Phase 2 Trial of Consolidation Pembrolizumab After Proton Reirradiation for Thoracic Recurrences of Non-Small Cell Lung Cancer

PURPOSE

Reirradiation (reRT) with proton beam therapy (PBT) may offer a chance of cure while minimizing toxicity for patients with isolated intrathoracic recurrences of non-small cell lung cancer (NSCLC). However, distant failure remains common, necessitating strategies to integrate more effective systemic therapy.

METHODS AND MATERIALS

This was a phase 2, single-arm trial (NCT03087760) of consolidation pembrolizumab after PBT reRT for locoregional recurrences of NSCLC. Four to 12 weeks after completion of 60 to 70 Gy PBT reRT, patients without progressive disease received pembrolizumab for up to 12 months. Primary endpoint was progression-free survival (PFS), measured from the start of reRT. Secondary endpoints were overall survival (OS) and National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0 toxicity.

RESULTS

Between 2017 and 2021, 22 patients received PBT reRT. Median interval from prior radiation end to reRT start was 20 months. Most recurrences (91%) were centrally located. Most patients received concurrent chemotherapy (95%) and pencil beam scanning PBT (77%), and 36% had received prior durvalumab. Fifteen patients (68%) initiated consolidation pembrolizumab on trial and received a median of 3 cycles (range, 2-17). Pembrolizumab was discontinued most commonly due to toxicity (n = 5; 2 were pembrolizumab-related), disease progression (n = 4), and completion of 1 year (n = 3). Median follow-up was 38.7 months. Median PFS and OS were 8.8 months (95% CI, 4.2-23.7) and 22.8 months (95% CI, 6.9-not reached), respectively. There was only one isolated in-field failure after reRT. Grade ≥3 toxicities occurred in 10 patients (45%); 2 were pembrolizumab-related. There were 2 grade 5 toxicities, an aorto-esophageal fistula at 6.9 months and hemoptysis at 46.8 months, both probably from reRT. The trial closed early due to widespread adoption of immunotherapy off-protocol.

CONCLUSIONS

In the first-ever prospective trial combining PBT reRT with consolidation immunotherapy, PFS was acceptable and OS favorable. Late grade 5 toxicity occurred in 2 of 22 patients. This approach may be considered in selected patients with isolated thoracic recurrences of NSCLC.

Differences in Radiotherapy-Treated Members with Cancer during COVID-19 Pandemic Using Nationwide Claim Data

PURPOSE/OBJECTIVE(S)

This study aimed to identify the impact of the pandemic on radiotherapy activity among members with cancer.

MATERIALS/METHODS

This retrospective study included fully-insured commercial members of a large national payor with cancer aged ≥18 years undergoing radiotherapy from March 1, 2018 to February 28, 2022. Radiotherapy activity was defined as the mean weekly number of treatment courses and attendances (fractions) per month pre-COVID (March 2018 to February 2020); during COVID (March 2020 to February 2021); and post-COVID (March 2021 to February 2022). T-tests assessed differences between pre-COVID and post-COVID on radiotherapy activity by age, gender, and cancer type. Interrupted time series analysis (ITS) assessed change in activity overtime, controlling for pre-COVID trends and other potential confounders. A p-value of <0.05 was considered significant.

RESULTS

The study included 9,275 members, 10,121 courses, and 169,257 fractions; most members were female (57%), the mean age was 57 years (SD = 12). Overall, there was a decline in mean weekly number of courses from the pre-COVID to post-COVID (-18%, p<0.05) timeframe. Females < 70 years experienced the largest decline in mean weekly number of courses (-23%, p<0.05) followed by males aged 70+ (-16%, p<0.05) and males < 70 years (-16%, p<0.05). All cancer types saw a significant decline (p<0.05); breast cancer reported the largest decline (-21%, p<0.05). Fraction numbers significantly declined overall by 27% (p<0.05) from the pre-COVID to post-COVID timeframe. The largest decline in fraction numbers was observed in females < 70 (-28%, p<0.05) followed by males < 70 years (-24%, p<0.05) and males aged 70+ (-22%, p<0.05). No difference between COVID and pre-COVID weeks for courses was observed once pre-COVID trends were accounted for using ITS. Females aged 70+ received 25% (p<0.05) fewer fractions during COVID compared to pre-COVID; a decline which continued to grow even as the pandemic eased (March 2021 to February 2022). Males aged 70+ also experienced a decreased level of fractions during the pandemic (-30%, p<0.05), but increased in the recovery period (+24%, p<0.05). Males < 70 years had an increased level of fractions during the pandemic (+14%, p<0.05).

CONCLUSION

Radiation mean weekly number of courses and fractions between pre-COVID and post-COVID declined with the effect more pronounced in females < 70 years. A decrease in fraction number was observed in all cancer types; specifically, breast cancer had the largest decline. ITS analysis revealed no difference between COVID and pre-COVID weeks for courses as the downward trend was already present prior to the pandemic. These findings suggest while radiotherapy courses and fractions were significantly impacted, fractionation was decreased to a greater extent, indicating an increased adoption of hypofractionation during the pandemic.

Cardiovascular Substructure Dose and Cardiac Events following Proton- and Photon-Based Chemoradiotherapy for Non-Small Cell Lung Cancer

Purpose

Radiation therapy (RT) plays a critical role in treating locally advanced non-small cell lung cancer but has been associated with deleterious cardiac effects. We hypothesized that RT dose to certain cardiovascular substructures may be higher among those who experience post-chemoradiation (CRT) cardiac events, and that dose to specific substructures-the great vessels, atria, ventricles, and left anterior descending coronary artery-may be lower with proton- versus photon-based RT.

Methods and Materials

In this retrospective review, we selected 26 patients who experienced cardiac events after CRT for locally advanced non-small cell lung cancer and matched them to 26 patients who did not experience cardiac events after CRT. Matching was done based on RT technique (protons vs photons), age, sex, and cardiovascular comorbidity. For each patient, the whole heart and 10 cardiovascular substructures on the RT planning computerized tomography scan were manually contoured. Dosimetric comparisons were made between those who did and did not experience cardiac events and between the proton and photon groups.

Results

There was no significant difference in heart or any cardiovascular substructure dose between those patients who experienced post-treatment cardiac events and those who did not (P > .05 for all). The mean heart dose in the patients receiving proton therapy was significantly lower than the mean heart dose in the patients receiving photon therapy (P = .032). The left ventricle, right ventricle, and the left anterior descending artery also had significantly lower doses (by multiple measures) when treated with protons (P = .0004, P < .0001, and P = .0002, respectively).

Conclusions

Proton therapy may have a significant effect on decreasing dose to individual cardiovascular substructures compared with photon therapy. There was no significant difference in heart dose or dose to any cardiovascular substructure between patients who did and did not experience post-treatment cardiac events. Further research should be done to assess the association between cardiovascular substructure dose and post-treatment cardiac events.

Utilization and factors precluding receipt of checkpoint inhibitor consolidation for stage III NSCLC in a large U.S. academic health system

OBJECTIVES

We sought to determine the proportion of patients with stage III non-small cell lung cancer (NSCLC) who initiate consolidation durvalumab or other immune checkpoint inhibitors (ICIs) after concurrent chemoradiotherapy (cCRT), as well as reasons for nonreceipt and prognostic implications.

MATERIALS AND METHODS

We retrospectively identified consecutive patients with unresectable stage III NSCLC treated with definitive cCRT between October 2017 and December 2021 within a large US academic health system. Patients either received consolidation ICIs (ICI group) or did not (no-ICI group). Baseline characteristics and overall survival (OS) of the groups were assessed. Factors predictive of ICI nonreceipt were evaluated using logistic regression.

RESULTS

Of 333 patients who completed cCRT, 229 (69%) initiated consolidation ICIs; 104 (31%) did not. Reasons for ICI nonreceipt included progressive disease post-cCRT (N = 31, 9%), comorbidity or intercurrent illness (N = 25, 8%), cCRT toxicity (N = 23, 7%; 19/23 pneumonitis), and EGFR/ALK alteration (N = 14, 4%). The no-ICI group had worse performance status and a higher rate of baseline pulmonary comorbidity. Larger planning target volume was associated with post-cCRT progressive disease, and higher lung radiation dose with cCRT toxicity. Median OS was 16 months in the no-ICI group and 34.4 months in the ICI group. In the no-ICI group, OS was superior among those with EGFR/ALK alterations (median 44.5 months) and worst among those with progressive disease (median 5.9 months, P < 0.001).

CONCLUSION

31% of patients who completed cCRT for stage III NSCLC did not receive consolidation ICIs. Survival amongst these patients is poor, especially for those with progressive disease post-cCRT.

Death without progression as an endpoint to describe cardiac radiation effects in locally advanced non-small cell lung cancer

Background and purpose

Prior studies have examined associations of cardiovascular substructure dose with overall survival (OS) or cardiac events after chemoradiotherapy (CRT) for non-small cell lung cancer (NSCLC). Herein, we investigate an alternative endpoint, death without cancer progression (DWP), which is potentially more specific than OS and more sensitive than cardiac events for understanding CRT toxicity.

Materials and methods

We retrospectively reviewed records of 187 patients with locally advanced or oligometastatic NSCLC treated with definitive CRT from 2008 to 2016 at a single institution. Dosimetric parameters to the heart, lung, and ten cardiovascular substructures were extracted. Charlson Comorbidity Index (CCI), excluding NSCLC diagnosis, was used to stratify patients into CCI low (0-2; n = 66), CCI intermediate (3-4; n = 78), and CCI high (≥5; n = 43) groups. Primary endpoint was DWP, modeled with competing risk regression. Secondary endpoints included OS. An external cohort consisted of 140 patients from another institution.

Results

Median follow-up was 7.3 years for survivors. Death occurred in 143 patients (76.5 %), including death after progression in 118 (63.1 %) and DWP in 25 (13.4 %). On multivariable analysis, increasing CCI stratum and mean heart dose were associated with DWP. For mean heart dose ≥ 10 Gy vs < 10 Gy, DWP was higher (5-year rate, 16.9 % vs 6.7 %, p = 0.04) and OS worse (median, 22.9 vs 34.1 months, p < 0.001). Ventricle (left, right, and bilateral) and pericardial but not atrial substructure dose were associated with DWP, whereas all three were inversely associated with OS. Cutpoint analysis identified right ventricle mean dose ≥ 5.5 Gy as a predictor of DWP. In the external cohort, we confirmed an association of ventricle, but not atrial, dose with DWP.

Conclusion

Cardiovascular substructure dose showed distinct associations with DWP. Future cardiotoxicity studies in NSCLC could consider DWP as an endpoint.

Combining natural and artificial intelligence for robust automatic anatomy segmentation: Application in neck and thorax auto-contouring

BACKGROUND

Automatic segmentation of 3D objects in computed tomography (CT) is challenging. Current methods, based mainly on artificial intelligence (AI) and end-to-end deep learning (DL) networks, are weak in garnering high-level anatomic information, which leads to compromised efficiency and robustness. This can be overcome by incorporating natural intelligence (NI) into AI methods via computational models of human anatomic knowledge.

PURPOSE

We formulate a hybrid intelligence (HI) approach that integrates the complementary strengths of NI and AI for organ segmentation in CT images and illustrate performance in the application of radiation therapy (RT) planning via multisite clinical evaluation.

METHODS

The system employs five modules: (i) body region recognition, which automatically trims a given image to a precisely defined target body region; (ii) NI-based automatic anatomy recognition object recognition (AAR-R), which performs object recognition in the trimmed image without DL and outputs a localized fuzzy model for each object; (iii) DL-based recognition (DL-R), which refines the coarse recognition results of AAR-R and outputs a stack of 2D bounding boxes (BBs) for each object; (iv) model morphing (MM), which deforms the AAR-R fuzzy model of each object guided by the BBs output by DL-R; and (v) DL-based delineation (DL-D), which employs the object containment information provided by MM to delineate each object. NI from (ii), AI from (i), (iii), and (v), and their combination from (iv) facilitate the HI system.

RESULTS

The HI system was tested on 26 organs in neck and thorax body regions on CT images obtained prospectively from 464 patients in a study involving four RT centers. Data sets from one separate independent institution involving 125 patients were employed in training/model building for each of the two body regions, whereas 104 and 110 data sets from the 4 RT centers were utilized for testing on neck and thorax, respectively. In the testing data sets, 83% of the images had limitations such as streak artifacts, poor contrast, shape distortion, pathology, or implants. The contours output by the HI system were compared to contours drawn in clinical practice at the four RT centers by utilizing an independently established ground-truth set of contours as reference. Three sets of measures were employed: accuracy via Dice coefficient (DC) and Hausdorff boundary distance (HD), subjective clinical acceptability via a blinded reader study, and efficiency by measuring human time saved in contouring by the HI system. Overall, the HI system achieved a mean DC of 0.78 and 0.87 and a mean HD of 2.22 and 4.53 mm for neck and thorax, respectively. It significantly outperformed clinical contouring in accuracy and saved overall 70% of human time over clinical contouring time, whereas acceptability scores varied significantly from site to site for both auto-contours and clinically drawn contours.

CONCLUSIONS

The HI system is observed to behave like an expert human in robustness in the contouring task but vastly more efficiently. It seems to use NI help where image information alone will not suffice to decide, first for the correct localization of the object and then for the precise delineation of the boundary.

Checkpoint inhibitor consolidation after definitive chemoradiation for stage III non–small cell lung cancer: Real-world experience in a large academic health system

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Background: The PACIFIC trial demonstrated a 10% improvement in 5-year survival with the addition of consolidation durvalumab versus placebo after chemoradiation (CRT) in good performance status patients (pts) with stage III non-small cell lung cancer (NSCLC). However, not all patients who complete CRT go on to receive consolidation durvalumab. We sought to describe real-world use of consolidation durvalumab or other immune checkpoint inhibitors (ICI) in this setting within a single academic health system. Methods: We retrospectively identified pts with unresectable stage III NSCLC treated with definitive CRT between October 2017 and October 2020 within the University of Pennsylvania Health System, including two urban hospitals and two satellite centers. Pts either received consolidation ICI (ICI group) or did not (no ICI group). Baseline characteristics of the groups were compared with the Chi-squared, Fisher exact, or Wilcoxon rank-sum test as appropriate. Overall survival (OS), measured from the last day of CRT, was compared using the Kaplan-Meier method and log-rank test. Results: Of the 148 consecutively treated pts who completed CRT, 108 (73%) received consolidation ICI; 40 (27%) did not. Within the ICI group, 42% completed 1 year (yr) of treatment. Within the no ICI group, reasons for non-receipt included disease progression (n = 14, 35%), CRT toxicity (n = 7, 18%), comorbidity or decline unrelated to CRT (n = 7, 18%), provider choice (n = 6, 15%) due to EGFR mutation (n = 5) or atypical histology (n = 1), pt refusal (n = 3, 8%), and death without progression (n = 3, 8%). The ICI group had better performance status (ECOG 0/1/2, 46%/49%/5% ICI vs 25%/48%/28% no ICI, p < 0.001) lower Charlson Comorbidity Index (median, 5 [IQR 4-6] ICI vs 6 [IQR 5-8] no ICI, p = 0.02), and lower rates of active autoimmune disease or immunosuppression (5% ICI vs 15% no ICI, p = 0.03). There were no differences between groups in age (median, 68 yrs [IQR 63-73] ICI vs 71 yrs [IQR 65-73] no ICI, p = 0.25), sex (female, 60% ICI vs 50% no ICI, p = 0.27), race (Black, 19% ICI vs 20% no ICI, p = 0.82), stage (IIIA/B/C, 42%/48%/11% ICI vs 40%/50%/10% no ICI, p = 0.96), and PD-L1 expression ( < 1%/1-50%/ > 50%/unknown, 36%/25%/29%/10% ICI vs 40%/25%/28%/8% no ICI, p = 0.97). 1- and 2-yr OS were 83% and 61% in the ICI group versus 52% and 34% in the no ICI group, respectively (p < 0.001). Within the no ICI group, OS was worse among those with versus those without disease progression (PD) post-CRT (1-yr OS 24% vs 74%, p = 0.03). Conclusions: In this retrospective study within a large academic health system, we found that over one-quarter of pts who completed chemoradiation for stage III NSCLC did not receive consolidation ICI, most commonly due to disease progression, CRT toxicity, or comorbidity. Survival amongst these pts is particularly poor, especially for those who experience PD shortly after CRT.

Activity Monitoring for Toxicity Detection and Management in Patients Undergoing Chemoradiation for Gastrointestinal Malignancies

PURPOSE

Physical activity is associated with decreased hospitalization during cancer treatment. We hypothesize that activity data can help identify and triage high-risk patients with GI cancer undergoing concurrent chemoradiation.

MATERIALS AND METHODS

This prospective study randomly assigned patients to activity monitoring versus observation. In the intervention arm, a 20% decrease in daily steps or 20% increase in heart rate triggered triage visits to provide supportive care, medication changes, and escalation of care. In the observation group, activity data were recorded but not monitored. The primary objective was to show a 20% increase in triage visits in the intervention group. Secondary objectives were estimating the rates of emergency department (ED) visits and hospitalizations. Crude and adjusted odds ratios were computed using logistic regression modeling.

RESULTS

There were 22 patients in the intervention and 18 in the observation group. Baseline patient and treatment characteristics were similar. The primary objective was met, with 3.4 more triage visits in the intervention group than in the observation group (95% CI, 2.10 to 5.50; P < .0001). Twenty-six (65.0%) patients required at least one triage visit, with a higher rate in the intervention arm compared with that in the observation arm (86.4% v 38.9%; odds ratio, 9.95; 95% CI, 2.13 to 46.56; P = .004). There was no statistically significant difference in ED visit (9.1% v 22.2%; P = .38) or hospitalization (4.5% v 16.7%; P = .31).

CONCLUSION

It is feasible to use activity data to trigger triage visits for symptom management. Further studies are investigating whether automated activity monitoring can assist with early outpatient management to decrease ED visits and hospitalizations.

Impact of telemedicine adoption on accessibility and time to treatment in patients with thoracic malignancies during the COVID-19 pandemic

Background

To ensure safe delivery of oncologic care during the COVID-19 pandemic, telemedicine has been rapidly adopted. However, little data exist on the impact of telemedicine on quality and accessibility of oncologic care. This study assessed whether conducting an office visit for thoracic oncology patients via telemedicine affected time to treatment initiation and accessibility.

Methods

This was a retrospective cohort study of patients with thoracic malignancies seen by a multidisciplinary team during the first surge of COVID-19 cases in Philadelphia (March 1 to June 30, 2020). Patients with an index visit for a new phase of care, defined as a new diagnosis, local recurrence, or newly discovered metastatic disease, were included.

Results

240 distinct patients with thoracic malignancies were seen: 132 patients (55.0%) were seen initially in-person vs 108 (45.0%) via telemedicine. The majority of visits were for a diagnosis of a new thoracic cancer (87.5%). Among newly diagnosed patients referred to the thoracic oncology team, the median time from referral to initial visit was significantly shorter amongst the patients seen via telemedicine vs. in-person (median 5.0 vs. 6.5 days, p < 0.001). Patients received surgery (32.5%), radiation (24.2%), or systemic therapy (30.4%). Time from initial visit to treatment initiation by modality did not differ by telemedicine vs in-person: surgery (22 vs 16 days, p = 0.47), radiation (27.5 vs 27.5 days, p = 0.86, systemic therapy (15 vs 13 days, p = 0.45).

Conclusions

Rapid adoption of telemedicine allowed timely delivery of oncologic care during the initial surge of the COVID19 pandemic by a thoracic oncology multi-disciplinary clinic.

Incorporation of plasma-based next-generation sequencing to improve guideline-concordant molecular testing in patients with newly diagnosed metastatic nonsquamous non-small cell lung cancer

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Background: Current NCCN guidelines recommend comprehensive molecular profiling for all newly diagnosed patients with metastatic non-squamous NSCLC to enable the delivery of personalized medicine. We have previously demonstrated that incorporation of plasma based next-generation gene sequencing (NGS) improves detection of clinically actionable mutations in patients with advanced NSCLC (Aggarwal et al, JAMA Oncology, 2018). To increase rates of comprehensive molecular testing at our institution, we adapted our clinical practice to include concurrent use of plasma (P) and tissue (T) based NGS upon initial diagnosis. P NGS testing was performed using a commercial 74 gene assay. We analyzed the impact of this practice change on guideline concordant molecular testing at our institution. Methods: A retrospective cohort study of patients with newly diagnosed metastatic non-squamous NSCLC following the implementation of this practice change in 12/2018 was performed. Tiers of NCCN guideline concordant testing were defined, Tier 1: complete EGFR, ALK, BRAF, ROS1, MET, RET, NTRK testing, Tier 2: included above, but with incomplete NTRK testing, Tier 3: > 2 genes tested, Tier 4: single gene testing, Tier 5: no testing. Proportion of patients with comprehensive molecular testing by modality (T NGS vs. T+P NGS) were compared using one-sided Fisher’s exact test. Results: Between 01/2019, and 12/2019, 170 patients with newly diagnosed metastatic non-Sq NSCLC were treated at our institution. Overall, 98.2% (167/170) patients underwent molecular testing, Tier 1: n = 100 (59%), Tier 2: n = 39 (23%), Tier 3/4: n = 28 (16.5%), Tier 5: n = 3 (2%). Amongst these patients, 43.1% (72/167) were tested with T NGS alone, 8% (15/167) with P NGS alone, and 47.9% (80/167) with T+P NGS. A higher proportion of patients underwent comprehensive molecular testing (Tiers 1+2) using T+P NGS: 95.7% (79/80) compared to T alone: 62.5% (45/72), p < 0.0005. Prior to the initiation of first line treatment, 72.4% (123/170) patients underwent molecular testing, Tier 1: n = 73 (59%), Tier 2: n = 27 (22%) and Tier 3/4: n = 23 (18%). Amongst these, 39% (48/123) were tested with T NGS alone, 7% (9/123) with P NGS alone and 53.6% (66/123) with T+P NGS. A higher proportion of patients underwent comprehensive molecular testing (Tiers 1+2) using T+P NGS, 100% (66/66) compared to 52% (25/48) with T NGS alone (p < 0.0005). Conclusions: Incorporation of concurrent T+P NGS testing in treatment naïve metastatic non-Sq NSCLC significantly increased the proportion of patients undergoing guideline concordant molecular testing, including prior to initiation of first-line therapy at our institution. Concurrent T+P NGS should be adopted into institutional pathways and routine clinical practice.

Multiblock Discriminant Analysis of Integrative 18F-FDG-PET/CT Radiomics for Predicting Circulating Tumor Cells in Early-Stage Non-small Cell Lung Cancer Treated With Stereotactic Body Radiation Therapy

PURPOSE

The main objective of the present study was to integrate 18F-FDG-PET/CT radiomics with multiblock discriminant analysis for predicting circulating tumor cells (CTCs) in early-stage non-small cell lung cancer (ES-NSCLC) treated with stereotactic body radiation therapy (SBRT).

METHODS

Fifty-six patients with stage I NSCLC treated with SBRT underwent 18F-FDG-PET/CT imaging pre-SBRT and post-SBRT (median, 5 months; range, 3-10 months). CTCs were assessed via a telomerase-based assay before and within 3 months after SBRT and dichotomized at 5 and 1.3 CTCs/mL. Pre-SBRT, post-SBRT, and delta PET/CT radiomics features (n = 1548 × 3/1562 × 3) were extracted from gross tumor volume. Seven feature blocks were constructed including clinical parameters (n = 12). Multiblock data integration was performed using block sparse partial least squares-discriminant analysis (sPLS-DA) referred to as Data Integration Analysis for Biomarker Discovery Using Latent Components (DIABLO) for identifying key signatures by maximizing common information between different feature blocks while discriminating CTC levels. Optimal input blocks were identified using a pairwise combination method. DIABLO performance for predicting pre-SBRT and post-SBRT CTCs was evaluated using combined AUC (area under the curve, averaged across different blocks) analysis with 20 × 5-fold cross-validation (CV) and compared with that of concatenation-based sPLS-DA that consisted of combining all features into 1 block. CV prediction scores between 1 class versus the other were compared using the Wilcoxon rank sum test.

RESULTS

For predicting pre-SBRT CTCs, DIABLO achieved the best performance with combined pre-SBRT PET radiomics and clinical feature blocks, showing CV AUC of 0.875 (P = .009). For predicting post-SBRT CTCs, DIABLO achieved the best performance with combined post-SBRT CT and delta CT radiomics feature blocks, showing CV AUCs of 0.883 (P = .001). In contrast, all single-block sPLS-DA models could not attain CV AUCs higher than 0.7.

CONCLUSIONS

Multiblock integration with discriminant analysis of 18F-FDG-PET/CT radiomics has the potential for predicting pre-SBRT and post-SBRT CTCs. Radiomics and CTC analysis may complement and together help guide the subsequent management of patients with ES-NSCLC.

Phase II Trial of Flaxseed to Prevent Acute Complications After Chemoradiation for Lung Cancer

Background: Thoracic radiotherapy is complicated by acute radiation-induced adverse events such as radiation pneumonitis (RP) and radiation esophagitis (RE). Based on preclinical work and a randomized pilot trial from our laboratory, this single-arm phase II trial investigated administering flaxseed as a radioprotector in patients receiving definitive chemoradiation for nonsmall cell lung cancer (NSCLC). Methods: Between June 2015 and February 2018, 33 patients with locally advanced or metastatic NSCLC with planned definitive chemoradiation were enrolled. Finely-ground Linum usitatissimum L. (Linaceae; flaxseed or linseed) in 40-g packets were provided for daily consumption in any patient-desired formulation 1 week before radiotherapy and throughout radiotherapy as tolerated. The primary outcomes were overall adverse events, with particular focus on Grade ≥3 RP, and flaxseed tolerability. Adverse events were graded according to CTCAE v4.0. Results: Of the 33 patients enrolled, 5 patients (15%) did not receive chemoradiation, 4 (12%) withdrew promptly after enrollment, 4 (12%) did not return a flaxseed consumption log, and 1 patient had irritable bowel syndrome (3%). The remaining 19 patients (57%) had chemoradiation and flaxseed ingestion with a mean completion and standard deviation of the intended flaxseed course of 62% ± 8.3%. Nine (50%) of these 19 patients reported difficulties with flaxseed consumption, citing nausea, constipation, odynophagia, or poor taste or texture. One patient (5%), with unverifiable flaxseed consumption, developed Grade 3 RP. There were no cases of Grade 2 RP. Six patients (32%) developed Grade 2 RE, but no patients developed Grade ≥3 RE. Median overall and progression-free survival were 31 and 12 months, respectively. Conclusions: Despite the low incidence of acute radiation-induced complications reported, significant treatment-related gastrointestinal toxicities and subsequently low flaxseed tolerability inhibit accurate determination of flaxseed effect in patients receiving concurrent thoracic chemoradiation. Thus, further investigations should focus on optimizing flaxseed formulation for improved tolerability and evaluation. CTR #: NCT02475330, https://clinicaltrials.gov/ct2/show/study/NCT02475330.

Final results of a phase I “RadVax” trial of hypofractionated radiation combined with pembrolizumab in patients with metastatic solid tumors

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Background: Many patients treated with anti-PD-1 therapy do not show a clinical response. Preclinical studies suggest that adding hypofractionated radiotherapy (HFRT) to anti-PD1 can increase the efficacy of immunotherapy through several mechanisms including increased antigen presentation. We conducted a prospective trial testing the combination of pembrolizumab and HFRT in patients with metastatic solid tumors. Methods: This prospective single-institution phase I trial tested pembrolizumab in combination with HFRT in patients with metastatic cancers (NSCLC, melanoma, pancreas, breast, others) and an ECOG performance status of 0-1. Melanoma and NSCLC patients were required to have progression of disease on anti-PD1, having received ≥ 2 doses of anti-PD1 and progression documented by RECIST v1.1. Patients were required to have an index lesion ≥1 cm that was amenable to HFRT and at least one other lesion that was not irradiated and could be followed for response using RECIST criteria. Pembrolizumab 200 mg IV every 3 weeks was administered beginning 1 week prior to the first fraction of radiation. The HFRT dose was 8 Gy x 3 fractions or 17 Gy x 1 fraction, determined by randomization during the Expansion phase. The primary objective was the safety of HFRT combined with pembrolizumab, with dose-limiting toxicity (DLT) defined as Grade ≥ 3 non-hematological toxicity related to the combination of Pembrolizumab and HFRT. The secondary objective was the radiographic response of metastatic lesions outside the radiation field as measured by RECIST. Results: 59 patients aged 27-90 years (median 60) were enrolled from March 2015 to December 2018 (24 in the Safety Phase and 35 in Expansion Phase). 40 patients (67.7%) had treatment-related AEs, of which 4 were grade 3 and none were grade 4. One patient experienced hepatitis, classified as DLT. While most patients did not have a radiologic response, in patients with metastatic melanoma, 7 of 16 (43.8%, exact 95% CI 19.8-70.1%) had an objective response to HFRT + pembrolizumab, including 3 complete and 4 partial responses. Responses are durable with 3/3 complete responders alive with no progression, and 3/4 partial responders alive with 2 having no evidence of progression. Among melanoma patients, only 2 of 7 (29%) responders received ipilimumab prior to enrollment, compared to 8 of 9 (89%) non-responders (p = 0.035). An increase in Ki67+ PD-1+ non-naïve CD8 T-cells was observed in the blood 2 weeks after HFRT, but the magnitude did not correlate with likelihood of response. Responses were observed after either 17 Gy x 1 fraction or 8 Gy x 3 fractions, with no difference in response rate by fractionation. Conclusions: This study suggests that HFRT administered with concurrent pembrolizumab is associated with acceptable toxicity and that in patients with metastatic melanoma progressing on anti-PD-1 therapy, this approach yields an ORR of 44%. Clinical trial information: NCT02303990.

Abstract P17: Effect of telemedicine adoption on accessibility and time to treatment in patients with thoracic malignancies during the COVID-19 pandemic

Introduction: To ensure safe delivery of oncologic care in the COVID-19 pandemic, telemedicine has been rapidly adopted. We assessed accessibility and time to treatment initiation for thoracic oncology patients seen via telemedicine or in-person during the initial phase of the COVID-19 pandemic. Methods: We conducted a retrospective cohort study of patients with thoracic malignancies seen within a multidisciplinary team at the University of Pennsylvania Health System (UPHS) during the first surge of COVID-19 cases in Philadelphia (March 1 to June 30, 2020). Patients with an index visit for a new phase of care, defined as a new diagnosis, local recurrence, or newly discovered metastatic disease were included. Patients who did not receive subsequent oncologic care within the UPHS were excluded. Dates of referral, index visit, and treatment initiation were abstracted from the electronic medical record (EMR). Patients were divided into groups based on index visit type (in-person vs. telemedicine). Comparisons of time to care between groups were evaluated using the Wilcoxon rank-sum test. Results: Between March 1 and June 30, 2020, 241 distinct thoracic oncology patients were seen for a new phase of care and managed with surgery (n=78, 32.4%), radiation (including concurrent chemoradiation) (n=59, 24.5%), or systemic therapy (n=73, 30.3%). The majority of visits were for a diagnosis of a new thoracic cancer (87.1%). 133 patients (55.2%) were seen in-person and 108 (44.8%) were seen via telemedicine. Baseline characteristics of patients seen via telemedicine vs in-person were well balanced. As expected, the proportion of telemedicine to in-person visit types changed with the local phase of the pandemic with an initial increase of telemedicine during the lockdown period and a decrease during the re-opening phase. A higher proportion of visits were conducted via telemedicine when receiving systemic therapy or radiation as compared to surgery. Among patients with new diagnoses (n=210), the median time from referral to initial visit was significantly shorter amongst the patients seen via telemedicine vs. in-person (4.5 vs. 6.0 days, p=0.006), though only 67.1% had referral dates reported in the EMR. Time-to-treatment stratified by treatment modality received did not differ by type of initial visit (median values in-person vs. telemedicine: surgery 16 vs. 22 days, p= 0.48; radiation 26.5 vs. 28 days, p=0.90; systemic therapy 13.5 vs. 14 days, p=0.49). A sensitivity analysis limited to new diagnoses only (210/241) confirmed the same results. Conclusions: Rapid adoption of telemedicine sustained timely delivery of oncologic care during the initial surge of the COVID19 pandemic across a thoracic oncology multi-disciplinary clinic. While the full impact of telemedicine on long term clinical outcomes remains to be determined, faster times from referral to initial visit in the telemedicine group provide preliminary evidence that telemedicine could sustain or improve accessibility to oncologic care, especially during current and future pandemics.

Citation Format: Vivek U. Nimgaonkar, Abigail T. Berman, Peter Gabriel, John Kucharczuk, Lawrence N. Shulman, Charu Aggarwal, Melina E. Marmarelis. Effect of telemedicine adoption on accessibility and time to treatment in patients with thoracic malignancies during the COVID-19 pandemic [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2021 Feb 3-5. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(6_Suppl):Abstract nr P17.

Early Changes in Physical Activity and Quality of Life With Thoracic Radiation Therapy in Breast Cancer, Lung Cancer, and Lymphoma

PURPOSE

The effects of thoracic radiation therapy (RT) on physical functioning and quality of life (QoL) are incompletely defined. We determined the associations between thoracic RT dose volume metrics, physical activity, and QoL in patients with cancer.

METHODS AND MATERIALS

Participants with breast cancer, lung cancer, or mediastinal lymphoma treated with radiation with or without chemotherapy were enrolled in a prospective, longitudinal cohort study. Data were collected pre-RT, immediately post-RT, and 5 to 9 months post-RT. At each timepoint, self-reported physical activity was assessed via the Godin-Shephard Leisure-Time Physical Activity Questionnaire, and QoL metrics were assessed via Functional Assessment of Chronic Illness Therapy Fatigue and Dyspnea Scales. Multivariable adjusted linear regression models were stratified by breast cancer alone and lung cancer and lymphoma combined.

RESULTS

One hundred thirty participants were included in the study. In breast cancer (n = 80), each 1-Gy increase in mean heart dose was associated with worse Functional Assessment of Chronic Illness Therapy Fatigue scores (-1.0; 95% confidence interval [CI], -1.9 to -0.2; P = .021); similar associations were observed between V5 and fatigue (-2.5; 95% CI, -4.4 to -0.6; P = .010 for each 10% increase in V5). In lung cancer and lymphoma (n = 50), each 10% increase in V5 was associated with decreased physical activity (Godin-Shephard Leisure-Time Physical Activity Questionnaire score -2.3; 95% CI, -4.3 to -0.4; P = .017). Although the associations between baseline levels of physical activity and fatigue and dyspnea were of borderline significance in breast cancer alone (P < .10), increased physical activity over time was associated with improvements in fatigue and dyspnea across all cancer types (P < .05 for all).

CONCLUSIONS

Higher cardiac RT dose was associated with worse fatigue and physical activity across breast cancer, lung cancer, and mediastinal lymphoma. Longitudinal increases in physical activity were associated with concurrent improvements in QoL measures. Strategies to increase physical activity and decrease cardiac RT dose may improve physical functioning and QoL for patients with cancer.

Phase 1 Trial of Pembrolizumab Administered Concurrently With Chemoradiotherapy for Locally Advanced Non-Small Cell Lung Cancer: A Nonrandomized Controlled Trial

Importance

Consolidative programmed death ligand-1 (PD-L) inhibition after chemoradiotherapy improves overall survival and progression-free survival (PFS) for stage III non-small cell lung cancer (NSCLC) and requires safety evaluation for incorporation of programmed cell death 1 (PD-1) inhibition at the onset of chemoradiotherapy.

Objective

To determine the safety and tolerability of PD-1 inhibition concurrently with definitive chemoradiotherapy for NSCLC.

Design, Setting, and Participants

This phase 1 prospective multicenter nonrandomized controlled trial using a 3 plus 3 design was performed from August 30, 2016, to October 24, 2018, with a median follow-up of 16.0 (95% CI, 12.0-22.6) months and data locked on July 25, 2019. Twenty-one participants had locally advanced, unresectable, stage III NSCLC as determined by multidisciplinary review, Eastern Cooperative Oncology Group performance status 0 or 1, and adequate hematologic, renal, and hepatic function. Data were analyzed from October 17, 2016, to July 19, 2019.

Interventions

Pembrolizumab was combined with concurrent chemoradiotherapy (weekly carboplatin and paclitaxel with 60 Gy of radiation in 2 Gy per d). Dose cohorts evaluated included full-dose pembrolizumab (200 mg intravenously every 3 weeks) 2 to 6 weeks after chemoradiotherapy (cohort 1); reduced-dose pembrolizumab (100 mg intravenously every 3 weeks) starting day 29 of chemoradiotherapy (cohort 2); full-dose pembrolizumab starting day 29 of chemoradiotherapy (cohort 3); reduced-dose pembrolizumab starting day 1 of chemoradiotherapy (cohort 4); and full-dose pembrolizumab starting day 1 of chemoradiotherapy (cohort 5). A safety expansion cohort of 6 patients was planned based on the maximum tolerated dose of pembrolizumab. Dose-limiting toxic effects were defined as pneumonitis of at least grade 4 within cycle 1 of pembrolizumab treatment.

Main Outcomes and Measures

Safety and tolerability of PD-1 inhibition with chemoradiotherapy for NSCLC. Secondary outcomes included PFS and pneumonitis rates.

Results

Among the 21 patients included in the analysis (11 female [52%]; median age, 69.5 [range, 53.0-85.0] years), no dose-limiting toxic effects in any cohort were observed. One case of grade 5 pneumonitis occurred in the safety expansion cohort with the cohort 5 regimen. Immune-related adverse events of at least grade 3 occurred in 4 patients (18%). Median PFS for patients who received at least 1 dose of pembrolizumab (n = 21) was 18.7 (95% CI, 11.8-29.4) months, and 6- and 12-month PFS were 81.0% (95% CI, 64.1%-97.7%) and 69.7% (95% CI, 49.3%-90.2%), respectively. Median PFS for patients who received at least 2 doses of pembrolizumab (n = 19) was 21.0 (95% CI, 15.3 to infinity) months.

Conclusions and Relevance

These findings suggest that combined treatment with PD-1 inhibitors and chemoradiotherapy for stage III NSCLC is tolerable, with promising PFS of 69.7% at 12 months, and requires further study.

Trial Registration

ClinicalTrials.gov Identifier: NCT02621398.

Initial Clinical Experience Treating Patients With Lung Cancer on a 6MV-Flattening-Filter-Free O-Ring Linear Accelerator

Introduction Modern technologies, like intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), have improved the therapeutic ratio of thoracic radiotherapy (TRT) for lung cancer (LC). Halcyon™ (Varian Medical Systems, Palo Alto, CA, USA), a novel 6MV-flattening-filter-free O-ring linear accelerator (6X-FFF ORL), was designed to deliver IMRT and VMAT with greater speed than a C-arm linac. Herein, we report our initial clinical experience treating patients with LC on this linac. Methods All patients who received TRT for LC on the 6X-FFF ORL at our institution were retrospectively identified. Patients' clinicopathologic data, radiotherapy details, early disease-control and toxicity outcomes, dosimetric data, couch corrections, and treatment times are reported. Results Between 10/2018-12/2019, 30 consecutive patients (median age 66 years, range 54-94 years) received definitive or post-operative TRT for LC (median 66 Gy/33 fractions; range 5-70 Gy/2-37 fractions) following four-dimensional computed tomography (CT) simulation (97%) using daily kilovoltage KV cone-beam CT (CBCT) (100%) on a 6X-FFF ORL for non-small cell LC (84%) or small cell LC (16%), with 53% receiving VMAT, 43% receiving static-field IMRT, and 77% receiving concurrent systemic therapy. All plans were approved through institutional peer review. The average three-dimensional vector couch correction based on CBCT guidance was 0.90 ± 0.50 cm. The average beam-on and beam on plus CBCT times were 1.7 ± 1.1 min, and 5.0 ± 3.2 min, respectively. Grade 3 dyspnea and fatigue occurred in 3% and 3% of patients, respectively. There were no grade ≥4 toxicities. Conclusion In this first clinical report of TRT for LC on a 6X-FFF ORL, daily CBCT-guided treatment was fast and safe with respect to dosimetry and clinical outcomes. Thus, use of this linac for TRT may increase LC patient throughput without a detriment in radiotherapy quality.

Multi-institutional analysis of stereotactic body radiotherapy for sarcoma pulmonary metastases: High rates of local control with favorable toxicity

BACKGROUND/OBJECTIVES

Oligometastatic sarcoma pulmonary metastases (PM's) are traditionally treated with resection and/or chemotherapy. We hypothesize that stereotactic body radiotherapy (SBRT) is an effective, safe alternative to surgery that can achieve excellent local control (LC) with a favorable toxicity profile.

METHODS

Patients treated with SBRT for sarcoma PM's from 2011 to 2016 at Massachusetts General Hospital and the University of Pennsylvania were included. Median dose was 50 Gy. Patients underwent computed tomography (CT) or positron emission tomography/CT Q3 months post-SBRT.

RESULTS

44 patients with 56 separate PM's were treated with SBRT. Median age was 59 (range 19-82). 82% received prior chemotherapy, 66% had prior pulmonary resections (range, 1-5 resections), and 32% received prior thoracic radiotherapy. Median lesion size was 2.0 cm (range, 0.5-8.1 cm). Median follow-up was 16 months and 25 months for patients alive at last follow-up. Overall survival at 12 and 24 months was 74% (95% confidence interval [CI], 67%-81%) and 46% (95% CI, 38%-55%). LC at 12 and 24 months was 96% (95% CI, 93%-98%) and 90% (95% CI, 84%-96%). LC and overall survival did not differ based on age, gender, histology, fractionation, lesion location, or size (P > .05). Three developed Common Terminology Criteria for Adverse Events version 4 grade-2 chest-wall toxicities; one had grade-2 pneumonitis.

CONCLUSIONS

In the first multi-institutional series on SBRT for sarcoma PM's, SBRT has excellent LC and is well-tolerated. SBRT should be considered as an alternative/complement to resection.

Patient-Centered Outcomes in Radiation Oncology

Patient-reported outcome and health-related quality of life scales have the potential to engage patients and providers, allowing for better communication and shared decision-making in oncology care. When monitored longitudinally, they facilitate earlier interventions that may help with symptom management and improve traditional outcome metrics, including survival. Their use in clinical trials has allowed for changes in guidelines in the management of various cancers. The voice and experience of the patient, captured by these scales, enable providers to better detail the journey patients can expect to experience during and after treatment.

Management of Lung Cancer During the COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) has had a devastating impact around the world. With high rates of transmission and no curative therapies or vaccine yet available, the current cornerstone of management focuses on prevention by social distancing. This includes decreased health care contact for patients. Patients with lung cancer are a particularly vulnerable population, where the risk of mortality from cancer must now be balanced by the potential risk of a life-threatening infection. In these unprecedented times, a collaborative and multidisciplinary approach is required to streamline but not compromise care. We have developed guidelines at our academic cancer center to standardize management of patients with lung cancer across our health care system and provide guidance to the larger oncology community. We recommend that general principles of lung cancer treatment continue to be followed in most cases where delays could result in rapid cancer progression. We recognize that our recommendations may change over time based on clinical resources and the evolving nature of the COVID-19 pandemic. In principle, however, treatment paradigms must continue to be individualized, with careful consideration of risks and benefits of continuing or altering lung cancer-directed therapy.

Outcomes in patients with metastatic non-small cell lung cancer (mNSCLC) with brain metastases treated with pembrolizumab-based therapy

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Background: Patients (pts) with mNSCLC with active brain metastases (BM) are often excluded from clinical trials; data on efficacy and safety of immunotherapy in this population are limited. We compared outcomes of pts with mNSCLC with and without BM who received pembrolizumab-based therapy. Methods: We conducted a retrospective single-center study of pts with mNSCLC treated with pembrolizumab (P) with or without chemotherapy. Progression-free survival (PFS) and overall survival (OS) were determined by Kaplan-Meier methodology and compared using multivariable Cox regression and log rank testing. Results: We identified 587 consecutive pts with mNSCLC who began P-based therapy between 8/2013 and 12/2018: 306 (52%) female, median age 67 years (range 32-98), 437 (74%) adenocarcinoma, and 508 (87%) former/current smokers. 388 (66%) patients received P in first line therapy, and 334 (57%) received single-agent P. 131 pts (22%) had detectable BM at baseline (start of P-based therapy). Pts with BM were younger (median 65 y vs 68 y, p < 0.01) and more likely to have adenocarcinoma (86% vs. 71%, p < 0.01) and baseline steroid use (22% vs 1%, p < 0.01). Presence of BM did not differ by race, sex, line of therapy, treatment regimen, or PD-L1 status. Of the 131 patients with detectable BM on pre-treatment brain MRI, 55 (42%) had stable BM as a result of prior local therapy, while 76 (58%) had active (new or growing) BM on pre-treatment imaging. Most patients with active BM underwent radiation therapy (RT) in either the 30 days before (n = 46) or 30 days after (n = 17) P start; of the remaining 13 treated with P-based therapy alone, intracranial responses included 2 CR, 2 PR, 3 SD, and 4 PD. As of 1/1/2020, with 15-month median follow up, there was no difference in mPFS (9.2 vs 7.3 months, p = 0.41) or mOS (18.3 vs 18.0 mo, p = 0.67) between pts with and without BM in our P-treated cohort. On multivariable analysis, female sex, ECOG 0-1, adenocarcinoma histology, and P as first line therapy were associated with improved PFS and OS. Presence of BM, baseline steroid use, and timing of local RT (before vs. after P) were not associated with inferior survival. Conclusions: In our single-center experience of pts with mNSCLC treated with P, pts with and without BM had similar PFS and OS. We observed several intracranial responses to P-based therapy alone, but most pts with active BM underwent local RT. mNSCLC pts with BM should be considered for P-based therapy; BM may be treated with RT immediately before or even after P with similar survival outcomes.

Updating Photon-Based Normal Tissue Complication Probability Models for Pneumonitis in Patients With Lung Cancer Treated With Proton Beam Therapy

PURPOSE

No validated models for predicting the risk of radiation pneumonitis (RP) with proton beam therapy (PBT) currently exist. Our goal was to externally validate and recalibrate multiple established photon-based normal tissue complication probability models for RP in a cohort with locally advanced nonsmall cell lung cancer treated with contemporary doses of chemoradiation using PBT.

METHODS AND MATERIALS

The external validation cohort consisted of 99 consecutive patients with locally advanced nonsmall cell lung cancer treated with chemoradiation using PBT. RP was retrospectively scored at 3 and 6 months posttreatment. We evaluated the performance of the photon Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) pneumonitis model, the QUANTEC model adjusted for clinical risk factors, and the newer Netherlands updated QUANTEC model. A closed testing procedure was performed to test the need for model updating, either by recalibration-in-the-large (re-estimation of intercept), recalibration (re-estimation of intercept/slope), or model revision (re-estimation of all coefficients).

RESULTS

There were 21 events (21%) of ≥grade 2 RP. The closed testing procedure on the PBT data set did not detect major deviations between the models and the data and recommended adjustment of the intercept only for the photon-based Netherlands updated QUANTEC model (intercept update: -1.2). However, an update of the slope and revision of the model coefficients were not recommended by the closed testing procedure, as the deviations were not significant within the power of the data.

CONCLUSIONS

The similarity between the dose-response relationship for PBT and photons for normal tissue complications has been an assumption until now. We demonstrate that the preexisting, widely used photon based models fit our PBT data well with minor modifications. These now-validated and updated normal tissue complication probability models can aid in individualizing selection of the most optimal treatment technique for a particular patient.

Circulating Tumor Cells Are Associated with Recurrent Disease in Patients with Early-Stage Non-Small Cell Lung Cancer Treated with Stereotactic Body Radiotherapy

PURPOSE

Although stereotactic body radiotherapy (SBRT) is effective in early-stage non-small cell lung cancer (NSCLC), approximately 10%-15% of patients will fail regionally and 20%-25% distantly. We evaluate a novel circulating tumor cell (CTC) assay as a prognostic marker for increased risk of recurrence following SBRT.

EXPERIMENTAL DESIGN

Ninety-two subjects (median age, 71 years) with T1a (64%), T1b (23%), or T2a (13%) stage I NSCLC treated with SBRT were prospectively enrolled. CTCs were enumerated by utilizing a GFP-expressing adenoviral probe that detects elevated telomerase activity in cancer cells. Samples were obtained before, during, and serially up to 24 months after treatment. SBRT was delivered to a median dose of 50 Gy (range, 40-60 Gy), mostly commonly in four to five fractions (92%).

RESULTS

Thirty-eight of 92 subjects (41%) had a positive CTC test prior to SBRT. A cutoff of ≥5 CTCs/mL before treatment defined favorable (n = 78) and unfavorable (n = 14) prognostic groups. Increased risk of nodal (P = 0.04) and distant (P = 0.03) failure was observed in the unfavorable group. Within 3 months following SBRT, CTCs continued to be detected in 10 of 35 (29%) subjects. Persistent detection of CTCs was associated with increased risk of distant failure (P = 0.04) and trended toward increased regional (P = 0.08) and local failure (P = 0.16).

CONCLUSIONS

Higher pretreatment CTCs and persistence of CTCs posttreatment is significantly associated with increased risk of recurrence outside the targeted treatment site. This suggests that CTC analysis may potentially identify patients at higher risk for regional or distant recurrences and who may benefit from either systemic therapy and/or timely locoregional salvage treatment.