Faculty Bibliography

PURPOSE/OBJECTIVE:Breast reirradiation (reRT) after breast conserving surgery (BCS) has emerged as a viable alternative to mastectomy for women presenting with recurrent or new primary breast cancer. There are limited data on safety of different fractionation regimens. This study reports safety and efficacy among women treated with repeat BCS and reRT. METHODS AND MATERIALS/METHODS:Patients who underwent repeat BCS followed by RT from 2015 to 2021 at 2 institutions were analyzed. Univariate logistic regression models were used to identify predictors of acute and late toxicities. Kaplan-Meier estimates were used to evaluate overall survival (OS), distant metastasis-free survival (DMFS) and locoregional recurrence-free survival (LR-RFS). RESULTS:Sixty-six patients were reviewed with median follow-up of 16 months (range: 3-60 months). At time of first recurrence, 41% had invasive carcinoma with a ductal carcinoma in situ (DCIS) component, 41% had invasive carcinoma alone and 18% had DCIS alone. All were clinically node negative. For the reirradiation course, 95% received partial breast irradiation (PBI) (57.5% with 1.5 Gy BID; 27% with 1.8 Gy daily; 10.5% with hypofractionation), and 5% received whole breast irradiation (1.8-2 Gy/fx), all of whom had received PBI for initial course. One patient experienced grade 3 fibrosis, and one patient experienced grade 3 telangiectasia. None had grade 4 or higher late adverse events. We found no association between the fractionation of the second course of RT or the cumulative dose (measured as EQD2) with acute or late toxicity. At 2 years, OS was 100%, DMFS was 91.6%, and LR-RFS was 100%. CONCLUSION/CONCLUSIONS:In this series of patients with recurrent or new primary breast cancer, a second breast conservation surgery followed by reirradiation was effective with no local recurrences and an acceptable toxicity profile across a range of available fractionation regimens at a median follow up of 16 months. Longer follow up is required.

PURPOSE/OBJECTIVE:The optimal local therapy of patients with nodal disease in supraclavicular (SCV), internal mammary nodes (IMN) and level III axilla is not well studied. We aimed to evaluate the outcomes of patients with breast cancer and advanced nodal disease that received a nodal boost. METHODS AND MATERIALS/METHODS:This retrospective study included 79 patients with advanced nodal disease who underwent adjuvant radiation with a nodal boost to the SCV, IMNs, and/or axilla. All patients had radiographic changes after systemic therapy concerning for gross nodal disease. Overall survival, disease-free survival (DFS), and local recurrence-free survival were estimated using the Kaplan-Meier method. RESULTS:All patients received an initial 50 Gy to the breast/chest wall and regional nodes, of whom 46.8% received an IMN boost, 38.0% axillary (ax)/SCV boost, and 15.2% both IMN and ax/SCV boost (IMN + ax/SCV). Most patients had hormone receptor positive (74.7%) and human epidermal growth factor receptor 2 negative disease (83.5%). In addition, 12.7% of patients had clinical (c) N2 disease, 21.5% cN3A disease, 51.9% cN3B disease, and 5.1% cN3C disease. Most patients received chemotherapy (97.5%). The median nodal boost dose was 10 Gy (range, 10-20 Gy), with 21.6% of IMN, 16.7% of ax/SCV, and 16.7% of IMN + ax/SCV receiving 14 to 20 Gy. With a median follow up of 30 months, the 3-year local recurrence-free survival, DFS, and overall survival rates were 94.5%, 86.3%, and 93.8%, respectively. Crude rates of failure were 13.9% (10.1% distant failure [DF] alone; 3.8% DF + locoregional failure [LRF]). Rates of failure by boost group were 13.3% for ax/SCV (10.0% DF alone; 3.3% DF + LRF), 5.4% for IMN (2.7% DF alone, 2.7% DF + LRF), and 41.7% for IMN + ax/SCV (33.3% DF, 8.3% DF + LRF). There were no LRFs without DFs. The median time to failure was 22.8 months (interquartile range, 18-34 months). Clinical tumor size and IMN + ax/SCV versus IMN or ax/SCV alone was associated with worse DFS (hazard ratio [HR]: 9.78; 95% confidence interval [CI], 2.07-46.2; P = .004 and HR: 9.49; 95% CI, 2.67-33.7; P = .001, respectively). On multivariate analysis, IMN + ax/SCV versus IMN or ax/SCV alone retained significance (HR: 4.80; 95% CI, 1.27-18.13; P = .02). CONCLUSIONS:In this population of patients with locally advanced breast cancer, the majority of failures were distant with no isolated LRFs. Failures were the highest in the IMN + ax/SCV group (∼40%). Further treatment escalation is necessary for these patients.

PURPOSE/UNASSIGNED:Cardiac radioablation is an emerging therapy for recurrent ventricular tachycardia. Electrophysiology (EP) data, including electroanatomic maps (EAM) and electrocardiographic imaging (ECGI), provide crucial information for defining the arrhythmogenic target volume. The absence of standardized workflows and software tools to integrate the EP maps into a radiation planning system limits their use. This study developed a comprehensive software tool to enable efficient utilization of the mapping for cardiac radioablation treatment planning. METHODS AND MATERIALS/UNASSIGNED:After the scar area is outlined on the mapping surface, the tool extracts and extends the annotated patch into a closed surface and converts it into a structure set associated with the anatomic images. The tool then exports the structure set and the images as The Digital Imaging and Communications in Medicine Standard in Radiotherapy for a radiation treatment planning system to import. Overlapping the scar structure on simulation CT, a transmural target volume is delineated for treatment planning. RESULTS/UNASSIGNED:The tool has been used to transfer Ensite NavX EAM data into the Varian Eclipse treatment planning system in radioablation on 2 patients with ventricular tachycardia. The ECGI data from CardioInsight was retrospectively evaluated using the tool to derive the target volume for a patient with left ventricular assist device, showing volumetric matching with the clinically used target with a Dice coefficient of 0.71. CONCLUSIONS/UNASSIGNED:HeaRTmap smoothly fuses EP information from different mapping systems with simulation CT for accurate definition of radiation target volume. The efficient integration of EP data into treatment planning potentially facilitates the study and adoption of the technique.

Purpose/Objective(s): Breast re-irradiation (reRT) after repeat breast conserving surgery (BCS) has emerged as a viable alternative to mastectomy in women presenting with low risk in-breast tumor recurrence (IBTR). However, there is limited data on optimal patient selection and safety of different fractionation regimens. This multi-institutional study reports safety and efficacy in a large cohort of women with IBTR treated with repeat BCS and reRT. Materials/Methods: Using electronic medical record search tools, we identified all patients who underwent repeat BCS followed by breast reRT from 2015-2021 at 2 institutions. Univariate logistic regression models were used to identify clinical and dosimetric factors associated with development of acute and late toxicities. All statistical tests were two-sided, and the null hypothesis was rejected for p<0.05. Kaplan Meier methodology was used to calculate overall survival (OS), disease-free survival (DFS) and locoregional recurrence-free survival (LR-RFS).
Result(s): We identified 66 patients with an IBTR treated with repeat BCS. In the initial RT course, 55% received whole breast RT (WBI) with conventional fractionation (<=2 Gy/fraction[fx]), 29% WBI with hypofractionation (2.6-2.7 Gy/fx), 6% partial breast irradiation (PBI) ultrahypofractionation (6-8 Gy/fx) and 11% had unavailable treatment details. There was a median of 11 years between initial breast cancer and IBTR. At time of recurrence, 36% of patients had tumors located in the same quadrant as the initial cancer, 41% had invasive carcinoma with ductal carcinoma in situ (DCIS), 41% had invasive carcinoma alone, 18% had DCIS alone, 92% had tumors < 2 cm, 68% had low-intermediate grade tumors and all were clinically node negative. For reRT, 95% received PBI (57.5% 45 Gy/1.5 Gy twice daily; 27% 45 Gy/1.8 Gy daily; 10.5% hypofractionation), and 5% received WBI (45-46.8 Gy in 1.8 Gy/fx), all of whom had received PBI for the initial course. Nine patients (13%) underwent adjuvant chemotherapy and 44 (67%) adjuvant hormone therapy. Median follow-up was 16 months (range 3-60). Twenty-one patients (32%) experienced any acute >= grade 2 events, and 17 (26%) experienced any late >= grade 2 toxicities. One patient experienced grade 3 fibrosis and one patient experienced grade 3 telangiectasia at 36 months. None had grade 4 or higher late adverse events. We found no association between fractionation of reRT or cumulative dose (measured as EQD2) with acute or late toxicity. At 2 years, OS was 100%, DMFS was 91.6%, and LR-RFS was 100%.
Conclusion(s): In this large multi-institutional series of patients with recurrent breast cancer, second breast conservation surgery followed by reRT was effective with no local recurrences and excellent disease control outcomes, and toxicity appears to be acceptable. Longer follow-up and more prospective study are needed to further inform patient selection and establish the efficacy and tolerability of repeat breast conservation therapy in the setting of limited, low-risk recurrence.
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PURPOSE/OBJECTIVES/OBJECTIVE:Since the COVID-19 pandemic, telemedicine has emerged as an alternative to office visits in routine radiation oncology practice. The purpose of this study was to identify factors associated with patient preference for an initial consult via telemedicine and correlation with clinical trial enrollment. MATERIALS/METHODS/METHODS:We evaluated breast cancer patients seen during the open enrollment of a prospective randomized trial from 06/01/2020 to 05/13/2021. Univariate and multivariate logistic regression models were used to identify factors associated with virtual vs in-person initial consultation. All statistical tests were two-sided and the null hypothesis was rejected for p<0.05. RESULTS:We identified 476 patient consultations with 259 office visits and 217 telemedicine visits. On multivariate analysis, increased age, unemployment, chemotherapy receipt and radiation at our institution were associated with decreased usage of telemedicine for consultation visit. Out of 217 patients who underwent a telemedicine initial consultation, 10% were eligible to enroll on the trial and of those eligible, 76% enrolled. Out of 259 patients who underwent office visit initial consultation, 14% were eligible to enroll on the trial and of those eligible, 53% enrolled. Among eligible patients, there was no statistically significant difference in clinical trial enrollment between telemedicine and office visits. CONCLUSION/CONCLUSIONS:Older patients, unemployed patients, those receiving chemotherapy and those who subsequently received radiation at our institution were less likely to use telemedicine for their initial consult. Despite these disparities in telemedicine usage, there was no difference in clinical trial enrollment. Telemedicine may be an effective platform for clinical trial enrollment though further strategies to improve its access are essential.

BACKGROUND:Computerized surgical planning (CSP) in osseous reconstruction of head and neck cancer defects has become a mainstay of treatment. However, the consequences of CSP-designed titanium plating systems on planning adjuvant radiation remains unclear. METHODS:Two patients underwent head and neck cancer resection and maxillomandibular free fibula flap reconstruction with CSP-designed plates and immediate placement of osseointegrated dental implants. Surgical treatment was followed by adjuvant intensity modulated radiation therapy (IMRT). RESULTS:Both patients developed osteoradionecrosis (ORN), and one patient had local recurrence. The locations of disease occurred at the areas of highest titanium plate burden, possibly attributed to IMRT dosing inaccuracy caused by the CSP-designed plating system. CONCLUSION/CONCLUSIONS:Despite proven benefits of CSP-designed plates in osseous free flap reconstruction, there may be an underreported risk to adjuvant IMRT treatment planning leading to ORN and/or local recurrence. Future study should investigate alternative plating methods and materials to mitigate this debilitating outcome.

PURPOSE/OBJECTIVE:Randomized data support accelerated partial breast irradiation (APBI) for early-stage breast cancer with variable techniques and cosmesis outcomes. We have treated patients with 5-fraction prone external beam APBI for over a decade and herein report acute and late outcomes. METHODS AND MATERIALS/METHODS:Patients receiving APBI 600 cGy × 5 between 2010 and 2019 were included. APBI was primarily delivered prone, with opposed tangents targeting the tumor bed expanded by 1.5 cm (cropped 6 mm from skin). Ipsilateral breast was constrained to V50% < 60% and V100% < 35%. Survival was estimated with Kaplan-Meier. Late toxicities and clinician- and patient-rated cosmesis were evaluated for patients with >6 months follow-up (FU). RESULTS:Of 345 patients meeting criteria, 14 were excluded due to APBI given for ipsilateral breast tumor recurrence (IBTR; n = 3), palliation (n = 9), and incomplete radiation therapy course (n = 2). Of the 331 remaining, median age was 70, 7.2% had ductal carcinoma in situ, and 94.3% were treated prone, with 32% treated every other day and 68% on consecutive days. Mean heart dose was 23.8 cGy for left-sided and 12.7 cGy for right-sided cancers. Ipsilateral lung V30% was 0.4%. At 5-year median FU, there were 7 (2.1%) IBTR, 9 (2.7%) contralateral recurrences, and 1 (0.3%) distant metastasis. Five-year local recurrence-free, disease-free, and overall survival was 99.5%, 96.7%, and 98.1%, respectively. When comparing patients with IBTR versus without, a higher proportion did not receive hormone therapy (71.4% vs. 26.2%, P = .018). Rates of acute grade 1 to 2 dermatitis, fatigue, and pain were 35.4%, 21.8%, and 9.4%, respectively, with no grade 3 toxicity. The rate of good-excellent physician- and patient-rated cosmesis (n = 199, median FU 2.8 years) was 92.5% and 89.4%, respectively. Patients experienced low rates of telangiectasia, fibrosis, and retraction/atrophy. CONCLUSIONS:We report excellent dosimetric, oncologic, cosmetic, and late toxicity outcomes for patients treated with 5-fraction APBI. To our knowledge this is the largest series of women treated with prone APBI.