR 6 - 7 mo). MVA revealed pre-SRT PSA >0.5 (OR 5.05 [1.89 - 15.33]) and pT3b/T4 disease (OR 4.23 [1.40 - 14.56]) were significantly associated with ADT use (p <0.05), but not grade group (GG) or margin status. PLNRT was significantly associated with pre-SRT PSA >0.5 (OR 3.04 [1.21 - 8.42], p <0.05) but not pT stage, margin status, or GG. PET imaging was performed in 37% of men (52% negative, 21% prostate bed alone uptake, and 26% lymph node positivity) and genomic classifiers were performed in 24%.

CONCLUSION

Nearly 75% of biochemically recurrent prostate cancer patients within MROQC received early SRT, and about half received ADT. A pre-SRT PSA >0.5 was strongly associated with ADT and PLNRT. With prostate bed SRT alone, very few received ADT. Given the considerable heterogeneity in treatment, additional studies may help identify patients who most benefit from ADT + PLNRT, and who may be spared potential added toxicity.

Cross-Comparison Individual Patient Level Analysis of Three Gene Expression Signatures in Localized Prostate in over 50,000 Men

PURPOSE/OBJECTIVE(S)

Risk stratification guides the management of localized prostate cancer. Multiple commercial gene expression biomarkers have been developed to improve estimates of prognosis, however the 22-gene Decipher genomic classifier (22-GC) is the only test with level 1 evidence supporting its use per NCCN guidelines. It is unknown whether other commercial signatures, Oncotype (GPS) or Prolaris (CCP), are sufficiently correlated to negate the differences in evidence supporting these commercial tests. Herein, we aim to perform a cross-comparison of these signatures in a large cohort of patients diagnosed with localized prostate cancer.

MATERIALS/METHODS

Patients diagnosed with localized prostate cancer who underwent whole transcriptome gene expression microarray analysis on their primary tumor biopsy specimen were included. The 22-GC score was calculated by Veracyte using a commercially locked model. Individual genes in each of the GPS and CCP gene signatures were identified, and the gene weights in each signature were retrained for prediction of metastasis in a multi-institutional cohort of 1,574 men with long-term outcome data. This was performed to improve correlation performance of GPS and CCP given only the 22-GC was trained for prediction of metastasis. For each of the three signatures, both continuous and categorical scores were calculated. Linear regression and spearman correlations were calculated both on univariable and multivariable analyses adjusting for age, grade group, PSA, and T-stage.

RESULTS

A total of 50,881 patients were included (15,379 (30.2%) NCCN low-risk, 14,773 (29.0%) favorable intermediate-risk, 15,544 (30.5%) unfavorable intermediate-risk, and 5,185 (10.2%) high/very high-risk) with a median age of 68 years, and a median PSA of 6.2 ng/mL. On linear regression, the GPS model had poor goodness-of-fit to the 22-GC with an R2 of 0.36, as did the CCP model to the 22-GC with an R2 of 0.32. For CCP, the linear sum of the 31-genes was also tested but had inferior performance (R2 0.28) compared to the reoptimized CCP model. Results were similar on multivariable analysis adjusting for age, PSA, clinical stage and grade group. Spearman correlation between the continuous GPS model scores and the 22-GC was moderate at 0.59, as was the correlation between CCP model and the 22-GC of 0.54. CCP is a measure of proliferation, but in 22-GC high-risk patients, the majority (64.1%) of patients had low-average proliferation and only 35.9% had high proliferation, potentially explaining the lack of strong correlation.

CONCLUSION

There is minimal to moderate correlation between the 22-GC and GPS or CCP gene expression signatures tested. Therefore, these tests should not be viewed as interchangeable, and utilization should be based on the level of evidence supporting each gene expression biomarker.

Increasing Use of Conservative Management of Low-Risk Prostate Cancer in the Veterans Affairs System from 2012 to 2021

PURPOSE/OBJECTIVE(S)

Conservative management (CM), including either active surveillance or watchful waiting, is the preferred management strategy for men with low-risk prostate cancer. We sought to describe contemporary trends in CM among men with localized prostate cancer across the equal-access Veterans Affairs (VA) system.

MATERIALS/METHODS

Using VA tumor registry data, we identified all men with a new diagnosis of biopsy-proven, clinically node-negative, non-metastatic prostatic adenocarcinoma from 2012 to 2021, excluding men with missing National Comprehensive Cancer Network risk group. We quantified the yearly proportion of patients with low and favorable intermediate-risk (FIR) prostate cancer undergoing conservative management and examined age-specific rates. Multivariable logistic regression was used to identify independent clinical predictors of CM among men with low-risk and FIR disease.

RESULTS

The cohort included 86,415 patients with localized prostate cancer, of whom 20,290 (23.5%) had low risk and 25,447 (29.5%) had FIR disease. The proportion of men diagnosed with low-risk disease decreased from 27.7% in 2012 to 20.1% in 2021. The proportion of men with localized prostate cancer who were 70 years or older at diagnosis increased from 19.5% in 2012 to 46.4% in 2021, with similar increases seen across risk groups. The proportion of men with low-risk disease undergoing CM increased from 63.1% in 2012 to 86.6% in 2021. CM rates in 2021 among low-risk patients were largely consistent across age groups (50-59: 85.1%; 60-69: 87.4%; 70+: 86.3%). For FIR patients, CM rates increased among the subset with Gleason 6 disease (49.5% in 2012 to 80.7% in 2021). In multivariable models, independent predictors of CM in low-risk patients included older age, more recent year, lower PSA at diagnosis, North Atlantic or Pacific region, and presence of another cancer at diagnosis; similar predictors were found in FIR patients. Self-reported race (Black, White, or Other) was not associated with CM. While there was wide geographic variation in CM rates among low-risk patients early in the study period (2012-2014: 56.1% in Southeast region vs 74.1% in Pacific), these disparities resolved in recent years (2019-2021: 83.2% in Southeast vs 83.8% in Pacific).

CONCLUSION

Rates of conservative management for localized prostate cancer increased dramatically over time in the VA, with over 85% of low-risk patients managed conservatively in 2021. Recent years showed no differences in CM rates by self-reported race, geographic region, or age group. Despite this progress, we observed a concomitant increase in the proportion of men 70 years or older diagnosed with localized prostate cancer, including low risk disease. This raises a need to consider strategies to reduce the diagnosis of low-risk disease in elderly Veterans.

Results of a Multi-institutional Randomized Phase 3 Trial of Parotid-Sparing Whole Brain Radiotherapy

PURPOSE/OBJECTIVE(S)

Observational studies have reported that xerostomia is common after conventional whole brain radiotherapy (WBRT) and associated with parotid dose. In this multi-institutional, single-blind randomized controlled trial, we hypothesized that patient-reported xerostomia is reduced in patients randomized to parotid-sparing vs. standard WBRT fields.

MATERIALS/METHODS

Between 2018 and 2021, patients receiving conventional WBRT (30-35 Gy in 10-15 fractions) for any diagnosis were enrolled at 3 academic institutions. Patients were randomized between standard WBRT fields covering the C1 vertebra with no prospective parotid delineation (control) vs. parotid-sparing fields without C1 coverage (experimental). Patients completed the University of Michigan Xerostomia Questionnaire (Scored 0-100, higher is worse) at baseline, EndRT, 2 weeks, 1 month, 3 months, and 6 months. Patients were excluded from toxicity analyses if baseline xerostomia score was >50 or if they did not complete any post-baseline questionnaires. The primary endpoint was proportion of patients with ≥15 point absolute increase in xerostomia score from baseline to 1 month; 108 patients were needed for an 80% power to detect a 22% absolute difference (1-sided significance of 0.05). The secondary endpoint was the rate of marginal failures.

RESULTS

The study closed early after 56 patients were randomized. Median survival was 4.6 months. 46 patients (23 in each arm) were eligible for analysis. Mean parotid dose was 17 vs. 10 Gy in the standard vs. parotid-sparing arms, respectively. The table below shows mean xerostomia score and proportion of patients with ≥15 increase in xerostomia score at each time point. There was no difference in the proportion of patients experiencing ≥15 increase in xerostomia score at 1 month, though there was a trend toward lower xerostomia score at 1 month in patients randomized to parotid-sparing fields (p = 0.07, Table). Xerostomia rates were also significantly improved in the parotid-sparing arm at EndRT (p = 0.03), but no longer-term difference was observed with greater attrition at 3 and 6 months. On linear regression, there was a trend toward association between mean parotid dose and xerostomia score at 1 month (p = 0.06). There were no reported marginal failures in either arm.

CONCLUSION

Parotid-sparing without coverage of the C1 vertebra appears safe and may meaningfully reduce acute xerostomia in patients with limited life expectancy who are candidates for conventional WBRT, although the study was underpowered to detect a significant difference at 1 month.

Androgen Deprivation Therapy Use among Intermediate Risk Prostate Cancer Patients Undergoing Radiation Therapy across a Statewide Radiation Oncology Quality Consortium

PURPOSE/OBJECTIVE(S)

For men with intermediate (INT) risk prostate cancer, the addition of androgen deprivation therapy (ADT) reduces risk of PSA failure, distant metastasis, and cancer-related mortality. Moreover, the relative reduction in cancer-related adverse outcomes with ADT use appears consistent across all INT risk subgroups. The absolute benefit of ADT, however, varies by baseline risk. In contemporary practice, it is unknown which clinical factors are most strongly associated with intended ADT use. Therefore, we sought to identify such factors within the diverse practices of the Michigan Radiation Oncology Quality Consortium (MROQC).

MATERIALS/METHODS

Patients with localized prostate cancer undergoing definitive radiation therapy were enrolled from 6/9/20 to 11/4/22 (n = 599). Standardized patient, physician, and physicist forms were used to collect baseline and follow-up information. Intended ADT use, defined by the treating physician, was prospectively collected and is the primary outcome of this analysis. Univariable (UVA) and multivariable analyses (MVA) associations with patient (age, race, comorbidities), tumor (T stage, Gleason, percent cores positive, and PSA), and practice-related (academic vs private) factors were performed. In addition, advanced modality testing (PET, MRI, and genomic classifiers) was available as of March 2021, and subgroup analysis were performed where appropriate.

RESULTS

A total 351 patients across 26 centers were enrolled with INT risk disease. ADT use was intended for 46% of men (n = 162/351) which differed by men with NCCN favorable INT (21%, n = 22/105) vs unfavorable INT risk disease (57%, n = 140/246), p<0.001. Sixty two percent (n = 100/162) had an intended ADT duration of 4-6 months and 21% (n = 34/162) had ≥12 months. Older age was associated with ADT use (70 vs 67, p < 0.01); there were no significant differences by race or comorbidities number. MVA showed Gleason 4+3 (OR 4.61 [2.91 - 7.42]) and > = 50% positive cores (2.56 [1.52 - 4.37]) were significantly associated with ADT use. No significant differences were noted based on practice setting. Pelvic MRI was obtained for 71% of men (n = 197/279), genomic classifiers in 47% (n = 130/279), and PET in 2% (n = 6/282). In the subset with MRI (n = 197), adverse features (ECE, SVI, or equivocal LNs) were associated with intended ADT use (OR 3.0 [1.4 - 7.1]) after adjustment for NCCN favorable/unfavorable INT risk classification.

CONCLUSION

Within a state-wide consortium, intended ADT use for intermediate prostate cancer is most strongly associated with Gleason score, ≥50% positive cores, NCCN unfavorable intermediate risk classification, and adverse features on MRI. Nearly half of men had genomic classifier testing underscoring the importance ongoing trials such as NRG/GU 010.

A Systematic Review and Network Meta-Analysis Assessing the Impact of Adding First Generation Non-Steroidal Anti-Androgens (NSAA) to LHRH Agonists (LHRHa) in Men Receiving Radiotherapy for Localized Prostate Cancer

PURPOSE/OBJECTIVE(S)

Randomized clinical trials consistently demonstrate that the addition of androgen deprivation therapy (ADT) to prostate radiation therapy improves overall survival (OS). However, there is substantial heterogeneity regarding the type of ADT: LHRHa alone, first generation NSAA alone (e.g., bicalutamide) or combination androgen blockade (CAB) with NSAA and LHRHa. There are no published randomized trials in localized disease that specifically compare the efficacy of NSAA to LHRHa, nor the utility of CAB over monotherapy ADT. We herein performed a systematic review and network meta-analysis to assess the impact of NSAA in relation to LHRHa in men receiving radiotherapy for localized prostate cancer.

MATERIALS/METHODS

We performed a systematic literature search in PubMed to identify clinical trials of patients with localized prostate cancer for which ADT duration was the primary randomization variable. Both definitive and salvage radiation trials were included. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated from data extracted from published survival curves. A network meta-analysis was performed to compare OS by ADT regimens. We defined NSAA toxicity as early discontinuation of any ADT agent due to side effects given the inconsistent reporting of specific related toxicity. A meta-regression was performed to assess association with NSAA toxicity, adjusted for study year, patient age, T stage, Gleason score and total ADT duration. NSAA duration was assessed as a continuous variable.

RESULTS

Of the 11 trials (8,169 patients) with OS data, the median duration of any ADT was 3 months (range 0-36 months) and the median duration of NSAA specifically was 3.5 months (range 0-24 months). There was no significant difference in OS between those treated with LHRHa (n = 369) vs. CAB (n = 4,792; HR 1.10, 95% CI 0.78-1.55). Among those receiving CAB, increased NSAA duration did not improve OS (versus 0 months; 1-6 months HR 1.41, 95% CI 0.94-2.13; 7-12 months HR 1.43, 95% CI 0.87-2.34) when controlling for total ADT duration. Of the 19 trials (15,067 patients) with toxicity data, patients on NSAA (n = 503) appeared more likely to discontinue treatment early compared to those receiving LHRHa (n = 902), though this was not statistically significant (odds ratio [OR] 4.20, 95% CI 0.16-109.19). A longer duration of NSAA did not adversely affect ADT compliance. Patients were more likely to discontinue ADT prematurely, regardless of type, if the planned duration was longer (OR 1.08, 95% CI 1.07-1.09).

CONCLUSION

We did not detect an overall survival benefit to adding NSAA to LHRHa, and NSAA appeared less well tolerated than LHRHa in men receiving radiation therapy for localized prostate cancer. These data suggest that providers should consider LHRHa without the addition of a NSAA as optimal when clinically appropriate.

Practical recommendations for timely, accurate diagnosis of symptomatic Alzheimer's disease (MCI and dementia) in primary care: a review and synthesis

The critical role of primary care clinicians (PCCs) in Alzheimer's disease (AD) prevention, diagnosis and management must evolve as new treatment paradigms and disease-modifying therapies (DMTs) emerge. Our understanding of AD has grown substantially: no longer conceptualized as a late-in-life syndrome of cognitive and functional impairments, we now recognize that AD pathology builds silently for decades before cognitive impairment is detectable. Clinically, AD first manifests subtly as mild cognitive impairment (MCI) due to AD before progressing to dementia. Emerging optimism for improved outcomes in AD stems from a focus on preventive interventions in midlife and timely, biomarker-confirmed diagnosis at early signs of cognitive deficits (i.e. MCI due to AD and mild AD dementia). A timely AD diagnosis is particularly important for optimizing patient care and enabling the appropriate use of anticipated DMTs. An accelerating challenge for PCCs and AD specialists will be to respond to innovations in diagnostics and therapy for AD in a system that is not currently well positioned to do so. To overcome these challenges, PCCs and AD specialists must collaborate closely to navigate and optimize dynamically evolving AD care in the face of new opportunities. In the spirit of this collaboration, we summarize here some prominent and influential models that inform our current understanding of AD. We also advocate for timely and accurate (i.e. biomarker-defined) diagnosis of early AD. In doing so, we consider evolving issues related to prevention, detecting emerging cognitive impairment and the role of biomarkers in the clinic.

A mid-treatment break and reassessment maintains tumor control and reduces toxicity in patients with hepatocellular carcinoma treated with stereotactic body radiation therapy

BACKGROUND AND PURPOSE

Patients with hepatocellular carcinoma (HCC) commonly have underlying liver dysfunction with variable tolerance to liver stereotactic body radiation therapy (SBRT). We hypothesized that insertion of a 1-month mid-treatment break would allow us to adapt treatment to the individual patient response, thereby reducing toxicity without compromising local control (LC).

MATERIALS AND METHODS

We analyzed HCC patients receiving 3-5 fraction SBRT at our institution from 2005 to 2017. Over this time, patients were offered enrollment on prospective trials assessing individualized adaptive SBRT. Based on normal tissue complication probability and modeling of changes in liver function following a 1-month treatment break between fractions 3 and 4, patients could receive a total of 3 or 5 fractions. Patients not on trial received 3 or 5 fractions without a break. Toxicity was defined as a ≥2 point rise in Child-Pugh (CP) score within 6 months of SBRT.

RESULTS

178 patients were treated with SBRT to 263 HCCs. Median follow-up was 23 months. 86 treatments had a 1-month break. 1-Year LC was 95.4%; this was not different between patients treated with or without a break (p = 0.14). Controlling for tumor size and dose a break was not associated with inferior LC (HR: 0.58, 95%CI: 0.1-3.34, p = 0.54). 54 patients experienced a ≥2 point rise in CP score. Controlling for the number of prior liver directed therapies and mean liver dose, a treatment break reduced the odds of toxicity (OR: 0.42, 95% CI: 0.17-1.03, p = 0.06).

CONCLUSION

A one-month mid-treatment break and reassessment may reduce the odds of treatment related toxicity without compromising LC.

Amylophagia presenting as gestational diabetes

Amylophagia, or the practice of consuming purified starch, is a particular expression of the more general phenomenon of pica. This compulsive dietary aberration, observed in many pregnant patients worldwide, is common among rural African American women in the southern United States. The effect this practice has on the course of gestational diabetes has not been examined. We report 2 cases of gestational diabetes, refractory to initial dietary management, in which the patients were consuming one-half to 1 box of cornstarch per day. Following cessation of amylophagia, the gestational hyperglycemia spontaneously resolved. Amylophagia is a complex behavioral phenomenon arising from the interplay of biochemical, hematological, psychological, and cultural factors. In some patient populations, it may represent an often overlooked etiologic or exacerbating factor in the condition of gestational diabetes. Family physicians practicing obstetrics should inquire about amylophagia in patients who are at risk for this behavior and in patients who present with gestational hyperglycemia.

Differential Effect of Tetrazolium Dyes upon Bacteriophage Plaque Assay Titers

This study examined whether the practice of incorporating either tetrazolium red or tetrazolium violet dye into plaque assay medium deleteriously influences plaque assay titers. Representative members of six different virus families were studied: Cystoviridae (ϕ6), Leviviridae (MS2), Microviridae (ϕX174), Myoviridae (T2), Podoviridae (P22), and Siphoviridae (Denver, T1, and VD13). Each of the members of the Podoviridae and Siphoviridae families appeared to be suppressed by either one or both dyes at a 300-μg/ml concentration. The chosen representatives of the other bacteriophage families were not suppressed by either dye at a 300-μg/ml concentration. Subsequent trials revealed no suppression of Podoviridae or Siphoviridae plaque assay titers when members of these virus families were tested with the same two dyes at the lower concentrations of 150 and 50 μg/ml. Interestingly, the bacteriophage families whose members were affected by the dyes have additional commonality in that they are the two bacteriophage families whose members possess both double-stranded DNA genomes and noncontractile tails.