Diffusion MRI correlation with p16 status and prediction for tumor progression in locally advanced head and neck cancer

Purpose

To investigate p16 effects on diffusion image metrics and associations with tumor progression in patients with locally advanced head and neck cancers.

Methods

Diffusion images pretreatment and after 20 Gy (2wk) of RT were analyzed in patients with cT4/N3 p16+ oropharynx cancer (OPSCC) (N=51) and locoregionally advanced head and neck squamous cell carcinoma (LAHNSCC) (N=28), enrolled onto a prospective adaptive RT trial. Mean ADC values, subvolumes with ADC <1.2 um2/ms (TVLADC), and peak values of low (µL) and high (µH) components of ADC histograms in primary and total nodal gross tumor volumes were analyzed for prediction of freedom from local, distant, or any progression (FFLP, FFDP or FFLRDP) using multivariate Cox proportional-hazards model with clinical factors. P value with false discovery control <0.05 was considered as significant.

Results

With a mean follow up of 36 months, 18 of LAHNSCC patients and 16 of p16+ OPSCC patients had progression. After adjusting for p16, small µL and ADC values, and large TVLADC of primary tumors pre-RT were significantly associated with superior FFLRDP, FFLP and FFDP in the LAHNSCC (p<0.05), but no diffusion metrics were significant in p16+ oropharynx cancers. Post ad hoc analysis of the p16+ OPSCC only showed that large TVLADC of the total nodal burden pre-RT was significantly associated with inferior FFDP (p=0.05).

Conclusion

ADC metrics were associated with different progression patterns in the LAHNSCC and p16+ OPSCC, possibly explained by differences in cancer biology and morphology. A deep understanding of ADC metrics is warranted to establish imaging biomarkers for adaptive RT in HNSCC.

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.

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.

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.

Dosimetric Predictors for Acute Esophagitis during Radiation Therapy for Lung Cancer: An Update of a Large Statewide Observational Study

PURPOSE/OBJECTIVE(S)

Acute esophagitis remains a clinical challenge during the treatment of locally advanced non-small cell lung cancer (NSCLC). Here, we analyze the dosimetric and patient-level characteristics associated with acute grade 2+ and 3+ esophagitis in patients undergoing radiation therapy for NSCLC across a statewide consortium.

MATERIALS/METHODS

Demographic, dosimetric, and acute toxicity data were prospectively collected for patients undergoing definitive radiation therapy +/- chemotherapy for stage II-III NSCLC from 2012-2022 across the Michigan Radiation Oncology Quality Consortium (MROQC). Logistic regression models were used to characterize the risk of grade 2+ and 3+ esophagitis as a function of dosimetric and clinical covariates. Multivariate regression models were fitted to predict the 50% risk of grade 2 esophagitis or 3% risk of grade 3 esophagitis at each dose value.

RESULTS

Of 1760 patients evaluated, 84.2% had stage III disease and 85.3% received concurrent chemotherapy. 79.2% of patients had an ECOG performance status ≤1. Rates of acute grade 2+ and 3+ esophagitis were 48.4% and 2.2%, respectively. On multivariate analyses, performance status, mean esophageal dose and esophageal D2cc were significantly associated with grade 2+ and 3+ esophagitis. Concurrent chemotherapy was associated with grade 2+ but not grade 3+ esophagitis. Dose-response relationships were modeled for grade 2+ and 3+ esophagitis by mean esophageal dose and esophageal D2cc, stratified by performance status and/or receipt of concurrent chemotherapy. For all patients, mean esophageal dose of 29 Gy and esophageal D2cc of 61 Gy corresponded to a 3% risk of acute grade 3+ esophagitis. For patients receiving chemotherapy, mean esophageal dose of 22 Gy and esophageal D2cc of 49.5 Gy corresponded to a 50% risk of acute grade 2+ esophagitis.

CONCLUSION

Performance status, concurrent chemotherapy, mean esophageal dose and esophageal D2cc are associated with acute esophagitis during definitive treatment of NSCLC. Models that quantitatively account for these factors can be useful in individualizing radiation plans. Mean esophageal dose of 29 Gy and esophageal D2cc of 61 Gy corresponded to a 3% risk of acute grade 3+ esophagitis and merit consideration as contemporary treatment planning constraints.

Assessing Patterns of Practice in Early-Stage Lung Cancer Radiation Therapy: Findings from a Large Statewide Consortium Study on Hypofractionation

PURPOSE/OBJECTIVE(S)

There are many different acceptable radiation dose and fractionation regimens for the treatment of early-stage non-small cell lung cancer (NSCLC), including hypofractionation (HypoRT). There are limited data supporting when to use HypoRT. We investigated which factors led physicians to choose HypoRT rather than stereotactic body radiation therapy (SBRT) or conventional fractionation (CRT) for early-stage NSCLC patients in a statewide consortium.

MATERIALS/METHODS

We examined patients with T1-3N0M0 NSCLC treated at multiple institutions in a statewide consortium from January 2012-July 2022. We classified treatments as SBRT if 5 fractions or fewer, HypoRT if 6-20 fractions, and CRT if 1.8-2 Gy per fraction (Gy/Fx) for 25 or greater fractions. We excluded patients between 20 and 25 fractions as most appeared to be CRT that did not finish treatment (5% of total). We then performed a classification tree using age, race, gender, smoking status, T stage, PTV within 2cm of esophagus, PTV within 2cm of heart, and concurrent chemotherapy as covariates with a three-variable output (SBRT, HypoRT, and CRT). We excluded ECOG as it was not significant on initial analysis and was missing for 100 patients. We also reran the classification tree without CRT as an output to better discriminate between SBRT and HypoRT.

RESULTS

A total of 418 patients were included in the analysis. 184 patients had T1, 123 with T2, and 111 with T3 tumors. In total, 228 patients underwent SBRT (median 50 Gy), 51 patients HypoRT (median 60 Gy), and 139 CRT (median 63 Gy). Covariates significant for discriminating between all three treatment regimens included T2, T3 vs T1, PTV within 2cm of the esophagus, and T3 vs T2. 94% of T1 patients were treated with SBRT. Among T2 and T3 patients, those within 2cm of the esophagus were significantly more likely to be treated with CRT or HypoRT (80% vs 15%). Patients with T3 tumor not within 2cm of the esophagus, were more likely to be treated with CRT or HypoRT than the T2 patients (85% vs 36%). Patients treated with CRT were also more likely to receive chemotherapy, particularly for T3 tumors (80% received concurrent chemotherapy). Excluding CRT as an output variable, proximity to the heart became significant in addition to the other previously described covariates. Notably, the branch with the highest likelihood of HypoRT were patients with T2/T3 tumors within 2 cm of both the esophagus and heart (94% HypoRT vs 6% SBRT). Patients with tumors not close to central structures but with T3 rather than T2 tumors were more likely to be treated with HypoRT as well (62% vs 38%).

CONCLUSION

Based on this large prospective real-world data of early-stage NSCLC, larger tumors and those located near central structures are more likely to be treated with HypoRT. The patient's age, performance status, race, and smoking status were not significant in this analysis. Additional analysis on outcomes and toxicity related to treatments is underway.