NCCN Guidelines® Insights: Merkel Cell Carcinoma, Version 1.2024

The NCCN Guidelines for Merkel Cell Carcinoma (MCC) provide recommendations for diagnostic workup, clinical stage, and treatment options for patients. The panel meets annually to discuss updates to the guidelines based on comments from expert review from panel members, institutional review, as well as submissions from within NCCN and external organizations. These NCCN Guidelines Insights focus on the introduction of a new page for locally advanced disease in the setting of clinical node negative status, entitled "Clinical N0 Disease, Locally Advanced MCC." This new algorithm page addresses locally advanced disease, and the panel clarifies the meaning behind the term "nonsurgical" by further defining locally advanced disease. In addition, the guideline includes the management of in-transit disease and updates to the systemic therapy options.

Basal Cell Skin Cancer, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology

Basal cell carcinoma (BCC) is the most common form of skin cancer in the United States. Due to the high frequency, BCC occurrences are not typically recorded, and annual rates of incidence can only be estimated. Current estimated rates are 2 million Americans affected annually, and this continues to rise. Exposure to radiation, from either sunlight or previous medical therapy, is a key player in BCC development. BCC is not as aggressive as other skin cancers because it is less likely to metastasize. However, surgery and radiation are prevalent treatment options, therefore disfigurement and limitation of function are significant considerations. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) outline an updated risk stratification and treatment options available for BCC.

Abstract OT3-15-01: TBCRC-053: P-RAD: A Randomized Study of Preoperative Chemotherapy, Pembrolizumab and No, Low or High Dose RADiation in Node-Positive, HER2-Negative Breast Cancer

Background: The introduction of immune checkpoint inhibitors (ICI) to standard neoadjuvant chemotherapy regimens has been shown to significantly improve outcomes in patients with triple negative breast cancer and is being investigated for high-risk hormone receptor-positive (HR+)/human epidermal growth factor-2 negative (HER2-) breast cancer. Preclinical evidence suggests radiation therapy (RT) can stimulate intra-tumoral T cell infiltration and enhance the expression and immune detection of tumor-specific neoantigens. This phase II pilot randomized study (NCT04443348) aims to evaluate the safety and efficacy of two different doses of preoperative primary tumor RT boost when combined with neoadjuvant pembrolizumab, then followed by standard neoadjuvant chemotherapy. Dual co-primary endpoints include determining the pathologic complete response (pCR) rate in the non-irradiated and pathologically confirmed metastatic axillary lymph node(s) in each treatment arm and quantifying tumor-infiltrating T lymphocytes in on-treatment (C1D14) tumor biopsies. We hypothesize that high-dose RT will increase the proportion of tumors with high T cell infiltration (i.e., top quartile) from 25% to 55%. Secondary endpoints include measuring residual cancer burden, evaluating tolerability of the regimen, and assessing quality of life. Exploratory endpoints include evaluation of treatment-associated changes in the tumor immune microenvironment, circulating immune cell analyses, and circulating tumor DNA kinetics. Methods: The study plans to enroll 128 participants with either triple negative (n=80) or high-risk HR=/HER2- (n=48) breast cancer who will be randomized to receive no, low (9 Gy), or high (24 Gy) dose of preoperative RT boost, after which 24 participants of either breast cancer subtype will be enrolled to an exploratory high dose proton therapy boost cohort. The eligibility criteria include patients who have biopsy-proven, axillary lymph node-positive breast cancer that is either triple negative (defined as ER< 10%, PR< 10%, and HER2-negative) or high-risk HR+/HER2- (grade III or having a high-risk genomic assay score). Study treatment is given in 6-week cycles, with 400 mg Pembrolizumab given on day 1 of each cycle. For those participants randomized to receive a preoperative RT boost, treatment is delivered in 3 fractions (3 × 3 Gy or 3 × 8 Gy) over consecutive business days, where one of the fractions is given on the same day as C1D1 Pembrolizumab. Standard neoadjuvant chemotherapy begins on C1D15 with paclitaxel (plus carboplatin for triple negative) administered weekly for 12 weeks, and then starting on C3D15, dose-dense doxorubicin/cyclophosphamide is administered every 2 weeks for 8 weeks. Following neoadjuvant treatment, participants will receive standard breast surgery (including removal of the pathologically confirmed metastatic lymph node) followed by adjuvant pembrolizumab, radiation therapy, and standard-of-care systemic therapy as clinically indicated. Tissue samples from the primary tumor and biopsy-proven lymph node are taken at baseline, C1D14, and at the time of surgery. There are eleven blood collection timepoints throughout the neoadjuvant and adjuvant settings. Participants will be followed for 2 years after surgery to assess safety and durability of responses. Results: This study has accrued 12 participants to date, including 10 with triple negative breast cancer and 2 with high-risk HR+/HER2- breast cancer. Formal results for this study are forthcoming, as the trial is actively accruing at 6 institutions, with plans to open at 3 more within the year. For persons with a specific interest in this trial, please contact Joseph Connolly, Multi-Center Coordinator, at jconnolly28@mgh.harvard.edu.

Citation Format: Joseph J. Connolly, Laura M. Spring, Alphonse G. Taghian, Michele Gadd, Laura Warren, Ana C. Garrido-Castro, Tari King, Elizabeth A. Mittendorf, Jose P. Leone, Dana L. Casey, Lisa Carey, Tiffany A. Traina, Yara Abdou, Atif Khan, George Plitas, Jean Wright, Cesar Augusto Santa-Maria, Lisa Jacobs, Rachel Blitzblau, E Shelley Hwang, Carey Anders, Ian Krop, Antonio C. Wolff, Alastair M. Thompson, Elyssa Denault, Gaorav Gupta, Alice Ho. TBCRC-053: P-RAD: A Randomized Study of Preoperative Chemotherapy, Pembrolizumab and No, Low or High Dose RADiation in Node-Positive, HER2-Negative 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 OT3-15-01.

Abstract OT2-09-01: TBCRC-055: A Phase II Study of NirAparib, Dostarlimab, and Radiotherapy in Metastatic, PD-L1 Negative or Immunotherapy-Refractory Triple-Negative Breast Cancer (NADiR) – NCT04837209

Background: Metastatic triple negative breast cancer (mTNBC) is associated with high recurrence and mortality rates. Prior studies have shown an immune checkpoint inhibitor (ICI) + chemotherapy improves progression-free survival for patients with PD-L1 positive mTNBC. There remains a need for treatment options in patients who do not respond to ICI or are PD-L1 negative. Preclinical data suggests that a PARP inhibitor (PARPi) may promote innate immune signaling, and combination with an ICI has shown a positive response in patients with mTNBC. Radiotherapy (RT) is a potent immune stimulator and used for local control in the setting of metastatic breast cancer. This phase II study (NCT04837209) proposes combination of PARPi, ICI, and RT to combat ICI resistance and improve response rates in patients with mTNBC who are PD-L1 negative or who have progressed on prior ICI. Methods: 32 patients with mTNBC defined as ER< 1%, PR< 1%, HER-2-neu 0-1+ by IHC or non-FISH-amplified or patients with metastatic HR+/HER2- breast cancer are anticipated to participate. Eligibility criteria for mTNBC patients includes those who are PD-L1 negative or have progressed on prior ICI. Eligibility criteria for HR+/HER2- patients is specific to those who harbor a deleterious BRCA1 or BRCA2 mutation with or without high tumor mutational burden (TMB). All trial patients should have at least 1 lesion amenable to RT and at least 1 measurable lesion that will not be radiated. Study treatment consists of 3-week cycles, with 500mg dostarlimab given on day 1 of each cycle through cycle 5, then 1000mg given every 6 weeks. RT (24 Gy) is delivered in 3 consecutive fractions starting day 1 of cycle 1. Niraparib (200mg) is dosed orally daily. Tumor biopsies are taken within 28 days pre-treatment, and at C3D1-8. Blood samples are taken at baseline and every odd cycle for cfDNA and PBMC analysis. The primary endpoint is to assess overall response rate as measured by RECIST v1.1 of the combination of niraparib, dostarlimab, and RT. Secondary objectives include assessing safety and toxicity, overall survival, progression free survival, and quality of life. Results: To date, this study has accrued 4 subjects, including 3 with mTNBC, and 1 with HR+/HER2-/BRCA mutant + TMB high mBC. The study is currently open at MGH and Sibley, and the addition of UPenn, Johns Hopkins, and Duke are in progress. Funding for this study was provided by GSK. GSK was provided the opportunity to review a preliminary version of this abstract for factual accuracy, but the authors are solely responsible for final content and interpretation. People with specific interest in the trial should reach out to Elizabeth Scott, Clinical Research Coordinator, at ecscott@mgh.harvard.edu.

Citation Format: Elizabeth Scott, Steven J. Isakoff, Alphonse G. Taghian, Jean Wright, Cesar Augusto Santa-Maria, Payal Shah, Neil Taunk, Carey Anders, Rachel Blitzblau, Gaorav Gupta, Alice Ho. TBCRC-055: A Phase II Study of NirAparib, Dostarlimab, and Radiotherapy in Metastatic, PD-L1 Negative or Immunotherapy-Refractory Triple-Negative Breast Cancer (NADiR) – NCT04837209 [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 OT2-09-01.

Abstract P3-04-04: Multi-institutional perspective on screening mammography and breast cancer stage at diagnosis during the COVID-19 pandemic

Background: During the SARS-CoV-2 pandemic in 2020, the use of routine screening mammography (SM) and diagnostic mammography (DM) was limited for several months in order to reduce patient exposure and redeploy medical personnel. Previous studies suggest such delays result in more late-stage breast cancer diagnoses. We hypothesized that this impact would vary between institutions depending on regional variations in shutdown periods and the ability and willingness of patients to resume screening. Methods: Patients diagnosed with invasive breast cancers from 2016-2020 were identified using the Beth Israel Deaconess Medical Center (BIDMC) and the Duke University Medical Center (DUMC) cancer registries. Rates of mammography were ascertained from billing data. Baseline patient characteristics, demographics, and clinical information were gathered and cross-referenced with the electronic medical record. Late-stage was defined as Anatomic Stage III-IV disease (AJCC 8th edition). Chi-squared analysis was used to examine monthly distributions in stage at presentation for diagnosis in 2016-2019 compared to in 2020 at each institution. Results: There were 5907 patients diagnosed with invasive breast cancer between 2016-2019 (1597 at BIDMC and 4310 at DUMC) and 1075 in 2020 (333 and 742, respectively). Mammography was limited from 3/16/20-6/8/20 at BIDMC and from 3/16/20-4/20/20 at DUMC. There were fewer SM at each institution during their respective shutdown periods in 2020 than in the same months in 2019: BIDMC 1713 versus 8566 (80% reduction) and at DUMC 1649 versus 5698 (71% reduction). Following the pandemic shutdown, SM volume increased in July-December 2020 compared to July-December 2019 (108% at BIDMC and 116% at DUMC). The proportion of patients diagnosed with late-stage disease at BIDMC was greater in 2020 than in 2016-2019, at 12.6% and 6.6%, respectively (p < 0.001); 86% of late-stage diagnoses and 68% of all diagnoses in 2020 at BIDMC occurred from July-December following the initial shutdown period. The proportion of patients diagnosed with late-stage disease at DUMC in these two cohorts were 14.3% in 2020 and 16.2%% in 2016-2019 (p = 0.1); 50% of late-stage diagnoses and 51% of all diagnoses in 2020 at DUMC occurred in the period following the initial shutdown from July-December. Conclusion: We identified variation between two large academic medical centers in the impact of the SARS-CoV-2 pandemic shutdown on the proportion of late-stage breast cancer diagnoses. These dissimilar outcomes may be the result of differences in referral patterns as well as regional differences in the approach to SM during the pandemic. In particular, a shorter closure time and substantial increase in SM volume following the initial shutdown period in the Southeast region may have prevented an increase in late-stage diagnoses. Further information and analysis may help suggest additional strategies to minimize adverse effects of reduced cancer screening in future public-health emergencies.

Table 1.Proportion of SM in 2020 compared to 2019 and proportion of late disease per month in 2020BIDMC 2020JanFebMarAprMayJunJulAugSepOct NovDecSM, %96109480034104106112105113112Late Disease, n(%)0 (0)2 (10)1 (3)0 (0)0 (0)3 (21)1 (7)9 (21)10 (15)10 (19)5 (12)1 (8)DUMC 2020JanFebMarAprMayJunJulAugSepOctNovDecSM, %565860040123111109127116120119Late Disease, n(%)12 (11)13 (19)14 (19)4 (18)4 (12)6 (11)12 (13)10 (13)6 (10)12 (19)7 (13)5 (13)

Citation Format: Sarah J Stephens, Maxwell R Lloyd, Julian C Hong, Tejas Mehta, Ted A James, Rachel Blitzblau, Abram Recht, Daphna Y Spiegel. Multi-institutional perspective on screening mammography and breast cancer stage at diagnosis during the COVID-19 pandemic [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-04-04.

Dosimetric variation in preoperative partial breast radiosurgery assessed by deformable image registrations

Objective

To assess dosimetric variation caused by breast deformation in breast radiosurgery based on deformable image registration.

Methods

This study included 30 patients who were treated in the prone position for preoperative partial breast radiosurgery. The biopsy clip in CBCT was aligned to the one from the planning CT. Deformable image registration (DIR) was performed to deform the planning CT into the CBCT, focusing on the breast shape. The treated plan (P_Tx) was recalculated based on the deformed CT. Thus, P_Tx represented the actual treatment delivered to the patient and was compared to the original plan (P_Org).

Results

The mean differences of target volumes covered by 95% and 100% of the prescribed dose between P_Org and P_Tx were less than 0.5%. The mean differences ± standard division for skin maximum dose (D_max), dose to 1cc (D_1cc) and D_10cc were 0.3 ± 0.7 Gy, 0.3 ± 0.6 Gy and 0.6 ± 0.6Gy between P_Org and P_Tx, respectively.

Conclusion

The treated plan was accurately recalculated based on the deformed CT. Despite slight variance in breast deformation, the dosimetric variation was very small, ensuring that adequate target coverage and skin dose were maintained during treatment as planned originally.

NCCN Guidelines® Insights: Squamous Cell Skin Cancer, Version 1.2022

The NCCN Guidelines for Squamous Cell Skin Cancer provide recommendations for diagnostic workup, clinical stage, and treatment options for patients with cutaneous squamous cell carcinoma. The NCCN panel meets annually to discuss updates to the guidelines based on comments from panel members and the Institutional Review, as well as submissions from within NCCN and external organizations. These NCCN Guidelines Insights focus on the introduction of a new surgical recommendation terminology (peripheral and deep en face margin assessment), as well as recent updates on topical prophylaxis, immunotherapy for regional and metastatic disease, and radiation therapy.

Cancer patient satisfaction with telehealth: Survey results from a large NCI-designated cancer institute

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Background: Telehealth (TH) utilization for patients at our cancer institute increased in 2020 in response to the COVID-19 pandemic, however oncology-specific TH patient satisfaction is unknown. Methods: Monthly TH utilization at a single large NCI-designated institute from 3/1/2020-11/30/2020 was reviewed. Utilization was calculated as chargeable TH visits (new video, established video, phone) as a proportion of all consult/follow up visits. Patient satisfaction surveys for oncology TH visits for MD/PA/NP providers were reviewed from 4/1/2020-11/30/2020. Surveys were sent after every TH visit, unless the patient had a prior visit in the past 3 months. Percent (%) top box score (TBS) was defined as proportion of responses in the highest possible response category (i.e. very good). % TBS was reported for 14 survey items in 4 domains: technology, access, care provider (CP), and overall assessment. Satisfaction was assessed over time and according to patient factors: generation, gender, insurance type, employment status, and clinic site. The Cochrane-Armitage trend test was used to compare proportions of TBS responses across monthly time points. Results: TH comprised 21% (22,055/103,461) of all encounters in the study period. TH use increased from 9% in 3/2020 to a peak of 47% in 4/2020. In 11/2020, TH use was 18%. 28.0% (2,286/8,173) of TH patient surveys were returned. Multiple patient satisfaction metrics were improved over time (Table). Patients had higher satisfaction with phone compared to video visits with regards to technology (86% vs 76%) and access (80% vs 72%). Millennials (born 1981-1995) had higher satisfaction with access to TH (87%) compared to Gen X (1965-1980) (77%), Baby Boomer (1946-1964) (74%), and Silent Generation (1928-1945) (72%), however all generations had similar levels of satisfaction with technology (range 77-80%). Disabled patients had higher overall satisfaction of TH (82%) versus those working full time or retired (71%). Patients with commercial insurance had worse overall satisfaction of TH compared to other insurance types (65% vs 72%). Patients with encounters in genitourinary, thoracic, and endocrine oncology clinics had the highest levels of overall satisfaction (75%) compared to other clinics (69%). There were no observed differences in TH satisfaction according to gender. Conclusions: TH cancer patient satisfaction is high and has improved over time, however satisfaction differs by patient demographics. Further data are needed to best select patients appropriate for TH.[Table: see text]

Clinical Experience With Machine Learning-Based Automated Treatment Planning for Whole Breast Radiation Therapy

PURPOSE

The machine learning-based automated treatment planning (MLAP) tool has been developed and evaluated for breast radiation therapy planning at our institution. We implemented MLAP for patient treatment and assessed our clinical experience for its performance.

METHODS AND MATERIALS

A total of 102 patients of breast or chest wall treatment plans were prospectively evaluated with institutional review board approval. A human planner executed MLAP to create an auto-plan via automation of fluence maps generation. If judged necessary, a planner further fine-tuned the fluence maps to reach a final plan. Planners recorded the time required for auto-planning and manual modification. Target (ie, breast or chest wall and nodes) coverage and dose homogeneity were compared between the auto-plan and final plan.

RESULTS

Cases without nodes (n = 71) showed negligible (<1%) differences for target coverage and dose homogeneity between the auto-plan and final plan. Cases with nodes (n = 31) also showed negligible difference for target coverage. However, mean ± standard deviation of volume receiving 105% of the prescribed dose and maximum dose were reduced from 43.0% ± 26.3% to 39.4% ± 23.7% and 119.7% ± 9.5% to 114.4% ± 8.8% from auto-plan to final plan, respectively, all with P ≤ .01 for cases with nodes (n = 31). Mean ± standard deviation time spent for auto-plans and additional fluence modification for final plans were 12.1 ± 9.3 and 13.1 ± 12.9 minutes, respectively, for cases without nodes, and 16.4 ± 9.7 and 26.4 ± 16.4 minutes, respectively, for cases with nodes.

CONCLUSIONS

The MLAP tool has been successfully implemented for routine clinical practice and has significantly improved planning efficiency. Clinical experience indicates that auto-plans are sufficient for target coverage, but improvement is warranted to reduce high dose volume for cases with nodal irradiation. This study demonstrates the clinical implementation of auto-planning for patient treatment and the significant importance of integrating human experience and feedback to improve MLAP for better clinical translation.

Abstract P4-12-10: Clinical implementation of the machine learning-based automated treatment planning tool for whole breast radiotherapy

Objectives: The machine learning (ML)-based automated treatment planning tool has been developed and evaluated for whole breast radiotherapy. This study implemented the tool in clinic and compared plan quality and planning efficiency with the manual treatment process for whole breast radiotherapy using irregular surface compensator technique.

Methods: This study involved two phases. The 1st phase was to evaluate and the 2nd phase was to implement in the clinic. In the 1st phase, thirty whole breast or chest wall cases were planned by using the irregular surface compensator technique with fluence maps manually and iteratively edited to achieve uniform dose distribution to the target by planners. Patients were treated with these manual plans after physician’s approval. The evaluation phase thus compared our in-house ML-based automated treatment planning tool implemented in Eclipse Scripting Application Programming Interface (ESAPI) to these manual plans. The ML-based planning tool generated the fluence maps with the same beam parameters such as beam energy, gantry angle, collimator angle, and aperture shape as manual plans. Breast or chest wall clinical target volume (CTV) coverage based on the percentage CTV volume receiving 95% of the prescribed dose (V95%) and high-dose volume based on V105% were compared to evaluate the plan quality as well as the planning efficiency. Two-tailed Wilcoxon Signed-Rank test was performed to test the null hypothesis that the two planning schemes yield equivalent plan quality.

In the 2nd phase, the planners used the automated planning tool for fourteen plans (twelve patients) followed by manual fluence modification as needed. Physicians reviewed and approved the plans, and patients were treated.

Results: For the 1st phase, the mean planning time was 110.2 min with standard deviation (SD) of 62.8 min for the manual planning with the range from 25 to 270 min, and 6.4 min with SD of 2.1 min for the automated planning with the range from 4 to 12 min (p&lt;0.01). CTV mean V95% was 96.7% (SD: 5.0%) for the manual planning and 96.7% (SD: 4.8%) for the automated planning (p=0.89). CTV mean V105% was 21.6% (SD: 29.8%) for the manual planning and 20.4% (SD: 30.5%) for the automated planning (p=0.22). Differences in doses to heart and lungs were negligible between the paired plans as the two planning schemes used the same beam parameters.

For the 2nd phase, the mean planning time was 16.4 min (SD: 9.1 min) and the mean time for additional manual editing was 12.7 min (SD: 12.5 min). The mean total treatment planning time was 29.1 min (SD: 14.8 min).). CTV mean V95% was 97.2% (SD: 4.2%) and mean V105% was 8.2 % (SD: 3.6%). The manual post modifications were added by the planners with intention to improve the target coverage or to reduce high doses, yet, the difference between the plans without and without the manual post modification was negligible.

Conclusion: The ML-based automated treatment planning tool through Varian ESAPI has been successfully implemented for clinical use going through two phases of study. Abiding to the same plan quality as manual process, the automated tool significantly reduced the planning time as the ML-based tool automate the iterative fluence editing process.

Citation Format: Sua Yoo, Yang Sheng, Rachel Blitzblau, Suzanne Catalano, Jay Morrison, Leigh O'Neill, Fangfang Yin, Q. Jackie Wu. Clinical implementation of the machine learning-based automated treatment planning tool for whole breast radiotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-12-10.

Accuracy and efficiency of image-guided radiation therapy (IGRT) for preoperative partial breast radiosurgery

OBJECTIVE

To analyze and evaluate accuracy and efficiency of IGRT process for preoperative partial breast radiosurgery.

METHODS

Patients were initially setup with skin marks and 5 steps were performed: (1) Initial orthogonal 2D kV images, (2) pre-treatment 3D CBCT images, (3) verification orthogonal 2D kV images, (4) treatment including mid-treatment 2D kV images (for the final 15 patients only), and (5) post-treatment orthogonal 2D kV or 3D CBCT images. Patient position was corrected at each step to align the biopsy clip and to verify surrounding soft tissue positioning.

RESULTS

The mean combined vector magnitude shifts and standard deviations at the 5 imaging steps were (1) 0.96 ± 0.69, (2) 0.33 ± 0.40, (3) 0.05 ± 0.12, (4) 0.15 ± 0.17, and (5) 0.27 ± 0.24 in cm. The mean total IGRT time was 40.2 ± 13.2 minutes. Each step was shortened by 2 to 5 minutes with improvements implemented. Overall, improvements in the IGRT process reduced the mean total IGRT time by approximately 20 minutes. Clip visibility was improved by implementing oblique orthogonal images.

CONCLUSION

Multiple imaging steps confirmed accurate patient positioning. Appropriate planning and imaging strategies improved the effectiveness and efficiency of the IGRT process for preoperative partial breast radiosurgery.

Merkel Cell Carcinoma, Version 1.2018, NCCN Clinical Practice Guidelines in Oncology

This selection from the NCCN Guidelines for Merkel Cell Carcinoma (MCC) focuses on areas impacted by recently emerging data, including sections describing MCC risk factors, diagnosis, workup, follow-up, and management of advanced disease with radiation and systemic therapy. Included in these sections are discussion of the new recommendations for use of Merkel cell polyomavirus as a biomarker and new recommendations for use of checkpoint immunotherapies to treat metastatic or unresectable disease. The next update of the complete version of the NCCN Guidelines for MCC will include more detailed information about elements of pathology and addresses additional aspects of management of MCC, including surgical management of the primary tumor and draining nodal basin, radiation therapy as primary treatment, and management of recurrence.

Automatic Planning of Whole Breast Radiation Therapy Using Machine Learning Models

Purpose: To develop an automatic treatment planning system for whole breast radiation therapy (WBRT) based on two intensity-modulated tangential fields, enabling near-real-time planning. Methods and Materials: A total of 40 WBRT plans from a single institution were included in this study under IRB approval. Twenty WBRT plans, 10 with single energy (SE, 6MV) and 10 with mixed energy (ME, 6/15MV), were randomly selected as training dataset to develop the methodology for automatic planning. The rest 10 SE cases and 10 ME cases served as validation. The auto-planning process consists of three steps. First, an energy prediction model was developed to automate energy selection. This model establishes an anatomy-energy relationship based on principle component analysis (PCA) of the gray level histograms from training cases' digitally reconstructed radiographs (DRRs). Second, a random forest (RF) model generates an initial fluence map using the selected energies. Third, the balance of overall dose contribution throughout the breast tissue is realized by automatically selecting anchor points and applying centrality correction. The proposed method was tested on the validation dataset. Non-parametric equivalence test was performed for plan quality metrics using one-sided Wilcoxon Signed-Rank test. Results: For validation, the auto-planning system suggested same energy choices as clinical-plans in 19 out of 20 cases. The mean (standard deviation, SD) of percent target volume covered by 100% prescription dose was 82.5% (4.2%) for auto-plans, and 79.3% (4.8%) for clinical-plans (p > 0.999). Mean (SD) volume receiving 105% Rx were 95.2 cc (90.7 cc) for auto-plans and 83.9 cc (87.2 cc) for clinical-plans (p = 0.108). Optimization time for auto-plan was <20 s while clinical manual planning takes between 30 min and 4 h. Conclusions: We developed an automatic treatment planning system that generates WBRT plans with optimal energy selection, clinically comparable plan quality, and significant reduction in planning time, allowing for near-real-time planning.

Findings on Surveillance Imaging After Preoperative Partial Breast Irradiation for Early Stage Breast Cancer

PURPOSE

To evaluate the mammographic sequelae of preoperative accelerated partial breast irradiation (APBI) delivered via either stereotactic radiosurgery or a conventionally fractionated regimen.

METHODS AND MATERIALS

This multicenter, retrospective study evaluated surveillance mammograms from patients enrolled in 2 prospective, preoperative APBI clinical trials. At 1 site, 31 patients with cT1N0 invasive carcinomas or low- or intermediate-grade ductal carcinoma in situ (<2 cm) received preoperative stereotactic radiosurgery and had a total of 186 mammograms available for review. At the second site, 180 mammograms from 25 patients with cT1-2 (<3 cm) unifocal invasive carcinomas treated with conventionally fractionated, preoperative APBI were reviewed. Findings were compared with those of 26 early stage breast cancers treated with conventional postoperative whole breast radiation therapy.

RESULTS

At a median follow-up of 61 months, 17 patients (55%) treated with single-dose APBI exhibited exuberant fat necrosis at the lumpectomy site. Fat necrosis was believed to be clinically palpable in 5 (16%) of these patients within the first 3 years of follow-up. Exuberant fat necrosis developed in 5 patients (20%) treated with fractionated APBI over a median 68-month follow-up period but only 2 of those patients (8%) who underwent conventional whole breast radiation therapy.

CONCLUSIONS

In situ tumor targeting in the preoperative setting allows relative sparing of normal tissue but results in a larger and more vigorous area of change on surveillance imaging, potentially reflecting the interaction of surgical resection with an irradiated tissue bed. High-dose stereotactic radiosurgery in particular increases the risk of developing a uniquely robust and well-demarcated pattern of fat necrosis on mammogram that may also present clinically. With many ongoing studies evaluating the preoperative treatment approach, defining the landscape of expected imaging sequelae will provide useful anticipatory guidance for clinicians and patients.

Abstract P1-10-02: Adjuvant radiation after lumpectomy: A cost comparison of treatment patterns in 43,247 women from the National Cancer Data Base

BACKGROUND: Breast cancer treatment contributes the greatest proportion of cancer-related health care spending in the United States. Locoregional therapy comprises a significant share of these costs. We hypothesized that among eligible women with early-stage breast cancer treated with lumpectomy, evidence-based utilization of hypofractionated whole breast radiation or omission of radiotherapy could substantially reduce cancer-related treatment costs.

METHODS: Using the National Cancer Data Base which captures approximately 70% of all newly diagnosed cancers in the United States, we identified 43,247 women with clinically node-negative, T1-T2 invasive breast cancers treated with lumpectomy during 2011. Women with DCIS, those treated with mastectomy, accelerated partial breast irradiation (APBI), or unknown or questionable radiation regimens were excluded. Adjuvant radiation was categorized into the following regimens: conventionally fractionated whole breast irradiation therapy (CF-WBI) [25-40 fractions, 45-66 Gy], hypofractionated whole-breast irradiation (HF-WBI) [15-24 fractions, 40-58 Gy), and lumpectomy without radiation (no RT). Women were considered eligible for no RT if ≥70 years with T1N0, ER+ breast cancers, and for HF-WBI if ≥50 years, with T1-T2 N0 invasive breast cancer. Treatment costs were calculated using Medicare Physician Fee Schedule payment information for 2011, and based on average current procedural codes billed per regimen. Costs per patient were estimated as follows: CF-WBI $13,358.37, HF-WBI $8,327.98, and lumpectomy without RT $0. Actual treatment costs were compared to evidence-based, reduced-cost radiation regimens for which patients were potentially eligible.

RESULTS: Median patient age was 63 years (range 19-90). Median tumor size was 1.2 cm. Of the total study cohort, 84.5% was eligible for HF-WBI, and 22.3% for no RT. Among the 36,562 (84.5%) patients eligible for treatment with HF-WBI, 28,383 (77.6%) received radiation therapy. Of these, 22,653 (79.8%) received CF-WBI, 5,289 (18.6%) received HF-WBI, and 441 (1.6%) received accelerated partial breast irradiation (APBI). Among 9,651 women ≥70 years with ER+ tumors eligible for no-RT, 4,245 (44.0%) received CF-WBI, 1,768 (18.3%) received HF-WBI, 153 (1.6%) received APBI, and 3,485 (36.1%) received no RT. 26% of women received the least expensive evidence-based radiation regimen for which they were eligible, while 67% of patients were treated with more costly radiation regimens. Estimated costs of actual treatment were $420.2 million during 2011, compared to $256.2 million had women been treated with the least expensive radiation regimen for which they were eligible. This translates into an annual cost savings of $164.0 million, a 39% reduction in costs.

CONCLUSIONS: Utilization of evidence-based adjuvant radiation following lumpectomy is associated with reductions in cancer-related costs in the locoregional treatment of early-stage breast cancer. Although treatment decisions should not be driven by health care costs alone, consideration of hypofractionated regimens or omission of radiotherapy for patients that fit evidence-based eligibility criteria could translate into dramatic reductions in annual health care spending.

Citation Format: Rachel A Greenup, Rachel Blitzblau, Kevin Houck, Janet Horton, Lynn Howie, Manisha Palta, Aimee Mackey, Randy Scheri, Julie A Sosa, Alphonse G Taghian, Jeffrey Peppercorn, Barbara L Smith, E Shelley Hwang. Adjuvant radiation after lumpectomy: A cost comparison of treatment patterns in 43,247 women from the National Cancer Data Base [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-10-02.

Abstract P5-15-11: The distress screening tool: Initial experience with electronically curated patient reported measures

Background: In June 2013, our health system transitioned to an electronic medical record (EMR) which included collecting patient quality of life data at each clinic visit. We used the NCCN distress thermometer (DT), a short, simple to use, self-report measure which uses a 10-point scale from 0 (no distress) to 10 (extreme distress) as well as an associated problem checklist which queries the source(s) of their distress. Among our breast cancer clinic population, we studied the severity and sources of distress as well as whether the DT score was associated with stage at diagnosis and time interval since diagnosis.

Methods: Between October 1, 2013 and April 30, 2014, starting 3 months after implementation of a comprehensive EMR, all patients seen at our tertiary breast cancer clinic were asked to complete the DT survey at each clinic visit. DT data were collected and entered into the EMR at point of care. The DT tool was correlated with demographic and tumor information from our prospectively curated electronic datamart.

Results: We collected 7276 DT surveys from 3267 unique patients over seven months. Median age of the cohort was 60 years; 73% were white and 21% were black. Among those with available staging data and a diagnosis of breast cancer, stage distribution was 10% stage 0, 34% stage I, 37% stage II, 15% stage III and 4% stage IV. The median reported distress score was 1.0 (range 0-10) with score distribution shown in Figure 1. The most commonly reported source of stress was fatigue (8.0%) followed by pain (6.8%). For new patient appointments the most commonly reported sources were worry (9.5%) followed by nervousness (8.0%). There was no significant correlation between overall distress score and stage at diagnosis. Among patients who were seen more than once during the study interval, the DT score changed for 33.7% of patients. The lowest distress scores were reported among women &gt;3 years from initial diagnosis.

Conclusions: The transition to an integrated EMR system has allowed collection of analyzable patient reported data to inform medical and psychosocial intervention. Structured data collection at point of care allows for efficient identification of and management for the major sources of distress among patients during breast cancer treatment and survivorship.

Citation Format: Shelley Hwang, Steve Power, Ilona Stashko, Rachel Blitzblau, Rachel Greenup, Janet Horton, Kellly Westbrook, Kimberly Blackwell, Heather Sperling, Jeffrey Peppercorn, Gretchen Kimmick, Kelly Marcom. The distress screening tool: Initial experience with electronically curated patient reported measures [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-15-11.

Dosimetric comparison of preoperative single-fraction partial breast radiotherapy techniques: 3D CRT, noncoplanar IMRT, coplanar IMRT, and VMAT

The purpose of this study was to compare dosimetric parameters of treatment plans among four techniques for preoperative single‐fraction partial breast radiotherapy in order to select an optimal treatment technique. The techniques evaluated were noncoplanar 3D conformal radiation therapy (3D CRT), noncoplanar intensity‐modulated radiation therapy (IMRTNC), coplanar IMRT (IMRTCO), and volumetric‐modulated arc therapy (VMAT). The planning CT scans of 16 patients in the prone position were used in this study, with the single‐fraction prescription doses of 15 Gy for the first eight patients and 18 Gy for the remaining eight patients. Six (6) MV photon beams were designed to avoid the heart and contralateral breast. Optimization for IMRT and VMAT was performed to reduce the dose to the skin and normal breast. All plans were normalized such that 100% of the prescribed dose covered greater than 95% of the clinical target volume (CTV) consisting of gross tumor volume (GTV) plus 1.5 cm margin. Mean homogeneity index (HI) was the lowest (1.05±0.02) for 3D CRT and the highest (1.11±0.04) for VMAT. Mean conformity index (CI) was the lowest (1.42±0.32) for IMRTNC and the highest (1.60±0.32) for VMAT. Mean of the maximum point dose to skin was the lowest (73.7±11.5%) for IMRTNC and the highest (86.5±6.68%) for 3D CRT. IMRTCO showed very similar HI, CI, and maximum skin dose to IMRTNC (differences<1%). The estimated mean treatment delivery time, excluding the time spent for patient positioning and imaging, was 7.0±1.0,8.3±1.1,9.7±1.0, and 11.0±1.5min for VMAT,IMRTCO,IMRTNC and 3D CRT, respectively. In comparison of all four techniques for preoperative single‐fraction partial breast radiotherapy, we can conclude that noncoplanar or coplanar IMRT were optimal in this study as IMRT plans provided homogeneous and conformal target coverage, skin sparing, and relatively short treatment delivery time.

PACS numbers: 81.40.Wx, 87.55.D‐

Rare BRCA1 haplotypes including 3'UTR SNPs associated with breast cancer risk

Genetic markers identifying women at an increased risk of developing breast cancer exist, yet the majority of inherited risk remains elusive. While numerous BRCA1 coding sequence mutations are associated with breast cancer risk, BRCA1 mutations account for less then 5% of breast cancer risk. Since 3' untranslated region (3'UTR) polymorphisms disrupting microRNA (miRNA) binding can be functional and can act as genetic markers of cancer risk, we tested the hypothesis that such polymorphisms in the 3'UTR of BRCA1 and haplotypes containing these functional polymorphisms may be associated with breast cancer risk. We sequenced the BRCA1 3'UTR from breast cancer patients to identify miRNA disrupting polymorphisms. We further evaluated haplotypes of this region including the identified 3'UTR variants in a large population of controls and breast cancer patients (n = 221) with known breast cancer subtypes and ethnicities. We identified three 3'UTR variants in BRCA1 that are polymorphic in breast cancer populations, and haplotype analysis including these variants revealed that breast cancer patients harbor five rare haplotypes not generally found among controls (9.50% for breast cancer chromosomes, 0.11% for control chromosomes, p = 0.0001). Three of these rare haplotypes contain the rs8176318 BRCA1 3'UTR functional variant. These haplotypes are not biomarkers for BRCA1 coding mutations, as they are found rarely in BRCA1 mutant breast cancer patients (1/129 patients = 0.78%). These rare BRCA1 haplotypes and 3'UTR SNPs may represent new genetic markers of breast cancer risk.

A KRAS-variant in ovarian cancer acts as a genetic marker of cancer risk

Ovarian cancer (OC) is the single most deadly form of women's cancer, typically presenting as an advanced disease at diagnosis in part due to a lack of known risk factors or genetic markers of risk. The KRAS oncogene and altered levels of the microRNA (miRNA) let-7 are associated with an increased risk of developing solid tumors. In this study, we investigated a hypothesized association between an increased risk of OC and a variant allele of KRAS at rs61764370, referred to as the KRAS-variant, which disrupts a let-7 miRNA binding site in this oncogene. Specimens obtained were tested for the presence of the KRAS-variant from nonselected OC patients in three independent cohorts, two independent ovarian case-control studies, and OC patients with hereditary breast and ovarian cancer syndrome (HBOC) as well as their family members. Our results indicate that the KRAS-variant is associated with more than 25% of nonselected OC cases. Further, we found that it is a marker for a significant increased risk of developing OC, as confirmed by two independent case-control analyses. Lastly, we determined that the KRAS-variant was present in 61% of HBOC patients without BRCA1 or BRCA2 mutations, previously considered uninformative, as well as in their family members with cancer. Our findings strongly support the hypothesis that the KRAS-variant is a genetic marker for increased risk of developing OC, and they suggest that the KRAS-variant may be a new genetic marker of cancer risk for HBOC families without other known genetic abnormalities.

Expression of a variant form of the glutamate transporter GLT1 in neuronal cultures and in neurons and astrocytes in the rat brain

To identify glutamate transporters expressed in forebrain neurons, we prepared a cDNA library from rat forebrain neuronal cultures, previously shown to transport glutamate with high affinity and capacity. Using this library, we cloned two forms, varying in the C terminus, of the glutamate transporter GLT1. This transporter was previously found to be localized exclusively in astrocytes in the normal mature brain. Specific antibodies against the C-terminal peptides were used to show that forebrain neurons in culture express both GLT1a and GLT1b proteins. The pharmacological properties of glutamate transport mediated by GLT1a and GLT1b expressed in COS-7 cells and in neuronal cultures were indistinguishable. Both GLT1a and GLT1b were upregulated in astrocyte cultures by exposure to dibutyryl cAMP. We next investigated the expression of GLT1b in vivo. Northern blot analysis of forebrain RNA revealed two transcripts of approximately 3 and 11 kb that became more plentiful with developmental age. Immunoblot analysis showed high levels of expression in the cortex, hippocampus, striatum, thalamus, and midbrain. Pre-embedding electron microscopic immunocytochemistry with silver-enhanced immunogold detection was used to localize GLT1b in vivo. In the rat somatosensory cortex, GLT1b was clearly expressed in neurons in presynaptic terminals and dendritic shafts, as well as in astrocytes. The presence of GLT1b in neurons may offer a partial explanation for the observed uptake of glutamate by presynaptic terminals, for the preservation of input specificity at excitatory synapses, and may play a role in the pathophysiology of excitotoxicity.

The glutamate transport inhibitor L-trans-pyrrolidine-2,4-dicarboxylate indirectly evokes NMDA receptor mediated neurotoxicity in rat cortical cultures

Because of the well-documented importance of glutamate uptake in protecting neurons against glutamate toxicity, we were interested in testing the effects of L-trans-pyrrolidine-2,4-dicarboxylate (PDC) on rat cortical cultures. This compound is a substrate for glutamate transporters and is a potent glutamate transport inhibitor that does not interact significantly with glutamate receptors. Using a 30 min exposure, and assessing neuronal survival after 20-24 h, PDC was neurotoxic in conventional astrocyte-rich cortical cultures, with an EC50 in these cultures of 320 +/- 157 microM. In astrocyte-poor cultures, an EC50 for PDC of 50 +/- 5 microM was determined. The neurotoxicity of PDC in both astrocyte-rich and astrocyte-poor cultures was blocked by the NMDA antagonist MK-801, but not by the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). We tested the possibility that the neurotoxicity of PDC might be due to release of excitatory amino acids using several approaches. After pre-loading cells with the non-metabolizable analogue of glutamate, [3H]-D-aspartate, first we demonstrated that PDC caused significant efflux of [3H]-D-aspartate. This effect of PDC was dependent upon extracellular sodium. In contrast with glutamate neurotoxicity, PDC neurotoxicity was inhibited by removal of extracellular sodium. In the presence of 1 mM PDC, sodium caused neurotoxicity with an EC50 of 18 +/- 7.6 mM. Tetrodotoxin had no effect on either PDC neurotoxicity or on PDC-evoked [3H]-D-aspartate release. PDC-evoked release of [3H]-D-aspartate was demonstrable in astrocyte cultures with no neurons present. PDC also evoked release of endogenous glutamate. Finally, the neurotoxicity of PDC was blocked by coincubation with glutamate-pyruvate transaminase plus pyruvate to degrade extracellular glutamate. These results demonstrate the neurotoxicity of PDC, and suggest that the mechanism of this toxicity is the glutamate transporter-dependent accumulation of glutamate in the extracellular space.