Positive Nipple Margins in Nipple-Sparing Mastectomy: Management of Nipples Containing Cancer or Atypia.

BACKGROUND: Nipple-sparing mastectomy (NSM) is an oncologically safe approach for breast cancer treatment and prevention; however, there are little long-term data to guide management for patients whose nipple margins contain tumor or atypia. METHODS: NSM patients with tumor or atypia in their nipple margin were identified from a prospectively maintained, single-institution database of consecutive NSMs. Patient and tumor characteristics, treatment, recurrence, and survival data were assessed. RESULTS: A total of 3158 NSMs were performed from June 2007 to August 2019. Nipple margins contained tumor in 117 (3.7%) NSMs and atypia only in 164 (5.2%) NSMs. Among 117 nipple margins that contained tumor, 34 (29%) margins contained invasive cancer, 80 (68%) contained ductal carcinoma in situ only, and 3 (3%) contained lymphatic vessel invasion only. Management included nipple-only excision in 67 (57%) breasts, nipple-areola complex excision in 35 (30%) breasts, and no excision in 15 (13%) breasts. Only 23 (24%) excised nipples contained residual tumor. At 67 months median follow-up, there were 2 (1.8%) recurrences in areolar or peri-areolar skin, both in patients with nipple-only excision. Among 164 nipple margins containing only atypia, 154 (94%) nipples were retained. At 60 months median follow-up, no patient with atypia alone had a nipple or areola recurrence. CONCLUSIONS: Nipple excision is effective management for nipple margins containing tumor. No intervention is required for nipple margins containing only atypia. Our results support broad eligibility for NSM with careful nipple margin assessment.

Time to surgery: A health equity metric in breast cancer patients.

BACKGROUND: We evaluated whether time to surgery by race can be a health equity metric of surgical access. METHODS: An observational analysis was performed using the National Cancer Database from 2010 to 2019. Inclusion criteria were women with stage I-III breast cancer. We excluded women with multiple cancers and whose diagnosis was made at a different hospital. The primary outcome variable was surgery within 90 days of diagnosis. RESULTS: A total of 886,840 patients were analyzed, with 76.8% White and 11.7% Black patients. 11.9% of patients experienced delayed surgery, which was significantly more common in Black patients than White patients. On adjusted analysis, Black patients were still significantly less likely to receive surgery within 90 days when compared to White patients (OR 0.61, 95% CI 0.58-0.63). CONCLUSION: The delay in surgery experienced by Black patients highlights the contribution of system factors in cancer inequity and should be a focus for targeted interventions.

Oncologic Safety of Nipple-Sparing Mastectomy for Breast Cancer in BRCA Gene Mutation Carriers: Outcomes at 70 Months Median Follow-Up.

BACKGROUND: Retention of the nipple-areola complex with nipple-sparing mastectomy (NSM) techniques provides a more natural cosmetic result than procedures that sacrifice the nipple. While the oncologic safety of NSM is established by several studies, there is little long-term data on outcomes in BRCA mutation carriers with breast cancer. PATIENTS AND METHODS: BRCA1/2 mutation carriers who underwent NSM and immediate reconstruction from 2008 to 2019 were reviewed and patients with breast cancer on biopsy or final pathology were included. Patient demographics and tumor characteristics, as well as treatment, recurrence, and survival data were collected. RESULTS: A total of 114 therapeutic NSM were performed in 105 BRCA mutation carriers (56 BRCA1, 47 BRCA2, and two women with both mutations). Median age was 45 years. Cancers were 18% stage 0, 52% stage I, 27% stage II, and 3% stage III. Mean invasive tumor size was 1.6 cm and 33 (35%) invasive tumors were triple negative. There were five (4.4%) positive nipple margins on final pathology; all underwent nipple excision. Most patients (80, 76%) received systemic therapy: 65 (62%) received chemotherapy and 48 (46%) received endocrine therapy. At 70 months median follow-up (range 15-150 months), no patient had developed a recurrence in the retained nipple-areola complex or at the site of a nipple excised for a positive margin. The rate of locoregional recurrence outside the nipple was 2.6%, and the rate of distant recurrence was 3.8%. Overall survival was 96%. CONCLUSIONS: NSM is a safe option for BRCA1 and BRCA2 mutation carriers who undergo mastectomy for breast cancer.

The Timing of Acute and Late Complications Following Mastectomy and Implant-based Reconstruction.

BACKGROUND/OBJECTIVE: Implant-based breast reconstruction is a common plastic surgery procedure with well-documented clinical outcomes. Despite this, the natural history and timing of key complication endpoints are not well described. The goal of this study is to determine when patients are most likely to experience specific adverse events after implant-based reconstruction. METHODS: Retrospective consecutive series of patients who received mastectomy and implant-based reconstruction over a 6-year period were included. Complications and unfavorable outcomes including hematoma, seroma, wound infection, skin flap necrosis, capsular contracture, implant rippling, and implant loss were identified. A time-to-event analysis was performed and Cox regression models identified patient and treatment characteristics associated with each outcome. RESULTS: Of 1473 patients and 2434 total reconstructed breasts, 785 complications/unfavorable outcomes were identified. The 12-month cumulative incidence of hematoma was 1.4%, seroma: 4.3%, infection: 3.2%, skin flap necrosis: 3.9%, capsular contracture: 5.7%, implant rippling: 7.1%, and implant loss: 3.9%. In the analysis, 332/785 (42.3%) complications occurred within 60 days of surgery; 94% of hematomas, 85% of skin necrosis events, and 75% of seromas occurred during this period. Half of all infections and implant losses also occurred within 60 days. Of the remaining complications, 94% of capsular contractures and 93% of implant rippling occurred >60 days from surgery. CONCLUSIONS: Complications following mastectomy and implant-based reconstruction exhibit a discrete temporal distribution. These data represent the first comprehensive study of the timing of adverse events following implant-based reconstruction. These findings are immediately useful to guide postoperative care, follow-up, and clinical trial design.

Cost analysis of pre-pectoral implant-based breast reconstruction.

With improvement in mastectomy skin flap viability and increasing recognition of animation deformity following sub-pectoral implant placement, there has been a transition toward pre-pectoral breast reconstruction. While studies have explored the cost effectiveness of implant-based breast reconstruction, few investigations have evaluated cost with respect to pre-pectoral versus sub-pectoral breast reconstruction. A retrospective review of 548 patients who underwent mastectomy and implant-based breast reconstruction was performed from 2017 to 2020. The demographic and surgical characteristics of the pre-pectoral and sub-pectoral cohorts were well matched, except for reconstructive staging, as patients who underwent pre-pectoral reconstruction were more likely to undergo single-stage instead of two-stage reconstruction. Comparison of institutional cost ratios by reconstructive technique revealed that the sub-pectoral approach was more costly (1.70 ± 0.44 vs 1.58 ± 0.31, p < 0.01). However, further stratification by laterality and reconstructive staging failed to demonstrate difference in cost by reconstructive technique. These results were confirmed by multivariable linear regression, which did not reveal reconstructive technique to be an independent variable for cost. This study suggests that pre-pectoral breast reconstruction is a cost-effective alternative to sub-pectoral breast reconstruction and may confer cost benefit, as it is more strongly associated with direct-to-implant breast reconstruction.

Targeted Nipple Areola Complex Reinnervation: Technical Considerations and Surgical Efficiency in Implant-based Breast Reconstruction.

Background: Despite promising pilot study results, adoption of neurotization of immediate implant-based reconstructions has not occurred. Methods: For surgeons interested in adopting breast reinnervation techniques, we present ways to overcome initial barriers by decreasing operative time and maximizing chances of sensory recovery. Results: We discuss the combined experience at two academic teaching hospitals, where neurotization of both immediate tissue expander cases and direct-to-implant reconstructions are performed through varying mastectomy incisions. Conclusion: Initial barriers can be overcome by shortening operative time and providing an individualized reinnervation approach that aims to increase the chance of meaningful sensation.

Deep Learning vs Traditional Breast Cancer Risk Models to Support Risk-Based Mammography Screening.

BACKGROUND: Deep learning breast cancer risk models demonstrate improved accuracy compared with traditional risk models but have not been prospectively tested. We compared the accuracy of a deep learning risk score derived from the patient's prior mammogram to traditional risk scores to prospectively identify patients with cancer in a cohort due for screening. METHODS: We collected data on 119 139 bilateral screening mammograms in 57 617 consecutive patients screened at 5 facilities between September 18, 2017, and February 1, 2021. Patient demographics were retrieved from electronic medical records, cancer outcomes determined through regional tumor registry linkage, and comparisons made across risk models using Wilcoxon and Pearson χ2 2-sided tests. Deep learning, Tyrer-Cuzick, and National Cancer Institute Breast Cancer Risk Assessment Tool (NCI BCRAT) risk models were compared with respect to performance metrics and area under the receiver operating characteristic curves. RESULTS: Cancers detected per thousand patients screened were higher in patients at increased risk by the deep learning model (8.6, 95% confidence interval [CI] = 7.9 to 9.4) compared with Tyrer-Cuzick (4.4, 95% CI = 3.9 to 4.9) and NCI BCRAT (3.8, 95% CI = 3.3 to 4.3) models (P < .001). Area under the receiver operating characteristic curves of the deep learning model (0.68, 95% CI = 0.66 to 0.70) was higher compared with Tyrer-Cuzick (0.57, 95% CI = 0.54 to 0.60) and NCI BCRAT (0.57, 95% CI = 0.54 to 0.60) models. Simulated screening of the top 50th percentile risk by the deep learning model captured statistically significantly more patients with cancer compared with Tyrer-Cuzick and NCI BCRAT models (P < .001). CONCLUSIONS: A deep learning model to assess breast cancer risk can support feasible and effective risk-based screening and is superior to traditional models to identify patients destined to develop cancer in large screening cohorts.

Comparison of Wireless Localization Alternatives with Wire Localization for Nonpalpable Breast Lesions.

BACKGROUND: Radiofrequency identification tag localization (TL) and magnetic seed localization (MSL) are alternatives to wire localization (WL) for excision of nonpalpable breast lesions. We sought to compare localization methods with respect to operative time, specimen volume, and re-excision rate. STUDY DESIGN: A retrospective cohort analysis was performed on TL, MSL, and WL lumpectomies and excisional biopsies at a single institution. Association between localization method and operative time, specimen volume, and re-excision rate was assessed by multiple logistic regression using odds ratios (ORs) and 95% CIs. RESULTS: A total of 506 procedures were included: 147 TL (29.0%), 140 MSL (27.7%), and 219 WL (43.3%). On logistic regression analysis, MSL was associated with longer operative times than WL for excisional biopsies only (OR 4.24, 95% CI 1.92 to 9.34, p < 0.001). Mean excisional biopsy time was 39.1 minutes for MSL and 33.0 minutes for WL. Specimen volume did not vary significantly across surgery types between localization methods. In an analysis of all lumpectomies with an indication of carcinoma, marker choice was not associated with rate of re-excision (TL vs WL OR 0.64, 95% CI 0.26 to 1.60, p = 0.342; MSL vs WL OR 1.22, 95% CI 0.60 to 2.49, p = 0.587; TL vs MSL OR 0.65, 95% CI 0.26 to 1.64, p = 0.359). CONCLUSION: TL, MSL, and WL are comparable in performance for excision of nonpalpable breast lesions. Although increased operative time associated with MSL vs WL excisional biopsies is statistically significant, clinical significance warrants additional study. With similar outcomes, physicians may choose the marker most appropriate for the patient and setting.

One-Year Experience of Same-Day Mastectomy and Breast Reconstruction Protocol.

BACKGROUND: The prevalence of same-day mastectomy with reconstruction has continued to increase across the United States in recent years. Prior studies have shown that same-day mastectomy with reconstruction leads to increased patient satisfaction and allows hospitals to use resources better. This study sought to evaluate the implementation of same-day mastectomy with a reconstruction recovery protocol for patients undergoing mastectomy at our institution. METHODS: Under an institutional review board-approved protocol, a retrospective cohort analysis compared patients who underwent mastectomy April 2016 through April 2017 with those who had mastectomy March 2020 through March 2021. Length of stay, postoperative intravenous (IV) opioid administration, safety end points, and cost were the main variables examined. RESULTS: The study compared 457 patients in 2016-2017 with 428 patients in 2020-2021. The median hospital length of stay decreased from 24.6 h in 2016-2017 to 5.5 h in 2020-2021 (p < 0.001). The percentage of patients requiring postoperative IV opioids decreased from 69.1 % in 2016-2017 to 50 % in 2020-2021 (p < 0.001). The rates of unplanned readmissions within 30 days after mastectomy did not differ between the two groups, with a rate of 3.7 % in 2016-2017 and a rate of 5.1 % in 2020-2021 (p = 0.30). Reducing the rate of overnight admissions after mastectomy by 65.8 % resulted in a cost reduction of 65.8 %. CONCLUSIONS: Implementation of same-day mastectomy with a reconstruction protocol across a large academic center and two satellite sites was a safe alternative to conventional mastectomy recovery plans.

Pilot study to assess prolonged overnight fasting in breast cancer survivors (longfast).

PURPOSE: Retrospective analysis of nightly fasting among women with breast cancer suggests that fasting < 13 h may be associated with a higher risk of breast cancer recurrence. We sought to evaluate prolonged overnight fasting (POF), an accessible nonpharmacological intervention, in a prospective feasibility study. METHODS: We designed a single-arm, pilot study to evaluate the feasibility of fasting for 13 h overnight for 12 weeks among women with a history of early-stage breast cancer survivors. Baseline and end of study assessments included measurements of body mass index (BMI), blood biomarkers, quality of life (QOL), mood, fatigue, and physical activity. Patient-reported outcome questionnaires were also administered at 6 weeks. Feasibility was defined as ≥ 60% of participants documenting fasting for 13 h on at least 70% of nights during the study period. RESULTS: Forty women with a history of breast cancer were enrolled with a median age of 60 (range 35-76) and median time since diagnosis of 4.5 years (range 0.8-20.7). At baseline, BMI was ≥ 25 in 37.5%. Ninety-five percent of participants fasted ≥ 13 h for at least 70% of study days (95% CI 83-99%). There was a statistically significant improvement in anxiety (p = 0.0007) at 6 weeks and BMI (p = 0.0072), anxiety (p = 0.0141), depression (p = 0.0048), and fatigue (p = 0.0105) at 12 weeks. There was no significant change in overall QOL, physical activity levels, or blood biomarkers at 12 weeks. CONCLUSIONS: POF is feasible among patients with a history of breast cancer and may potentially improve BMI, mood, and fatigue without detrimental effects on overall QOL.

Magnetic Seeds: An Alternative to Wire Localization for Nonpalpable Breast Lesions.

INTRODUCTION: Magnetic seeds have emerged as an alternative to wires for localization of nonpalpable breast lesions. The purpose of this study was to evaluate the utility of magnetic seeds compared to wires for preoperative localization. MATERIALS AND METHODS: A retrospective cohort analysis of magnetic seed localization (MSL) and wire localization (WL) excisional biopsies and lumpectomies performed at a single institution was conducted. Indication, age, BMI, number of markers, procedure type, operative time, and postoperative opioid administration were reviewed. Impact of localization method on operative time, specimen volume, postoperative opioid administration, and re-excision rate were assessed. RESULTS: A total of 608 MSL procedures in 601 patients were compared to 628 WL procedures in 620 patients. MSL excisional biopsies were significantly longer (37.0 minutes) than WL excisional biopsies (31.9 minutes, P< .001), but in lumpectomies without axillary surgery, MSL procedures (42.3 minutes) were significantly shorter than WL procedures (46.9 minutes, P = .017). Significantly less tissue was excised during MSL lumpectomies (68.5 cm3) and excisional biopsies (32.3 cm3) than WL lumpectomies (78.1 cm3, P = .039) and excisional biopsies (38.7 cm3, P = .018). Postoperative opioid administration was similar for MSL and WL procedures (P = .076). Re-excision rates for MSL lumpectomies were significantly higher for ductal carcinoma in situ (35.3% MSL vs. 18.5% WL, P = .013), but were similar for invasive carcinoma (14.4% MSL vs. 17.7% WL, P = .290). Logistic regression analysis showed no association between localization method and re-excision (OR 1.007, 95% CI 0.681-1.488; P = .973). CONCLUSION: MSL is a feasible alternative to WL for excision of nonpalpable breast lesions with regard to surgical outcomes.

The safety of performing breast reconstruction during the COVID-19 pandemic.

PURPOSE: Elective operations including surgeries for breast cancer were significantly reduced during the height of the surge of COVID-19 cases in Massachusetts. The safety of performing breast reconstruction during the pandemic was unknown. This study aims to review the safety of performing mastectomy with immediate breast reconstruction during the first COVID-19 surge in Massachusetts. METHODS: A retrospective chart review of patients who underwent mastectomy with immediate breast reconstruction by Massachusetts General Hospital breast and plastic surgeons immediately preceding and during the COVID-19 pandemic was performed. RESULTS: Thirty patients (34 breasts) underwent mastectomies with immediate breast reconstruction during the COVID-19 restriction period in Massachusetts. Most reconstructions were unilateral. All reconstructions were performed with implants or expanders, and no autologous reconstructions were performed. Two patients (2 breasts) had operative complications. The complication rate during the pandemic was similar to the complication rate pre-pandemic. No patients or surgeons experienced symptoms or positive COVID-19 tests. Over 90% of patients were discharged the same day. CONCLUSION: Prosthetic breast reconstruction was able to be performed safely during the height of the COVID-19 pandemic surge in Massachusetts. Strict screening protocols, proper use of personal protective equipment, and same-day discharge when possible are essential for patient and surgeon safety during the pandemic.

Nipple-Sparing Mastectomy versus Skin-Sparing Mastectomy: Does Saving the Nipple Impact Short- and Long-Term Patient Satisfaction?

BACKGROUND: Nipple-sparing mastectomy (NSM) is an oncologically safe alternative to skin-sparing mastectomy (SSM). This study evaluated whether NSM patients were more satisfied than SSM patients in short- and long-term follow-up. METHODS: Women who underwent NSM or SSM between 2009 and 2019 completed a postoperative BREAST-Q survey at least 1 year after surgery and patient characteristics were compared. Patient satisfaction at 1-5 years and 6-10 years after NSM and SSM were analyzed. RESULTS: Overall, 431 patients were included; 247 had NSM and 184 had SSM 1-10 years prior to BREAST-Q survey completion. SSM patients were older, had higher body mass index (BMI), larger breast weight, and more hypertension than NSM patients, but oncologic treatments were similar between groups. BREAST-Q Psychosocial Well-Being and Sexual Well-Being scores were significantly higher in NSM patients compared with SSM patients in the 1-5 years cohort; however, scores attenuated in the 6-10 years cohort. Satisfaction with breasts was nearly significantly higher in NSM patients compared with SSM patients in the 1-5 years cohort (p = 0.056), but no different in the 6-10 years cohort. Receipt of adjuvant chemotherapy, receipt of postmastectomy radiation therapy, and BMI ≥30 were independent risk factors for dissatisfaction with breasts. CONCLUSIONS: Women who are not candidates for NSM should be reassured that long-term qualify of life is not significantly different between SSM and NSM. Dissatisfaction with reconstructed breasts is linked with other factors (besides the nipple), which patients should be made aware of at the time of surgical decision making.

Screening Mammography Recovery After COVID-19 Pandemic Facility Closures: Associations of Facility Access and Racial and Ethnic Screening Disparities.

BACKGROUND. Screening mammography facilities closed during the COVID-19 pandemic in spring 2020. Recovery of screening volumes has varied across patient subgroups and facilities. OBJECTIVE. We compared screening mammography volumes and patient and facility characteristics between periods before COVID-19 and early and later postclosure recovery periods. METHODS. This retrospective study included screening mammograms performed in the same 2-month period (May 26-July 26) in 2019 (pre-COVID-19), 2020 (early recovery), and 2021 (late recovery after targeted interventions to expand access) and across multiple facility types (urban, suburban, community health center). Suburban sites had highest proportion of White patients and the greatest scheduling flexibility and expanded appointments during initial reopening. Findings were compared across years. RESULTS. For White patients, volumes decreased 36.6% from 6550 in 2019 (4384 in 2020) and then increased 61.0% to 6579 in 2021; for patients with races other than White, volumes decreased 53.9% from 1321 in 2019 (609 in 2020) and then increased 136.8% to 1442 in 2021. The percentage of mammograms in patients with races other than White was 16.8% in 2019, 12.2% in 2020, and 18.0% in 2021. The proportion performed at the urban center was 55.3% in 2019, 42.2% in 2020, and 45.9% in 2021; the proportion at suburban sites was 34.0% in 2019, 49.2% in 2020, and 43.5% in 2021. Pre-COVID-19 volumes were reached by the sixth week after reopening for suburban sites but were not reached during early recovery for the other sites. The proportion that were performed on Saturday for suburban sites was similar across periods, whereas the proportion performed on Saturday for the urban site was 7.6% in 2019, 5.3% in 2020, and 8.8% in 2021; the community health center did not offer Saturday appointments during recovery. CONCLUSION. After reopening, screening shifted from urban to suburban settings, with a disproportionate screening decrease in patients with races other than White. Initial delayed access at facilities serving underserved populations exacerbated disparities. Interventions to expand access resulted in late recovery volumes exceeding prepandemic volumes in patients with races other than White. CLINICAL IMPACT. Interventions to support equitable access across facilities serving diverse patient populations may mitigate potential widening disparities in breast cancer diagnosis during the pandemic.

Systematic tissue collection during clinical breast biopsy is feasible, safe and enables high-content translational analyses.

Systematic collection of fresh tissues for research at the time of diagnostic image-guided breast biopsy has the potential to fuel a wide variety of innovative studies. Here we report the initial experience, including safety, feasibility, and laboratory proof-of-principle, with the collection and analysis of research specimens obtained via breast core needle biopsy immediately following routine clinical biopsy at a single institution over a 14-month period. Patients underwent one or two additional core biopsies following collection of all necessary clinical specimens. In total, 395 patients were approached and 270 consented to the research study, yielding a 68.4% consent rate. Among consenting patients, 238 lesions were biopsied for research, resulting in 446 research specimens collected. No immediate complications were observed. Representative research core specimens showed high diagnostic concordance with clinical core biopsies. Flow cytometry demonstrated consistent recovery of hundreds to thousands of viable cells per research core. Among a group of HER2 + tumor research specimens, HER2 assessment by flow cytometry correlated highly with immunohistochemistry (IHC) staining, and in addition revealed extensive inter- and intra-tumoral variation in HER2 levels of potential clinical relevance. Suitability for single-cell transcriptomic analysis was demonstrated for a triple-negative tumor core biopsy, revealing substantial cellular diversity in the tumor immune microenvironment, including a prognostically relevant T cell subpopulation. Thus, collection of fresh tissues for research purposes at the time of diagnostic breast biopsy is safe, feasible and efficient, and may provide a high-yield mechanism to generate a rich tissue repository for a wide variety of cross-disciplinary research.

How Protective are Nipple-Sparing Prophylactic Mastectomies in BRCA1 and BRCA2 Mutation Carriers?

BACKGROUND: Nipple-sparing mastectomy (NSM) is now routinely offered to BRCA mutation carriers for risk reduction. We assessed the rates of ipsilateral cancer events after prophylactic and therapeutic NSM in BRCA1 and BRCA2 mutation carriers. METHODS: BRCA1 and BRCA2 mutation carriers undergoing NSM from October 2007 to June 2019 were identified in a single-institution prospective database, with variants of unknown significance being excluded. Patient, tumor, and outcomes data were collected. Follow-up analysis was by cumulative breast-years (total years of follow-up of each breast) and woman-years (total years of follow-up of each woman). RESULTS: Overall, 307 BRCA1 and BRCA2 mutation carriers (160 BRCA1, mean age 41.4 years [range 21-65]; and 147 BRCA2, mean age 43.8 years [range 23-65]) underwent 607 NSMs, with a median follow-up of 42 months (range 1-143). 388 bilateral prophylactic NSMs had 744 cumulative woman-years of follow-up, with no new cancers seen (< 0.0013 new cancers per woman-years); 251 BRCA1 prophylactic NSMs had 1034 cumulative breast-years of follow-up, with no new ipsilateral cancers seen (< 0.0010 per breast-year); 66 BRCA1 therapeutic NSMs had 328 cumulative breast-years of follow-up, with one ipsilateral cancer recurrence not directly involving the nipple or areola (0.0030 per breast-year); 237 BRCA2 prophylactic NSMs had 926 cumulative breast-years of follow-up, with no new ipsilateral cancers seen (< 0.0011 per breast-year); and 53 BRCA2 therapeutic NSMs had 239 cumulative breast-years of follow-up, with two ipsilateral recurrent cancers, neither of which directly involved the nipple or areola (0.0084 per breast-year). CONCLUSIONS: The risk of new ipsilateral breast cancers is extremely low after NSM in BRCA1 and BRCA2 mutation carriers. NSM is an effective risk-reducing strategy for BRCA gene mutations.

Target coverage and cardiopulmonary sparing with the updated ESTRO-ACROP contouring guidelines for postmastectomy radiation therapy after breast reconstruction: a treatment planning study using VMAT and proton PBS techniques.

BACKGROUND: The European Society for Therapeutic Radiology and Oncology Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) recently released new contouring guidelines for postmastectomy radiation therapy (PMRT) after implant-based reconstruction (IBR). As compared to prior ESTRO guidelines, the new guidelines primarily redefined the chest wall (CW) target to exclude the breast prosthesis. In this study, we assessed the impact of these changes on treatment planning and dosimetric outcomes using volumetric-modulated arc therapy (VMAT) and proton pencil-beam scanning (PBS) therapy. METHODS: We performed a treatment planning study of 10 women with left-sided breast cancer who underwent PMRT after IBR. All target structures were delineated first using standard (ESTRO) breast contouring guidelines and then separately using the new (ESTRO-ACROP) guidelines. Standard organs-at-risk (OARs) and cardiac substructures were contoured. Four sets of plans were generated: (1) VMAT using standard ESTRO contours, (2) VMAT using new ESTRO-ACROP contours, (3) PBS using standard contours, and (4) PBS using new contours. RESULTS: VMAT plans using the new ESTRO-ACROP guidelines resulted in modest sparing of the left anterior descending coronary artery (LAD) (mean dose: 6.99 Gy standard ESTRO vs. 6.08 Gy new ESTRO-ACROP, p = 0.010) and ipsilateral lung (V20: 21.66% vs 19.45%, p = 0.017), but similar exposure to the heart (mean dose: 4.6 Gy vs. 4.3 Gy, p = 0.513), with a trend toward higher contralateral lung (V5: 31.0% vs 35.3%, p = 0.331) and CW doses (V5: 31.9% vs 35.4%, p = 0.599). PBS plans using the new guidelines resulted in further sparing of the heart (mean dose: 1.05 Gy(RBE) vs. 0.54 Gy(RBE), p < 0.001), nearly all cardiac substructures (LAD mean dose: 2.01 Gy(RBE) vs. 0.66 Gy(RBE), p < 0.001), and ipsilateral lung (V20: 16.22% vs 6.02%, p < 0.001). CONCLUSIONS: PMRT after IBR using the new ESTRO-ACROP contouring guidelines with both VMAT and PBS therapy is associated with significant changes in exposure to several cardiopulmonary structures.