Faculty Bibliography

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.
Copyright

Purpose/Objective(s): The LGBTQ community is an understudied and medically underserved population who experience increased cancer risk and worse cancer outcomes. Negative provider interactions, including discrimination and lack of knowledge regarding LGBTQ-specific health issues are cited by patients as barriers to care, including in radiation oncology (RO). Notably, little is known regarding LGBTQ knowledge and attitudes among RO residents (ROR) or LGBTQ-specific training in RO residency training programs. Thus, we sought to assess the extent of current LGBTQ-specific training in U.S. RO residency programs. Materials/Methods: Two published surveys of LGBTQ-education in residency were adapted to RO. The first assessed LGBTQ education from the perspective of program directors (PD) and associate PDs (APD), while the second survey was to RORs. The surveys were sent to all ACGME-accredited U.S. RO residency PD, APD, and program coordinators (PC), with the ROR survey being disseminated by the respective PCs. Each survey consisted of subsections of attitudes and knowledge in the care of LGBTQ patients, RO program characteristics, program inclusion of LGBTQ-specific education, and individual demographics.
Result(s): There were 69 responses (29 PD, APD and 40 ROR). The majority of respondents (PD, APD/ROR) identified as white (79%/58%), non-Hispanic (76%/72%), male (55%/55%), and heterosexual (86%/78%). The majority of PD, APDs did not receive LGBTQ education in medical school (60%) or residency training (96%), while the majority of residents (68%) did receive LGBTQ training in medical school; yet, both groups felt this training was insufficient to care for LGBTQ patients during residency (76%/68%). Overall, respondents felt comfortable treating LGB (90%/85%) and T (79%/62.5%) patients. However, the majority did not feel confident in their knowledge for LGB (52%/62.5%) or T (79%/85%) health needs. The majority of respondents' programs have never had a didactic session on LGBTQ health (78%/80%) resulting in 61%/61% of respondents feeling their program inadequately prepares residents to work confidently with LGBTQ patients. However, the majority felt their program is receptive to incorporating LGBTQ health content into their curriculum (75%/75%) and expressed a personal interest in such education (97%/80%). Additional data will be available by time of conference.
Conclusion(s): We found an increase of LGTBQ education in medical schools between PD, APD and ROR, suggestive of a recent improvement in LGBTQ content; yet most residency programs still lacked any LGBTQ-specific education. While the majority felt comfortable treating LGBTQ patients, they simultaneously lacked confidence in knowledge regarding LGBTQ health needs; yet, possessed desire for additional education and belief that such trainings should require. Conclusion is that residencies need to do a better job incorporating LGBTQ health content into their curricula, which is supported by interest from ROR and program leadership.
Copyright

Superior vena cava (SVC) syndrome is commonly caused by malignancy but is rarely associated with breast cancer. The following case series describes three female breast cancer patients who were found to have disease recurrence years after initial diagnosis, presenting as facial swelling, collateral vessel formation, and shortness of breath consistent with SVC syndrome. All patients were treated with radiation therapy, and one patient required stenting due to tumor thrombus in the SVC. These cases highlight a rare complication of breast cancer that clinicians should recognize in patients who have undergone treatment particularly for right sided breast cancer with lymph node involvement.

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.

PURPOSE/OBJECTIVE(S): The supraclavicular (SCV), medial axillary and internal mammary nodes (IMNs) are not typically resected in breast cancer patients (pts). The optimal local therapy of pts with nodal disease in these regions is not well-studied. We aim to evaluate outcomes of breast cancer patients with unresected nodal disease. MATERIALS/METHODS: We identified 79 pts at our institution from 2016- 2021 with unresected nodal disease in the axilla, SCV and/or IMNs defined as grossly enlarged nodes on CT, MRI or PET scan +/- biopsy confirmation. Pts were treated with breast/chest wall and regional nodal irradiation with an additional boost to the unresected nodal region. Distant failure (DF) and local-regional failure (LRF) were assessed. Kaplan-Meier was used to calculate disease-free survival (DFS), overall survival (OS) and local recurrence-free survival (LRFS). Logistic regression was used to identify variables associated with worse DFS. Acute and late toxicity of RT were evaluated.
RESULT(S): 33% of pts were treated with breast-conserving surgery, 65% with mastectomy and all had axillary surgery (81% ALND, 19% SLNB). 47% of pts received IMN boost (IMN), 40% axillary/SCV boost (axSCV) and 15% both IMN and axSCV boost (IMN/axSCV). Most had cT2-3 (72%), hormone receptor positive (75%), and HER-2 negative disease (84%). 57% of axSCV had cN3A disease; 84% of IMN and 83% of IMN/axSCV had cN3b disease. 7% of axSCV and 17% of IMN/axSCV had cN3c disease. Most pts received chemotherapy (97%). Median nodal boost dose was 10 Gy (range 10-20 Gy), with 17% axSCV, 22% IMN, and 17% IMN/axSCV receiving 14-20 Gy. Rates of acute and late grade 3 toxicity did not differ by boost location (acute: IMN: 20%, axSCV: 11% and IMN/axSCV 20%, P=0.559; late: IMN: 40%, axSCV: 25%, IMN/axSCV: 40%, P=0.630) nor by boost dose (10 Gy vs 14-20 Gy). There were no grade 4+ toxicities. With a median follow up of 30 months, the 3-year LRR, DFS, and OS was 94.5%, 86.3% and 93.8% respectively. Crude rates of failure for the entire group were 13.9% (10.1% DF; 3.8% DF+LRF). Rates of failure by boost group were axSCV: 13.3% (10% DF; 3.3% DF+LRF), IMN: 5.4% (2.7% DF, 2.7% DF+LRF), IMN/axSCV 41.7% (33.3% DF, 8.3% DF+LRF). There were no LRFs without DFs. Median time to failure was 23 months (IQR 18-34). On univariate analysis clinical tumor size (cT) and IMN/axSCV vs. IMN or axSCV alone was associated with worse DFS (HR: 9.78 95% CI 2.07-46.2, P=0.004 and HR: 9.49 95% CI 2.67-33.7, P=0.001). On multivariate analysis, cT approached significance (HR 6.15; 95% CI 0.95-39.8, P=0.05). IMN/axSCV vs. IMN or axSCV alone retained significance (HR 4.80; 95% CI 1.27-18.13, P=0.02). The difference between the axSCV vs. IMN group was not significant.
CONCLUSION(S): In this population of pts with unresected nodal disease, boost RT to radiographically positive LN regions can be safely delivered with low rates of grade 3+ toxicity. The majority of failures were distant with no isolated LRFs. Failures were highest in the IMN/axSCV group (~40%). Further treatment escalation is necessary for these pts.
Copyright

PURPOSE/OBJECTIVE:To compare heart and lung doses for adjuvant whole breast irradiation (WBI) between radiation plans generated supine with deep inspiratory breath hold (S-DIBH) and prone with free-breathing (P-FB) and examine the effect of breast volume (BV) on dosimetric parameters. MATERIALS/METHODS/METHODS:Patients with left breast DCIS or invasive cancer receiving adjuvant WBI were enrolled on a single-institutional prospective protocol. Patients were simulated S-DIBH and P-FB; plans were generated using both scans. Wilcoxon's Signed Rank and Rank Sum tests were used to compare intra-patient differences between plans for the entire cohort and within BV groups defined by tertiles. RESULTS:Forty patients were enrolled. Thirty-four patients are included in the analysis due to patient withdrawal or inability to hold breath. With WBI dose of 4005 - 4256 cGy, mean heart dose (MHD) was 80 cGy in S-DIBH, 77 cGy in P-FB (p=0.08). Mean ipsilateral lung dose (MLD) was 453 cGy in S-DIBH, 45 cGy in P-FB (p<0.0001). Mean and max LAD dose were 251 cGy and 551 cGy in S-DIBH respectively, 324 cGy (p=0.1) and 993 cGy in P-FB (p=0.3) respectively. Hot spot and separation was 109% and 22 cm in S-DIBH respectively, 107% and 16 cm in P-FB respectively (p<0.0001). For patients with smallest BV, S-DIBH improved MHD and LAD doses; for those with largest BV, P-FB improved cardiac dosimetry. With increasing BV, there was an increasing advantage of P-FB for MHD (p=0.05), and max (p=0.03) and mean (p=0.02) LAD dose, and the reduction in MLD, hot spot, and separation with P-FB increased (p<0.05). CONCLUSIONS:MHD did not differ between P-FB and S-DIBH, whereas MLD was significantly lower with P-FB. Analysis according to breast volume revealed improved cardiac dosimetry with S-DIBH for women with smallest BV and improved cardiac dosimetry with P-FB for women with larger BV, thereby providing a dosimetric rationale for using breast size to help determine the optimal positioning for WBI.

Two commonly used whole breast irradiation (WBI) techniques, deep inspiration breath hold (DIBH) and prone positioning, are compared with regard to dosimetry and estimated late cardiac morbidity and secondary lung cancer mortality using published models. Forty patients with left-sided DCIS or breast cancer who underwent lumpectomy and required adjuvant WBI were enrolled on a prospective trial comparing supine DIBH (S-DIBH) with prone free breathing (P-FB) planning. Patients underwent CT simulation in both positions; two plans were generated for each patient. Comparative dosimetry was available for 34 patients. Mean cardiac and lung doses were calculated. Risk of death from ischemic heart disease (IHD), risk of at least one acute coronary event (ACE), and lung cancer mortality were estimated from published data. Difference between S-DIBH and P-FB plans was compared using paired two-tailed t test. Estimated mean risk of death from IHD by age 80 was 0.1% (range 0.0%-0.2%) for both plans (P = 1.0). Mean risk of at least one ACE was 0.3% (range 0.1%-0.6%) for both plans (P = .6). Mean lung cancer mortality risk was 1.4% (range 0.5%-15.4%) for S-DIBH and 1.0% (range 0.4%-9.8%) for P-FB (P = .008). Excess lung cancer mortality due to radiation was 0.5% (range 0.1%-6.0%) with S-DIBH and 0.0% (range 0.0%-0.4%) with P-FB (P = .008). Both S-DIBH and P-FB provide excellent cardiac sparing. Prone positioning results in lower lung dose than S-DIBH and leads to an absolute decrease of 0.5% in excess lung cancer mortality for patients receiving WBI.

BACKGROUND:Patients with an in-breast tumor recurrence (IBTR) after breast-conserving therapy have a high risk of distant metastasis and disease-related mortality. Classifying clinical parameters that increase risk for recurrence after IBTR remains a challenge. AIM/OBJECTIVE:To describe primary and recurrent tumor characteristics in patients who experience an IBTR and understand the relationship between these characteristics and disease outcomes. METHODS:Patients with stage 0-II breast cancer treated with lumpectomy and adjuvant radiation were identified from institutional databases of patients treated from 2003-2017 at our institution. Overall survival (OS), disease-free survival, and local recurrence-free survival (LRFS) were estimated using the Kaplan Meier method. We identified patients who experienced an isolated IBTR. Concordance of hormone receptor status and location of tumor from primary to recurrence was evaluated. The effect of clinical and treatment parameters on disease outcomes was also evaluated. RESULTS:= 0.004) decreased the risk of IBTR. CONCLUSION/CONCLUSIONS:Among patients with early stage breast cancer who had breast conserving surgery treated with adjuvant RT, ER/PR status and quadrant were highly concordant from primary to IBTR. Tumor size greater than 1.5 cm and use of adjuvant endocrine therapy were significantly associated with decreased risk of IBTR.