Multimodality Management of Thoracic Tumors: Initial Experience With a Multidisciplinary Thoracic Ablation Conference

BACKGROUND

This study aimed to describe lesion-specific management of thoracic tumors referred for consideration of image-guided thermal ablation (IGTA) at a newly established multidisciplinary ablation conference.

METHODS

This retrospective single-center cohort study included consecutive patients with non-small cell lung cancer (NSCLC) or thoracic metastases evaluated from June 2020 to January 2022 in a multidisciplinary conference. Outcomes included the management recommendation, treatments received (IGTA, surgical resection, stereotactic body radiation therapy [SBRT], multimodality management), and number of tumors treated per patient. Pearson's chi-square test was used to assess for a change in management, and Poisson regression was used to compare the number of tumors by treatment received.

RESULTS

The study included 172 patients (58 % female; median age, 69 years; 56 % thoracic metastases; 27 % multifocal primary lung cancer; 59 % ECOG 0 [range, 0-3]) assessed in 206 evaluations. For the patients with NSCLC, IGTA was considered the most appropriate local therapy in 12 %, equal to SBRT in 22 %, and equal to lung resection in 3 % of evaluations. For the patients with thoracic metastases, IGTA was considered the most appropriate local therapy in 22 %, equal to SBRT in 12 %, and equal to lung resection in 3 % of evaluations. Although all patients were referred for consideration of IGTA, less than one third of patients with NSCLC or thoracic metastases underwent IGTA (p < 0.001). Multimodality management allowed for treatment of more tumors per patient than single-modality management (p < 0.01).

CONCLUSIONS

Multidisciplinary evaluation of patients with thoracic tumors referred for consideration of IGTA significantly changed patient management and facilitated lesion-specific multimodality management.

Recent Trends in "Manels" and Gender Representation Among Panelists at North American Annual Radiation Oncology Meetings

PURPOSE

Achieving gender equity in radiation oncology is an important goal, as a smaller proportion of women enter radiation oncology residency compared with those graduating from medical school. As invited speaking opportunities at academic medical conferences are vital for promotion/tenure, we investigated the prevalence of all-men panels ("manels") at American Society for Radiation Oncology (ASTRO) and Canadian Society of Radiation Oncology (CARO) annual meetings.

METHODS AND MATERIALS

Using ASTRO and CARO online meeting programs, 2018 to 2021 faculty information was obtained, including gender, panel role (chair vs nonchair), type of session, and topic. Primary outcomes included percentage of manels and proportion of female panelists over time. Representation of women among chairs was also evaluated.

RESULTS

Over the 4-year study period across both conferences, a total of 765 panel sessions were held with 2973 faculty members, of whom 1287 (43.3%) were women. Of these sessions, 127 of 765 (16.6%) were manels. ASTRO meetings had 1169 of 2742 (42.6%) female faculty members and held 107 of 680 (15.7%) manels, whereas CARO meetings had 118 of 231 (51.1%) female faculty and held 20 of 85 manels (23.5%). From 2018 to 2021, the proportion of manels decreased at ASTRO and CARO meetings from 25.6% to 8.2% (P < .001) and from 29.6% to 15.0% (P = .130), respectively. The role of chair was majority male in every year from 2018 to 2021 at ASTRO meetings (58.6% overall), but more balanced at CARO meetings (48.0% overall). Among session types, the highest proportion of manels was observed for scientific sessions (19.1%, P = .011) at ASTRO meetings and leadership sessions (29.4%, P = .533) at CARO meetings. The lowest proportion of female panelists was on genitourinary cancer topics at ASTRO meetings (31.9%, P = .018) and physics topics at CARO meetings (40.4%, P = .085).

CONCLUSIONS

During the study period, the proportion of female panelists increased with a corresponding decrease in manels. ASTRO and CARO should strive for further involvement of women and the elimination of manels whenever possible.

β1 integrin mediates unresponsiveness to PI3Kα inhibition for radiochemosensitization of 3D HNSCC models

Phosphoinositide 3-kinase (PI3K)-α represents a key intracellular signal transducer involved in the regulation of key cell functions such as cell survival and proliferation. Excessive activation of PI3Kα is considered one of the major determinants of cancer therapy resistance. Despite preclinical and clinical evaluation of PI3Kα inhibitors in various tumor entities, including head and neck squamous cell carcinoma (HNSCC), it remains elusive how conventional radiochemotherapy can be enhanced by concurrent PI3K inhibitors and how PI3K deactivation mechanistically exerts its effects. Here, we investigated the radiochemosensitizing potential and adaptation mechanisms of four PI3K inhibitors, Alpelisib, Copanlisib, AZD8186, and Idelalisib in eight HNSCC models grown under physiological, three-dimensional matrix conditions. We demonstrate that Alpelisib, Copanlisib and AZD8186 but not Idelalisib enhance radio- and radiochemosensitivity in the majority of HNSCC cell models (= responders) in a manner independent of PIK3CA mutation status. However, Alpelisib promotes MAPK signaling in non-responders compared to responders without profound impact on Akt, NFκB, TGFβ, JAK/STAT signaling and DNA repair. Bioinformatic analyses identified unique gene mutations associated with extracellular matrix to be more frequent in non-responder cell models than in responders. Finally, we demonstrate that targeting of the cell adhesion molecule β1 integrin on top of Alpelisib sensitizes non-responders to radiochemotherapy. Taken together, our study demonstrates the sensitizing potential of Alpelisib and other PI3K inhibitors in HNSCC models and uncovers a novel β1 integrin-dependent mechanism that may prove useful in overcoming resistance to PI3K inhibitors.

Genomic Tumor Correlates of Clinical Outcomes Following Organ-Sparing Chemoradiation Therapy for Bladder Cancer

PURPOSE

There is an urgent need for biomarkers of radiation response in organ-sparing therapies. Bladder preservation with trimodality therapy (TMT), consisting of transurethral tumor resection followed by chemoradiation, is an alternative to radical cystectomy for muscle-invasive bladder cancer (MIBC), but molecular determinants of response are poorly understood.

EXPERIMENTAL DESIGN

We characterized genomic and transcriptomic features correlated with long-term response in a single institution cohort of patients with MIBC homogeneously treated with TMT. Pretreatment tumors from 76 patients with MIBC underwent whole-exome sequencing; 67 underwent matched transcriptomic profiling. Molecular features were correlated with clinical outcomes including modified bladder-intact event-free survival (mBI-EFS), a composite endpoint that reflects long-term cancer control with bladder preservation.

RESULTS

With a median follow-up of 74.6 months in alive patients, 37 patients had favorable long-term response to TMT while 39 had unfavorable long-term response. Tumor mutational burden was not associated with outcomes after TMT. DNA damage response gene alterations were associated with improved locoregional control and mBI-EFS. Of these alterations, somatic ERCC2 mutations stood out as significantly associated with favorable long-term outcomes; patients with ERCC2 mutations had significantly improved mBI-EFS [HR, 0.15; 95% confidence interval (CI), 0.06-0.37; P = 0.030] and improved BI-EFS, an endpoint that includes all-cause mortality (HR, 0.33; 95% CI, 0.15-0.68; P = 0.044). ERCC2 mutant bladder cancer cell lines were significantly more sensitive to concurrent cisplatin and radiation treatment in vitro than isogenic ERCC2 wild-type cells.

CONCLUSIONS

Our data identify ERCC2 mutation as a candidate biomarker associated with sensitivity and long-term response to chemoradiation in MIBC. These findings warrant validation in independent cohorts.

Landscape of the Radiosensitizing Properties of Targeted Agents from the NCI CTEP Portfolio across Genomically Diverse 3D Tumor Models

PURPOSE/OBJECTIVE(S)

Clinical translation of molecular targeted radiosensitizers remains challenging. To improve the robustness of preclinical data, we sought to broadly examine across a wide spectrum of genomic cancer features the radiosensitizing properties of targeted drugs from the NCI Cancer Therapy Evaluation Program (CTEP).

MATERIALS/METHODS

As part of a U01 Consortium, we adapted a robotic high-throughput platform for testing ionizing radiation (IR) plus drug combinations in 3D cultures derived from non-small cell lung carcinoma (NSCLC), head/neck (HNSCC), and pancreatic cancers. All cell lines were annotated, mycoplasma free, and re-authenticated. Signal windows were established for all 3D growth formats. CTEP drugs were added in four concentrations 24 hours prior to IR exposure of 384-well plates. Five days after IR, cell viability was assessed, an endpoint previously benchmarked using colony formation. Each data point was based on 4-6 technical replicates with 2 biological repeats. A multistep statistical method combining Wilcoxon signed-rank and Spearman rank-order correlation tests together with adjusted Benjamini-Hochberg corrections for multiple comparisons was used to identify radiosensitization hits. Select validation experiments of hits were carried out.

RESULTS

We screened 73 3D tumor models with 34-42 CTEP drugs each plus IR (n = 10,744 cell line/drug concentration combinations). IR/drug patterns were comparable for the three cancer types. DNA damage response (DDR) inhibitors constituted the most active class of radiosensitizers with DNA-PKcs, PARP, and ATR being the top targets. In contrast, the majority of the other agents radiosensitized only a minority of models. Highlighting NSCLC, out of 1,120 cell line/drug combinations, 328 (29.3%) were associated with statistically significant radiosensitization. PARP inhibitors, of particular interest for clinical translation in this space, demonstrated relatively broad radiosensitization for talazoparib (62%) and olaparib (44%) but less so for veliparib (28%), which correlated with differential PARP trapping potentials. Radiosensitization was evident even for tumor genotypes associated with radioresistance such as mutant KRAS, KEAP1, and STK11. Interestingly, single-agent activity of olaparib was more pronounced in 11/30 3D cultures compared to 2D growth conditions but with only 2/11 having known homologous recombination defects. Lastly, for HPV negative HNSCC (735 combinations), there was radiosensitization in subsets of models for IAP, ATR, and AKT targets, which are under clinical investigation.

CONCLUSION

We present a unique resource for examining radiosensitizing drug properties in 3D cultures. The observed radiosensitization patterns strongly argue for the use of larger panels of clinically relevant tumor models rather than a few non-representative cell lines. Our data highlight the urgent need for predictive biomarkers to guide IR/drug combinations, even for some DDR inhibitors.

Risk of Esophagitis in Patients with Limited Stage SCLC Treated with QD or BID Chemoradiotherapy Regimens with Contralateral Esophagus Sparing

PURPOSE/OBJECTIVE(S)

Recent randomized phase III trials in limited stage (LS) small cell lung carcinoma (SCLC) demonstrate persistent high rates of grade (G) ≥ 3 esophagitis of 16-19% for 45 Gy BID and 66-70 Gy QD radiotherapy (RT). G3 esophagitis dramatically impairs quality of life and is a barrier to treatment intensification. We previously developed a contralateral esophagus sparing technique (CEST) that reduced esophagitis mainly in patients with locally advanced NSCLC treated with chemoRT to 70 Gy/7 weeks. It is not established whether CEST is effective in LS-SCLC patients, especially those receiving BID RT which may limit mucosal esophageal regeneration during treatment. Here, we report our single-institution experience with this approach.

MATERIALS/METHODS

We retrospectively analyzed the records of patients with LS-SCLC who received chemoRT between June 2014 and October 2022. Patients were treated with QD or BID schedules at physician discretion though QD has historically been favored at our institution. The esophageal wall contralateral to the tumor was contoured as an avoidance structure. IMRT or VMAT was used to drive steep dose fall-off across the esophagus while maintaining full tumor coverage. Daily cone-beam CT guidance was employed. Toxicity was assessed using CTCAE v5 criteria. Descriptive statistics were used to analyze outcomes. The study was approved by the IRB.

RESULTS

We identified 38 consecutive patients with LS-SCLC treated with definitive chemoRT. Median age was 67 years, and 60.5% were female. Twenty-seven were treated with QD RT to a median dose of 63 Gy (range 55.8-70) in 33 fractions (range 31-35). All remaining patients received BID RT 45 Gy in 30 fractions. Median CTV for the QD and BID cohorts was 205 cc and 214 cc, respectively. Almost all patients (n = 37) had tumor located within 1 cm of the esophagus. There were no ≥G3 esophagitis events (95% CI, 0-9.3%). The rate of G2 esophagitis was 21.1% (11.1-36.3%), with no significant difference between QD (26%) and BID (9%) cohorts (p = 0.3). Only two patients required narcotics. For BID patients, CE planning constraints were scaled to reflect the shortened RT course. The median CE maximum dose, V20, and V30 were 44.8 Gy, 7.9 cc, and 6.4 cc, respectively. For the QD cohort, the median CE maximum dose, V45, and V55 were 59.5 Gy, 3.0 cc, and 0.6 cc, respectively. Treatment breaks occurred in nine QD patients due to neutropenia. Median follow-up was 31.0 months. 3-year overall survival was 70.0% (95% CI, 49.8-83.3%).

CONCLUSION

While we are limited by small patient numbers and possible selection bias, our data suggest that CE sparing can be effective in LS-SCLC, with low severe esophagitis risk even for BID RT regimens. CEST is readily adaptable into clinical practice which should facilitate further refinement of empirically derived CE planning constraints.

Hippocampal Avoidance Whole Brain Radiotherapy with Reduced Whole Brain Dose in Patients with Non-Small Cell Lung Cancer Brain Metastases

PURPOSE/OBJECTIVE(S)

Hippocampal avoidance whole brain radiation (HA-WBRT) results in improved neurocognitive function (NCF) compared to standard WBRT, but > 50% of patients still experience NCF failure. We examined whether gentler fractionation of HA-WBRT with lower biologically effective dose (BED), typically delivering 30 Gy over 15 versus 10 fractions, may allow for better hippocampal sparing without impacting intracranial disease control in patients with non-small cell lung cancer (NSCLC).

MATERIALS/METHODS

We conducted a retrospective study of patients with NSCLC receiving HA-WBRT between 2014-2022. Endpoints were distant brain failure free survival (DBFFS), local brain failure free survival (LBFFS), left and right hippocampal mean BED2 and BED21%. Kaplan-Meier survival analysis and Welch's t-test were performed. NCF outcomes were graded with CTCAEv5. The IRB approved this study.

RESULTS

Sixty-nine consecutive patients treated with HA-WBRT were included, with median follow up of 51.2 weeks. Median age was 63 years and 29% had a targetable mutation. Thirty-six patients received standard HA-WBRT with median dose of 30 Gy (range 30-35 Gy) in 10 fractions (range 10-14). Thirty-three patients received reduced BED HA-WBRT, with median dose of 30 Gy (range 23-30) in 15 fractions (range 9-15) to the radiographically uninvolved brain. All patients in the reduced BED (RD) group had a simultaneous integrated boost (SIB) to gross disease (median 37.5 Gy (range 36-37.5 Gy)), while 18/36 in the standard dose (SD) group had an SIB (median 35 Gy (range 34-39 Gy)). There were no significant differences between SD and RD cohorts in age, systemic therapy use before WBRT or targetable mutations. There was no significant difference in median DBFFS of the SD [23.1 weeks (IQR 11.3-49.3)] and RD groups [40 weeks, (IQR 20.9-109.1)] (p = 0.27). There was also no difference in LBFFS of the SD (median 26.4 weeks, IQR 11.3-76.2) and RD groups (median 40 weeks, IQR (21-71.4) (p = 0.84). For the left and right hippocampi, both mean BED2 and D1% were significantly lower in the RD group (Table 1). Median cognitive disturbance was Grade (G) 0 (range 0-3) in both groups, with 4 G>2 events in the SD cohort vs. 3 in the RD cohort.

CONCLUSION

In this single-institution cohort, HA-WBRT using a gentler fractionation with SIB was associated with improved hippocampal sparing without compromising intracranial control in patients with NSCLC. We suggest that further optimization of HA-WBRT dose and schedule may improve both intracranial control and NCF outcomes. This study is limited by its retrospective nature and potential selection bias. A phase II prospective study to test these concepts is ongoing.

Effect of Contralateral Esophagus Sparing in Hypofractionated Radiotherapy for Ultra-Central NSCLC

PURPOSE/OBJECTIVE(S)

Esophageal toxicity is a known complication of radiotherapy (RT) for ultra-central lung tumors, with ∼5 - 15% of patients developing grade ≥3 esophagitis. Despite increasing adoption of hypofractionated regimens, there are no consensus recommendations for reducing esophageal toxicity in these patients. We previously demonstrated the utility of a novel contralateral esophagus sparing technique (CEST) in a prospective trial of patients with locally-advanced NSCLC receiving concurrent chemoRT (70 Gy/7 weeks). Whether CEST is effective for hypofractionated RT is unknown. The aims of this study were to identify outcomes and toxicities associated with use of CEST in patients receiving definitive hypofractionated RT to ultra-central lung tumors.

MATERIALS/METHODS

We retrospectively analyzed the records of consecutive patients with ultra-central NSCLC who received definitive RT to a dose of ≥60 Gy with fraction size ≥3 Gy per day, from 1/1/2015 to 6/30/2022. The esophageal wall contralateral to the tumor was contoured as an avoidance structure. VMAT planning was used to ensure steep dose fall-off across the esophagus while maintaining full tumor coverage. Treatment was delivered using daily cone-beam CT guidance. Toxicity was graded using CTCAE v 4.0. Descriptive statistics were used to analyze outcomes. The study was approved by the IRB.

RESULTS

We identified 45 patients with ultra-central NSCLC treated with definitive RT, with median follow-up of 27.3 months. Median age was 74.5 years old [57.6 - 88.2]. Median ECOG PS was 2 [1 - 3]. Twenty-three patients had PTVs located within 1 cm of the esophagus. Median ITV and PTV volumes were 17 cc [1.6 - 154 cc] and 43.6 cc [8.4 - 292 cc], respectively. Median total dose was 60 Gy [60 - 67.5 Gy] in 20 [10 - 20] fractions. Median esophageal Dmax was 24 Gy [2 - 66.7 Gy] for all patients and 36 Gy [12.3 - 66.7 Gy] for patients with tumors located within 1 cm of the esophagus. For the CE, median Dmax, V20 Gy and V25 Gy were 35.7 Gy [17 - 45.2 Gy], 2.1 cc [0 - 6.7 cc] and 0.95 cc [0 - 3 cc], respectively. There were no episodes of grade ≥2 esophagitis (95% CI, 0-7.9%). The rate of grade 1 esophagitis was 13.3% (6.2 - 26.1%). Esophageal Dmax was higher in patients who developed esophagitis (44.5 vs. 26.1 Gy, t = 2.5, p = 0.038). Two patients developed grade 2 pneumonitis (4.4%, 95% CI 0 - 10.5%). There were no episodes of grade ≥3 pulmonary toxicity. There were 3 (6.7%) local recurrences, with 2-year local recurrence rate of 4.4%.

CONCLUSION

Use of CEST to minimize esophageal dose for treatment of ultra-central NSCLC is associated with reduced rates of esophagitis compared with historical controls, without compromising local control. This technique is readily adaptable for clinical practice. More data are needed to refine the empirically derived CE dose-volume constraints, especially for tumors directly abutting the esophagus.

Pneumonitis in Patients Receiving Thoracic Radiotherapy and Osimertinib: A Multi-Institutional Study

Introduction

Thoracic radiotherapy (TRT) is increasingly used in patients receiving osimertinib for advanced NSCLC, and the risk of pneumonitis is not established. We investigated the risk of pneumonitis and potential risk factors in this population.

Methods

We performed a multi-institutional retrospective analysis of patients under active treatment with osimertinib who received TRT between April 2016 and July 2022 at two institutions. Clinical characteristics, including whether osimertinib was held during TRT and pneumonitis incidence and grade (Common Terminology Criteria for Adverse Events version 5.0) were documented. Logistic regression analysis was performed to identify risk factors associated with grade 2 or higher (2+) pneumonitis.

Results

The median follow-up was 10.2 months (range: 1.9-53.2). Of 102 patients, 14 (13.7%) developed grade 2+ pneumonitis, with a median time to pneumonitis of 3.2 months (range: 1.5-6.3). Pneumonitis risk was not significantly increased in patients who continued osimertinib during TRT compared with patients who held osimertinib during TRT (9.1% versus 15.0%, p = 0.729). Three patients (2.9%) had grade 3 pneumonitis, none had grade 4, and two patients had grade 5 events (2.0%, diagnosed 3.2 mo and 4.4 mo post-TRT). Mean lung dose was associated with the development of grade 2+ pneumonitis in multivariate analysis (OR = 1.19, p = 0.021).

Conclusions

Although the overall rate of pneumonitis in patients receiving TRT and osimertinib was relatively low, there was a small risk of severe toxicity. The mean lung dose was associated with an increased risk of developing pneumonitis. These findings inform decision-making for patients and providers.

US Cancer Mortality Trends Among Hispanic Populations From 1999 to 2020

Importance

Advances in cancer research and treatment access have led to decreasing cancer mortality in the US; however, cancer remains the leading cause of death among Hispanic individuals.

Objective

To evaluate longitudinal cancer mortality trends from 1999 to 2020 among Hispanic individuals by demographic characteristics and to compare age-adjusted cancer death rates between the Hispanic population and other racial and ethnic populations during 2000, 2010, and 2020.

Design, Setting, and Participants

This cross-sectional study obtained age-adjusted cancer death rates among Hispanic individuals of all ages between January 1999 and December 2020, using the Centers for Disease Control and Prevention WONDER database. Cancer death rates in other racial and ethnic populations were extracted for 2000, 2010, and 2020. Data were analyzed from October 2021 to December 2022.

Exposures

Age, gender, race, ethnicity, cancer type, and US census region.

Main Outcomes and Measures

Trends and average annual percent changes (AAPCs) in age-adjusted cancer-specific mortality (CSM) rates among Hispanic individuals were estimated by cancer type, age, gender, and region.

Results

From 1999 to 2020, 12 644 869 patients died of cancer in the US, of whom 690 677 (5.5%) were Hispanic; 58 783 (0.5%) were non-Hispanic American Indian or Alaska Native; 305 386 (2.4%), non-Hispanic Asian or Pacific Islander; 1 439 259 (11.4%), non-Hispanic Black or African American; and 10 124 361 (80.1%), non-Hispanic White. For 26 403 patients (0.2%), no ethnicity was stated. The overall CSM rate among Hispanic individuals decreased by 1.3% (95% CI, 1.2%-1.3%) annually. Overall CSM rate decreased more for Hispanic men (AAPC, -1.6%; 95% CI, -1.7% to -1.5%) compared with women (AAPC, -1.0%; 95% CI, -1.0% to -0.9%). While death rates among Hispanic individuals decreased for most cancer types, mortality rates for liver cancer (AAPC, 1.0%; 95% CI, 0.6%-1.4%) increased among Hispanic men, and rates of liver (AAPC, 1.0%; 95% CI, 0.8%-1.3%), pancreas (AAPC, 0.2%; 95% CI, 0.1%-0.4%), and uterine (AAPC, 1.6%; 95% CI, 1.0%-2.3%) cancers increased among Hispanic women. Overall CSM rates increased for Hispanic men aged 25 to 34 years (AAPC, 0.7%; 95% CI, 0.3%-1.1%). By US region, liver cancer mortality rates increased significantly in the West for both Hispanic men (AAPC, 1.6%; 95% CI, 0.9%-2.2%) and Hispanic women (AAPC, 1.5%; 95% CI, 1.1%-1.9%). There were differential findings in mortality rates when comparing Hispanic individuals with individuals belonging to other racial and ethnic populations.

Conclusions and Relevance

In this cross-sectional study, despite overall CSM decreasing over 2 decades among Hispanic individuals, disaggregation of data demonstrated that rates of liver cancer deaths among Hispanic men and women and pancreas and uterine cancer deaths among Hispanic women increased from 1999 to 2020. There were also disparities in CSM rates among age groups and US regions. The findings suggest that sustainable solutions need to be implemented to reverse these trends among Hispanic populations.

Recent trends of "manels": gender representation among invited panelists at an international oncology conference

BACKGROUND

Gender disparities in academic medicine are a long-acknowledged concern, particularly at medical conferences. We investigated gender representation and prevalence of "manels" (all-men panels) among invited speakers at the 2018-2021 American Society of Clinical Oncology Annual Meetings.

METHODS

Using American Society of Clinical Oncology online programs, 2018-2021 faculty information was obtained, including perceived or self-reported gender, medical specialty, session type, and topic. Primary outcomes were percentage of manels and proportion of women panelists over time; women representation among specialties and topics were evaluated. Cochran-Armitage and Fisher's exact tests were used to analyze trends in proportion of manels and women representation over time and to compare each session type, topic, or specialty with other categories combined, respectively.

RESULTS

During 2018-2021, there were 670 sessions, 81 of which (12.1%) were manels. Among 2475 panelists, 1181 (47.7%) were women. Over time, the percentage of manels significantly decreased from 17.4% in 2018 to 9.9% in 2021 (P = .030). The highest proportion of manels was observed for leadership or special sessions (17.1%, P = .419). Women panelists were underrepresented for the topics of genitourinary cancers (38.6%, P = .029) and translational or preclinical sciences (36.7%, P < .001). There was a positive trend toward improved women representation among translational or preclinical sciences (27.4% in 2018 vs 41.8% in 2021, P = .031) but not among genitourinary cancers (41.1% in 2018 vs 40.7% in 2021, P = .969).

CONCLUSIONS

The number of women panelists increased during the study period, with a corresponding decrease in the proportion of manels, specifically in education and leadership or special sessions. Ongoing underrepresentation of women in genitourinary cancers and translational or preclinical topics underscores the importance of annual meeting organizers continuing to strive for diverse gender representation.

Racial and ethnic disparities in a real-world precision oncology data registry

Biorepositories enable precision oncology research by sharing clinically annotated genomic data, but it remains unknown whether these data registries reflect the true distribution of cancers in racial and ethnic minorities. Our analysis of Project Genomics Evidence Neoplasia Information Exchange (GENIE), a real-world cancer data registry designed to accelerate precision oncology discovery, indicates that minorities do not have sufficient representation, which may impact the validity of studies directly comparing mutational profiles between racial/ethnic groups and limit generalizability of biomarker discoveries to all populations.

β-Endorphin mediates radiation therapy fatigue

Fatigue is a common adverse effect of external beam radiation therapy in cancer patients. Mechanisms causing radiation fatigue remain unclear, although linkage to skin irradiation has been suggested. β-Endorphin, an endogenous opioid, is synthesized in skin following genotoxic ultraviolet irradiation and acts systemically, producing addiction. Exogenous opiates with the same receptor activity as β-endorphin can cause fatigue. Using rodent models of radiation therapy, exposing tails and sparing vital organs, we tested whether skin-derived β-endorphin contributes to radiation-induced fatigue. Over a 6-week radiation regimen, plasma β-endorphin increased in rats, paralleled by opiate phenotypes (elevated pain thresholds, Straub tail) and fatigue-like behavior, which was reversed in animals treated by the opiate antagonist naloxone. Mechanistically, all these phenotypes were blocked by opiate antagonist treatment and were undetected in either β-endorphin knockout mice or mice lacking keratinocyte p53 expression. These findings implicate skin-derived β-endorphin in systemic effects of radiation therapy. Opioid antagonism may warrant testing in humans as treatment or prevention of radiation-induced fatigue.

Recent trends of “manels” and gender representation among panelists at the ASCO annual meeting

11053

Background: Gender disparities in academic medicine are a long-acknowledged concern. Efforts to recognize this imbalance and increase inclusivity continue, particularly in academic medical conferences. In June 2019, NIH Director Francis S. Collins MD, PhD publicly called for an end to all-male speaking panels (“manels”). It is unclear whether academic oncology conferences followed suit. We investigated the prevalence and longitudinal trends of manels and gender representation at the ASCO Annual Meeting during 2018-2021. Methods: Using ASCO online programs, 2018-2021 faculty information was obtained. Data collected included perceived or self-reported gender, medical specialty, panel role (chair vs. non-chair), type of session, and topic. Primary outcomes included percentage of manels and proportion of female panelists over time. Female representation among chairs, specialties, and topics were evaluated. Cochran-Armitage test was used to analyze time trends in the proportion of manels and female representation. Fisher’s exact test was used to compare each session type, topic, or specialty to other categories combined. P-values are based on a two-sided hypothesis. Results: During 2018-2021, there were 670 sessions total, 81 of which (12.1%) were manels. Among 2,475 faculty members, 1,181 (47.7%) were females. Over time, there was a significant decrease in the number of manels, from 17.4% in 2018 to 9.9% in 2021 (p = 0.030) and a corresponding increase in proportion of female panelists from 41.6% to 54.0% (p < 0.001). The largest decrease in manels occurred between 2018 (17.4%) and 2019 (10.5%). Among session type and topic, the highest proportion of manels was observed for leadership/special sessions (17.1%, p = 0.419) and translational/pre-clinical topics (19.6%, p = 0.024), respectively. The chair role was majority male (53.2%) in 2018 but increased to > 50% female representation in 2019-2021 (p = 0.157). The lowest proportion of female panelists were in pathology/radiology/dermatology specialties (combined 26.2%, p = 0.001). Female panelists were underrepresented for the topics of genitourinary cancers (38.6%, p = 0.029) and translational/pre-clinical sciences (36.7%, p < 0.001). Females were overrepresented in the topic of supportive oncology (70.3%, p < 0.001). There was a positive trend toward improved female representation among translational/pre-clinical sciences (27.4% in 2018 to 41.8% in 2021, p = 0.031), but with little improvement among genitourinary cancers (41.1% in 2018 to 40.7% in 2021, p = 0.969). Conclusions: The number of female ASCO panelists increased during the study period and surpassed 50% in 2021, with a corresponding decrease in the proportion of manels. Still, there are certain topics/specialties where female representation has remained stagnant. ASCO Annual Meeting organizers should continue to strive for diverse gender representation and the elimination of manels.

Incidence of Radiation Therapy Among Patients Enrolled in a Multidisciplinary Pulmonary Nodule and Lung Cancer Screening Clinic

IMPORTANCE

The number of pulmonary nodules discovered incidentally or through screening programs has increased markedly. Multidisciplinary review and management are recommended, but the involvement of radiation oncologists in this context has not been defined.

OBJECTIVE

To assess the role of stereotactic body radiation therapy among patients enrolled in a lung cancer screening program.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study was performed at a pulmonary nodule and lung cancer screening clinic from October 1, 2012, to September 31, 2019. Referrals were based on chest computed tomography with Lung Imaging Reporting and Data System category 4 finding or an incidental nodule 6 mm or larger. A multidisciplinary team of practitioners from radiology, thoracic surgery, pulmonology, medical oncology, and radiation oncology reviewed all nodules and coordinated workup and treatment as indicated.

EXPOSURES

Patients referred to the pulmonary nodule and lung cancer screening clinic with an incidental or screen-detected pulmonary nodule.

MAIN OUTCOMES AND MEASURES

The primary outcome was the proportion of patients undergoing therapeutic intervention with radiation therapy, stratified by the route of detection of their pulmonary nodules (incidental vs screen detected). Secondary outcomes were 2-year local control and metastasis-free survival.

RESULTS

Among 1150 total patients (median [IQR] age, 66.5 [59.3-73.7] years; 665 [57.8%] female; 1024 [89.0%] non-Hispanic White; 841 [73.1%] current or former smokers), 234 (20.3%) presented with screen-detected nodules and 916 (79.7%) with incidental nodules. For patients with screen-detected nodules requiring treatment, 41 (17.5%) received treatment, with 31 (75.6%) undergoing surgery and 10 (24.4%) receiving radiation therapy. Patients treated with radiation therapy were older (median [IQR] age, 73.8 [67.1 to 82.1] vs 67.6 [61.0 to 72.9] years; P < .001) and more likely to have history of tobacco use (67 [95.7%] vs 128 [76.6%]; P = .001) than those treated with surgery. Fifty-eight patients treated with radiation therapy (82.9%) were considered high risk for biopsy, and treatment recommendations were based on a clinical diagnosis of lung cancer after multidisciplinary review. All screened patients who received radiation therapy had stage I disease and were treated with stereotactic body radiation therapy. For all patients receiving stereotactic body radiation therapy, 2-year local control was 96.3% (95% CI, 91.1%-100%) and metastasis-free survival was 94.2% (95% CI, 87.7%-100%).

CONCLUSIONS AND RELEVANCE

In this unique prospective cohort, 1 in 4 patients with screen-detected pulmonary nodules requiring intervention were treated with stereotactic body radiation therapy. This finding highlights the role of radiation therapy in a lung cancer screening population and the importance of including radiation oncologists in the multidisciplinary management of pulmonary nodules.

Immunogenicity and Reactogenicity of SARS-CoV-2 Vaccines in Patients With Cancer: The CANVAX Cohort Study

PURPOSE

The immunogenicity and reactogenicity of SARS-CoV-2 vaccines in patients with cancer are poorly understood.

METHODS

We performed a prospective cohort study of adults with solid-organ or hematologic cancers to evaluate anti-SARS-CoV-2 immunoglobulin A/M/G spike antibodies, neutralization, and reactogenicity ≥ 7 days following two doses of mRNA-1273, BNT162b2, or one dose of Ad26.COV2.S. We analyzed responses by multivariate regression and included data from 1,638 healthy controls, previously reported, for comparison.

RESULTS

Between April and July 2021, we enrolled 1,001 patients; 762 were eligible for analysis (656 had neutralization measured). mRNA-1273 was the most immunogenic (log10 geometric mean concentration [GMC] 2.9, log10 geometric mean neutralization titer [GMT] 2.3), followed by BNT162b2 (GMC 2.4; GMT 1.9) and Ad26.COV2.S (GMC 1.5; GMT 1.4; P < .001). The proportion of low neutralization (< 20% of convalescent titers) among Ad26.COV2.S recipients was 69.9%. Prior COVID-19 infection (in 7.1% of the cohort) was associated with higher responses (P < .001). Antibody titers and neutralization were quantitatively lower in patients with cancer than in comparable healthy controls, regardless of vaccine type (P < .001). Receipt of chemotherapy in the prior year or current steroids were associated with lower antibody levels and immune checkpoint blockade with higher neutralization. Systemic reactogenicity varied by vaccine and correlated with immune responses (P = .002 for concentration, P = .016 for neutralization). In 32 patients who received an additional vaccine dose, side effects were similar to prior doses, and 30 of 32 demonstrated increased antibody titers (GMC 1.05 before additional dose, 3.17 after dose).

CONCLUSION

Immune responses to SARS-CoV-2 vaccines are modestly impaired in patients with cancer. These data suggest utility of antibody testing to identify patients for whom additional vaccine doses may be effective and appropriate, although larger prospective studies are needed.

Heterogeneous immunogenicity of SARS-CoV-2 vaccines in cancer patients receiving radiotherapy

The immunogenicity of SARS-CoV-2 vaccines in cancer patients receiving radiotherapy is unknown. This prospective cohort study demonstrates that anti-SARS-CoV-2 spike antibody and neutralization titers are reduced in a subset of thoracic radiotherapy patients, possibly due to immunosuppressive conditions. Antibody testing may be useful to identify candidates for additional vaccine doses.

Translation of DNA Damage Response Inhibitors as Chemoradiation Sensitizers From the Laboratory to the Clinic

Combination therapies with agents targeting the DNA damage response (DDR) offer an opportunity to selectively enhance the therapeutic index of chemoradiation or eliminate use of chemotherapy altogether. The successful translation of DDR inhibitors to clinical use requires investigating both their direct actions as (chemo)radiosensitizers and their potential to stimulate tumor immunogenicity. Beginning with high-throughput screening using both viability and DNA damage-reporter assays, followed by validation in gold-standard radiation colony-forming assays and in vitro assessment of mechanistic effects on the DDR, we describe proven strategies and methods leading to the clinical development of DDR inhibitors both with radiation alone and in combination with chemoradiation. Beyond these in vitro studies, we discuss the impact of key features of human xenograft and syngeneic mouse models on the relevance of in vivo tumor efficacy studies, particularly with regard to the immunogenic effects of combined therapy with radiation and DDR inhibitors. Finally, we describe recent technological advances in radiation delivery (using the small animal radiation research platform) that allow for conformal, clinically relevant radiation therapy in mouse models. This overall approach is critical to the successful clinical development and ultimate Food and Drug Administration approval of DDR inhibitors as (chemo)radiation sensitizers.

Racial and Ethnic Disparities Among Participants in Precision Oncology Clinical Studies

IMPORTANCE

Precision oncology is revolutionizing cancer care, allowing for personalized treatments to improve outcomes. Cancer research has benefitted from well-designed studies incorporating precision medicine objectives, but it is unclear if these studies are representative of the diverse cancer population.

OBJECTIVE

To evaluate racial and ethnic representation in breast, prostate, lung, and colorectal cancer studies incorporating precision oncology objectives in the Clinicaltrials.gov registry and compare with the incidence of these cancer types in racial and ethnic minority groups in the US population.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study identified US-based breast, prostate, lung, and colorectal cancer studies incorporating precision oncology objectives for reporting of race and ethnicity. The Surveillance, Epidemiology, and End Results and US Census databases were used to determine cancer incidence by race and ethnicity, linked with cancer type and median year of enrollment for each trial. Data were collected and analyzed between December 2020 and April 2021.

MAIN OUTCOMES AND MEASURES

The expected number of participants per study by each racial and ethnic group was calculated based on the corresponding US-based proportion. Under- and overrepresentation was defined as the ratio of the actual number of enrolled cases to the expected number of cases for each trial by cancer type. Ratios above 1 indicated overrepresentation while a ratio below 1 indicated underrepresentation. Random-effects meta-analysis of representation ratios of individual trials was performed to weigh each individual study.

RESULTS

Of 93 studies encompassing 5867 enrollees with race and ethnicity data; 4826 participants (82.3%) were non-Hispanic White, 587 (10.0%) were Black, and 238 (4.1%) were Asian. Per observed-to-expected ratios, White participants were overrepresented in all studies, with a ratio of 1.35 (95% CI, 1.30-1.37), as well as Asian participants, with a ratio of 1.46 (95% CI, 1.28-1.66), while Black participants (ratio, 0.49; 95% CI, 0.45-0.54), Hispanic participants (ratio, 0.24; 95% CI, 0.20-0.28), and American Indian and Alaskan Native participants (ratio, 0.43; 95% CI, 0.24-0.78) were underrepresented. By individual cancer site, White participants were consistently overrepresented in all studies, while Black and Hispanic participants were underrepresented.

CONCLUSIONS AND RELEVANCE

This analysis found that precision oncology studies for breast, lung, prostate, and colorectal cancers vastly underrepresent racial and ethnic minority populations relative to their cancer incidence in the US population. It is imperative to increase diversity among enrollees so that all individuals may benefit from cancer research breakthroughs and personalized treatments.

Automated clinical target volume delineation using deep 3D neural networks in radiation therapy of Non-small Cell Lung Cancer

Background and purpose

Clinical targeted volume (CTV) delineation accounting for the patient-specific microscopic tumor spread can be a difficult step in defining the treatment volume. We developed an intelligent and automated CTV delineation system for locally advanced non-small cell lung carcinoma (NSCLC) to cover the microscopic tumor spread while avoiding organs-at-risk (OAR).

Materials and methods

A 3D UNet with a customized loss function was used, which takes both the patients’ respiration-correlated (“4D”) CT scan and the physician contoured internal gross target volume (iGTV) as inputs, and outputs the CTV delineation. Among the 84 identified patients, 60 were randomly selected to train the network, and the remaining as testing. The model performance was evaluated and compared with cropped expansions using the shape similarities to the physicians’ contours (the ground-truth) and the avoidance of critical OARs.

Results

On the testing datasets, all model-predicted CTV contours followed closely to the ground truth, and were acceptable by physicians. The average dice score was 0.86. Our model-generated contours demonstrated better agreement with the ground-truth than the cropped 5 mm/8 mm expansion method (median of median surface distance of 1.0 mm vs 1.9 mm/2.0 mm), with a small overlap volume with OARs (0.4 cm³ for the esophagus and 1.2 cm³ for the heart).

Conclusions

The CTVs generated by our CTV delineation system agree with the physician's contours. This approach demonstrates the capability of intelligent volumetric expansions with the potential to be used in clinical practice.

Moving Beyond the Standard of Care: Accelerate Testing of Radiation-Drug Combinations

Radiation therapy is a major treatment modality used in > 60% of cancer patients as definitive local treatment for inoperable locoregionally confined tumors and as palliative therapy. Although cytotoxic chemotherapy enhances the effectiveness of treatment, the benefit over radiation therapy alone is modest. There is a need to enhance the effectiveness of local tumor control over what sequentially or concurrently administered cytotoxic chemotherapy provides. Although many biological pathways are known to enhance the effectiveness of radiation therapy, there is currently a paucity of drugs approved for use in combination. Several clinical trials have tested the effectiveness of combining targeted agents or immunotherapies with radiation therapy, but the results of these trials have been negative, likely stemming from the relative lack of preclinical evidence using appropriate experimental standardization or model systems. Accelerating the identification of agents tested in an appropriate clinical context and experimental systems or models would greatly enhance the potential to bring forward early testing of drugs that would not only be safe but also more effective. This article provides an overview of the opportunities and challenges of developing therapeutics to combine with radiation therapy, and some guidance toward preclinical and early clinical testing to improve the chance that advanced phase testing of drug-radiation combinations would be successful in the long term.

Screening and Validation of Molecular Targeted Radiosensitizers

The development of molecular targeted drugs with radiation and chemotherapy are critically important for improving the outcomes of patients with hard-to-treat, potentially curable cancers. However, too many preclinical studies have not translated into successful radiation oncology trials. Major contributing factors to this insufficiency include poor reproducibility of preclinical data, inadequate preclinical modeling of inter-tumoral genomic heterogeneity that influences treatment sensitivity in the clinic, and a reliance on tumor growth delay instead of local control (TCD50) endpoints. There exists an urgent need to overcome these barriers to facilitate successful clinical translation of targeted radiosensitizers. To this end, we have employed 3D cell culture assays to better model tumor behavior in vivo. Examples of successful prediction of in vivo effects with these 3D assays include radiosensitization of head and neck cancers by inhibiting epidermal growth factor receptor or focal adhesion kinase signaling, and radioresistance associated with oncogenic mutation of KRAS. To address the issue of tumor heterogeneity we leveraged institutional resources that allow high-throughput 3D screening of radiation combinations with small molecule inhibitors across genomically characterized cell lines from lung, head and neck, and pancreatic cancers. This high-throughput screen is expected to uncover genomic biomarkers that will inform the successful clinical translation of targeted agents from the NCI CTEP portfolio and other sources. Screening "hits" need to be subjected to refinement studies that include clonogenic assays, addition of disease-specific chemotherapeutics, target/biomarker validation, and integration of patient-derived tumor models. The chemoradiosensitizing activities of the most promising drugs should be confirmed in TCD50 assays in xenograft models with/without relevant biomarker and utilizing clinically relevant radiation fractionation. We predict that appropriately validated and biomarker-directed targeted therapies will have a higher likelihood than past efforts to be successfully incorporated into the standard management of hard-to-treat tumors.

Alginate-based 3D cancer cell culture for therapeutic response modeling

Two-dimensional (2D) culture of tumor cells fails to recapitulate some important aspects of cellular organization seen in in vivo experiments. In addition, cell cultures traditionally use non-physiological concentration of nutrients. Here, we describe a protocol for a facile three-dimensional (3D) culture format for cancer cells. This 3D platform helps overcome the 2D culture limitations. In addition, it allows for longitudinal modeling of responses to cancer therapeutics.

For complete details on the use and execution of this protocol, please refer to Lhuissier et al. (2017), Lehmann et al. (2016), Liu et al. (2016), and Duval et al. (2011).

•

A detailed protocol on hydrogel-based 3D culture of patient-derived tumor cell lines

•

No binding sites for cells in hydrogel polymers allowing for pure interaction of cells

•

Longitudinal 3D proliferation assays and drug-response assessments

•

Quick and easy recovery of 3D-cultured cells for downstream experiments

Assessment of a Contralateral Esophagus-Sparing Technique in Locally Advanced Lung Cancer Treated With High-Dose Chemoradiation: A Phase 1 Nonrandomized Clinical Trial

Importance

Severe acute esophagitis occurs in up to 20% of patients with locally advanced lung cancer treated with chemoradiation therapy to at least 60 Gy once daily and represents a dose-limiting toxic event associated with poor outcomes.

Objective

To assess whether formalized sparing of the contralateral esophagus (CE) is associated with reduced risk of severe acute esophagitis.

Design, Setting, and Participants

This single-center phase 1 nonrandomized clinical trial assessing an empirical CE-sparing technique enrolled patients from July 2015 to January 2019. In total, 27 patients with locally advanced non-small cell lung carcinoma (with or without solitary brain metastasis) or limited-stage small cell lung carcinoma with gross tumor within 1 cm of the esophagus were eligible.

Interventions

Intensity-modulated radiation therapy to 70 Gy at 2 Gy/fraction concurrent with standard chemotherapy with or without adjuvant durvalumab. The esophageal wall contralateral to gross tumor was contoured as an avoidance structure to guide a steep dose falloff gradient. Target coverage was prioritized over CE sparing, and 99% of internal and planning target volumes had to be covered by 70 Gy and at least 63 Gy, respectively.

Main Outcomes and Measures

The primary end point was the rate of at least grade 3 acute esophagitis as assessed by Common Terminology Criteria for Adverse Events, version 4.

Results

Of 27 patients enrolled, 25 completed chemoradiation therapy. Nineteen patients had non-small cell lung carcinoma, and 6 had small cell lung carcinoma. The median age at diagnosis was 67 years (range, 51-81 years), and 15 patients (60%) were men. Thirteen patients (52%) had stage IIIA cancer, 10 (40%) had stage IIIB cancer, and 2 (8%) had stage IV cancer. The median CE maximum dose was 66 Gy (range, 44-71 Gy); the median volume of CE receiving at least 55 Gy was 1.4 cm3 (range, 0-5.3 cm3), and the median volume of CE receiving at least 45 Gy was 2.7 cm3 (range, 0-9.2 cm3). The median combined percentage of lung receiving at least 20 Gy was 25% (range, 11%-37%). The median follow-up was 33.3 months (range, 11.1-52.2 months). Among the 20 patients who had treatment breaks of 0 to 3 days and were thus evaluable for the primary end point, the rate of at least grade 3 esophagitis was 0%. Other toxic events observed among all 25 patients included 7 (28%) with grade 2 esophagitis, 3 (12%) with at least grade 2 pneumonitis (including 1 with grade 5), and 2 (8%) with at least grade 3 cardiac toxic event (including 1 with grade 5). There was no isolated local tumor failure. The 2-year progression-free survival rate was 57% (95% CI, 33%-75%), and the 2-year overall survival rate was 67% (95% CI, 45%-82%).

Conclusions and Relevance

This phase 1 nonrandomized clinical trial found that the CE-sparing technique was associated with reduced risk of esophagitis among patients treated uniformly with chemoradiation therapy (to 70 Gy), with no grade 3 or higher esophagitis despite tumor within 1 cm of the esophagus. This technique may be translated into clinical practice.

Trial Registration

ClinicalTrials.gov Identifier: NCT02394548.

Racial and ethnic disparities among participants in precision oncology clinical studies

3014

Background: Precision medicine has revolutionized oncologic care in the United States (US) in the past two decades. While the US cancer population is rapidly diversifying, enrollment of a diverse patient population into clinical trials lags behind. In particular, it is unclear whether minority patients are adequately represented in precision oncology trials. Herein, we report racial/ethnic representation in precision oncology studies spanning four common cancer types (breast, lung, prostate, colorectal cancers). Methods: Completed US clinical studies incorporating precision medicine objectives based on a set of 12 precision oncology search terms (including tumor biomarker, whole exome sequencing, tumor mutation testing, gene expression signatures, tumor microarray, tumor genomics, et cetera) were identified from Clinicaltrials.gov. Studies were reviewed for reporting race/ethnicity for inclusion in the analysis. The Surveillance, Epidemiology, and End Results (SEER) database was used to determine incidence of race/ethnicity in the US cancer population, correlated with disease site and median year of enrollment for each trial. The difference in incidence (D-I) was defined as the median absolute difference in study racial enrollment and SEER incidence, with a negative value corresponding to underrepresentation. Wilcoxon signed-rank test was used to compare median D-I to a value of 0 by racial/ethnic subgroups. Results: Overall, 156 studies were identified; 40.3 and 27.5% studies enrolling from 2000 through 2020 met the inclusion criteria for racial and ethnic subgroups reporting, respectively. Of 4,418 total enrollees, 82.5% were White, 10.5% Black, 3.8% Asian, and 0.4% American Indian/Alaskan Native (AIAN). Ethnically, 6.4% were Hispanic. The D-I was +2.2% for Whites (interquartile range (IQR) = -43.7% to 25.4%; P < 0.013), -0.74% AIAN (IQR = -0.8% to +5.9%; P < 0.001), -2.5% Asians (IQR = -4.1% to 30.4%; P < 0.152), -4.6% Blacks (IQR = -20.1% to +45.0%; P < 0.001), and -8.1% Hispanics (IQR = -14.8% to + 29.6%; P < 0.001). By disease site, Blacks were significantly underrepresented proportional to their cancer incidence among prostate (D-I of -11.8%, p = 0.009) and lung studies (D-I of -5.9%, p = 0.013), while prostate studies significantly overrepresented Whites (D-I +14.0%, p = 0.005). Lung studies overrepresented Asians (D-I +0.49%) consistent with the prominent role of targetable oncogene drivers in this population. Conclusions: Results demonstrate an underrepresentation of minority racial groups and an overrepresentation of Whites in precision oncology studies. Increased emphasis on equitable enrollment onto these studies is critical, as resulting precision Omic conclusions are used to stratify populations and personalize treatments. A continued lack of diversity among enrollees may further leave behind vulnerable minority populations in the era of precision oncology.

Coronavirus Disease 2019 Infection in a Patient Population with Lung Cancer: Incidence, Presentation, and Alternative Diagnostic Considerations

Introduction

Lung cancer is associated with severe coronavirus disease 2019 (COVID-19) infections. Symptom overlap between COVID-19 and lung cancer may complicate diagnostic evaluation. We aimed to investigate the incidence, symptoms, differential diagnosis, and outcomes of COVID-19 in patients with lung cancer.

Methods

To determine an at-risk population for COVID-19, we retrospectively identified patients with lung cancer receiving longitudinal care within a single institution in the 12 months (April 1, 2019 to March 31, 2020) immediately preceding the COVID-19 pandemic, including an “active therapy population” treated within the last 60 days of this period. Among patients subsequently referred for COVID-19 testing, we compared symptoms, laboratory values, radiographic findings, and outcomes of positive versus negative patients.

Results

Between April 1, 2019 and March 31, 2020, a total of 696 patients received longitudinal care, including 406 (58%) in the active therapy population. Among 55 patients referred for COVID-19 testing, 24 (44%) were positive for COVID-19, representing a cumulative incidence of 3.4% (longitudinal population) and 1.5% (active therapy population). Compared with patients who were COVID-19 negative, those who were COVID-19 positive were more likely to have a supplemental oxygen requirement (11% versus 54%, p = 0.005) and to have typical COVID-19 pneumonia imaging findings (5 versus 56%, p = 0.001). Otherwise, there were no marked differences in presenting symptoms. Among patients who were COVID-19 negative, alternative etiologies included treatment-related toxicity (26%), atypical pneumonia (22%), and disease progression (22%). A total of 16 patients positive for COVID-19 (67%) required hospitalization, and seven (29%) died from COVID-related complications.

Conclusions

COVID-19 was infrequent in this lung cancer population, but these patients experienced high rates of morbidity and mortality. Oncologists should maintain a low threshold for COVID-19 testing in patients with lung cancer presenting with acute symptoms.

Low Rates of Chest Wall Toxicity When Individualizing the Planning Target Volume Margin in Patients With Early Stage Lung Cancer Treated With Stereotactic Body Radiation Therapy

PURPOSE

Chest wall (CW) toxicity is a potentially debilitating complication of stereotactic body radiation therapy for non-small cell lung cancer, occurring in 10% to 40% of patients. Smaller tumor-to-CW distance has been identified as a risk factor for CW toxicity. We report our experience with individualizing the planning target volume (PTV) along the CW in an effort to reduce the volume of this organ at risk receiving 30 Gy to 50 Gy.

METHODS AND MATERIALS

We performed an institutional review board-approved retrospective analysis of patients with stage I (T1-2aN0M0) non-small cell lung cancer who received stereotactic body radiation therapy between June 2009 and July 2016. Four-dimensional computed tomography was used for treatment planning. A uniform 5-mm expansion of the internal target volume was generated for the PTV. Areas of overlap with the CW were removed from the PTV. Treatment was delivered with cone beam computed tomography guidance. CW toxicity was assessed per the Common Terminology Criteria for Adverse Events, version 5. Descriptive statistics were used to analyze outcomes.

RESULTS

The median follow-up time was 36.8 months. A total of 260 tumors were treated in 225 patients. 225 tumors in 203 patients were peripheral. The internal target volumes for 143 tumors (63.6%) were located within 5 mm of the CW. The median total dose was 48 Gy (range, 42-60 Gy) in 4 fractions (range, 3-5 fractions). The overall rate of grade 1 to 2 CW toxicity was 2.2%, and 2.8% for tumors located within 5 mm of the CW. There were no grade 3/4 cases and no increase in local recurrences with the use of a truncated PTV with a 3-year local control of 92.1% (95% confidence interval, 87.4%-96.8%).

CONCLUSIONS

Truncation of the PTV margin along the CW resulted in a marked reduction of CW toxicity for tumors in close proximity to the CW, with only a 2.8% rate of grade 1 to 2 CW toxicity. Despite PTV reduction, there was no appreciable increase in local failures. A multi-institutional validation of this technique is needed before general incorporation into clinical practice.

Modeling Resistance and Recurrence Patterns of Combined Targeted-Chemoradiotherapy Predicts Benefit of Shorter Induction Period

Optimal integration of molecularly targeted therapies, such as tyrosine kinase inhibitors (TKI), with concurrent chemotherapy and radiation (CRT) to improve outcomes in genotype-defined cancers remains a current challenge in clinical settings. Important questions regarding optimal scheduling and length of induction period for neoadjuvant use of targeted agents remain unsolved and vary among clinical trial protocols. Here, we develop and validate a biomathematical framework encompassing drug resistance and radiobiology to simulate patterns of local versus distant recurrences in a non-small cell lung cancer (NSCLC) population with mutated EGFR receiving TKIs and CRT. Our model predicted that targeted induction before CRT, an approach currently being tested in clinical trials, may render adjuvant targeted therapy less effective due to proliferation of drug-resistant cancer cells when using very long induction periods. Furthermore, simulations not only demonstrated the competing effects of drug-resistant cell expansion versus overall tumor regression as a function of induction length, but also directly estimated the probability of observing an improvement in progression-free survival at a given cohort size. We thus demonstrate that such stochastic biological simulations have the potential to quantitatively inform the design of multimodality clinical trials in genotype-defined cancers. SIGNIFICANCE: A biomathematical framework based on fundamental principles of evolution and radiobiology for in silico clinical trial design allows clinicians to optimize administration of TKIs before chemoradiotherapy in oncogene-driven NSCLC.

Acquired Resistance of EGFR-Mutated Lung Cancer to Tyrosine Kinase Inhibitor Treatment Promotes PARP Inhibitor Sensitivity

Lung cancers with oncogenic mutations in the epidermal growth factor receptor (EGFR) invariably acquire resistance to tyrosine kinase inhibitor (TKI) treatment. Vulnerabilities of EGFR TKI-resistant cancer cells that could be therapeutically exploited are incompletely understood. Here, we describe a poly (ADP-ribose) polymerase 1 (PARP-1) inhibitor-sensitive phenotype that is conferred by TKI treatment in vitro and in vivo and appears independent of any particular TKI resistance mechanism. We find that PARP-1 protects cells against cytotoxic reactive oxygen species (ROS) produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). Compared to TKI-naive cells, TKI-resistant cells exhibit signs of increased RAC1 activity. PARP-1 catalytic function is required for PARylation of RAC1 at evolutionarily conserved sites in TKI-resistant cells, which restricts NOX-mediated ROS production. Our data identify a role of PARP-1 in controlling ROS levels upon EGFR TKI treatment, with potentially broad implications for therapeutic targeting of the mechanisms that govern the survival of oncogene-driven cancer cells.

Integrated, Multidisciplinary Management of Pulmonary Nodules Can Streamline Care and Improve Adherence to Recommendations

Every year millions of pulmonary nodules are discovered incidentally and through lung cancer screening programs. Management of these nodules is often suboptimal, with low follow-up rates and poor provider understanding of management approaches. There is an emerging body of literature about how to optimize management of pulmonary nodules. The Pulmonary Nodule and Lung Cancer Screening Clinic (PNLCSC) at Massachusetts General Hospital was founded in 2012 to manage pulmonary nodules via a multidisciplinary approach with optimized support staff. Recommendations from clinic providers and treatment details were recorded for all patients seen at the PNLCSC. Adherence to recommendations and outcomes were also tracked and reviewed. From October 2012 to September 2019, 1,136 patients were seen at the PNLCSC, each for a mean of 1.8 appointments (range, 1-10). A total of 356 procedures were recommended by the clinic and 271 patients were referred for surgery and/or radiation. The majority of interventions (74%) were recommended at the initial PNLCSC appointment. In total, 211 patients (19%) evaluated at the PNLCSC had pathologically confirmed pulmonary malignancies or were treated empirically with radiation. Among patients followed by the clinic, the adherence rate to clinic recommendations was 95%. This study shows how a multidisciplinary approach to pulmonary nodule management can streamline care and optimize follow-up. The PNLCSC provides a template that can be replicated in other health systems. It also provides an example of how multidisciplinary approaches can be applied to other complex conditions. IMPLICATIONS FOR PRACTICE: This work demonstrates how an integrated, multidisciplinary approach to management of pulmonary nodules can streamline patient care and improve adherence to provider recommendations. This approach has the potential to improve patient outcomes and reduce health care costs.

Modelling variable proton relative biological effectiveness for treatment planning

Dose in proton radiotherapy is generally prescribed by scaling the physical proton dose by a constant value of 1.1. Relative biological effectiveness (RBE) is defined as the ratio of doses required by two radiation modalities to cause the same level of biological effect. The adoption of an RBE of 1.1. assumes that the biological efficacy of protons is similar to photons, allowing decades of clinical dose prescriptions from photon treatments and protocols to be utilized in proton therapy. There is, however, emerging experimental evidence that indicates that proton RBE varies based on technical, tissue and patient factors. The notion that a single scaling factor may be used to equate the effects of photons and protons across all biological endpoints and doses is too simplistic and raises concern for treatment planning decisions. Here, we review the models that have been developed to better predict RBE variations in tissue based on experimental data as well as using a mechanistic approach.

Toward a New Framework for Clinical Radiation Biology

Radiation biology has entered the era of precision oncology, and this article reviews time-tested factors that determine the effects of fractionated radiation therapy in a wide variety of tumor types and normal tissues: the association of tumor control with radiation dose, the importance of fractionation and overall treatment time, and the role of tumor hypoxia. Therapeutic gain can only be achieved if the increased tumor toxicity produced by biological treatment modifications is balanced against injury to early-responding and late-responding normal tissues. Developments in precision oncology and immuno-oncology will allow an emphasis on treatment individualization and predictive biomarker development.

Integrative Molecular Characterization of Resistance to Neoadjuvant Chemoradiation in Rectal Cancer

PURPOSE

Molecular properties associated with complete response or acquired resistance to concurrent chemotherapy and radiotherapy (CRT) are incompletely characterized.Experimental Design: We performed integrated whole-exome/transcriptome sequencing and immune infiltrate analysis on rectal adenocarcinoma tumors prior to neoadjuvant CRT (pre-CRT) and at time of resection (post-CRT) in 17 patients [8 complete/partial responders, 9 nonresponders (NR)].

RESULTS

CRT was not associated with increased tumor mutational burden or neoantigen load and did not alter the distribution of established somatic tumor mutations in rectal cancer. Concurrent KRAS/TP53 mutations (KP) associated with NR tumors and were enriched for an epithelial-mesenchymal transition transcriptional program. Furthermore, NR was associated with reduced CD4/CD8 T-cell infiltrates and a post-CRT M2 macrophage phenotype. Absence of any local tumor recurrences, KP/NR status predicted worse progression-free survival, suggesting that local immune escape during or after CRT with specific genomic features contributes to distant progression.

CONCLUSIONS

Overall, while CRT did not impact genomic profiles, CRT impacted the tumor immune microenvironment, particularly in resistant cases.

Radioresistance of KRAS/TP53-mutated lung cancer can be overcome by radiation dose escalation or EGFR tyrosine kinase inhibition in vivo

Recent clinical data have linked KRAS/TP53 comutation (mut) to resistance to radiotherapy (RT), but supporting laboratory in vivo evidence is lacking. In addition, the ability of different radiation doses, with/without epidermal growth factor receptor (EGFR)-directed treatment, to achieve local tumor control as a function of KRAS status is unknown. Here, we assessed clonogenic radiation survival of a panel of annotated lung cancer cell lines. KRASmut/TP53mut was associated with the highest radioresistance in nonisogenic and isogenic comparisons. To validate these findings, isogenic TP53mut NCI-H1703 models, KRASmut or wild-type (wt), were grown as heterotopic xenografts in nude mice. A clinical RT schedule of 30 fractions over 6 weeks was employed. The dose that controlled 50% of tumors (TCD₅₀ ) was calculated. The TCD₅₀ for KRASwt/TP53mut xenografts was 43.1 Gy whereas KRASmut/TP53mut tumors required a 1.9-fold higher TCD₅₀ of 81.4 Gy. The EGFR inhibitor erlotinib radiosensitized KRASmut but not KRASwt cells and xenografts. The TCD₅₀ associated with adding erlotinib to RT was 58.8 Gy for KRASmut, that is, a ~1.4-fold dose enhancement. However, the EGFR antibody cetuximab did not have a radiosensitizing effect. In conclusion, we demonstrate for the first time that KRASmut in a TP53mut background confers radioresistance when studying a clinical RT schedule and local control rather than tumor growth delay. Despite the known unresponsiveness of KRASmut tumors to EGFR inhibitors, erlotinib radiosensitized KRASmut tumors. Our data highlight KRAS/TP53 comutation as a candidate biomarker of radioresistance that can be at least partially reversed by dose escalation or the addition of a targeted agent.

Patient-Specific Tumor Growth Trajectories Determine Persistent and Resistant Cancer Cell Populations during Treatment with Targeted Therapies

The importance of preexisting versus acquired drug resistance in patients with cancer treated with small-molecule tyrosine kinase inhibitors (TKI) remains controversial. The goal of this study is to provide a general estimate of the size and dynamics of a preexisting, drug-resistant tumor cell population versus a slow-growing persister population that is the precursor of acquired TKI resistance. We describe a general model of resistance development, including persister evolution and preexisting resistance, solely based on the macroscopic trajectory of tumor burden during treatment. We applied the model to 20 tumor volume trajectories of EGFR-mutant lung cancer patients treated with the TKI erlotinib. Under the assumption of only preexisting resistant cells or only persister evolution, it is not possible to explain the observed tumor trajectories with realistic parameter values. Assuming only persister evolution would require very high mutation induction rates, while only preexisting resistance would lead to very large preexisting populations of resistant cells at the initiation of treatment. However, combining preexisting resistance with persister populations can explain the observed tumor volume trajectories and yields an estimated preexisting resistant fraction varying from 10^-4 to 10^-1 at the time of treatment initiation for this study cohort. Our results also demonstrate that the growth rate of the resistant population is highly correlated to the time to tumor progression. These estimates of the size of the resistant and persistent tumor cell population during TKI treatment can inform combination treatment strategies such as multi-agent schedules or a combination of targeted agents and radiotherapy. SIGNIFICANCE: These findings quantify pre-existing resistance and persister cell populations, which are essential for the integration of targeted agents into the management of locally advanced disease and the timing of radiotherapy in metastatic patients.