Association of Sarcopenia With Toxicity-Related Discontinuation of Adjuvant Endocrine Therapy in Women With Early-Stage Hormone Receptor-Positive Breast Cancer

PURPOSE

Sarcopenia, an age-related decline in muscle mass and physical function, is associated with increased toxicity and worse outcomes in women with breast cancer (BC). Sarcopenia may contribute to toxicity-related early discontinuation of adjuvant endocrine  therapy (aET) in women with hormone receptor-positive (HR+) BC but remains poorly characterized.

METHODS AND MATERIALS

This multicenter, retrospective cohort study included consecutive women with stage 0-II HR+ BC who received breast conserving therapy (lumpectomy and radiation therapy) and aET from 2011 to 2017 with a 5-year follow-up. Skeletal muscle index (SMI, cm2/m2) was analyzed using a deep learning model on routine cross-sectional radiation simulation imaging; sarcopenia was dichotomized according to previously validated reports. The primary endpoint was toxicity-related aET discontinuation; logistic regression analysis evaluated associations between SMI/sarcopenia and aET discontinuation. Cox regression analysis evaluated associations with time to aET toxicity, ipsilateral breast tumor recurrence (IBTR), and disease-free survival (DFS).

RESULTS

A total of 305 women (median follow-up, 89 months) were included with a median age of 67 years and early-stage BC (12% stage 0, 65% stage I). A total of 60 (20%) women experienced toxicity-related aET discontinuation. Sarcopenia was associated with toxicity-related early discontinuation of aET (odds ratio, 2.18; P = .036) and shorter time to aET toxicity (hazard ratio [HR], 1.62; P = .031). SMI or sarcopenia were not independently associated with IBTR or DFS; toxicity-related aET discontinuation was associated with worse IBTR (HR, 9.47; P = .002) and worse DFS (HR, 4.53; P = .001).

CONCLUSIONS

Among women with early-stage HR+ BC who receive adjuvant radiation therapy and hormone therapy, sarcopenia is associated with toxicity-related early discontinuation of aET. Further studies should validate these findings in women who did not receive adjuvant radiation therapy. These high-risk patients may be candidates for aggressive symptom management and/or alternative treatment strategies to improve outcomes.

A Potent Kalihinol Analogue Disrupts Apicoplast Function and Vesicular Trafficking in P. falciparum Malaria

Here we report the discovery of MED6-189, a new analogue of the kalihinol family of isocyanoterpene (ICT) natural products. MED6-189 is effective against drug-sensitive and -resistant P. falciparum strains blocking both intraerythrocytic asexual replication and sexual differentiation. This compound was also effective against P. knowlesi and P. cynomolgi. In vivo efficacy studies using a humanized mouse model of malaria confirms strong efficacy of the compound in animals with no apparent hemolytic activity or apparent toxicity. Complementary chemical biology, molecular biology, genomics and cell biological analyses revealed that MED6-189 primarily targets the parasite apicoplast and acts by inhibiting lipid biogenesis and cellular trafficking. Genetic analyses in P. falciparum revealed that a mutation in PfSec13, which encodes a component of the parasite secretory machinery, reduced susceptibility to the drug. The high potency of MED6-189 in vitro and in vivo, its broad range of efficacy, excellent therapeutic profile, and unique mode of action make it an excellent addition to the antimalarial drug pipeline.

Automated temporalis muscle quantification and growth charts for children through adulthood

Lean muscle mass (LMM) is an important aspect of human health. Temporalis muscle thickness is a promising LMM marker but has had limited utility due to its unknown normal growth trajectory and reference ranges and lack of standardized measurement. Here, we develop an automated deep learning pipeline to accurately measure temporalis muscle thickness (iTMT) from routine brain magnetic resonance imaging (MRI). We apply iTMT to 23,876 MRIs of healthy subjects, ages 4 through 35, and generate sex-specific iTMT normal growth charts with percentiles. We find that iTMT was associated with specific physiologic traits, including caloric intake, physical activity, sex hormone levels, and presence of malignancy. We validate iTMT across multiple demographic groups and in children with brain tumors and demonstrate feasibility for individualized longitudinal monitoring. The iTMT pipeline provides unprecedented insights into temporalis muscle growth during human development and enables the use of LMM tracking to inform clinical decision-making.

Patient-Reported Outcomes, Tumor Markers, and Survival Outcomes in Advanced GI Cancer

Importance

Patient-reported outcomes (PROs), such as quality of life (QOL) and symptoms, are often associated with clinical outcomes in patients with cancer. In practice, oncologists use serum tumor markers (TMs) (ie, carcinoembryonic antigen [CEA] and carbohydrate antigen 19-9 [CA 19-9]) and imaging to monitor clinical outcomes in patients with gastrointestinal cancer.

Objective

To examine associations of 1-month changes in PROs and TMs with treatment response and survival among patients with gastrointestinal cancer.

Design, Setting, and Participants

This cohort study enrolled patients at Massachusetts General Hospital Cancer Center with at least 1 month follow-up from May 2019 to December 2020. Included patients were beginning first-line systemic therapy, aged 18 years or older, and had been diagnosed with metastatic pancreaticobiliary, colorectal, or gastroesophageal cancer. Data analyses took place from January 2021 to January 2022.

Intervention

PROs were collected, including QOL (Functional Assessment of Cancer Therapy General [FACT-G]), physical symptoms (Edmonton Symptom Assessment System [ESAS]), and psychological symptoms (Patient Health Questionnaire-4 [PHQ4] total, PHQ4-depression, and PHQ4-anxiety), as well as TMs (CEA and CA 19-9), at the time of chemotherapy initiation and 1 month later.

Main Outcomes and Measures

Associations of 1-month changes in PROs and TMs with treatment response (clinical benefit vs disease progression) at first scan, progression-free survival (PFS), and overall survival (OS), adjusted for baseline values using regression models.

Results

This study included 159 patients, with 134 patients (84.3%) evaluable for analysis. Patients had a median (range) age of 64.0 (28.0-84.0) years and 86 (64.2%) were male. One-month PRO changes (FACT-G: OR, 1.07; 95% CI, 1.03-1.11; P = .001; ESAS-total: OR, 0.97; 95% CI, 0.94-1.00; P = .02; ESAS-physical: OR, 0.96; 95% CI, 0.92-1.00; P = .03; PHQ4-depression: OR, 0.67; 95% CI, 0.49-0.92; P = .01) were significantly associated with treatment response, but PHQ4-total or TMs were not. Changes in FACT-G (HR, 0.97; 95% CI, 0.95-0.99; P = .003), ESAS-total (HR, 1.03; 95% CI, 1.01-1.05; P = .004), ESAS-physical (HR, 1.03; 95% CI, 1.00-1.05; P = .02), PHQ4-depression (HR, 1.22; 95% CI, 1.01-1.48; P = .04), and CEA (HR, 1.00; 95% CI, 1.001-1.004; P = .001) were associated with PFS, but changes in PHQ4-total or TMs were not. Changes in ESAS-total (HR, 1.03, 95% CI, 1.01-1.06; P = .006) and ESAS-physical (HR, 1.04, 95% CI, 1.01-1.06; P = .015) were associated with OS, but changes in TMs were not associated with OS.

Conclusions and Relevance

These findings suggest that 1-month changes in PROs can be associated with treatment response and survival in patients with advanced gastrointestinal cancer. Notably, 1-month changes in TMs were not consistently associated with these outcomes. These findings highlight the potential for monitoring early changes in PROs to associate with clinical outcomes while underscoring the need to address the QOL and symptom concerns of patients with advanced cancer.

The Importance of Timing of Physical Therapy in Relation to Radiation Therapy during Multimodality Breast Cancer Treatment to Maximize Shoulder Range of Motion

PURPOSE/OBJECTIVE(S)

Physical therapy (PT) is an effective tool for improving range of motion (ROM) for breast cancer patients to reduce long-term impairment. There is a paucity of data surrounding when PT should be initiated to optimally reduce upper limb disability. We hypothesized that patients who initiated PT early after surgery and before radiation therapy (RT), would experience greater gains in functionality compared to PT during/after RT.

MATERIALS/METHODS

Demographic/clinical variables were assessed via retrospective chart review for patients referred to outpatient PT and receiving multimodality treatment for breast cancer between January 2015 and August 2021. Three distinct cohorts were established: patients who received PT and no RT, PT initiated before radiation therapy (pre-RT), and PT initiated during/after RT (d/a RT). The primary endpoint was percent change of total ROM of the ipsilateral shoulder between the first and last PT visits. Secondary endpoints included absolute change in degrees of total ROM of the ipsilateral shoulder between first and last PT visits. Associations between ROM across PT groups and baseline characteristics were evaluated with analysis of variance (ANOVA) testing.

RESULTS

Thirty-seven patients were identified, median age 47 years (range 28-76). Higher tumor stage and axillary lymph node dissection were associated with the receipt of RT (p = 0.023, p = 0.003 respectively). Baseline ROM was associated with both percent and absolute improvement in ROM (p = 0.007). Patients receiving no RT demonstrated the greatest mean percent improvement in ROM with PT (84%), compared to the pre-RT and d/a RT cohorts, which demonstrated a 63% and 40% improvement, respectively. In pairwise comparisons, patients in the no RT group and those in the PT pre-RT group both demonstrated a statistically greater improvement in percent change in ROM compared to patients receiving PT d/a RT (no RT 74% vs d/a RT 20%, p = 0.006; pre-RT 59% vs d/a RT 20%, p = 0.045). There was no difference in percent change in ROM between the no RT and pre-RT groups (p = 0.528). On univariate analysis, baseline worse ROM was associated with statistically worse percent change in ROM after PT (p = 0.008), no other baseline characteristics were associated with ROM after PT. When adjusting for baseline ROM, the no RT cohort continued to be associated with improvement in ROM compared to the PT d/a RT group (p = 0.024), while there was no difference in percent change in ROM between patients who received physical therapy pre-RT compared to no RT (p = 0.829).

CONCLUSION

Physical therapy is helpful in improving shoulder ROM at all stages of multimodality breast cancer treatment, however early initiation of PT prior to the start of RT may help maximize range of motion gains.

Teaching Trainees to be Effective Mentors: A Needs-Based Assessment in Radiation Oncology

PURPOSE/OBJECTIVE(S)

Mentorship plays a critical role in the training and career development of medical trainees. Teaching-the-teacher workshops for residents translate to higher long-term job satisfaction and improved patient communication skills. Further, near-peer mentorship has been associated with increased job satisfaction and patient care experience. Resident-as-mentors can add benefit to the mentorship networks of students, particularly in resource-limited environments, while benefiting residents' own mentorship relations and career satisfaction. We hypothesized that residents would desire to be a mentor, but would lack specific skills needed for effective mentoring of students in radiation oncology.

MATERIALS/METHODS

A multi-institution, cross-sectional study was conducted among residents in the Radiation Oncology Education Collaborative Study Group (ROECSG) Graduate Medical Education working group from 06/2022-10/2022. Participants completed the Mentorship Competency Assessment (MCA), a validated 26-item questionnaire, scored on a Likert scale from 0-7 (0: most unprepared with mentorship skill, 7: most prepared with mentorship skill). The primary endpoint was the average score in individual mentorship skills among participants. Kruskal-Wallis test assessed associations between total MCA score (range 0-182) and demographics.

RESULTS

A total of 36 of 39 participants (92% response rate) responded. A majority were male (58%), from a residency size >10 (75%), and P Gy-2/3 (52%). Most had no formal training in teaching (86%) or mentorship (89%). Many believed they would be a good mentor to students on a rotation (89%), but most felt they would benefit from a formal mentorship program (92%). From the MCA, the mentorship skills residents felt most unprepared for were: coordinating effectively with other mentors (3.4/7), helping mentees acquire resources (3.6/7), negotiating a path to professional independence with mentees (3.6/7), helping mentees network effectively (3.7/7), and working with mentees to set clear expectations of the mentoring relationship (3.9/7). The mentorship skills residents felt most prepared for were: acknowledging mentees' professional contributions (5.6/7), establishing a relationship based on trust (5.6/7), active listening (5.5/7), building mentees' confidence (4.9/7), and working effectively with mentees with personal backgrounds differing from one's own (4.8/7). Higher MCA scores were associated with former training in mentorship (p = 0.0143), and a trend for former training in teaching (p = 0.0525), but was not associated with sex (p = 0.5986), residency size (p = 0.1415), or P Gy-year (p = 0.9747).

CONCLUSION

Residents are interested in mentorship training and report unpreparedness in several important skills. Future work should focus on formal training and assessment of mentoring skills for residents.

TEAMRO: TEAching Mentorship in Radiation Oncology, a Multicenter Prospective Phase 2 Intervention Study on Teaching Mentorship Skills to Residents Working with Medical Students

PURPOSE/OBJECTIVE(S)

While formal curriculum on resident teaching have been associated with improved career growth and sustained positive impact on patient care, mentorship skills are rarely taught in academic medicine. We hypothesized that a formalized resident mentorship curriculum coupled with a near-peer resident-medical student mentoring program would improve resident career growth.

MATERIALS/METHODS

A multi-institutional, prospective, phase 2 intervention study, approved by each participating center's institutional review board, was conducted from 4/2022-10/2022 among interested residents in the Radiation Oncology Education Collaborative Study Group Graduate Medical Education. Intervention included: 1) a 4-week mentorship curriculum (utilizing a Six Steps approach) composed of self-guided readings, didactic lecture, and 30-minute faculty check-in, and 2) a formalized 1:1 resident-medical student mentorship program during an existing radiation oncology sub-internship with weekly meetings. Resident participants completed the Mentorship Competency Assessment (MCA), a 26-item validated survey on mentorship skills in medicine scored from 0 (most unprepared) to 7 (most prepared) before and after the intervention. The primary endpoint was average change in MCA skill from pre- to post-intervention survey, with score ranges from -7 (a decrease in 7 points) to +7 (an increase of 7 points).

RESULTS

A total of 8 residents participated and all completed pre- and post-intervention surveys. Most residents were PGY-4/5 (75%), from programs with >10 residents (68%), and did not have prior training in teaching (88%) or mentorship (88%). Residents met students on average twice weekly (range 1-3) for an average of 2 hours a week (range 1-5). After the program, most residents felt confident in being a future mentor to students (100%), their overall well-being was positively impacted (63%), and their mentorship relationships were positively impacted (50%). All 26 mentorship skills increased on MCA after intervention (average +1.3/7 per skill). Skills that showed greatest improvement were helping mentees network effectively (+2.6/7), acquire resources (+2.1/7), negotiate a path to professional independence (+2.0/7), set career goals (+1.8/7), and balance work and personal life (+1.7/7). Skills that showed least improvement were establishing a relationship based on trust (+0.4/7), identifying and accommodating different communication styles (+0.6/7), providing constructive feedback (+0.7/7), and aligning mentor-mentee expectations (+0.8/7).

CONCLUSION

The formalized mentorship program improved mentorship skills among residents, translating to increased satisfaction in residents' own mentorship relations and overall well-being. Further studies are needed to assess the sustainability of these skills, as well as impact on career growth and satisfaction.

Automated Sarcopenia Assessment and Outcomes in Head and Neck Cancer with Deep Learning Analysis of Cervical Neck Skeletal Muscle

PURPOSE/OBJECTIVE(S)

Sarcopenia is an established prognostic factor in patients diagnosed with head and neck cancers (HNC), typically measured by the skeletal muscle index (SMI) from abdominal muscle mass at L3. While sarcopenia assessment could inform HNC management, it remains impractical, time- and labor-intensive, and operator-dependent. To overcome these challenges, we developed an automated deep learning (DL) platform to calculate SMI at L3 by quantifying cross-sectional cervical skeletal muscle area (SMA) at C3 through auto-segmentation, externally validated it, and evaluated associations with clinical outcomes.

MATERIALS/METHODS

Eight hundred twenty-one patients diagnosed with HNC from multiple institutes from 1999-2013, treated with definitive chemoradiation with baseline pre-treatment CT scans, were included for model development (335 training, 96 tuning) and for independent testing (48 internal, and 342 external). Ground truth single-slice segmentations of SM at the mid-C3 vertebral level were manually annotated by radiation oncologists using an established protocol. A multi-stage DL pipeline was developed, with a 2D DenseNet to select the middle slice of C3 section and a 2D UNet to segment the SM, from which SMA was calculated. The model was evaluated using the Dice Similarity Coefficient (DC) for the internal test set, and human acceptability testing on the external test set was performed by two radiation oncologists not involved in annotations. SMI was calculated from C3 SMA based on prior literature, and sarcopenia was defined by an established, sex-specific SMI cutoff. Sarcopenia associations with overall survival (OS) and toxicities were assessed on the external dataset with Cox and logistic multivariable regressions, as indicated.

RESULTS

Model DC on the internal test set as 0.90 [95% CI: 0.90-0.91], with an intra-class coefficient of 0.96 for SMA. Human acceptability testing showed a pass rate of 94.4%. Of the 342 patients in the clinical analysis, 261 (76.3%) patients had sarcopenia. Five-year survival was 84.4% in patients without sarcopenia vs 73.1% in patients with sarcopenia (HR 2.21, p = 0.028) (median f/u: 44 mo (IQR: 25 - 66 mo)). On multivariable regression, sarcopenia (HR 2.06, p = 0.037), ACE-27 score 2+ (HR 2.25, p = 0.001), non-oropharynx diagnosis (HR 3.96, p<0.001), and T3-4 stage (HR 2.37, p<0.001) were associated with worse OS. Sarcopenia was associated with longer PEG tube duration on multivariable analysis (HR 1.59, p = 0.003), along with ACE-27 score (HR 1.20, p = 0.012) and non-oropharynx primary site (HR 1.46, p = 0.034). Sarcopenia was associated with higher risk of having PEG tube at last follow up (OR 2.25, p = 0.046). An observed increase in risk of hospitalization <3 months after RT was non-significant (OR 2.18, p = 0.117).

CONCLUSION

We developed and externally validated a fully-automated platform for sarcopenia assessment that can be used on routine HNC imaging. This algorithm is positioned for prospective testing to determine if use will inform HNC management.

PfMORC protein regulates chromatin accessibility and transcriptional repression in the human malaria parasite, P. falciparum

The environmental challenges the human malaria parasite, Plasmodium falciparum, faces during its progression into its various lifecycle stages warrant the use of effective and highly regulated access to chromatin for transcriptional regulation. Microrchidia (MORC) proteins have been implicated in DNA compaction and gene silencing across plant and animal kingdoms. Accumulating evidence has shed light into the role MORC protein plays as a transcriptional switch in apicomplexan parasites. In this study, using CRISPR/Cas9 genome editing tool along with complementary molecular and genomics approaches, we demonstrate that PfMORC not only modulates chromatin structure and heterochromatin formation throughout the parasite erythrocytic cycle, but is also essential to the parasite survival. Chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) experiments suggest that PfMORC binds to not only sub-telomeric regions and genes involved in antigenic variation but is also most likely a key modulator of stage transition. Protein knockdown experiments followed by chromatin conformation capture (Hi-C) studies indicate that downregulation of PfMORC induces the collapse of the parasite heterochromatin structure leading to its death. All together these findings confirm that PfMORC plays a crucial role in chromatin structure and gene regulation, validating this factor as a strong candidate for novel antimalarial strategies.

Development and Validation of an Automated Image-Based Deep Learning Platform for Sarcopenia Assessment in Head and Neck Cancer

Importance

Sarcopenia is an established prognostic factor in patients with head and neck squamous cell carcinoma (HNSCC); the quantification of sarcopenia assessed by imaging is typically achieved through the skeletal muscle index (SMI), which can be derived from cervical skeletal muscle segmentation and cross-sectional area. However, manual muscle segmentation is labor intensive, prone to interobserver variability, and impractical for large-scale clinical use.

Objective

To develop and externally validate a fully automated image-based deep learning platform for cervical vertebral muscle segmentation and SMI calculation and evaluate associations with survival and treatment toxicity outcomes.

Design, Setting, and Participants

For this prognostic study, a model development data set was curated from publicly available and deidentified data from patients with HNSCC treated at MD Anderson Cancer Center between January 1, 2003, and December 31, 2013. A total of 899 patients undergoing primary radiation for HNSCC with abdominal computed tomography scans and complete clinical information were selected. An external validation data set was retrospectively collected from patients undergoing primary radiation therapy between January 1, 1996, and December 31, 2013, at Brigham and Women's Hospital. The data analysis was performed between May 1, 2022, and March 31, 2023.

Exposure

C3 vertebral skeletal muscle segmentation during radiation therapy for HNSCC.

Main Outcomes and Measures

Overall survival and treatment toxicity outcomes of HNSCC.

Results

The total patient cohort comprised 899 patients with HNSCC (median [range] age, 58 [24-90] years; 140 female [15.6%] and 755 male [84.0%]). Dice similarity coefficients for the validation set (n = 96) and internal test set (n = 48) were 0.90 (95% CI, 0.90-0.91) and 0.90 (95% CI, 0.89-0.91), respectively, with a mean 96.2% acceptable rate between 2 reviewers on external clinical testing (n = 377). Estimated cross-sectional area and SMI values were associated with manually annotated values (Pearson r = 0.99; P < .001) across data sets. On multivariable Cox proportional hazards regression, SMI-derived sarcopenia was associated with worse overall survival (hazard ratio, 2.05; 95% CI, 1.04-4.04; P = .04) and longer feeding tube duration (median [range], 162 [6-1477] vs 134 [15-1255] days; hazard ratio, 0.66; 95% CI, 0.48-0.89; P = .006) than no sarcopenia.

Conclusions and Relevance

This prognostic study's findings show external validation of a fully automated deep learning pipeline to accurately measure sarcopenia in HNSCC and an association with important disease outcomes. The pipeline could enable the integration of sarcopenia assessment into clinical decision making for individuals with HNSCC.

Fully-automated sarcopenia assessment in head and neck cancer: development and external validation of a deep learning pipeline

Purpose

Sarcopenia is an established prognostic factor in patients diagnosed with head and neck squamous cell carcinoma (HNSCC). The quantification of sarcopenia assessed by imaging is typically achieved through the skeletal muscle index (SMI), which can be derived from cervical neck skeletal muscle (SM) segmentation and cross-sectional area. However, manual SM segmentation is labor-intensive, prone to inter-observer variability, and impractical for large-scale clinical use. To overcome this challenge, we have developed and externally validated a fully-automated image-based deep learning (DL) platform for cervical vertebral SM segmentation and SMI calculation, and evaluated the relevance of this with survival and toxicity outcomes.

Materials and Methods

899 patients diagnosed as having HNSCC with CT scans from multiple institutes were included, with 335 cases utilized for training, 96 for validation, 48 for internal testing and 393 for external testing. Ground truth single-slice segmentations of SM at the C3 vertebra level were manually generated by experienced radiation oncologists. To develop an efficient method of segmenting the SM, a multi-stage DL pipeline was implemented, consisting of a 2D convolutional neural network (CNN) to select the middle slice of C3 section and a 2D U-Net to segment SM areas. The model performance was evaluated using the Dice Similarity Coefficient (DSC) as the primary metric for the internal test set, and for the external test set the quality of automated segmentation was assessed manually by two experienced radiation oncologists. The L3 skeletal muscle area (SMA) and SMI were then calculated from the C3 cross sectional area (CSA) of the auto-segmented SM. Finally, established SMI cut-offs were used to perform further analyses to assess the correlation with survival and toxicity endpoints in the external institution with univariable and multivariable Cox regression.

Results

DSCs for validation set (n = 96) and internal test set (n = 48) were 0.90 (95% CI: 0.90 - 0.91) and 0.90 (95% CI: 0.89 - 0.91), respectively. The predicted CSA is highly correlated with the ground-truth CSA in both validation (r = 0.99, p < 0.0001) and test sets (r = 0.96, p < 0.0001). In the external test set (n = 377), 96.2% of the SM segmentations were deemed acceptable by consensus expert review. Predicted SMA and SMI values were highly correlated with the ground-truth values, with Pearson r β 0.99 (p < 0.0001) for both the female and male patients in all datasets. Sarcopenia was associated with worse OS (HR 2.05 [95% CI 1.04 - 4.04], p = 0.04) and longer PEG tube duration (median 162 days vs. 134 days, HR 1.51 [95% CI 1.12 - 2.08], p = 0.006 in multivariate analysis.

Conclusion

We developed and externally validated a fully-automated platform that strongly correlates with imaging-assessed sarcopenia in patients with H&N cancer that correlates with survival and toxicity outcomes. This study constitutes a significant stride towards the integration of sarcopenia assessment into decision-making for individuals diagnosed with HNSCC.

SUMMARY STATEMENT

In this study, we developed and externally validated a deep learning model to investigate the impact of sarcopenia, defined as the loss of skeletal muscle mass, on patients with head and neck squamous cell carcinoma (HNSCC) undergoing radiotherapy. We demonstrated an efficient, fullyautomated deep learning pipeline that can accurately segment C3 skeletal muscle area, calculate cross-sectional area, and derive a skeletal muscle index to diagnose sarcopenia from a standard of care CT scan. In multi-institutional data, we found that pre-treatment sarcopenia was associated with significantly reduced overall survival and an increased risk of adverse events. Given the increased vulnerability of patients with HNSCC, the assessment of sarcopenia prior to radiotherapy may aid in informed treatment decision-making and serve as a predictive marker for the necessity of early supportive measures.

Abstract P2-03-01: Sarcopenia on baseline imaging is associated with toxicity-related discontinuation of endocrine therapy in women with early-stage hormone-positive breast cancer

Background Adjuvant endocrine therapy (ET) is standard of care in women with hormone receptor-positive (HR+) breast cancer (BC) with the goal to reduce recurrence. However, early discontinuation of ET occurs in 30-40% of women, largely attributable to toxicity, and leads to increased recurrence risk. There is considerable overlap in risk factors that predict toxicity from ET and chemotherapy, including age, co-morbidities, and geriatric conditions. Baseline low skeletal muscle area (SMA) on chest computed tomography (CT) is a surrogate marker for sarcopenia and predicts for significant toxicity and intolerance to chemotherapy in women with BC. No study has assessed the association of sarcopenia with toxicity-related discontinuation of ET in women with early-stage HR+ BC. Methods This single center retrospective cohort study included consecutive women with Stage 0-II HR+ BC who received ET and adjuvant radiotherapy (RT) from 01/2011-12/2017. Inclusion required a minimum of 5-year clinical follow-up after diagnosis. We used a validated deep learning pipeline to quantify SMA (cm2) at the tenth thoracic (T10) vertebral body on existing RT planning CT. The skeletal muscle index (SMI [cm2/m2] = SMA/(patient height (m))2) was calculated to adjust for patient height. Sarcopenia was defined as SMI&lt; 32.3 cm2/m2, based on a previously validated independent cohort of young healthy women. The primary endpoint was toxicity-related discontinuation of ET less than 60 months after initiation of ET. Secondary endpoints included any NCI CTCAE v5.0 Grade 3-5 toxicity from ET and ipsilateral breast tumor recurrence. We assessed associations between ET discontinuation and SMI (continuous), as well as thoracic sarcopenia (dichotomous), using logistic regression adjusting for baseline characteristics. We used cox proportional hazards regression to assess disease-free survival (DFS), defined as ipsilateral breast tumor recurrence, locoregional recurrence, or distant metastasis adjusting for baseline and treatment characteristics. Results A total of 265 women (median age 67 years) met inclusion criteria. The majority of women had a comorbidity index of 0-1 (89%) and were Caucasian (89%). The median follow-up was 82 months, 5-year overall survival was 96% and 5-year DFS was 94%. Diagnoses included DCIS (12%), IDC (76%), or ILC (12%); most were T1 (69%) or T2 (18%) and N0 (85%), ER-positive (100%), PR-positive (85%), or HER2-negative (9%). Most common ET type was anastrozole (63%), letrozole (16%), and tamoxifen (17%). SMI (continuous) was not associated with older age, Charlson Comorbidity Index (CCI), race, or tumor stage. A total of 64 (24%) women experienced toxicity-related early discontinuation of ET. On multivariate analysis (MVA), lower SMI was associated with increased toxicity-related early discontinuation of ET (Odds Ratio [OR] 0.89 per 1 cm2/m2 SMI, p=0.001) independent of age, CCI, ET type, or receipt of adjuvant chemotherapy. Lower SMI was associated with higher risk of grade 3-5 toxicity from ET (OR 0.89 per 1 unit SMI, p=0.001) independent of age, CCI, ET type, or receipt of adjuvant chemotherapy. On MVA, sarcopenia was associated with higher risk of toxicity-related early discontinuation of ET (OR 2.43, p=0.019). DFS was associated with toxicity-related early discontinuation of ET (HR 8.06, p=0.005), grade 3 histology (HR 1.42, p=0.042), and multifocal disease (HR 2.55, p=0.040), but not age, histology, stage, or lymphovascular invasion (p&gt;.05 for all). Conclusion Low baseline thoracic skeletal muscle is associated with toxicity-related early ET discontinuation in women with early-stage HR+ BC. Further studies should attempt to generalize this association to all HR+ BC who are candidates for ET. High-risk patients may be candidates for aggressive symptom management or alternative adjuvant therapies.

Citation Format: Anurag Saraf, Ismail Tahir, Bonnie Hu, Anna-Sophia Dietrich, Paul Erik Tonnesen, Greg Sharp, Gayle Tillman, Florian Fintelmann, Rachel Jimenez. Sarcopenia on baseline imaging is associated with toxicity-related discontinuation of endocrine therapy in women with early-stage hormone-positive breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-03-01.

BIOM-37. EVALUATION OF TEMPORALIS MUSCLE THICKNESS WITH TOXICITY AND SURVIVAL IN GLIOBLASTOMA PATIENTS RECEIVING CHEMORADIATION

BACKGROUND

Treatment-related toxicity is common in patients with glioblastoma (GBM) receiving chemotherapy and radiotherapy (RT). Temporalis muscle thickness (TMT) is a biomarker associated with sarcopenia and worse clinical outcomes in GBM, however its relation to treatment toxicity is less studied. We hypothesize that TMT may predict toxicity and survival in GBM patients.

METHODS

We reviewed consecutive patients with IDH-wildtype GBM treated from 2014-2019 at a single academic center. TMT was retrospectively assessed on T1-weighted MRI scans and dichotomized based upon previously validated sex-specific cutoff values. TMT was measured on baseline MRI scan at time of diagnosis. Cox regression multivariable analysis (MVA) was used to assess survival.

RESULTS

We evaluated 351 patients with median age of 60y (range 20-94) and median follow-up of 14mo. Most patients were male (59%), baseline KPS &gt;70 (95%), and MGMT unmethylated (55%). After maximal safe resection, most patients received standard (90%) or hypofractionated (10%) RT with concurrent systemic therapy (89%). On MVA, baseline low TMT (HR 1.93, p=0.01), age &gt;65y, baseline KPS, and MGMT-unmethylated status were associated with worse OS. On MVA, baseline low TMT (HR 1.95, p=0.01), age &gt;65y, MGMT-unmethylated status, and discontinuing systemic therapy were associated with worse profession-free survival (PFS). 21 patients did not complete anticipated treatment course of chemoradiation and adjuvant systemic therapy due to toxicity, primarily thrombocytopenia, associated with worse OS on MVA (HR 1.99, p&lt; 0.01). Low TMT was associated with higher risk of stopping treatment due to adverse events (OR 5.25, p&lt; 0.01) independent of age, sex, extent of resection, RT dose on MVA.

CONCLUSION

Baseline low TMT was associated with worse PFS and OS, and it was associated with treatment interruption due to treatment toxicity in GBM patients. While further validation is needed, TMT may help identify patients who will benefit from aggressive symptom management or treatment deintensification.

Optimal Neoadjuvant Strategies for Locally Advanced Rectal Cancer by Risk Assessment and Tumor Location

Neoadjuvant therapy is standard of care for locally advanced rectal cancer (LARC). Advancements in multimodality therapy options and sequencing of radiation therapy (RT), surgery, and chemotherapy make decision-making challenging. Traditional treatment of patients with LARC involves neoadjuvant chemoradiation followed by total mesorectal excision and consideration of adjuvant chemotherapy. Advancement in RT has led to trials offering both short-course and long-course RT with good long-term clinical outcomes. Intensification of therapy in high-risk patients has led to studies of total neoadjuvant therapy with chemotherapy and chemoradiation, now standard management for most LARC. De-escalation of therapy in patients with favorable prognosis has led to several considerations, including non–total mesorectal excision management or neoadjuvant chemotherapy only. Several considerations of patient and disease factors can help inform the optimal chemotherapy regimens in different sequencing of neoadjuvant strategies. Finally, novel biomarkers, such as microsatellite instability, has led to utilization of novel therapies, including neoadjuvant immunotherapy, with substantial response. This review attempts to frame the rapidly growing data in LARC in context of disease and patient risk factors, to inform optimal, personalized treatment of patients with LARC.

Novel Clinical Trial Designs in Neuro-Oncology

Scientific and technologic advances have led to a boon of candidate therapeutics for patients with malignancies of the central nervous system. The path from drug development to clinical use has generally followed a regimented order of sequential clinical trial phases. The recent increase in novel therapies, however, has strained the regulatory process and unearthed limitations of the current system, including significant cost, prolonged development time, and difficulties in testing therapies for rarer tumors. Novel clinical trial designs have emerged to increase efficiencies in clinical trial conduct to better evaluate and bring impactful drugs to patients in a timely manner. In order to better capture meaningful benefits for brain tumor patients, new endpoints to complement or replace traditional endpoints are also an increasingly important consideration. This review will explore the current challenges in the current clinical trial landscape and discuss novel clinical trial concepts, including consideration of limitations and risks of novel trial designs, within the context of neuro-oncology.

Clinical validation of deep learning algorithms for radiotherapy targeting of non-small-cell lung cancer: an observational study

BACKGROUND

Artificial intelligence (AI) and deep learning have shown great potential in streamlining clinical tasks. However, most studies remain confined to in silico validation in small internal cohorts, without external validation or data on real-world clinical utility. We developed a strategy for the clinical validation of deep learning models for segmenting primary non-small-cell lung cancer (NSCLC) tumours and involved lymph nodes in CT images, which is a time-intensive step in radiation treatment planning, with large variability among experts.

METHODS

In this observational study, CT images and segmentations were collected from eight internal and external sources from the USA, the Netherlands, Canada, and China, with patients from the Maastro and Harvard-RT1 datasets used for model discovery (segmented by a single expert). Validation consisted of interobserver and intraobserver benchmarking, primary validation, functional validation, and end-user testing on the following datasets: multi-delineation, Harvard-RT1, Harvard-RT2, RTOG-0617, NSCLC-radiogenomics, Lung-PET-CT-Dx, RIDER, and thorax phantom. Primary validation consisted of stepwise testing on increasingly external datasets using measures of overlap including volumetric dice (VD) and surface dice (SD). Functional validation explored dosimetric effect, model failure modes, test-retest stability, and accuracy. End-user testing with eight experts assessed automated segmentations in a simulated clinical setting.

FINDINGS

We included 2208 patients imaged between 2001 and 2015, with 787 patients used for model discovery and 1421 for model validation, including 28 patients for end-user testing. Models showed an improvement over the interobserver benchmark (multi-delineation dataset; VD 0·91 [IQR 0·83-0·92], p=0·0062; SD 0·86 [0·71-0·91], p=0·0005), and were within the intraobserver benchmark. For primary validation, AI performance on internal Harvard-RT1 data (segmented by the same expert who segmented the discovery data) was VD 0·83 (IQR 0·76-0·88) and SD 0·79 (0·68-0·88), within the interobserver benchmark. Performance on internal Harvard-RT2 data segmented by other experts was VD 0·70 (0·56-0·80) and SD 0·50 (0·34-0·71). Performance on RTOG-0617 clinical trial data was VD 0·71 (0·60-0·81) and SD 0·47 (0·35-0·59), with similar results on diagnostic radiology datasets NSCLC-radiogenomics and Lung-PET-CT-Dx. Despite these geometric overlap results, models yielded target volumes with equivalent radiation dose coverage to those of experts. We also found non-significant differences between de novo expert and AI-assisted segmentations. AI assistance led to a 65% reduction in segmentation time (5·4 min; p<0·0001) and a 32% reduction in interobserver variability (SD; p=0·013).

INTERPRETATION

We present a clinical validation strategy for AI models. We found that in silico geometric segmentation metrics might not correlate with clinical utility of the models. Experts' segmentation style and preference might affect model performance.

FUNDING

US National Institutes of Health and EU European Research Council.

Randomized Clinical Trials of Machine Learning Interventions in Health Care: A Systematic Review

IMPORTANCE

Despite the potential of machine learning to improve multiple aspects of patient care, barriers to clinical adoption remain. Randomized clinical trials (RCTs) are often a prerequisite to large-scale clinical adoption of an intervention, and important questions remain regarding how machine learning interventions are being incorporated into clinical trials in health care.

OBJECTIVE

To systematically examine the design, reporting standards, risk of bias, and inclusivity of RCTs for medical machine learning interventions.

EVIDENCE REVIEW

In this systematic review, the Cochrane Library, Google Scholar, Ovid Embase, Ovid MEDLINE, PubMed, Scopus, and Web of Science Core Collection online databases were searched and citation chasing was done to find relevant articles published from the inception of each database to October 15, 2021. Search terms for machine learning, clinical decision-making, and RCTs were used. Exclusion criteria included implementation of a non-RCT design, absence of original data, and evaluation of nonclinical interventions. Data were extracted from published articles. Trial characteristics, including primary intervention, demographics, adherence to the CONSORT-AI reporting guideline, and Cochrane risk of bias were analyzed.

FINDINGS

Literature search yielded 19 737 articles, of which 41 RCTs involved a median of 294 participants (range, 17-2488 participants). A total of 16 RCTS (39%) were published in 2021, 21 (51%) were conducted at single sites, and 15 (37%) involved endoscopy. No trials adhered to all CONSORT-AI standards. Common reasons for nonadherence were not assessing poor-quality or unavailable input data (38 trials [93%]), not analyzing performance errors (38 [93%]), and not including a statement regarding code or algorithm availability (37 [90%]). Overall risk of bias was high in 7 trials (17%). Of 11 trials (27%) that reported race and ethnicity data, the median proportion of participants from underrepresented minority groups was 21% (range, 0%-51%).

CONCLUSIONS AND RELEVANCE

This systematic review found that despite the large number of medical machine learning-based algorithms in development, few RCTs for these technologies have been conducted. Among published RCTs, there was high variability in adherence to reporting standards and risk of bias and a lack of participants from underrepresented minority groups. These findings merit attention and should be considered in future RCT design and reporting.

Long-term outcomes and late toxicity of adult medulloblastoma treated with combined modality therapy: A contemporary single-institution experience

BACKGROUND

Medulloblastoma (MB) is a rare central nervous system malignancy of adults, with limited contemporary studies to define treatment guidelines and expected late toxicity.

METHODS

A single-center, retrospective study was conducted of patients age ≥18 years from 1997-2019 with MB and who were treated with postoperative radiotherapy. Late toxicity was defined as a minimum of 18 months from diagnosis. Overall survival (OS) and progression-free survival (PFS) were characterized using Kaplan-Meier and Cox regression analyses.

RESULTS

Fifty-nine patients met criteria, with median age of 25 years (range 18-62 y) and median follow-up of 6.5 years (range 0.7-23.1 y). At diagnosis, 68% were standard-risk, 88% Chang M0, and 22% with anaplastic histology. Gross total resection was achieved in 75%; median craniospinal irradiation dose was 30.6 Gy (relative biological effectiveness [RBE]), median total dose was 54.0 Gy (RBE), 80% received proton radiotherapy; 81% received chemotherapy. 5 year PFS and OS were 86.5% and 95.8%, respectively; 10 year PFS and OS were 83.9% and 90.7%, respectively. Anaplastic histology was associated with worse PFS (P = .04). Among eight recurrences, 25% presented after 5 years. Most common grade ≥2 late toxicities were anxiety/depressive symptoms (30%), motor dysfunction (25%), and ototoxicity (22%). Higher posterior fossa radiation dose was associated with increased risk of late toxicity, including worse cognitive dysfunction (P = .05).

CONCLUSIONS

Adults with MB have favorable survival outcomes, but late failures and toxicity are not uncommon. Better understanding of prognostic factors, possibly from molecular subtyping, may help to define more personalized treatments for patients with high risk of recurrence and long-term treatment sequelae.

Low skeletal muscle area and association with toxicity and hospitalization with chemotherapy in advanced non–small cell lung cancer

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Background: Significant toxicity is common in the treatment of advanced non-small cell lung cancer (NSCLC) and can be associated with adverse events, such as unplanned hospitalization, and worse clinical outcomes. Baseline low skeletal muscle (SM) area is a marker of sarcopenia and has been associated with worse survival in other malignancies, but the association of SM area and toxicity in NSCLC is less studied. Methods: Patients with locally advanced or oligo-metastatic NSCLC treated with combined chemotherapy and radiotherapy with or without surgery from 2002-2013 at a single institution were reviewed. A deep-learning pipeline utilized existing pre-treatment computed tomography scans to calculate SM area at the 3rd lumbar vertebral level. Gold standard SM index (SMI) was calculated, adjusting for height, sex, and dichotomized per previously validated cutoff values. Grade 3 or higher hematologic (G3+ heme) toxicity, was assessed per NCI CTCAE v5.0, within 21-days of first chemotherapy cycle. Hospital use was defined as unplanned ED visit or inpatient hospitalization during chemotherapy. Multivariate analysis (MVA) of toxicity endpoints with SMI and baseline characteristics were analyzed by logistic regression analysis, and with overall survival (OS) using Cox regression analysis. Results: A total of 369 patients met inclusion criteria with median follow-up of 23.0mo (range 1-193mo), median age of 64y (range 29-88y), and were mostly male (51%). Most were clinical stage (AJCC 7th edition) IIIA (44%), IIIB (31%), or IV (10%), while 10% had upfront surgery and adjuvant chemotherapy. Most common regimen was cisplatin-based (48%). Median OS was 25.5mo and PFS was 14.0mo. Patients with low SMI were more likely to be younger (median age 70y vs 62y), ECOG performance status (PS) > 0 (74% vs 59%), lower BMI (median BMI 23.3 vs 27.7), and not receive cisplatin-based regimen (35% vs 53%). There was no difference in histology, stage, surgery, or every 3-week (q3w) chemotherapy dosing. On MVA, low SMI was associated with increased risk of G3+ heme toxicity (OR 1.74, p = 0.04) and increased hospital use (OR 1.79, p = 0.04). G3+ heme toxicity was also associated with surgery and q3w dosing, but not age, PS, BMI, or regimen. Hospital use was also associated with BMI, surgery, and cisplatin-based regimen, but not age, PS, or q3w dosing. G3+ heme toxicity (HR 1.48, p < 0.01), older age (HR 1.02, p = 0.02), and stage 4 (HR 3.32, p < 0.01) were associated with worse survival on MVA, but not low SMI (HR 1.25, p = 0.11), PS, BMI, surgery, or regimen. Conclusions: Low SMI predicted higher risk of G3+ toxicity during first cycle of chemotherapy. High-risk patients with low SMI experienced significant adverse events and should be considered for more aggressive symptom management or alternative treatment strategies.

Changes in Functional Assessment of Cancer Therapy: General (FACT-G) to predict treatment response and survival outcomes in patients with metastatic gastrointestinal (GI) cancer

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Background: The FACT-G contains 27 questions within 4 subscale domains [Physical Well-Being, Social/Family Well-Being, Emotional Well-Being, Functional Well-Being] related to health-related quality of life (QOL) in the past 7 days, with higher scoring indicating better QOL. In this prospective cohort study, we assessed longitudinal FACT-G data with treatment response and survival outcomes among patients with metastatic GI cancer. Methods: From 5/2019-11/2021, we enrolled patients at Massachusetts General Hospital with metastatic GI cancer to study before their treatment start. We collected the FACT-G survey at baseline (start of treatment) and 1-month later. We then used regression models to assess associations of 1-month changes in FACT-G with treatment response and survival outcomes (progression-free survival [PFS] and overall survival [OS]). For treatment response, clinical benefit was defined as decreased or stable tumor burden versus progressive disease at the time of first scan. All models were adjusted for baseline values of each respective variable. Results: We enrolled 203 of 262 patients approached (77.5% enrollment); 160 had 1-month follow-up data (median age = 63.0 years [range: 28.0-84.0 years], 66.3% male, 45.6% pancreaticobiliary cancer). For treatment response, 66.3% experienced a clinical benefit and 33.8% had progressive disease at the time of first scan (mean time to first scan = 2.7 months). Increases in FACT-G Total were predictors for treatment response (OR = 1.05, p = 0.0028), and improved PFS (HR = 0.98, p = 0.026) and OS (HR = 0.98, p = 0.038). Increases in FACT-G Emotional were associated with clinical benefit at the time of first scan (OR = 1.18, p = 0.0024), improved PFS (HR = 0.94, p = 0.023), and improved OS (HR = 0.93, p = 0.012). Improvement in FACT-G Physical were predictors for clinical benefit at time of first scan (OR = 1.08, p = 0.038) and better PFS (HR = 0.96, p = 0.038), while increases in FACT-G Functional were associated with improved PFS (HR = 0.96, p = 0.034) and OS (HR = 0.96, p = 0.019). Finally, changes in FACT-G Social were only associated with treatment response (OR = 1.16, p = 0.011). Conclusions: We found that 1-month increases in FACT-G can predict for treatment response and improved survival outcomes in patients with metastatic GI cancers. Notably, the FACT-G Total and FACT-G Emotional subscore predicted for all three outcomes of interest, while the FACT-G Social only predicted for clinical benefit at first scan. These data support previous findings indicating the possible use of early changes in patient-reported outcomes as a biomarker for early treatment response while emphasizing the growing need to integrate more patient-centric interventions into clinical care for cancer patients. Clinical trial information: NCT04776837.

Fractionated Proton Radiation Therapy and Hearing Preservation for Vestibular Schwannoma: Preliminary Analysis of a Prospective Phase 2 Clinical Trial

BACKGROUND

Local management for vestibular schwannoma (VS) is associated with excellent local control with focus on preserving long-term serviceable hearing. Fractionated proton radiation therapy (FPRT) may be associated with greater hearing preservation because of unique dosimetric properties of proton radiotherapy.

OBJECTIVE

To investigate hearing preservation rates of FPRT in adults with VS and secondarily assess local control and treatment-related toxicity.

METHODS

A prospective, single-arm, phase 2 clinical trial was conducted of patients with VS from 2010 to 2019. All patients had serviceable hearing at baseline and received FPRT to a total dose of 50.4 to 54 Gy relative biological effectiveness (RBE) over 28 to 30 fractions. Serviceable hearing preservation was defined as a Gardner-Robertson score of 1 to 2, measured by a pure tone average (PTA) of ≤50 dB and a word recognition score (WRS) of ≥50%.

RESULTS

Twenty patients had a median follow-up of 4.0 years (range 1.0-5.0 years). Local control at 4 years was 100%. Serviceable hearing preservation at 1 year was 53% (95% CI 29%-76%), and primary end point was not yet reached. Median PTA and median WRS both worsened 1 year after FPRT (P < .0001). WRS plateaued after 6 months, whereas PTA continued to worsen up to 1 year after FPRT. Median cochlea D90 was lower in patients with serviceable hearing at 1 year (40.6 Gy [RBE] vs 46.9 Gy [RBE]), trending toward Wilcoxon rank-sum test statistical significance (P = .0863). Treatment was well-tolerated, with one grade 1 cranial nerve V dysfunction and no grade 2+ cranial nerve dysfunction.

CONCLUSION

FPRT for VS did not meet the goal of serviceable hearing preservation. Higher cochlea doses trended to worsening hearing preservation, suggesting that dose to cochlea correlates with hearing preservation independent of treatment modality.

Body fat composition as biomarker for clinical outcomes and treatment tolerance in high-risk prostate cancer

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Background: Androgen deprivation therapy (ADT) is a standard of care for high-risk prostate cancer, but treatment tolerance is variable. Prior work has demonstrated the correlation between body composition (BC) and clinical outcomes in prostate cancer. Specifically, high visceral fat density has been associated with fat depletion phenomenon and poor prognosis in prostate cancer. However, the interaction of long-term ADT tolerance and body fat composition is less studied. We investigated if BC could predict for outcomes and treatment tolerance in patients with high-risk prostate cancer with planned ADT. Methods: An IRB-approved retrospective review was conducted at a tertiary care center of patients with high-risk (T3a or prostate-specific antigen [PSA] > 20 ng/mL or Gleason score 8-10 or N/M+) prostate cancer who received definitive external beam radiation therapy (RT) from 2006 to 2013. A previously validated, fully automated deep learning BC analysis pipeline was performed on RT simulation scans to compute BC at the top of L3 slice, including total skeletal muscle (SM), subcutaneous fat (SF), and visceral fat (VF) surface area (cm2) and average CT density (Hounsfield Units (HU)); results were manually validated by experts. BC was stratified by median value. Adult Comorbidity Evaluation-27 (ACE) was used to measure co-morbidity. Long-term ADT was defined as > 2 years, tolerance was defined as unplanned discontinuation > 3-month difference in intended/actual duration of ADT. The association between BC markers, oncologic outcomes, and treatment tolerance was analyzed using univariable Cox regression and chi-square test. Results: A total of 207 men were analyzed with a median follow up time of 10.8 years (range 0.7-17.3y). Median age was 65 (range 42-83), with 61 (29.4%) patients classified as high-risk, 134 (64.7%) very-high-risk, and 12 (5.8%) N+/M+ at diagnosis. High VF density was associated with worse overall survival (OS) (HR 1.71, 95%CI 1.09-2.68, p = 0.0204) but not cancer-specific survival (CSS) (p = 0.08) or biochemical-relapse free survival (bRFS) (p = 0.97). SM and SF density, as well as area of SM, VF, SF, and total fat were not associated with outcomes. N/M stage was associated with bRFS (p = 0.0139), and N/M stage (p = 0.0101) and higher ACE score (p = 0.0218) were associated with OS. Among 88 (42.5%) patients planned for long-term ADT use, 24 (27%) patients discontinued ADT prior to duration, of which 15 (17%) patients discontinued due to toxicity. BC markers did not correlate with tolerance to long-term ADT (p = 0.17). Tolerance to long-term ADT was not associated with bRFS or OS. Conclusions: High VF density is associated with worse OS but not bRFS or CSS in high-risk prostate cancer patients, and not associated with adipose area or ADT tolerance. VF density may be a biomarker of underlying metabolic health in prostate cancer patients independent of disease, and a potential area of intervention.

Associations of sarcopenia with hematologic toxicity, treatment intensity, and healthcare utilization in patients with metastatic colorectal cancer

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Background: We evaluated the impact of baseline sarcopenia on hematologic toxicity, treatment intensity, and healthcare utilization in patients with mCRC receiving FOLFOX or FOLFIRI. Methods: We retrospectively analyzed patients with mCRC who received care at our institution from 1/2011-11/2018 and were part of a biobanking protocol. Included adults received either first-line palliative FOLFOX- or FOLFIRI-based regimens and were followed for 6 months. We categorized sarcopenia based on skeletal muscle index measured at diagnosis of metastatic disease and pre-defined sex-specific cutoff values (F < 39 cm2/m2, M < 55cm2/m2). Our primary aim was to evaluate the association of sarcopenia and hematologic toxicity, defined as the incidence of grade ≥3 (G≥3) neutropenia, thrombocytopenia, or anemia (NCI CTCAE v5.0). Secondary endpoints included treatment intensity (dose reductions, treatment delays, relative-dose intensity [RDI]), and healthcare utilization (ED visits and/or hospitalizations). Bivariate analyses were used to evaluate associations between baseline sarcopenia and outcomes. Results: 126 of 177 screened patients met inclusion criteria (70 (56%) males, median age 61 yrs (range, 29-85)). 59 (46.8%) patients were sarcopenic. More patients received FOLFOX than FOLFIRI (92 [73.0%] vs. 34 [27.0%]). At baseline, patients had a median weight 76.9kg (IQR, 70.0-90.4 kg), BMI 26.6 kg/m2 (IQR, 24.1-30.5 kg/m2), and BSA 1.90 m2 (IQR, 1.72-2.01 m2). The incidence of G≥3 hematologic toxicity was 39.0% vs. 23.9% in sarcopenic and non-sarcopenic patients, respectively (p = 0.06). Patients with sarcopenia experienced higher incidence of G≥3 neutropenia (30.5% vs. 14.9%, p = 0.03), while G≥3 thrombocytopenia was similar (3.4% vs. 1.5%). The incidence of dose reductions and treatment delays did not differ significantly (86.4% vs. 89.5%, 72.9% vs. 71.6%, respectively). RDI was decreased for the 5FU bolus (52.5% vs. 65.0%, p = 0.02). Rates of ED visits (32.2% vs. 19.4%, p = 0.10) and hospitalizations (32.2% vs. 26.9%, p = 0.51) did not differ compared between patients with and without sarcopenia. Conclusions: Patients with mCRC and baseline sarcopenia receiving FOLFOX- or FOLFIRI experienced a higher incidence of G≥3 neutropenia and lower 5FU bolus treatment intensity. Studies are needed to understand how best to adjust treatment according to patients’ muscle mass.

Five decades of risk perception measurements of tobacco use: a review of literature

Perceptions of risk are beliefs about the likelihood of damage orloss. People make subjective judgments regarding the intensityand features of a danger. Smoking start and continuation areinfluenced by risk perception. Risk perception of tobacco useor smoking has always been controversial. Few studies foundthat risk perception is overestimated by smokers and tobaccousers, while other studies found that smokers underestimatethe risk of smoking. It has been observed that different authorshave been using different approaches to measure the risk perceptionof tobacco use. The present literature review is an ontologicalexploration of the process of calculating this constructand determining which method gives more holistic and robustinformation. A literature survey was carried out to understanddifferent ways in which risk perception can be measured. Fifty-seven studies were identified from 1970 to 2020 in which riskperception was calculated for any form of tobacco use. Theliterature review found that the researchers used two practicalapproaches to measure risk perception. In the first approach,the researchers tried to measure only the health risks of tobaccouse, and in the second, multiple dimensions of tobaccouse were measured. Most commonly perceived addictionand then the social risk of tobacco use was accessed. Thoughrecent literature is dominated by an approach where a singledimension, i.e., perceived health risk of tobacco use, is mostcommonly access, it is inferring from the available literature thattools that access multiple sizes of the perceived risk of tobaccouse give more comprehensive and robust information aboutthat construct which can be used further to create tobacco useprevention intervention.

Characterization of an Iodinated Rectal Spacer for Prostate Photon and Proton Radiation Therapy

PURPOSE

Conventional rectal spacers (nonI-SPs) are low-contrast on computed tomography (CT), often necessitating magnetic resonance imaging for accurate delineation. A new formulation of spacers (I-SPs) incorporates iodine to improve radiopacity and CT visualization. We characterized placement, stability, and plan quality of I-SPs compared to nonI-SPs.

METHODS AND MATERIALS

Patients with intact prostate cancer (n = 50) treated with I-SPs and photons were compared to randomly selected patients (n = 50) with nonI-SPs (photon or proton therapy). The I-SP was contoured on the planning CT and cone beam CTs at 3 timepoints: first, middle, and final treatment (n = 200 scans). I-SPs Hounsfield units (HU), volume, surface area (SA), centroid position relative to prostate centroid, and distance between prostate/rectum centroids were compared on the planning CTs between each cohort. I-SP changes were evaluated on cone beam CTs over courses of treatment. Dosimetric evaluations of plan quality and robustness were performed. I-SP was tested in a phantom to characterize its relative linear stopping power for protons.

RESULTS

I-SPs yielded a distinct visible contrast on planning CTs compared to nonI-SPs (HU 138 vs 12, P < .001), allowing delineation on CT alone. The delineated volume and SA of I-SPs were smaller than nonI-SPs (volume 8.9 vs 10.6 mL, P < .001; SA 28 vs 35 cm², P < .001), yet relative spacer position and prostate-rectal separation were similar (P = .79). No significant change in HU, volume, SA, or relative position of the I-SPs hydrogel occurred over courses of treatment (all P > .1). Dosimetric analysis concluded there were no significant changes in plan quality or robustness for I-SPs compared to nonI-SPs. The I-SP relative linear stopping power was 1.018, necessitating HU override for proton planning.

CONCLUSIONS

I-SPs provide a manifest CT contrast, allowing for delineation on planning CT alone with no magnetic resonance imaging necessary. I-SPs radiopacity, size, and relative position remained stable over courses of treatment from 28 to 44 fractions. No changes in plan quality or robustness were seen comparing I-SPs and nonI-SPs.

A Paradigm Shift in Radiation Oncology Training

The coronavirus disease 2019 pandemic has been intertwined with the movement for racial justice in the United States and has highlighted and risks aggravating educational and workforce disparities within radiation oncology. We discuss wide-ranging changes within radiation oncology training that are essential to developing and maintaining diversity, including utilization of competency-based educational models that allow for streamlining of training and examinations; responsiveness to the needs of residents and medical students of different gender, racial/ethnic, and socioeconomic groups; and technological integration to increase educational efficiency and decrease barriers.

Improving Diversity and Inclusion in the Post-Coronavirus Disease 2019 Era Through a Radiation Oncology Intensive Shadowing Experience (RISE)

Purpose

In response to the coronavirus disease 2019 pandemic, current Association of American Medical Colleges guidelines discourage away rotations, posing significant challenges for attracting students to radiation oncology (RO). This is particularly concerning for medical students underrepresented in medicine (UIM) due to the potential of widening existing disparities in applicant and workforce composition. To proactively address this, we created a Radiation Oncology Intensive Shadowing Experience (RISE) to expose UIM students to the field of RO.

Methods and Materials

Key stakeholders within the residency program, including both UIM faculty and residents with experience in health disparities and medical education, designed a 1-week virtual RISE intended for fourth year UIM students recruited through established national organizations serving UIM medical students. A 1-week disease-specific curriculum was developed using 4 components: (1) foundational exposure to RO, (2) didactic teaching, (3) mentorship opportunities, and (4) a capstone experience. Mentorship was continuously weaved through the experience by attendings, peer resident mentors, and a UIM resident panel to optimize exposure.

Results

RISE was successfully initiated at 2 academic medical centers with 12 UIM students enrolled through August. Anonymized pre- and postclerkship surveys were developed for students, residents, and faculty involved in RISE to evaluate participants’ satisfaction, resident and attending time burden, and perceptions of program effectiveness.

Conclusions

We created a unique virtual RO shadowing experience for UIM students to address a critical gap in exposure to RO, heightened by the corona virus disease 2019 pandemic, with the goal of improving diversity, equity, and inclusion in our field.

A low percentage of metastases in deep brain and temporal lobe structures

BACKGROUND

Whole-brain radiotherapy (WBRT) in patients with brain metastases (BM) is associated with neurocognitive decline. Given its crucial role in learning and memory, efforts to mitigate this toxicity have mostly focused on sparing radiation to the hippocampus. We hypothesized that BM are not evenly distributed across the brain and that several additional areas may be avoided in WBRT based on a low risk of developing BM.

METHODS

We contoured 2757 lesions in a large, single-institution database of patients with newly diagnosed BM. BM centroids were mapped onto a standard brain atlas of 55 anatomic subunits and the observed percentage of BM was compared with what would be expected based on that region's volume. A region of interest (ROI) analysis was performed in a validation cohort of patients from 2 independent institutions using equivalence and one-sample hypothesis tests.

RESULTS

The brainstem and bilateral thalami, hippocampi, parahippocampal gyri, amygdala, and temporal poles had a cumulative risk of harboring a BM centroid of 4.83% in the initial cohort. This ROI was tested in 157 patients from the validation cohort and was found to have a 4.1% risk of developing BM, which was statistically equivalent between the 2 groups (P < 1 × 10-6, upper bound).

CONCLUSION

Several critical brain structures are at a low risk of developing BM. A risk-adapted approach to WBRT is worthy of further investigation and may mitigate the toxicities of conventional radiation.

Treating the SARS-CoV-2-positive patient with cancer: A proposal for a pragmatic and transparent ethical process

The treatment of patients with cancer who test positive for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) poses unique challenges. In this commentary, the authors describe the ethical rationale and implementation details for the creation of a novel, multidisciplinary treatment prioritization committee, including physicians, frontline staff, an ethicist, and an infectious disease expert. Organizational obligations to health care workers also are discussed. The treatment prioritization committee sets a threshold of acceptable harm to patients from decreased cancer control that is justified to reduce risk to staff. The creation of an ethical, consistent, and transparent decision‐making process involving such frontline stakeholders is essential as departments across the country are faced with decisions regarding the treatment of SARS‐CoV‐2–positive patients with cancer.

This commentary describes the ethical rationale and implementation details for a novel, multidisciplinary, treatment prioritization committee that makes treatment decisions regarding patients with cancer who are positive for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). This consistent, ethical, and transparent process could be adapted to any oncology department in which there is risk disparity between physician decision makers and the frontline staff who are implementing these decisions.

BRK phosphorylates SMAD4 for proteasomal degradation and inhibits tumor suppressor FRK to control SNAIL, SLUG, and metastatic potential

The tumor-suppressing function of SMAD4 is frequently subverted during mammary tumorigenesis, leading to cancer growth, invasion, and metastasis. A long-standing concept is that SMAD4 is not regulated by phosphorylation but ubiquitination. Our search for signaling pathways regulated by breast tumor kinase (BRK), a nonreceptor protein tyrosine kinase that is up-regulated in ~80% of invasive ductal breast tumors, led us to find that BRK competitively binds and phosphorylates SMAD4 and regulates transforming growth factor-β/SMAD4 signaling pathway. A constitutively active BRK (BRK-Y447F) phosphorylates SMAD4, resulting in its recognition by the ubiquitin-proteasome system, which accelerates SMAD4 degradation. Activated BRK-mediated degradation of SMAD4 is associated with the repression of tumor suppressor gene FRK and increased expression of mesenchymal markers, SNAIL, and SLUG. Thus, our data suggest that combination therapies targeting activated BRK signaling may have synergized the benefits in the treatment of SMAD4 repressed cancers.

Natural history, clinical course and predictors of interval time from initial diagnosis to development of subsequent NSCLC brain metastases

PURPOSE

Non-small cell lung cancer (NSCLC) brain metastases are associated with substantial morbidity and mortality. During recent years, accompanying dramatic improvements in systemic disease control, NSCLC brain metastases have emerged as an increasingly relevant clinical problem. However, optimal surveillance practices remain poorly defined. This purpose of this study was to further characterize the natural history, clinical course and risk factors associated with earlier development of subsequent NSCLC brain metastases to better inform clinical practice and help guide survivorship care.

METHODS

We retrospectively reviewed all institutional NSCLC brain metastasis cases treated with radiotherapy between 1997 and 2015. Exclusion criteria included presence of brain metastases at initial NSCLC diagnosis and incomplete staging information. Interval time to brain metastases and subsequent survival were characterized using Kaplan-Meier and multivariate Cox regression analyses.

RESULTS

Among 105 patients within this cohort, median interval time to development of brain metastases was 16 months. Median interval times were 29, 19, 16 and 13 months for Stage I-IV patients, respectively (P = 0.016). Additional independent predictors for earlier development of NSCLC brain metastases included non-adenocarcinomatous histopathology (HR 3.036, P < 0.001), no prior surgical resection (HR 1.609, P = 0.036) and no prior systemic therapy (HR 3.560, P = 0.004). Median survival following intracranial progression was 16 months. Delayed development of brain metastases was associated with better prognosis (HR 0.970, P < 0.001) but not survival following intracranial disease onset.

CONCLUSIONS

Collectively, our results provide valuable insights into the natural history of NSCLC brain metastases. NSCLC stage, histology, prior surgical resection and prior systemic therapy emerged as independent predictors for interval time to brain metastases.

Single institution validation of a modified graded prognostic assessment of patients with breast cancer brain metastases

Aim:

The number of breast cancer brain metastases is a prognostic clinical variable in the modified graded prognostic assessment (GPA) Index for breast cancer.

Patients & methods:

We retrospectively gathered data from 127 breast cancer patients who underwent radiation therapy for brain metastasis. Patients were stratified by both breast GPA and modified breast GPA scores, and survival was determined using the Kaplan–Meier curves and Cox proportional hazards model.

Results & Conclusion:

The Kaplan–Meier curve for patients under the breast GPA classification were not significant, but were significant under the modified breast GPA classification. The inclusion of number of brain metastases into the modified breast GPA index improved prognosis, thus validating the use of the modified breast GPA in prognosticating patient outcome.

Breast cancer subtype and stage are prognostic of time from breast cancer diagnosis to brain metastasis development

Breast cancer brain metastasis (BCBM) is associated with high morbidity and mortality. Patients with breast cancer risk factors associated with rapid development of BCBM could potentially benefit from early brain metastasis screening. We retrospectively reviewed all BCBM patients treated with brain radiotherapy at our institution from 1997 to 2015. Interval time to BCBM was defined as date of pathologic breast cancer diagnosis to date of radiographic evidence of brain metastasis. Patients were stratified by breast cancer molecular subtype and stage at diagnosis. Kaplan Meier analysis was conducted on time to development of BCBM. Breast cancer risk factors were correlated with time to BCBM on Cox proportion hazard analysis. The study cohort comprised 121 BCBM patients, with median interval time to BCBM of 46 months. Times to BCBM for Her2+/2HR+, Her2+, Her2-/HR+, and triple-negative (TNBC) subtypes were 70, 44, 42, and 28 months respectively (p = 0.002). Time to BCBM for stages I, II, III, and IV were 70, 54, 29, and 24 months, respectively (p = 0.000). BCBM patients were further stratified by both molecular subtype (TNBC vs. non-TNBC) and stage (I, II vs. III, IV). Median times to BCBM for non-TNBC/stage I-II, TNBC/stage I-II, non-TNBC stage III-IV, and TNBC/stage III-IV were 68, 47, 29, and 6 months respectively (p = 0.000). Subtype and stage were associated with shorter time to BCBM on multivariate analysis. Subtype and initial stage are independently correlated with decreased time to development of BCBM. Patients with advanced high stage and triple negative breast cancer develop brain metastases significantly earlier.

Measurements of ionization states in warm dense aluminum with betatron radiation

Time-resolved measurements of the ionization states of warm dense aluminum via K-shell absorption spectroscopy are demonstrated using betatron radiation generated from laser wakefield acceleration as a probe. The warm dense aluminum is generated by irradiating a free-standing nanofoil with a femtosecond optical laser pulse and was heated to an electron temperature of ∼20-25 eV at a close-to-solid mass density. Absorption dips in the transmitted x-ray spectrum due to the Al^{4+} and Al^{5+} ions are clearly seen during the experiments. The measured absorption spectra are compared to simulations with various ionization potential depression models, including the commonly used Stewart-Pyatt model and an alternative modified Ecker-Kröll model. The observed absorption spectra are in approximate agreement with these models, though indicating a slightly higher state of ionization and closer agreement for simulations with the modified Ecker-Kröll model.

Obesity and survival in the neoadjuvant breast cancer setting: Role of tumor subtype and race

e12136

Background: Obesity may adversely influence survival in breast cancer; however, studies are conflicting and limited in the neoadjuvant setting. Results may also vary by tumor subtype and race/ethnicity. Our study seeks to examine associations between obesity and survival in women receiving neoadjuvant chemotherapy (NAC) and the role of tumor subtype and race/ethnicity. Methods: In a retrospective review of women with operable invasive breast cancer administered Adriamycin/Taxane-based NAC at a single intuition from 2004-2016, we identified n = 273 women with completed BMI data at diagnosis. Obesity was defined as body mass index (BMI) > = 30. We assessed associations between obesity and progression-free survival (PFS), using STEEP criteria, and overall survival (OS), using all-cause mortality, both overall and stratified by tumor subtype in three groups: Hormone Receptor Positive (HR+)/HER2- (n = 135), HER2+ regardless of hormonal status (n = 94), and Triple Negative Breast Cancer (TNBC) (n = 44), examining race/ethnicity (Non-Hispanic White, Black and Hispanic) in each subtype. Results: There were 60 events and 33 deaths observed. Overall, obesity was associated with worse PFS (HR1.71 95% CI 1.03-2.85, p = 0.04) and a trend towards worse OS (HR 1.70 95% CI 0.86-3.37, p = 0.13). In HR+/HER2- disease, there was an interaction between obesity and hormonal therapy. In those receiving only tamoxifen (n = 35), obesity was associated with worse PFS (HR 2.96 95% CI 1.02-8.6, p = 0.047) and OS (HR 14.3 95% CI 1.67-123.1, p = 0.015). In those receiving an aromatase inhibitor (AI) (n = 96), there was no association between obesity and survival, p > 0.05. In TNBC, obesity was associated with worse PFS (HR 2.62 95% CI 1.03-6.66, p = 0.043) and OS (HR 3.00 95% CI 0.95-9.51, p = 0.062). In HER2+ disease, obesity was associated with worse PFS (HR 3.37 95% CI 0.97-11.72, p = 0.056) but not OS (HR 1.35 95% CI 0.22-8.19, p = 0.75). Race/ethnicity was not significantly associated with survival in any tumor subtype, and there were no interactions between race/ethnicity and obesity with survival. Conclusions: Obesity negatively impacts survival in all tumor subtypes, including TNBC, and may be influenced by hormonal therapy class in HR+/HER2- disease.

Whole-brain Irradiation Field Design: A Comparison of Parotid Dose

Whole-brain radiation therapy (WBRT) plays an important role in patients with diffusely metastatic intracranial disease. Whether the extent of the radiation field design to C1 or C2 affects parotid dose and risk for developing xerostomia is unknown. The goal of this study is to examine the parotid dose based off of the inferior extent of WBRT field to either C1 or C2. Patients treated with WBRT with either 30 Gy or 37.5 Gy from 2011 to 2014 at a single institution were examined. Parotid dose constraints were compared with Radiation Therapy Oncology Group (RTOG) 0615 nasopharyngeal carcinoma for a 33-fraction treatment: mean <26 Gy, volume constraint at 20 Gy (V20) < 20 cc, and dose at 50% of the parotid volume (D50) < 30 Gy. Biologically effective dose (BED) conversions with an α/β of 3 for normal parotid were performed to compare with 10-fraction and 15-fraction treatments of WBRT. The constraints are as follows: mean < BED 32.83 Gy, V15.76 (for 10-fraction WBRT) or V17.35 (for 15-fraction WBRT) < 20 cc, and D50 < BED 39.09 Gy. Nineteen patients treated to C1 and 26 patients treated to C2 were analyzed. Comparing WBRT to C1 with WBRT to C2, the mean left, right, and both parotids' doses were lower when treated to C1. Converting mean dose to BED₃, the parotid doses were lower than BED₃ constraint of 32.83 Gy: left (30.12 Gy), right (30.69 Gy), and both parotids (30.32 Gy). V20 to combined parotids was lower in patients treated to C1. When accounting for fractionation of WBRT received, the mean corrected V20 volume was less than 20 cc when treating to C1. D50 for C1 was lower than C2 for the left parotid, right parotid, and both parotids. BED₃ conversion for the mean D50 of the left, right, and both parotids was less than 39.09 Gy. In conclusion, WBRT to C1 limits parotid dose, and parotid dose constraints are achievable compared with inferior border at C2. A possible mean parotid dose constraint with BED₃ should be less than 32.83 Gy.