Phase I Trial of Definitive Concurrent Chemoradiotherapy and Trametinib for KRAS-Mutated Non-Small Cell Lung Cancer

OBJECTIVE

This phase I trial (NCT01912625) evaluated the safety and pharmacokinetics of definitive concurrent chemoradiotherapy (cCRT) and the radiosensitizer trametinib (MEK1/2 inhibitor) for KRAS-mutated nonmetastatic non-small cell lung cancer (NSCLC).

METHODS

Patients received cCRT (carboplatin/paclitaxel and 60 Gy/30 fractions radiotherapy); oral trametinib (7 days/week) commenced on day 1 and completed on the final day of radiotherapy. Dose-finding of trametinib was done using the time-to-event continual reassessment method (TiTE-CRM); dose levels were 0.5mg (level -1), 1mg (initial, level 1), 1.5mg (level 2), and 2mg (level 3). Progression-free (PFS) and overall survival (OS) times were also recorded.

RESULTS

Fifteen patients (stage III, variety of KRAS mutations) were treated, with 1/5/4/5 at dose levels -1/1/2/3, respectively. Five patients received dose reductions (n=2, levels 2 and 3; n=1, level 1). Twelve patients completed the full cCRT course. One patient (following 12d trametinib) was taken off protocol for an unrelated/unresolved grade 1 event and later experienced grade 5 sepsis/respiratory failure. There was one grade 4 retinal detachment; grade 3 events included skin rash (n=2) and ventricular dysfunction, pneumonitis, pain, fatigue, and diarrhea (n=1 each). The final dose selected by the TiTE-CRM of trametinib was 1.5 mg. Pharmacokinetic profiles were elucidated and extensively described. At median follow-up of 70 months, median PFS was 11 months and median OS was 38 months.

CONCLUSIONS

The MTD for trametinib when combined with cCRT is 1.5 mg, with encouraging preliminary outcomes. This combination merits further study to combine with consolidation durvalumab in non-metastatic KRAS mutant NSCLC.

Novel Inpatient Radiation Oncology Consult Service Model Reduces Hospital Length of Stay

Palliative care and radiation therapy have played an expanding role in the management of patients with advanced cancers. Recent advances in our understanding of oligometastatic disease have led to increasing demand for familiarity with ablative techniques. Recognizing the demands of hospitalized patients for rapid access to care, we created an inpatient radiation oncology consult service (IROC) with consolidated expertise in palliative radiation and ablative techniques. In this quality improvement cohort study, we analyzed inpatient radiation oncology consults placed before and after IROC implementation and found that IROC led to increased delivery of specialty care and decreased hospital length of stay (median 8 days v 7 days, P = .005). This difference was most pronounced for patients for whom radiation therapy was indicated (14.5 v 11 days, P = .007). Our institutional experience demonstrates the value of recognizing metastatic disease as a distinct discipline and providing rapid access to palliative treatments for patients with advanced malignancies.

Increased biologically effective dose (BED) to the primary tumor is associated with improved survival in patients with oligometastatic NSCLC

PURPOSE

Local consolidative therapy (LCT) for oligometastatic non-small cell lung cancer (NSCLC) is an evolving treatment paradigm. We investigated whether the biologically effective dose (BED) of consolidative radiation therapy (RT) to the primary tumor predicted for improved local control, progression-free survival (PFS), and overall survival (OS) among NSCLC patients presenting with oligometastatic disease.

MATERIALS AND METHODS

Patients presenting to a single institution (2000-2017) with stage IV NSCLC, ≤3 synchronous metastatic lesions at diagnosis, and treated with RT to the primary tumor were identified. Univariate and multivariable Cox proportional-hazards regression modeling were performed to identify factors associated with local recurrence-free survival (LRFS), PFS, and OS.

RESULTS

One hundred twenty-four patients were identified meeting our inclusion criteria. With a median follow-up of 55.1 months, median PFS and OS for the entire cohort were 11.0 months and 25.3 months, respectively. The median BED (α/β = 10) of RT to the primary tumor was 74.3 Gy. On univariate analysis, increased BED to the primary tumor predicted for improved PFS (p < 0.001) and LRFS (p = 0.01), with a median PFS of 8.5 vs 12.8 months and median LRFS of 23.4 vs 58.4 months between patients treated with BED < 75 Gy and ≥75 Gy, respectively. Increased BED to the primary tumor was also associated with significantly improved OS (p = 0.02); patients treated with a BED of <75 Gy demonstrated a median OS of 22.9 months vs 27.5 months if treated with BED ≥ 75 Gy. On multivariable analysis, primary site BED remained a significant predictor of OS (p = 0.02) and PFS (p = 0.002).

CONCLUSIONS

We found that delivery of >75 Gy BED RT regimens to the primary lesion in patients with synchronous oligometastatic NSCLC is associated with improved local control, PFS, and OS. These data support results of recent prospective trials and other ongoing prospective efforts to characterize therapeutic benefits associated with this management strategy.

Factors Associated With Age Disparities Among Cancer Clinical Trial Participants

Importance

Seminal investigation 2 decades ago alerted the oncology community to age disparities in participation in cooperative group trials; less is known about whether these disparities persist in industry-funded research.

Objective

To characterize the age disparities among trial enrollees on randomized clinical trials (RCTs) of common cancers in clinical oncology and identify factors associated with wider age imbalances.

Data Sources

Phase 3 clinical oncology RCTs were identified through ClinicalTrials.gov.

Study Selection

Multiarm RCTs assessing a therapeutic intervention for patients with breast, prostate, colorectal, or lung cancer (the 4 most common cancer disease sites) were included.

Data Extraction and Synthesis

Trial data were extracted from ClinicalTrials.gov. Trial screening and parameter identification were independently performed by 2 individuals. Data were analyzed in 2018.

Main Outcomes and Measures

The difference in median age (DMA) between the trial participant median age and the population-based disease-site-specific median age was determined for each trial.

Results

Three hundred two trials met inclusion criteria. The trials collectively enrolled 262 354 participants; 249 trials (82.5%) were industry-funded. For all trials, the trial median age of trial participants was a mean of 6.49 years younger than the population median age (95% CI, -7.17 to -5.81 years; P < .001). Age disparities were heightened among industry-funded trials compared with non-industry-funded trials (mean DMA, -6.84 vs -4.72 years; P = .002). Enrollment criteria restrictions based on performance status or age cutoffs were associated with age disparities; however, industry-funded trials were not more likely to use these enrollment restrictions than non-industry-funded trials. Age disparities were also larger among trials that evaluated a targeted systemic therapy and among lung cancer trials. Linear regression modeling revealed a widening gap between trial and population median ages over time at a rate of -0.19 years annually (95% CI, -0.37 to -0.01 years; P = .04).

Conclusions and Relevance

Age disparities between trial participants and the incident disease population are pervasive across trials and appear to be increasing over time. Industry sponsorship of trials is associated with heightened age imbalances among trial participants. With an increasing role of industry funding among cancer trials, efforts to understand and address age disparities are necessary to ensure generalizability of trial results as well as equity in trial access.

Results of a Phase 1/2 Trial of Chemoradiotherapy With Simultaneous Integrated Boost of Radiotherapy Dose in Unresectable Locally Advanced Esophageal Cancer

Importance

Effective treatment options for locally advanced esophageal cancer are limited, and rates of local recurrence after standard chemoradiotherapy remain high.

Objective

To evaluate toxic effects, local control, and overall survival rates after chemoradiotherapy with a simultaneous integrated boost of radiotherapy dose to the gross tumor and nodal disease for patients with unresectable locally advanced esophageal cancer.

Design, Setting, and Participants

A phase 1/2, single-arm trial was conducted in 46 patients from April 28, 2010, to April 9, 2015 (median follow-up, 52 months [range, 2-86 months]), at a tertiary academic cancer center. Outcomes of the study patients were compared with those of 97 similar patients treated at the same institution from January 10, 2010, to December 5, 2014, as part of the interim analysis. Statistical analysis was performed from December 15, 2018, to February 12, 2019.

Interventions

Chemoradiotherapy with a simultaneous integrated boost of radiotherapy dose (50.4 Gy to subclinical areas at risk and 63.0 Gy to the gross tumor and involved nodes, all given in 28 fractions) with concurrent docetaxel and capecitabine or fluorouracil.

Main Outcomes and Measures

Toxic effects, local (in-field) control, and overall survival rates.

Results

All 46 patients (11 women and 35 men; median age, 65.5 years [range, 37.3-84.4 years]) received per-protocol therapy, as intensity-modulated photon therapy (39 [85%]) or intensity-modulated proton therapy (7 [15%]); 11 patients (24%) ultimately underwent resection. No patients experienced grade 4 or 5 toxic effects; the 10 acute grade 3 toxic events were esophagitis (4), dysphagia (3), and anorexia (3) and the 3 late grade 3 toxic events were all esophageal strictures. The actuarial local recurrence rates were 22% (95% CI, 11%-35%) at 6 months, 30% (95% CI, 18%-44%) at 1 year, and 33% (95% CI, 20%-46%) at 2 years. Overall, 15 patients (33%) experienced local failure, at a median interval of 5 months (range, 1-24 months). The median overall survival time was 21.5 months (range, 2.3-86.4 months). Exploratory comparison with a 97-patient contemporaneous institutional cohort receiving standard-dose (non-simultaneous integrated boost) chemoradiotherapy showed superior local control (hazard ratio, 0.49; 95% CI, 0.26-0.92; P = .03) and overall survival (hazard ratio, 0.66; 95% CI, 0.47-0.94; P = .02) in the group that received chemoradiotherapy with a simultaneous integrated boost.

Conclusions and Relevance

These findings suggest that chemoradiotherapy with a simultaneous integrated boost of radiotherapy dose for locally advanced esophageal cancer is well tolerated, with encouraging local control, and thus warrants further study.

Trial Registration

ClinicalTrials.gov identifier: NCT01102088.

The Impact of Durvalumab on Local-Regional Control in Stage III NSCLCs Treated With Chemoradiation and on KEAP1-NFE2L2-Mutant Tumors

INTRODUCTION

KEAP1-NFE2L2-mutant NSCLCs are chemoradiation resistant and at high risk for local-regional failure (LRF) after concurrent chemoradiation (cCRT). To elucidate the impact of durvalumab on local-regional control, we evaluated LRF in patients with NSCLC treated with cCRT with and without durvalumab.

METHODS

Patients with stage III NSCLC treated with cCRT or cCRT and durvalumab who underwent tumor genomic profiling were evaluated. The incidence of LRF and outcomes of patients with and without KEAP1-NFE2L2-mutant tumors were evaluated.

RESULTS

We analyzed 120 consecutive patients (cCRT alone, n = 54; cCRT and durvalumab, n = 66). Patients treated with cCRT alone had significantly more LRF events compared with those treated with cCRT and durvalumab, with 12-month LRF incidence of 39% (95% confidence interval [CI]: 24%-54%) and 18% (95% CI: 8%-28%), respectively (p = 0.002). Among patients treated with cCRT alone and cCRT and durvalumab, 20 patients (37%) and 18 patients (27%), respectively, had KEAP1-NFE2L2-mutant tumors. In patients treated with cCRT alone, those with KEAP1-NFE2L2-mutant tumors had worse local-regional control (p = 0.015), and on multivariate analysis, KEAP1-NFE2L2 mutation predicted for LRF (hazard ratio = 3.9, 95% CI: 1.6-9.8, p = 0.003). Nevertheless, patients with and without KEAP1-NFE2L2-mutant tumors had similar LRF outcomes (p = 0.541) when treated with cCRT and durvalumab, and mutational status did not predict for LRF (p = 0.545). Among those with KEAP1-NFE2L2-mutant tumors, cCRT and durvalumab significantly reduced the incidence of LRF compared with cCRT alone: 12-month LRF incidence of 62% (95% CI: 40%-84%) versus 25% (95% CI: 4%-46%), respectively (p = 0.021).

CONCLUSIONS

Durvalumab after cCRT significantly improves local-regional control and reduces LRF in chemoradiation-resistant KEAP1-NFE2L2-mutant NSCLC tumors.

Postoperative Radiotherapy for Locally Advanced NSCLC: Implications for Shifting to Conformal, High-Risk Fields

BACKGROUND

To examine the effect of radiotherapy field size on survival outcomes and patterns of recurrence in patients treated with postoperative radiotherapy (PORT) for non-small-cell lung cancer (NSCLC).

METHODS

We retrospectively reviewed the records of 216 patients with T1-4 N1-2 NSCLC following surgery and PORT using whole mediastinum (WM) or high-risk (HR) nodal fields from 1998 to 2015. Survival rates were calculated using the Kaplan-Meier method. Univariate and multivariable analyses were conducted using Cox proportional hazards modeling for outcomes and logistic regression analysis for treatment toxicities.

RESULTS

Median follow-up was 28 months (interquartile range [IQR] 13-75 months) and 38 months (IQR 19-73 months) for WM (n = 131) and HR (n = 84) groups, respectively. Overall survival (OS) was not significantly different between groups (median OS: HR 49 vs. WM 32 months; P = .08). There was no difference in progression-free survival (PFS), freedom from locoregional recurrence (LRR), or freedom from distant metastasis (P > .2 for all). Field size was not associated with OS, PFS, or LRR (P > .40 for all). LRR rates were 20% for HR and 26% for WM groups (P = .30). There was no significant difference in patterns of initial site of LRR between groups (P > .1). WM fields (OR 3.73, P = .001) and concurrent chemotherapy (odds ratio 3.62, P = .001) were associated with grade ≥2 toxicity.

CONCLUSIONS

Locoregional control and survival rates were similar between PORT groups; an improved toxicity profile was observed in the HR group. Results from an ongoing prospective randomized clinical trial will provide further insight into the consequences of HR PORT fields.

Early and Midtreatment Mortality in Palliative Radiotherapy: Emphasizing Patient Selection in High-Quality End-of-Life Care

BACKGROUND

Palliative radiotherapy (RT) is effective, but some patients die during treatment or too soon afterward to experience benefit. This study investigates end-of-life RT patterns to inform shared decision-making and facilitate treatment consistent with palliative goals.

MATERIALS AND METHODS

All patients who died ≤6 months after initiating palliative RT at an academic cancer center between 2015 and 2018 were identified. Associations with time-to-death, early mortality (≤30 days), and midtreatment mortality were analyzed.

RESULTS

In total, 1,620 patients died ≤6 months from palliative RT initiation, including 574 (34%) deaths at ≤30 days and 222 (14%) midtreatment. Median survival was 43 days from RT start (95% CI, 41-45) and varied by site (P<.001), ranging from 36 (head and neck) to 53 days (dermal/soft tissue). On multivariable analysis, earlier time-to-death was associated with osseous (hazard ratio [HR], 1.33; P<.001) and head and neck (HR, 1.45; P<.001) sites, multiple RT courses ≤6 months (HR, 1.65; P<.001), and multisite treatments (HR, 1.40; P=.008), whereas stereotactic technique (HR, 0.77; P<.001) and more recent treatment year (HR, 0.82; P<.001) were associated with longer survival. No difference in time to death was noted among patients prescribed conventional RT in 1 to 10 versus >10 fractions (median, 40 vs 47 days; P=.272), although the latter entailed longer courses. The 30-day mortality group included 335 (58%) inpatients, who were 27% more likely to die midtreatment (P=.031). On multivariable analysis, midtreatment mortality among these inpatients was associated with thoracic (odds ratio [OR], 2.95; P=.002) and central nervous system (CNS; OR, 2.44; P=.002) indications, >5-fraction courses (OR, 3.27; P<.001), and performance status of 3 to 4 (OR, 1.63; P=.050). Conversely, palliative/supportive care consultation was associated with decreased midtreatment mortality (OR, 0.60; P=.045).

CONCLUSIONS

Earlier referrals and hypofractionated courses (≤5-10 treatments) should be routinely considered for palliative RT indications, given the short life expectancies of patients at this stage in their disease course. Providers should exercise caution for emergent thoracic and CNS indications among inpatients with poor prognoses due to high midtreatment mortality.

Management of Synchronous Extrathoracic Oligometastatic Non-Small Cell Lung Cancer

Stage IV non-small cell lung cancer (NSCLC) accounts for 35 to 40% of newly diagnosed cases of NSCLC. The oligometastatic state-≤5 extrathoracic metastatic lesions in ≤3 organs-is present in ~25% of patients with stage IV disease and is associated with markedly improved outcomes. We retrospectively identified patients with extrathoracic oligometastatic NSCLC who underwent primary tumor resection at our institution from 2000 to 2018. Event-free survival (EFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Factors associated with EFS and OS were determined using Cox regression. In total, 111 patients with oligometastatic NSCLC underwent primary tumor resection; 87 (78%) had a single metastatic lesion. Local consolidative therapy for metastases was performed in 93 patients (84%). Seventy-seven patients experienced recurrence or progression. The five-year EFS was 19% (95% confidence interval (CI), 12-29%), and the five-year OS was 36% (95% CI, 27-50%). Factors independently associated with EFS were primary tumor size (hazard ratio (HR), 1.15 (95% CI, 1.03-1.29); p = 0.014) and lymphovascular invasion (HR, 1.73 (95% CI, 1.06-2.84); p = 0.029). Factors independently associated with OS were neoadjuvant therapy (HR, 0.43 (95% CI, 0.24-0.77); p = 0.004), primary tumor size (HR, 1.18 (95% CI, 1.02-1.35); p = 0.023), pathologic nodal disease (HR, 1.83 (95% CI, 1.05-3.20); p = 0.033), and visceral-pleural invasion (HR, 1.93 (95% CI, 1.10-3.40); p = 0.022). Primary tumor resection represents an important treatment option in the multimodal management of extrathoracic oligometastatic NSCLC. Encouraging long-term survival can be achieved in carefully selected patients, including those who received neoadjuvant therapy and those with limited intrathoracic disease.

Emerging Paradigm of Consolidative Thoracic Radiotherapy in Oligometastatic NSCLC

The concept of oligometastatic disease has evolved substantially over the past decade. During this time, there has been a transition from retrospective and single-arm prospective studies to randomized evidence suggesting a benefit of local consolidative therapy (LCT) in the setting of limited metastatic non-small cell lung cancer. These trials had constraints and were thus limited in the strength of their conclusions, but led to several other ongoing randomized trials examining the role of LCT. These studies span various disease states (synchronous oligometastatic vs oligoprogressive), the scope of histologies included, and in how they define oligometastases. In addition, parallel biologic work is attempting to integrate relevant biomarkers and molecular classifications, with the ultimate goal of more precisely defining oligometastases and triaging patients to appropriate care. Finally, consensus guidelines have been initiated that provide a framework for designing future studies and for maintaining consistency across analyses that will facilitate the interpretation of results. This review describes the prior randomized data, the limitations therein, and future directions of clinical and preclinical studies that highlight the emerging paradigms for treatment of this select patient cohort.

Treatment planning and outcomes effects of reducing the preferred mean esophagus dose for conventionally fractionated non-small cell lung cancer radiotherapy

Based on an analysis of published literature, our department recently lowered the preferred mean esophagus dose (MED) constraint for conventionally fractionated (2 Gy/fraction in approximately 30 fractions) treatment of locally advanced non-small cell lung cancer (LA-NSCLC) with the goal of reducing the incidence of symptomatic acute esophagitis (AE). The goal of the change was to encourage treatment planners to achieve a MED close to 21 Gy while still permitting MED to go up to the previous guideline of 34 Gy in difficult cases. We compared all our suitable LA-NSCLC patients treated with plans from one year before through one year after the constraint change. The primary endpoint for this study was achievability of the new constraint by the planners; the secondary endpoint was reduction in symptomatic AE. Planners were able to achieve the new constraint in statistically significantly more cases during the year following its explicit implementation than in the year before (P = 0.0025). Furthermore, 38% of patients treated after the new constraint developed symptomatic AE during their treatment as opposed to 48% of the patients treated before. This is a clinically desirable endpoint although the observed difference was not statistically significant. A subsequent power calculation suggests that this is due to the relatively small number of patients in the study.

Impact of Telemedicine on Patient Satisfaction and Perceptions of Care Quality in Radiation Oncology

BACKGROUND

The COVID-19 pandemic has transformed cancer care with the rapid expansion of telemedicine, but given the limited use of telemedicine in oncology, concerns have been raised about the quality of care being delivered. We assessed the patient experience with telemedicine in routine radiation oncology practice to determine satisfaction, quality of care, and opportunities for optimization.

PATIENTS AND METHODS

Patients seen within a multistate comprehensive cancer center for prepandemic office visits and intrapandemic telemedicine visits in December 2019 through June 2020 who completed patient experience questionnaires were evaluated. Patient satisfaction between office and telemedicine consultations were compared, patient visit-type preferences were assessed, and factors associated with an office visit preference were determined.

RESULTS

In total, 1,077 patients were assessed (office visit, n=726; telemedicine, n=351). The telemedicine-consult survey response rate was 40%. No significant differences were seen in satisfaction scores between office and telemedicine consultations, including the appointment experience versus expectation, quality of physician's explanation, and level of physician concern and friendliness. Among telemedicine survey respondents, 45% and 34% preferred telemedicine and office visits, respectively, and 21% had no preference for their visit type. Most respondents found their confidence in their physician (90%), understanding of the treatment plan (88%), and confidence in their treatment (87%) to be better or no different than with an office visit. Patients with better performance status and who were married/partnered were more likely to prefer in-person office visit consultations (odds ratio [OR], 1.04 [95% CI, 1.00-1.08]; P=.047, and 2.41 [95% CI, 1.14-5.47]; P=.009, respectively). Patients with telephone-only encounters were more likely to report better treatment plan understanding with an office visit (OR, 2.25; 95% CI, 1.00-4.77; P=.04).

CONCLUSIONS

This study is the first to assess telemedicine in routine radiation oncology practice, and found high patient satisfaction and confidence in their care. Optimization of telemedicine in oncology should be a priority, specifically access to audiovisual capabilities that can improve patient-oncologist communication.

Clinical and Dosimetric Predictors of Radiation Pneumonitis in Patients With Non-Small Cell Lung Cancer Undergoing Postoperative Radiation Therapy

PURPOSE

Radiation pneumonitis (RP) is a common and potentially life-threatening toxicity from lung cancer radiation therapy. Data sets reporting RP rates after postoperative radiation therapy (PORT) have historically been small and with predominantly outdated field designs and radiation techniques. We examined a large cohort of patients in this context to assess the incidence and causes of RP in the modern era.

METHODS AND MATERIALS

We reviewed 285 patients with non-small cell lung cancer treated with PORT at our institution from May 2004 to January 2017. Complete dosimetric data and clinical records were reviewed and analyzed with grade 2 or higher RP as the endpoint (RP2+) (Common Terminology Criteria for Adverse Events v4.0). Patients were a median of 67 years old (range, 28-87), and most had pathologic stage III non-small cell lung cancer (91%) and received trimodality therapy (90%). Systematic dosimetric analyses using Dx increments of 5% and Vx increments of 2 Gy were performed to robustly evaluate dosimetric variables. Lung V₅ was also evaluated.

RESULTS

The incidence of RP2+ after PORT was 12.6%. Dosimetric factors most associated with RP2+ were total lungV₄ (hazard ratio [HR] 1.04, P < .001) and heart V₁₆ (HR 1.03, P = .001). On univariate analysis, the clinical factors of age (HR 1.05, P = .006) and carboplatin chemotherapy (HR 2.32, P = .012) were correlated with RP2+. On step-up multivariate analysis, only bivariate models remained significant, including lungV₅ (HR 1.037, P < .001) and age (HR 1.052, P = .011).

CONCLUSIONS

The incidence of RP after PORT is consistent with the literature. Factors correlated with RP include lung and heart doses, age, and carboplatin chemotherapy. These data also suggest that elderly patients may be more susceptible to lower doses of radiation to the lung. Based on these data, dose constraints to limit the risk of RP2+ to <5% in the setting of PORT include lungV₅ ≤65% in patients <65 years old and lungV₅ ≤36% in patients 65 years or older.

Development and application of an elastic net logistic regression model to investigate the impact of cardiac substructure dose on radiation-induced pericardial effusion in patients with NSCLC

BACKGROUND

Typically, cardiac substructures are neither delineated nor analyzed during radiation treatment planning. Therefore, we developed a novel machine learning model to evaluate the impact of cardiac substructure dose for predicting radiation-induced pericardial effusion (PCE).

MATERIALS AND METHODS

One-hundred and forty-one stage III NSCLC patients, who received radiation therapy in a prospective clinical trial, were included in this analysis. The impact of dose-volume histogram (DVH) metrics (mean and max dose, V5Gy[%]-V70Gy[%]) for the whole heart, left and right atrium, and left and right ventricle, on pericardial effusion toxicity (≥grade 2, CTCAE v4.0 grading) were examined. Elastic net logistic regression, using repeat cross-validation (n = 100 iterations, 75%/25% training/test set data split), was conducted with cardiac-based DVH metrics as covariates. The following model types were constructed and analyzed: (i) standard model type, which only included whole-heart DVH metrics; and (ii) a model type trained with both whole-heart and substructure DVH metrics. Model performance was analyzed on the test set using area under the curve (AUC), accuracy, calibration slope and calibration intercept. A final fitted model, based on the optimal model type, was developed from the entire study population for future comparisons.

RESULTS

Grade 2 PCE incidence was 49.6% (n = 70). Models using whole heart and substructure dose had the highest performance (median values: AUC = 0.820; calibration slope/intercept = 1.356/-0.235; accuracy = 0.743) and outperformed the standard whole-heart only model type (median values: AUC = 0.799; calibration slope/intercept = 2.456/-0.729; accuracy = 0.713). The final fitted elastic net model showed high performance in predicting PCE (median values: AUC = 0.879; calibration slope/intercept = 1.352/-0.174; accuracy = 0.801).

CONCLUSIONS

We developed and evaluated elastic net regression toxicity models of radiation-induced PCE. We found the model type that included cardiac substructure dose had superior predictive performance. A final toxicity model that included cardiac substructure dose metrics was developed and reported for comparison with external datasets.

Radiation Oncologist Perceptions of Telemedicine from Consultation to Treatment Planning: A Mixed-Methods Study

PURPOSE

Telemedicine was rapidly implemented for initial consultations and radiation treatment planning in the wake of the coronavirus disease 2019 (COVID-19) pandemic. In this study, we explore utilization of and physician perspectives on this approach in an attempt to identify patient populations that may benefit most from virtual care.

METHODS AND MATERIALS

This is a mixed-methods study with a convergent design. Approximately 6 to 8 weeks after implementation of telemedicine, all radiation oncologists in a single academic radiation oncology department were invited to participate in either semistructured interviews with embedded survey questions or a concurrently administered survey only. Rapid qualitative analysis was used to identify common themes, and quantitative data was assessed using descriptive statistics and univariable analyses.

RESULTS

At the apex of the pandemic, 92% of radiation oncology visits were conducted via telemedicine. In total, 51 of 61 radiation oncologists participated in the study (response rate 84%). Most (71%) reported no difference in ability to treat cancer appropriately via telemedicine, which was more common among specialized physicians (P = .01) but not those with higher visit volume or years of experience. Over half (55%) perceived no difference or even improvement in overall visit quality with telemedicine. Virtual visits were deemed acceptable for a median of 70% to 96% of patients, which varied by disease site. Need for physical examination, and availability of an acceptable proxy, factored into telemedicine acceptability. Most (88%) found telemedicine better than expected, but opinions were split on how telemedicine would affect physician burnout. Almost all (96%) foresaw a role for telemedicine beyond the pandemic and would opt for a median of 50% (interquartile range 20%-66%) of visits conducted via telemedicine.

CONCLUSIONS

Among radiation oncologists in an academic setting, telemedicine was perceived to be highly appropriate and acceptable for most patients. Future studies should focus on identifying the 5% to 30% of patients whose care may be optimized with in-person visits, and if there is alignment with patient preferences.

Safety of thoracic radiotherapy in patients with prior immune-related adverse events from immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) and thoracic radiotherapy are increasingly used to treat advanced cancers. Despite data indicating exaggerated radiation toxicities in patients with autoimmune disease, the safety of thoracic radiotherapy in patients with prior ICI-associated immune-related adverse events (irAEs) is undefined.

PATIENTS AND METHODS

Patients treated from 2014 to 2020 with ICIs were queried for receipt of corticosteroids and radiotherapy. Patients who received thoracic radiation after symptomatic irAEs were assessed for ≥grade 2 radiation pneumonitis (RP). Characteristics predictive of RP were assessed using logistic regression and response relationships were modeled.

RESULTS

Among 496 assessed patients, 41 with irAE history subsequently treated with thoracic radiotherapy were analyzed. Most irAEs were grade 2 (n = 21) and 3 (n = 19). Median time from irAE onset to radiotherapy was 8.1 months. Most patients received stereotactic body radiation therapy (n = 20) or hypofractionated radiotherapy (n = 18). In total, 25 patients (61%) developed ≥grade 2 RP at a median of 4 months from radiotherapy and 11 months from onset of irAEs. Three months from RP onset, 16 of 24 (67%) assessable patients had persistent symptoms. Among patients with prior ICI pneumonitis (n = 6), five patients (83%) developed ≥grade 2 RP (grade 2, n = 3; grade ≥3, n = 2). The mean lung radiation dose (MLD) predicted for RP (odds ratio: 1.60, P = 0.00002). The relationship between MLD and RP was strong (area under the receiver-operating characteristic curve: 0.85) and showed an exaggerated dose-response. Among patients with an MLD >5 Gy (n = 26), 21 patients (81%) developed ≥grade 2 RP.

CONCLUSION

This is the first study assessing the toxicity of radiotherapy among patients with prior irAEs from ICIs. Patients with prior irAEs were found to be at very high risk for clinically significant and persistent RP from thoracic radiotherapy. Careful consideration should be given to the possibility of an increased risk of RP, and close monitoring is recommended in these patients.

Sex-Based Disparities Among Cancer Clinical Trial Participants

Landmark investigation two decades ago demonstrated sex-based disparities among participants in cancer cooperative group trials. Although federal efforts have aimed to improve representation of female patients in government-sponsored research, less is known about sex disparities in the broader landscape of modern oncologic randomized controlled trials. Using ClinicalTrials.gov, we identified randomized controlled trials related to colorectal or lung cancer (the two most common non-sex-specific disease sites). Among the 147 included trials, the proportion of female patients enrolled on trial was on average 6.8% (95% confidence interval = -8.8% to -4.9%) less than the proportion of female patients in the population by disease site (P < .001). Whereas no statistically significant underrepresentation of women was noted within the 26 cooperative group trials, sex disparities were markedly heightened for the 121 noncooperative-group-sponsored trials. Furthermore, underrepresentation of women did not improve with time. Future efforts should therefore focus on addressing these pervasive sex-based enrollment disparities beyond cooperative group trials alone.

Need for Caution in the Diagnosis of Radiation Pneumonitis During the COVID-19 Pandemic

PURPOSE

Patients with cancer are at high risk for mortality from coronavirus disease 2019 (COVID-19). Radiation pneumonitis (RP) is a common toxicity of thoracic radiation therapy with clinical and imaging features that overlap with those of COVID-19; however, RP is treated with high-dose corticosteroids, which may exacerbate COVID-19-associated lung injury. We reviewed patients who presented with symptoms of RP during the intensification of a regional COVID-19 epidemic to report on their clinical course and COVID-19 testing results.

METHODS AND MATERIALS

The clinical course and chest computed tomography (CT) imaging findings of consecutive patients who presented with symptoms of RP in March 2020 were reviewed. The first regional COVID-19 case was diagnosed on March 1, 2020. All patients underwent COVID-19 qualitative RNA testing.

RESULTS

Four patients with clinical suspicion for RP were assessed. Three out of 4 patients tested positive for COVID-19. All patients presented with symptoms of cough and dyspnea. Two patients had a fever, of whom only 1 tested positive for COVID-19. Two patients started on an empirical high-dose corticosteroid taper for presumed RP, but both had clinical deterioration and ultimately tested positive for COVID-19 and required hospitalization. Chest CT findings in patients suspected of RP but ultimately diagnosed with COVID-19 showed ground-glass opacities mostly pronounced outside the radiation field.

CONCLUSIONS

As this pandemic continues, patients with symptoms of RP require diagnostic attention. We recommend that patients suspected of RP be tested for COVID-19 before starting empirical corticosteroids and for careful attention to be paid to chest CT imaging to prevent potential exacerbation of COVID-19 in these high-risk patients.

Thoracic Radiation Therapy During Coronavirus Disease 2019: Provisional Guidelines from a Comprehensive Cancer Center within a Pandemic Epicenter

Coronavirus disease 2019 is an unprecedented pandemic with significant and evolving impact on the practice of radiation oncology. Radiation oncology departments must anticipate and account for coronavirus disease 2019 exposure risk for both patients and staff. The potential for severe radiation therapy resource constraints, particularly due to staff illness, must also be considered. Here we present provisional guidelines for thoracic radiation therapy adopted at our facility, a high-volume cancer center located in a United States pandemic epicenter. Generally, these guidelines reflect the principle that where evidence-supported hypofractionated schedules with comparable efficacy and toxicity exist, the shortest such schedules should be employed. In addition, we discuss potential adaptations in the prioritization and timing of radiation therapy for thoracic malignancies under these circumstances.