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Introduction Cyclin-dependent-kinase 4/6(CDK4/6) inhibitors are widely used as a first-line systemic treatment for patients with hormone receptor-positive, human epidermal growth factor receptor-2 negative metastatic breast cancer. Although many patients with metastatic breast cancer require palliative radiotherapy (RT), there are limited data on the safety of combining a CDK4/6 inhibitor with palliative RT. Case Report Presented is a case of acute high-grade radiation dermatitis with low-dose palliative RT following administration of palbociclib. A 49-year-old woman with newly diagnosed hormone receptor-positive invasive ductal carcinoma of the left breast presented with lytic bone lesions in the left femur and lumbar spine. The patient initiated treatment with goserelin, tamoxifen, and palbociclib. She underwent prophylactic surgical fixation of the left femur and received post-operative RT encompassing the entire surgical nail (30 Gy/10 fractions) and palliative RT to the lumbar spine for pain relief (20 Gy/5 fractions). During cycle 4, palbociclib was stopped 3 days prior to the start of RT to reduce the risk of toxicity risk. However, 16 days after starting RT, she developed painful erythematous papules and bullae with moist desquamation on the left groin and lumbar spine. Management & Outcome Her symptoms were managed with topical Aquaphor-lidocaine, silver sulfadiazine, and aluminum acetate soaks. Dermatitis subsided to dry desquamation within 2 weeks. The patient denied late toxicity at 11 months follow-up. Discussion Larger retrospective or prospective studies are needed to further elucidate the safety of combined CDK4/6 inhibitors and RT. In the meantime, special precautions are warranted in patients receiving combined therapy.

Supplementary Data from MYC Levels Regulate Metastatic Heterogeneity in Pancreatic Adenocarcinoma

The degree of metastatic disease varies widely among patients with cancer and affects clinical outcomes. However, the biological and functional differences that drive the extent of metastasis are poorly understood. We analyzed primary tumors and paired metastases using a multifluorescent lineage-labeled mouse model of pancreatic ductal adenocarcinoma (PDAC)—a tumor type in which most patients present with metastases. Genomic and transcriptomic analysis revealed an association between metastatic burden and gene amplification or transcriptional upregulation of MYC and its downstream targets. Functional experiments showed that MYC promotes metastasis by recruiting tumor-associated macrophages, leading to greater bloodstream intravasation. Consistent with these findings, metastatic progression in human PDAC was associated with activation of MYC signaling pathways and enrichment for MYC amplifications specifically in metastatic patients. Collectively, these results implicate MYC activity as a major determinant of metastatic burden in advanced PDAC.Significance:Here, we investigate metastatic variation seen clinically in patients with PDAC and murine PDAC tumors and identify MYC as a major driver of this heterogeneity.This article is highlighted in the In This Issue feature, p. 275

Supplementary Figure from MYC Levels Regulate Metastatic Heterogeneity in Pancreatic Adenocarcinoma

Prevention and early intervention can improve survival and quality of life across all cancers. Patient understanding of risk factors and associated actionable lifestyle changes and screening programs is not well understood by clinicians METHODS: An Internet-based tool, Reduce My Risk, was created in 2009 and made available on oncolink.org. Users voluntarily completed a survey regarding demographics and cancer risk factors, and received information about their cancer risk RESULTS: Twenty eight thousand and one surveys were completed from 2009 to 2019. Median age was 26 years (18-101); 60% were females, 87% lived in North America, and 37% had at least a bachelor's degree. Users reported on behavioral/ modifiable risk factors: 13% were current smokers, 52% were current consumers of alcohol, and 8% of those had ≥14 drinks/week. Body mass index (BMI) was ≥30 in 19%; 74% of all surveys reported dietary risks and 36% reported infrequent exercise. Excess UV exposure was reported by 19%. Among women, 36% reported performing breast self-examinations monthly, and 50% reported receiving clinician breast examinations at least once every 3 years. Sixty seven percent of men 55-75 years reported screening prostate specific antigen testing, with 50% receiving annual digital rectal examinations. Nonmodifiable risk factors included family cancer history (64%), genetic syndrome (3%), and cancer-predisposing health conditions (26%) CONCLUSIONS: Ninety-seven percent of users reported modifiable risk factors, and 60% reported ≥4 of these risk factors. Understanding detailed characteristics of a large number of respondents has the potential to improve educational interventions to reduce cancer risk through behavioral modification and cancer screening across the general public.

Mutations Analyzed

Purpose:The role of plasma-based tumor mutation burden (pTMB) in predicting response to pembrolizumab-based first-line standard-of-care therapy for metastatic non–small cell lung cancer (mNSCLC) has not been explored.Experimental Design:A 500-gene next-generation sequencing panel was used to assess pTMB. Sixty-six patients with newly diagnosed mNSCLC starting first-line pembrolizumab-based therapy, either alone or in combination with chemotherapy, were enrolled (Clinicaltrial.gov identifier: NCT03047616). Response was assessed using RECIST 1.1. Associations were made for patient characteristics, 6-month durable clinical benefit (DCB), progression-free survival (PFS), and overall survival (OS).Results:Of 66 patients, 52 (78.8%) were pTMB-evaluable. Median pTMB was 16.8 mutations per megabase (mut/Mb; range, 1.9–52.5) and was significantly higher for patients achieving DCB compared with no durable benefit (21.3 mut/Mb vs. 12.4 mut/Mb, P = 0.003). For patients with pTMB ≥ 16 mut/Mb, median PFS was 14.1 versus 4.7 months for patients with pTMB < 16 mut/Mb [HR, 0.30 (0.16–0.60); P < 0.001]. Median OS for patients with pTMB ≥ 16 was not reached versus 8.8 months for patients with pTMB < 16 mut/Mb [HR, 0.48 (0.22–1.03); P = 0.061]. Mutations in ERBB2 exon 20, STK11, KEAP1, or PTEN were more common in patients with no DCB. A combination of pTMB ≥ 16 and absence of negative predictor mutations was associated with PFS [HR, 0.24 (0.11–0.49); P < 0.001] and OS [HR, 0.31 (0.13–0.74); P = 0.009].Conclusions:pTMB ≥ 16 mut/Mb is associated with improved PFS after first-line standard-of-care pembrolizumab-based therapy in mNSCLC. STK11/KEAP1/PTEN and ERBB2 mutations may help identify pTMB-high patients unlikely to respond. These results should be validated in larger prospective studies.

Figure S1. Sample cohort of this study, which included 204 subjects in total. Workflow shows patient cohorts involved in each classification. * indicated 8 patients repeated in the discovery set and the training set. ** indicated 32 locally advanced patients that were not used in the occult metastases detection as training set did not have locally advanced PDAC patients.

pTMBand PD-L1 expression levels.

Development and validation of a plasma-based panel for mutation detection and assessment of TMB.

Recent improvements in chemoimmunotherapies, targeted agents, hematopoietic stem cell transplants, and cellular therapies have revolutionized treatment paradigms for patients with diffuse large B-cell lymphoma (DLBCL). Even in the relapsed or refractory setting, contemporary treatment options are delivered with curative intent and can lead to lasting remissions. Although such therapies have improved overall outcomes, they have increasingly led to a wide variety of presentations of recurrent tumors in need of palliation. Here, we review the use of radiotherapy (RT) in the palliation of DLBCL. We draw particular attention to the evolving role for hypofractionated RT and low-dose RT for DLBCL. We review the available literature on these topics and focus on commonly encountered clinical scenarios.

The degree of metastatic disease varies widely among patients with cancer and affects clinical outcomes. However, the biological and functional differences that drive the extent of metastasis are poorly understood. We analyzed primary tumors and paired metastases using a multifluorescent lineage-labeled mouse model of pancreatic ductal adenocarcinoma (PDAC)—a tumor type in which most patients present with metastases. Genomic and transcriptomic analysis revealed an association between metastatic burden and gene amplification or transcriptional upregulation of MYC and its downstream targets. Functional experiments showed that MYC promotes metastasis by recruiting tumor-associated macrophages, leading to greater bloodstream intravasation. Consistent with these findings, metastatic progression in human PDAC was associated with activation of MYC signaling pathways and enrichment for MYC amplifications specifically in metastatic patients. Collectively, these results implicate MYC activity as a major determinant of metastatic burden in advanced PDAC. Significance: Here, we investigate metastatic variation seen clinically in patients with PDAC and murine PDAC tumors and identify MYC as a major driver of this heterogeneity. This article is highlighted in the In This Issue feature, p. 275

Among non-small cell lung cancer (NSCLC) patients with therapeutically targetable tumor mutations in epidermal growth factor receptor (EGFR), not all patients respond to targeted therapy. Combining circulating-tumor DNA (ctDNA), clinical variables, and radiomic phenotypes may improve prediction of EGFR-targeted therapy outcomes for NSCLC. This single-center retrospective study included 40 EGFR-mutant advanced NSCLC patients treated with EGFR-targeted therapy. ctDNA data included number of mutations and detection of EGFR T790M. Clinical data included age, smoking status, and ECOG performance status. Baseline chest CT scans were analyzed to extract 429 radiomic features from each primary tumor. Unsupervised hierarchical clustering was used to group tumors into phenotypes. Kaplan–Meier (K–M) curves and Cox proportional hazards regression were modeled for progression-free survival (PFS) and overall survival (OS). Likelihood ratio test (LRT) was used to compare fit between models. Among 40 patients (73% women, median age 62 years), consensus clustering identified two radiomic phenotypes. For PFS, the model combining radiomic phenotypes with ctDNA and clinical variables had c-statistic of 0.77 and a better fit (LRT p = 0.01) than the model with clinical and ctDNA variables alone with a c-statistic of 0.73. For OS, adding radiomic phenotypes resulted in c-statistic of 0.83 versus 0.80 when using clinical and ctDNA variables (LRT p = 0.08). Both models showed separation of K–M curves dichotomized by median prognostic score (p EGFR mutations.

Introduction: In the setting of metastatic pancreatic adenocarcinoma (mPDAC), lower baseline plasma KRAS mutation levels have been associated with improved survival. While tissue-agnostic, plasma-based copy number instability (CNI) has been demonstrated as an early indicator of response to immunotherapy for some solid tumors, it has not been assessed for patients with mPDAC, nor in combination with KRAS mutations for patients receiving standard of care chemo/radiotherapy. Here we evaluate the combination of mutant KRAS (mKRAS) and CNI detection in plasma as a predictor of overall and progression-free survival (OS/PFS) in mPDAC patients who received standard of care therapy. Methods: Cell-free DNA was extracted from plasma and libraries prepared at baseline (Week 0) and weeks 8, 16 and 24 on therapy, and analyzed by next-generation sequencing (CNI) and droplet digital PCR (mKRAS). Descriptive statistics were computed for variables including CNI (score is a measure of circulating tumor DNA) and mKRAS variant allele fraction. Detection was defined as above the limit of detection (mKRAS=0.13%) and above the 95th percentile of the value in normal individuals (CNI=24). Therapy response was assessed by OS and PFS. Results: 196 plasma samples from 64 mPDAC patients were analyzed. When dichotomized as detectable vs undetectable, CNI alone was significantly associated with OS at all on-therapy timepoints but not baseline, whereas mKRAS was significantly associated with OS for all 4 timepoints (Table 1). Detection of both CNI and mKRAS in combination was strongly associated with worse OS at all timepoints, yielding the highest HR. Similar results were obtained when mKRAS and CNI were dichotomized at their respective median values or with PFS as the clinical endpoint. Conclusions: Combined CNI and mKRAS detection at baseline and on-therapy may provide a strong and early indication of worse prognosis for patients with mPDAC. Table 1. Association of CNI and mKRAS with Overall Survival (HazardRatio [95% CI], log-rank p-value) Timepoint CNI mKRAS CNI and KRAS Baseline/Week 0 1.54 [0.89-2.68], 0.1 2.05 [1.12-3.78], 0.02 2.50 [1.46-4.28], 0.0006 Week 8 1.78 [0.99-3.18], 0.05 2.21 [1.19-4.08], 0.01 9.81 [3.40-28.28], Citation Format: Samuele Cannas, Jacob E. Till, Kristine Kim, Michael J. LaRiviere, Charles M. Vollmer, Jennifer R. Eads, Thomas B. Karasic, Peter J. O'Dwyer, Charles J. Schneider, Ursina R. Teitelbaum, Kim A. Reiss Binder, Mark H. O'Hara, Douglas T. Ross, Kim McGregor, Kirsten Bornemann-Kolatzki, Ekkehard Schütz, Julia Beck, Erica L. Carpenter. Liquid biopsy signature combining copy number instability and mutant KRAS detection is associated with survival for patients with metastatic pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1043.

Precision medicine approaches for managing patients with metastatic castrate-resistant prostate cancer (mCRPC) are lacking. Non-invasive approaches for molecular monitoring of disease are urgently needed, especially for patients suffering from bone metastases for whom tissue biopsy is challenging. Here we utilized baseline blood samples to identify mCRPC patients most likely to benefit from abiraterone plus prednisone (AAP) or enzalutamide. Baseline blood samples were collected for circulating tumor cell (CTC) enumeration and qPCR-based gene expression analysis from 51 men with mCRPC beginning treatment with abiraterone or enzalutamide. Of 51 patients (median age 68 years [51–82]), 22 received AAP (abiraterone 1000 mg/day plus prednisone 10 mg/day) and 29 received enzalutamide (160 mg/day). The cohort was randomly divided into training (n = 37) and test (n = 14) sets. Baseline clinical variables (Gleason score, PSA, testosterone, and hemoglobin), CTC count, and qPCR-based gene expression data for 141 genes/isoforms in CTC-enriched blood were analyzed with respect to overall survival (OS). Genes with expression most associated with OS included MSLN, ARG2, FGF8, KLK3, ESRP2, NPR3, CCND1, and WNT5A. Using a Cox-elastic net model for our test set, the 8-gene expression signature had a c-index of 0.87 (95% CI [0.80, 0.94]) and was more strongly associated with OS than clinical variables or CTC count alone, or a combination of the three variables. For patients with a low-risk vs. high-risk gene expression signature, median OS was not reached vs. 18 months, respectively (HR 5.32 [1.91–14.80], p = 0.001). For the subset of 41 patients for whom progression-free survival (PFS) data was available, the median PFS for patients with a low-risk vs high-risk gene expression signature was 20 vs. 5 months, respectively (HR 2.95 [1.46–5.98], p = 0.003). If validated in a larger prospective study, this test may predict patients most likely to benefit from second-generation antiandrogen therapy.

Managing pediatric patients requiring daily general anesthesia (GA) for radiation therapy (RT) in the setting of COVID-19 is complex, owing to the aerosolizing nature of GA procedures, the risk of cardiopulmonary complications for infected patients, and the treatment of immunocompromised oncology patients in a busy, densely populated radiation oncology clinic.We developed an institutional protocol to define procedures for COVID-19 testing and protection of patients, caregivers, and staff, hypothesizing that this protocol would allow patients requiring GA to be safely treated, minimizing COVID-19 transmission risk to both patients and staff, and at the same time maintaining pre-COVID-19 patient volumes. All patients underwent COVID-19 testing before their first treatment and thrice weekly during treatment. For patients who tested positive for COVID-19, RT was delivered in the last end-of-day treatment appointment. A negative pressure room was used for GA induction and recovery, and separate physician/nurse teams were designated for in-room versus out-of-room patient management.Seventy-eight pediatric patients received RT under GA, versus 69 over the same prior year timeframe, and 2 patients received 2 courses of RT under GA, for a total of 80 courses. The mean age was 4.9 years (range, 0.5-19.0 years) and 41 of 78 (52.6%) were male. Two patients (2.6%) received 2 courses of RT under GA, establishing a total of 80 courses. The mean number of treatment fractions was 22.2 (range, 1-40). Two of 78 patients (2.6%) tested positive for COVID-19; both were asymptomatic. Both patients completed treatment as prescribed. Neither patient developed cardiopulmonary symptoms complicating anesthesia, and neither patient experienced grade 3+ acute radiation toxicity.With careful multidisciplinary planning to mitigate COVID-19 risk, pediatric RT with GA was carried out for a large patient volume without widespread infection and without increased toxic effects from either GA or RT.

Patients newly diagnosed with metastatic pancreatic ductal adenocarcinoma generally have poor survival, with heterogeneous rates of progression. Biomarkers that could predict progression and/or survival would help inform patients and providers as they make care decisions. In a previous retrospective study, we discovered that circulating thrombospondin-2 (THBS2) could, in combination with CA19-9, better distinguish patients with PDAC versus healthy controls. Here we evaluated whether THBS2 levels, previously not known to be prognostic, were associated with outcome in 68 patients at time of diagnosis of metastatic PDAC. Specifically, we interrogated the association of THBS2 level, alone or in combination with CA19-9, with progression by 90 days and/or survival to 180 days. The results indicate that elevated THBS2 levels alone, at the time of a metastatic PDAC diagnosis, can identify patients with a shorter time to death and thus help patients and providers when planning treatment.

Purpose/Objective(s) Managing pediatric patients (pts) requiring daily general anesthesia (GA) for radiation (RT) in the setting of COVID-19 is complex, due to both the aerosolizing nature of GA procedures and the risk of cardiopulmonary complications for infected pts. We hypothesized that deliberate management of pts requiring GA for RO during COVID-19 would allow safe operations to continue. Materials/Methods Pediatric pts treated under GA at our tertiary hospital from 3/1/2020 to 1/29/2021 were identified; development of COVID-19 precautions began on 3/1/2020. Pts underwent COVID testing prior to their first treatment and thrice weekly (MWF) during treatment. Pts were accompanied by only one designated adult caregiver through the entire RT course; caregivers were verbally screened; and staff personal protective equipment (PPE) included surgical mask and eye protection. For COVID+ pts, RT was delivered at the end of day; a negative pressure room was used for GA induction and recovery; staff PPE included N-95 masks or powered air purifying respirators (PAPRs); and separate physician/nurse teams were designated for in-room vs. out-of-room pt management. Results 78 pediatric pts received RT under GA (vs. 69 pts over the same prior-year timeframe). From 3/1/2020-1/29/2021, mean age was 4.9 y (range 5.5 m - 19.0 y), 41/78 (52.6%) were male, and 2/78 (2.6%) received 2 courses of RT under GA, for a total of 80 courses. 24/80 (30.0%) courses were delivered to the chest, abdomen, and/or pelvis, 21/80 (26.3%) craniospinal axis, 17/80 (21.3%) brain, 9/80 (11.3%) total body irradiation, 5/80 (6.3%) head/neck, and 4/80 (5%) other. 64/80 (80%) of courses were delivered with curative intent. 39/80 (48.8%) used proton therapy, 18/80 (22.5%) photons, and 23/80 (28.8%) both modalities. Mean number of treatment fractions was 22.2 (range 1-40). 2/78 pts (2.6%) tested positive for COVID-19, both asymptomatic. Early in the pandemic (4/2020), pt 1 (a 3 yo female with neuroblastoma) had simulation delay for known household contact; after 5 weeks, COVID testing returned positive after the first day of RT. A 2 d treatment interruption was required to finalize institutional COVID guidelines, and treatment continued without incident. Because eye protection was not yet routinely used early in the pandemic, 17 staff were quarantined, but no further staff exposures occurred after precautions for the positive test were implemented. Later in the pandemic (1/2021), pt 2 (a 3 yo male with relapsed medulloblastoma) tested positive on initial COVID testing, requiring 10 d of COVID precautions for treatment; no staff exposures occurred. No caregivers screened positive, and no children presented for treatment without the designated parent. Conclusion With careful multidisciplinary planning to mitigate COVID-19 risk, pediatric RT with GA was carried out for a large pt volume without widespread infection, and without increased toxicities from either GA or RT. Frequent pt COVID testing and attention to PPE limited staff exposures.

The degree of metastatic disease varies widely amongst cancer patients and impacts clinical outcomes. However, the biological and functional differences that drive the extent of metastasis are poorly understood. We analyzed primary tumors and paired metastases using a multi-fluorescent lineage-labeled mouse model of pancreatic ductal adenocarcinoma (PDAC) – a tumor type where most patients present with metastases. Genomic and transcriptomic analysis revealed an association between metastatic burden and gene amplification or transcriptional upregulation ofMYCand its downstream targets. Functional experiments showed that MYC promotes metastasis by recruiting tumor associated macrophages (TAMs), leading to greater bloodstream intravasation. Consistent with these findings, metastatic progression in human PDAC was associated with activation of MYC signaling pathways and enrichment for MYC amplifications specifically in metastatic patients. Collectively, these results implicate MYC activity as a major determinant of metastatic burden in advanced PDAC.

Purpose: To determine whether a multianalyte liquid biopsy can improve the detection and staging of pancreatic ductal adenocarcinoma (PDAC). Experimental Design: We analyzed plasma from 204 subjects (71 healthy, 44 non-PDAC pancreatic disease, and 89 PDAC) for the following biomarkers: tumor-associated extracellular vesicle miRNA and mRNA isolated on a nanomagnetic platform that we developed and measured by next-generation sequencing or qPCR, circulating cell-free DNA (ccfDNA) concentration measured by qPCR, ccfDNA KRAS G12D/V/R mutations detected by droplet digital PCR, and CA19-9 measured by electrochemiluminescence immunoassay. We applied machine learning to training sets and subsequently evaluated model performance in independent, user-blinded test sets. Results: To identify patients with PDAC versus those without, we generated a classification model using a training set of 47 subjects (20 PDAC and 27 noncancer). When applied to a blinded test set (N = 136), the model achieved an AUC of 0.95 and accuracy of 92%, superior to the best individual biomarker, CA19-9 (89%). We next used a cohort of 20 patients with PDAC to train our model for disease staging and applied it to a blinded test set of 25 patients clinically staged by imaging as metastasis-free, including 9 subsequently determined to have had occult metastasis. Our workflow achieved significantly higher accuracy for disease staging (84%) than imaging alone (accuracy = 64%; P < 0.05). Conclusions: Algorithmically combining blood-based biomarkers may improve PDAC diagnostic accuracy and preoperative identification of nonmetastatic patients best suited for surgery, although larger validation studies are necessary.

Cancer-related fatigue (CRF), a prevalent symptom among cancer patients, is a side effect of external beam radiation therapy (EBRT). Even when targeting organs unrelated to caloric intake or the central nervous system, radiation therapy can increase CRF, a poorly understood toxicity resulting from patient-specific, systemic therapy-related, and radiation-specific factors. We sought to determine factors associated with fatigue among patients receiving EBRT for breast cancer.To determine the variables associated with fatigue among patients with nonmetastatic breast cancer, we retrospectively analyzed prospectively collected toxicity data for a cohort of 1286 adult females with breast cancer who began curative-intent EBRT between April 4, 2010, and October 10, 2017. We hypothesized certain variables are associated with provider-reported Common Terminology Criteria for Adverse Events version 4 fatigue, graded 0 to 3, at baseline and over the course of radiation treatment.All patients were women, with a median age of 57 (range, 24-90). Mean fatigue was low (0.35 [95% confidence interval, 0.32-0.38]) at the start of radiation, increasing weekly and peaking at week 6 (0.85 [0.81-0.90]). Baseline fatigue was associated with higher American Joint Committee on Cancer stage (P.001), N-stage (P.001), anxiolytics (P.001), anticonvulsants (P = .002), antidepressants (P = .006), antihistamines (P.001), and antipsychotics (P.001). Chemotherapy was not associated with baseline fatigue. Over the course of treatment, on multivariable analysis, only lower dose per fraction (P.001) was significantly associated with increasing fatigue. In a subgroup analysis, heart and lung mean, V5, and V20 doses were not found to be associated with increasing fatigue.This work informs clinicians which factors are associated with CRF at the start of radiation therapy (more advanced disease and prescription of anxiolytics, anticonvulsants, antidepressants, antihistamines, and antipsychotics) and increase CRF over the course of radiation (smaller fraction size). This extensive analysis of factors associated with fatigue provides further evidence that hypofractionated radiation therapy for breast cancer is associated with less acute toxicity than conventionally fractionated treatment.

Purpose CD19-targeting chimeric antigen receptor T-cell (CART) therapy has emerged as a promising treatment for relapsed/refractory aggressive B-cell lymphoma (r/rABL), culminating in 2 US Food and Drug Administration–approved therapies: tisagenlecleucel (tisa-cel) and axicabtagene ciloleucel (axi-cel). Following leukapheresis and in preparation for CART infusion, contemporary bridging and lymphodepletion regimens rely mostly on cytotoxic chemotherapy. Here, in a cohort of patients treated with commercial tisa-cel and axi-cel, we show that bridging-RT may offer a supplemental approach. Methods and Materials Thirty-one patients receiving commercial tisa-cel (n = 13) or axi-cel (n = 18) between August 2018 and February 2019 for r/rABL were retrospectively reviewed. Patients were categorized into 2 groups: (1) bridging-RT within 30 days of CART infusion or (2) nonbridging-RT (NBRT), in which patients received either remote RT greater than 30 days before CART infusion or no prior RT. Results Five patients received bridging-RT within 30 days of CART infusion. Median bridging-RT dose was 37.5 Gy and was completed a median of 13 days before infusion. No grade 3 (G3) or higher RT-toxicities occurred. No patients in the bridging-RT group experienced G3 or higher CART-related toxicities (CRS or neurotoxicity), and 23% (n = 6) and 15% (n = 4) experienced G3-5 CRS and G3-5 neurotoxicity in the NBRT group, respectively. Overall treatment response in the bridging-RT and NBRT groups was 80% and 64%, respectively. The axi-cel CART product was associated with CRS (odds ratio [OR] = 26.67, P = .001) and CRS correlated with neurotoxicity (OR = 12.22, P = .028). There was a trend toward an association for CRS with metabolic tumor volume (OR = 1.06/mL, P = .141) and TLG (OR = 1.01/mL x standard uptake value, P = .099). Conclusions Bridging-RT before commercial CART does not appear to increase the risk for CART-related toxicities or negatively affect outcomes in r/rABL patients. No G3 or higher RT-toxicities occurred in this series. Pretreatment metabolic tumor burden may be associated with CART-associated CRS; however, larger patient numbers are required to elucidate significant associations. Future work to prospectively assess the value of bridging-RT is warranted.

Purpose/Objective(s) Common risk factors for head and neck cancer (HNC) include tobacco and alcohol use, HPV and EBV infection, and certain occupational exposures, including radiation. Genetics also play a role, though these effects are multifactorial and are likely not well appreciated in the lay population. We sought to understand the association between family history (FH) of HNC and other personal risk factors for cancer and hypothesized that those with a FH of HNC would be more likely to use tobacco and alcohol. Materials/Methods Reduce My Risk is an online tool available on OncoLink.org. Voluntary participants input information related to demographics, FH, risk-factors, and risk-associated behavior and then receive personalized information regarding their cancer risk. Use of collected data was IRB approved. Differences between respondents with vs without FH of HNC were analyzed using chi-square test and adjusted via logistic regression. Results 25179 responses were analyzed; 580 (2.3%) reported FH of HNC. Of these, median age was 30 (Range 18 - 72), 66.7% were female, 79.5% from North America, 83.1% White, 78.4% had at least some college, and 68.0% household income > $45,000. Comparing those with FH of HNC to those without, there were no significant differences in education, household income, or home setting. Those with FH of HNC were more likely to be “light” drinkers (1-7 per week), obese, and to have significant secondhand smoke exposure (Table). There were no significant differences in cigarette, marijuana, or “exotic” smoking, or use of smokeless tobacco products. (Table). There were also no differences in UV, radiation, or occupational exposures, except for hydrocarbons (OR 1.7, CI 0.99-2.74, P = 0.041). Conclusion Those with a FH of HNC were more likely to have secondhand smoke exposure but were not more likely to use tobacco products themselves, suggesting differences in inter-generational behavior. Those with FH also reported increased non-modifiable risks. Limitations of this work include a convenience sample frame that is disproportionately white and high income, and results may not be applicable to a more diverse population. Future work should explore targeted intervention for those with a FH of HNC to educate on risk of external exposures and promote preventive behaviors.

Purpose: The role of plasma-based tumor mutation burden (pTMB) in predicting response to pembrolizumab-based first-line standard-of-care therapy for metastatic non–small cell lung cancer (mNSCLC) has not been explored. Experimental Design: A 500-gene next-generation sequencing panel was used to assess pTMB. Sixty-six patients with newly diagnosed mNSCLC starting first-line pembrolizumab-based therapy, either alone or in combination with chemotherapy, were enrolled (Clinicaltrial.gov identifier: NCT03047616). Response was assessed using RECIST 1.1. Associations were made for patient characteristics, 6-month durable clinical benefit (DCB), progression-free survival (PFS), and overall survival (OS). Results: Of 66 patients, 52 (78.8%) were pTMB-evaluable. Median pTMB was 16.8 mutations per megabase (mut/Mb; range, 1.9–52.5) and was significantly higher for patients achieving DCB compared with no durable benefit (21.3 mut/Mb vs. 12.4 mut/Mb, P = 0.003). For patients with pTMB ≥ 16 mut/Mb, median PFS was 14.1 versus 4.7 months for patients with pTMB < 16 mut/Mb [HR, 0.30 (0.16–0.60); P < 0.001]. Median OS for patients with pTMB ≥ 16 was not reached versus 8.8 months for patients with pTMB < 16 mut/Mb [HR, 0.48 (0.22–1.03); P = 0.061]. Mutations in ERBB2 exon 20, STK11, KEAP1, or PTEN were more common in patients with no DCB. A combination of pTMB ≥ 16 and absence of negative predictor mutations was associated with PFS [HR, 0.24 (0.11–0.49); P < 0.001] and OS [HR, 0.31 (0.13–0.74); P = 0.009]. Conclusions: pTMB ≥ 16 mut/Mb is associated with improved PFS after first-line standard-of-care pembrolizumab-based therapy in mNSCLC. STK11/KEAP1/PTEN and ERBB2 mutations may help identify pTMB-high patients unlikely to respond. These results should be validated in larger prospective studies.

Despite the fact that a large portion of medical students pursue training in a cancer-related discipline, oncology is emphasized to a disproportionately lesser extent than are other disciplines in medical school. Medical students have wide gaps in their oncology-specific knowledge, and undergraduate medical education fails to address the multidisciplinary nature of oncology. To address these shortcomings and improve medical students’ understanding of the multidisciplinary nature of oncology, we have instituted a clinical oncology elective for medical students: an optional, 2-day session held after classes and promoted by student interest groups. Day 1 comprised a series of short faculty lectures beginning with the concepts of and rationale for staging, an approach to breaking bad news, guideline-based management, and multidisciplinary tumor board discussion. Three multidisciplinary tumor boards were simulated on the second day, run by attending surgeons, medical oncologists, and radiation oncologists with expertise in the cancer of interest, using real patient examples. Ultimately, the clinical oncology elective shows medical students how the oncology care team works together to care for cancer patients.

Cell-based immunotherapies have the potential to redefine modern oncologic care, providing promising new treatments for patients with otherwise poor prognoses. Chimeric antigen receptor (CAR) T cell therapy has produced remarkable remission rates in patients with even the most treatment-refractory hematologic malignancies. In 2018 the FDA approved two CAR-T cell therapies for relapsed/refractory aggressive non-Hodgkin lymphoma (r/rNHL). With the emergence of these novel therapies, there are many questions regarding treatment safety, tolerability, efficacy, and practicality with regards to radiotherapy. In this review we summarize the existing literature on CAR-T cell therapy in r/rNHL and propose a potential role for radiation therapy in the treatment of patients undergoing CAR-T cell therapy.

Background: Lung cancer is one of the most common cancers in the United States and the most fatal, with 142,670 deaths in 2019. Accurately determining tumor response is critical to clinical treatment decisions, ultimately impacting patient survival. To better differentiate between non-small cell lung cancer (NSCLC) responders and non-responders to therapy, radiomic analysis is emerging as a promising approach to identify associated imaging features undetectable by the human eye. However, the plethora of variables extracted from an image may actually undermine the performance of computer-aided prognostic assessment, known as the curse of dimensionality. In the present study, we show that correlative-driven hierarchical clustering improves high-dimensional radiomics-based feature selection and dimensionality reduction, ultimately predicting overall survival in NSCLC patients. Methods: To select features for high-dimensional radiomics data, a correlation-incorporated hierarchical clustering algorithm automatically categorizes features into several groups. The truncation distance in the resulting dendrogram graph is used to control the categorization of the features, initiating low-rank dimensionality reduction in each cluster, and providing descriptive features for Cox proportional hazards (CPH)-based survival analysis. Using a publicly available non- NSCLC radiogenomic dataset of 204 patients’ CT images, 429 established radiomics features were extracted. Low-rank dimensionality reduction via principal component analysis (PCA) was employed (𝒌 = 𝟏, 𝒏 < 𝟏) to find the representative components of each cluster of features and calculate cluster robustness using the relative weighted consistency metric. Results: Hierarchical clustering categorized radiomic features into several groups without primary initialization of cluster numbers using the correlation distance metric (as a function) to truncate the resulting dendrogram into different distances. The dimensionality was reduced from 429 to 67 features (for truncation distance of 0.1). The robustness within the features in clusters was varied from -1.12 to -30.02 for truncation distances of 0.1 to 1.8, respectively, which indicated that the robustness decreases with increasing truncation distance when smaller number of feature classes (i.e., clusters) are selected. The best multivariate CPH survival model had a C-statistic of 0.71 for truncation distance of 0.1, outperforming conventional PCA approaches by 0.04, even when the same number of principal components was considered for feature dimensionality. Conclusions: Correlative hierarchical clustering algorithm truncation distance is directly associated with robustness of the clusters of features selected and can effectively reduce feature dimensionality while improving outcome prediction.

10546 Background: Risk factors for melanoma (ML) include UV exposure, sunburns, multiple nevi, and fair skin. Smoking and alcohol use may also play a role. Demographics associated with increased UV exposure include male gender, white race, age 18-29, and high-income. Those with family history (FH) of ML have increased risk of developing ML themselves yet are often unaware or do not engage in preventive behaviors. We sought to understand the association between FH of ML and other personal risk factors for cancer. Methods: Since 2009, voluntary participants could receive personalized information regarding their cancer risk via the OncoLink.org Reduce My Risk tool. Survey data was collected on demographics, FH, risk-factors, and risk-associated behaviors. Use of data was IRB approved. Differences between respondents with v. without FH of ML were analyzed using chi-square test and adjusted via logistic regression. Results: 25255 responses were analyzed; 1928 (7.6%) had FH of ML. Of these, median age was 26 (range 18-75), 73.1% were female, 88.6% from North America, 91.4% White, 78.2% had at least some college, and 62.0% household income > $45,000. Comparing those with FH of ML to those without, no significant differences were observed in education, income, or home setting. Those with a FH of ML were less likely to be “light” smokers ( < 1 pack per day) but were more likely to be both “light” drinkers and “heavy” drinkers (Table). There were no significant differences in BMI or exercise habits. Those with FH of ML were more likely to sunbathe, to have had “blistering” sunburns, have 50+ moles, show signs of sun damage on their skin, and have dysplastic nevi (Table). There were no differences in use of indoor tanning beds (Table). Conclusions: Those with a FH of ML were more likely to sunbathe and to report skin damage and history of blistering sunburns; they were more likely to use tanning beds, though not statistically significant. These behaviors are modifiable and may suggest parental influence on sun-protective behaviors. Those with FH also reported increased non-modifiable risks. Future work should continue to explore targeted intervention for those with a FH of ML to educate on risk and promote sun-protective behaviors.[Table: see text]

Tumor heterogeneity - resulting from genetic and epigenetic alterations acquired during tumor progression - is a critical driver of phenotypic diversity in most cancers. A lethal consequence of tumor heterogeneity is the acquisition of metastatic traits by tumor cells, leading to poor clinical outcomes. This remains a major problem in pancreatic ductal adenocarcinoma (PDAC), which continues to have the worst prognosis of any major cancer type. While most cases of PDAC present with metastatic disease at the time of diagnosis, the patterns and burden of metastasis can vary widely, with some patients exhibiting a limited metastatic burden while others have more extensive spread, which impacts clinical outcomes. However, the biological and functional differences that drive metastatic heterogeneity are poorly understood. One barrier to understanding metastatic heterogeneity has been a paucity of model systems that capture this natural variation and allow for direct assessment of paired primary tumors and metastases. We previously developed an autochthonous model of PDAC – the KPCX model – that employs multiplexed fluorescence-based labeling to track the contribution of multiple distinct tumor populations to metastasis. Importantly, this technique allows for ascertainment of primary-metastatic lineage relationships in vivo, so that primary tumor clones with substantial metastatic potential can be distinguished with those having poor metastatic potential. To understand the factors underlying differences in metastatic potential, we analyzed paired primary tumors and metastases in the KPCX model and from a cohort of 398 PDAC patients. Genomic and transcriptomic analysis of murine and human metastatic PDAC revealed an association between the highly metastatic state and gene amplification or transcriptional upregulation of MYC and its transcriptional targets. Functional assessments showed that MYC promotes metastasis by recruiting tumor associated macrophages (TAMs), leading to greater bloodstream intravasation. Consistent with these findings, metastatic progression in human PDAC was also associated of MYC signaling pathways and enrichment for MYC amplification in metastasis. Collectively, these results implicate MYC activity as a major determinant of metastatic burden and heterogeneity in advanced PDA. Citation Format: Ravikanth Maddipati, Robert J. Norgard, Timour Baslan, Komal S. Rathi, Amy Zhang, Pichai Raman, Max D. Wengyn, Taiji Yamazoe, Jinyang Li, David Balli, Michael J. LaRiviere, Ian W. Folkert, Ian D. Millstein, Jonathan Bermeo, Erica L. Carpenter, Scott Lowe, Christine Iacobuzio-Donahue, Faiyaz Notta, Ben Z. Stanger. MYC Influences metastatic heterogeneity in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PO-053.

Tumor heterogeneity - resulting from genetic and epigenetic alterations acquired during tumor progression - is a critical driver of phenotypic diversity in most cancers. A lethal consequence of tumor heterogeneity is the acquisition of metastatic traits by tumor cells, leading to poor clinical outcomes. This remains a major problem in pancreatic ductal adenocarcinoma (PDAC), which continues to have the worst prognosis of any major cancer type. While most cases of PDAC present with metastatic disease at the time of diagnosis, the patterns and burden of metastasis can vary widely, with some patients exhibiting a limited metastatic burden while others have more extensive spread, which impacts clinical outcomes. However, the biological and functional differences that drive metastatic heterogeneity are poorly understood. Citation Format: Ravikanth Maddipati, Robert J. Norgard, Timour Baslan, Komal S. Rathi, Amy Zhang, Pichai Raman, Max D. Wengyn, Taiji Yamazoe, Jinyang Li, David Balli, Michael LaRiviere, Ian W. Folkert, Ian D. Millstein, Jonathan Bermeo, Erica L. Carpenter, Scott Lowe, Christine Iacobuzio-Donahue, Faiyaz Notta, Ben Z. Stanger. MYC influences metastatic heterogeneity in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Tumor Heterogeneity: From Single Cells to Clinical Impact; 2020 Sep 17-18. Philadelphia (PA): AACR; Cancer Res 2020;80(21 Suppl):Abstract nr PO-071.

e13605 Background: Well-established risk-factors exist for gynecologic cancers (GC): estrogen exposure increases risk of endometrial cancer (EC); HPV infection and smoking are associated with cervical cancer (CC); oral contraceptive (OCP) use may be associated with an increased risk of CC but a reduced risk of EC and ovarian cancer (OC). Women with a family history (FH) of cancer are more likely to receive regular CC screening, but the association between FH of GC and other risk factors has not been investigated. Methods: Reduce My Risk is an Internet tool created in 2009 to provide personalized information regarding cancer risk, available at OncoLink.org. Voluntary participants were asked about risk factors and risk-associated behaviors. Differences between female respondents with v. without FH of GC were analyzed using chi-square test. Results: Among 16,878 female respondents, 841 (5.0%) had FH of CC, 345 (2.0%) EC, 1,117 (6.6%) OC, and 92 (0.5%) vulvar/vaginal (VC) cancer. Those with FH of any GC showed no difference in alcohol consumption compared to those without FH. Those with FH of CC, EC, OC, and VC were more likely to be obese (34.1% v. 24.7%; 37.2% v. 24.9%; 31.4% v. 24.7%, 43.7% v. 25%, p < 0.001 for all). Those with FH of CC were more likely to have first sexual intercourse before age 18 (69.2% v. 57.8%, p < 0.001) and to have > 10 sexual partners (24.0% v. 16.7%, p < 0.001). This group was also more likely to be current smokers (19.3% v. 11.7%, p < 0.001), and to smoke > 1 pack/day (6.5% v. 2.8%, p < 0.001). They were more likely to receive regular CC screening (91.2% v. 86.8%, p = 0.09), though the difference was not statistically significant. Women < 35 y with a FH of CC showed no differences in HPV vaccination rate (37.0% v. 39.3%, p = 0.29). Those with FH of EC were more likely to have menarche before age 12 (39.3% v. 32.0%, p = 0.005), and to have taken post-menopausal HRT for ≥2 y (77.6% vs. 66.8%, p < 0.001). Those with FH of EC, and OC were more likely to have taken OCPs (77.6% v. 66.8%; 71.9% v. 66.7%, p < 0.001 for both). Conclusions: Many with a FH of GC have increased likelihood of both modifiable and non-modifiable risk factors that are associated with the development of cancer. FH of CC did not increase likelihood of regular screening or HPV vaccination, but was associated with smoking, early intercourse, and multiple sexual partners. Future work should explore targeted intervention for those with FH of GC as a teachable opportunity for the benefits of weight reduction, smoking cessation, pap screening, and HPV vaccination.