Thrombotic Consequences of COVID-19 Infection on Microsurgical Reconstruction.

BACKGROUND: Evidence has shown increased morbidity and mortality for patients with COVID-19 infection within 7 weeks of surgery. However, no studies have specifically investigated the effects of COVID-19 in microsurgical outcomes. This study evaluated thrombotic and overall complications after free tissue transfer for a variety of indications in patients with and without previous COVID-19 infection. METHODS: A retrospective cohort study was performed in adult patients with or without a history of COVID-19 infection who underwent microsurgical reconstruction between 2017 and 2022. Patients with a history of COVID-19 infection were matched to controls based on age, gender, race, body mass index, history of diabetes, coronary artery disease, hypertension, Caprini score, tobacco use, and flap indication. RESULTS: From 2017 to 2022, 35 patients had a documented history of COVID-19. Matched case analysis determined a 4.8 times increased odds ratio of postoperative complications in the COVID-19 group compared with controls (p = 0.002). Significantly, more patients with COVID-19 experienced total or partial flap loss and anastomotic issues (COVID-19: 7/35, Control: 0/35; p < 0.001). There was no significant difference in incidence of VTE (COVID-19: 1/35, Control: 0/35; p = 0.493). Of note, 62.9% of the COVID-19 group were discharged on anticoagulants (versus 14.3% in the control group [p < 0.001]). CONCLUSION: COVID-19 has dire, long-lasting effects on virtually every organ system, chief among them, the microcirculation. Further studies are needed to fully determine the extent and influence of COVID-19 on complex procedures such as free tissue transfer and how to optimize the screening, workup, and postoperative care to guard against the associated thrombotic consequences.

Salvage of Nipple-Areolar Complex Ischemia With Dimethyl Sulfoxide: A Case Series.

BACKGROUND: Nipple-areolar complex (NAC) necrosis is a known risk of breast surgery, particularly mastectomy. Disruption of the underlying blood supply to the NAC can lead to ischemia and subsequent necrosis. Nitroglycerin paste is currently used to combat NAC ischemia but has limited efficacy and an unfavorable side effect profile. Topical dimethyl sulfoxide (DMSO) has been shown to increase tissue perfusion in microsurgery and various skin flaps, but its role in the treatment and prevention of NAC ischemia has not been reported. Through a prospective case series, this study aims to introduce DMSO as a safe treatment for NAC ischemia after breast surgery. METHODS: Patients treated by 2 breast surgeons and a single plastic surgeon who underwent nipple-sparing mastectomy or breast reduction and developed NAC ischemia were identified via a prospectively maintained database. Ischemic changes were diagnosed, and treatment to the affected NAC with DMSO was initiated at the conclusion of the procedure, or postoperative day 1 in most cases, and continued 4 times daily until ischemic changes had resolved clinically. Collected demographic, surgical, and outcome variables were analyzed using descriptive statistics. RESULTS: Eleven patients with a mean age of 47.8 ± 9.5 years (range, 35-61 years) and mean body mass index of 26.0 ± 4.4 kg/m2 (range, 20.7-33.4 kg/m2) were identified. The mean duration of time between surgery and the clinical diagnosis of NAC ischemia was 1.3 ± 2.8 days (range, 0-7 days). The average length of time from DMSO initiation to clinical improvement or resolution of NAC ischemia was 7.5 ± 2.5 days (range, 5-12 days). All patients demonstrated significant improvement or complete resolution of NAC ischemia following serial topical DMSO application. CONCLUSIONS: This study demonstrates DMSO is a safe treatment for threatened NACs. All patients in this series showed either dramatic improvement or resolution of NAC ischemia after DMSO application, and threatened NACs of all 11 patients were successfully salvaged. These promising results set the basis for ongoing randomized controlled studies to determine the efficacy of DMSO treatment for NAC ischemia.

Intraoperative radiation therapy for early-stage breast cancer: a single-institution experience.

Background: To assess outcomes and toxicity after low-energy intraoperative radiotherapy (IORT) for early-stage breast cancer (ESBC). Materials and methods: We reviewed patients with unilateral ESBC treated with breast-conserving surgery and 50-kV IORT at our institution. Patients were prescribed 20 Gy to the surface of the spherical applicator, fitted to the surgical cavity during surgery. Patients who did not meet institutional guidelines for IORT alone on final pathology were recommended adjuvant treatment, including additional surgery and/or external-beam radiation therapy (EBRT). We analyzed ipsilateral breast tumor recurrence, overall survival, recurrence-free survival and toxicity. Results: Among 201 patients (median follow-up, 5.1 years; median age, 67 years), 88% were Her2 negative and ER positive and/or PR positive, 98% had invasive ductal carcinoma, 87% had grade 1 or 2, and 95% had clinical T1 disease. Most had pathological stage T1 (93%) N0 (95%) disease. Mean IORT applicator dose at 1-cm depth was 6.3 Gy. Post-IORT treatment included additional surgery, 10%; EBRT, 11%; adjuvant chemotherapy, 9%; and adjuvant hormonal therapy, 74%. Median total EBRT dose was 42.4 (range, 40.05-63) Gy and median dose per fraction was 2.65 Gy. At 5 years, the cumulative incidence of ipsilateral breast tumor recurrence was 2.7%, the overall survival rate was 95% with no breast cancer-related deaths, and the recurrence-free survival rate was 96%. For patients who were deemed unsuitable for postoperative IORT alone and did not receive recommended risk-adapted EBRT, the IBTR rate was 4.7% versus 1.7% (p = 0.23) for patients who were either suitable for IORT alone or unsuitable and received adjuvant EBRT. Cosmetic toxicity data was available for 83%, with 7% experiencing grade 3 breast toxicity and no grade 4-5 toxicity. Conclusions: IORT for select patients with ESBC results in acceptable outcomes in regard to ipsilateral breast tumor recurrence and toxicity.

Five-Year Breast Surgeon Experience in LYMPHA at Time of ALND for Treatment of Clinical T1-4N1-3M0 Breast Cancer.

BACKGROUND: Breast cancer-related lymphedema (BCRL) is a source of postoperative morbidity for breast cancer survivors. Lymphatic microsurgical preventive healing approach (LYMPHA) is a technique used to prevent BCRL at the time of axillary lymph node dissection (ALND). We report the 5-year experience of a breast surgeon trained in LYMPHA and investigate the outcomes of patients who underwent LYMPHA following ALND for treatment of cT1-4N1-3M0 breast cancer. METHODS: A retrospective review of patients with cT1-4N1-3M0 breast cancer was performed in patients who underwent ALND with and without LYMPHA. Diagnosis of BCRL was made by certified lymphedema therapists. Descriptive statistics and lymphedema surveillance data were analyzed using results of Fisher's exact or Wilcoxon rank-sum tests. Logistic regression and propensity matching were performed to assess the reduction of BCRL occurrence following LYMPHA. RESULTS: In a 5-year period, 132 patients met inclusion criteria with 76 patients undergoing LYMPHA at the time of ALND and 56 patients undergoing ALND alone. Patients who underwent LYMPHA at the time of ALND were significantly less likely to develop BCRL than those who underwent ALND alone (p = 0.045). Risk factors associated with BCRL development were increased patient age (p = 0.007), body mass index (BMI) (p = 0.003), and, in patients undergoing LYMPHA, number of positive nodes (p = 0.026). CONCLUSIONS: LYMPHA may be successfully employed by breast surgeons trained in lymphatic-venous anastomosis at the time of ALND. While research efforts should continue to focus on prevention and surveillance of BCRL, LYMPHA remains an option to reduce BCRL and improve patient quality of life.

A Lymphedema Surveillance Program for Breast Cancer Patients Reveals the Promise of Surgical Prevention.

BACKGROUND: Breast cancer-related lymphedema (BCRL) is one of the most significant survivorship issues in breast cancer management. Presently, there is no cure for BCRL. The single greatest risk factor for developing BCRL is an axillary lymph node dissection (ALND). Lymphatic Microsurgical Preventative Healing Approach (LYMPHA) is a surgical procedure to reduce the risk of lymphedema in patients undergoing an ALND. We present our single institution results after offering LYMPHA in the context of an established lymphedema surveillance program. MATERIALS AND METHODS: A retrospective review of our lymphedema surveillance program at the University of Florida was performed over a 2-year period (March 2014-March 2016). LYMPHA was offered to patients undergoing ALND beginning in March 2015. Patients who developed lymphedema were compared with those who did not. Demographics and potential risk factors for development of lymphedema such as age, body mass index, clinical stage, radiotherapy, and chemotherapy were reviewed. RESULTS: Eighty-seven patients participated in the surveillance program over the study period with an average age of 60 y (range 32-83) and body mass index of 30 kg/m2 (range 17-46). The single most significant risk factor for the development for lymphedema was an ALND (P < 0.001). One of 67 patients undergoing a sentinel lymph node biopsy developed lymphedema (1.5%). Four of 10 patients who underwent an ALND alone developed lymphedema (40%). One of 8 patients in the ALND + LYMPHA group developed transient lymphedema (12.5%). CONCLUSIONS: Offering LYMPHA with ALND decreased our institutional rate of lymphedema from 40% to 12.5%. Long-term follow-up and randomized control trials are necessary to further elucidate the promise of this surgical technique to reduce the incidence of BCRL.

Fluorescein Isothiocyanate: A Novel Application for Lymphatic Surgery.

The Lymphatic Microsurgical Preventing Healing Approach (LYMPHA) procedure entails performing a lymphovenous bypass (LVB) at the time of axillary lymph node dissection to reduce lymphedema risk. The two most common fluorophores utilized in LVB are blue dye and indocyanine green. We developed a novel application of fluorescein isothiocyanate for intraoperative lymphatic mapping. Our goal is to demonstrate the safety and efficacy of fluorescein isothiocyanate for this application. We reviewed a prospectively collected database on breast cancer patients who underwent LYMPHA from March to September 2015. Fluorescein isothiocyanate was used to identify arm lymphatic channels after axillary lymph node dissection to perform an LVB between disrupted lymphatics and axillary vein tributaries. Data on preoperative and intraoperative variables were analyzed. Thirteen patients underwent LYMPHA with intraoperative fluorescein isothiocyanate lymphatic mapping from March to September 2015. Average patient age was 50 years with a mean body mass index of 28. On average, 3.4 lacerated lymphatic channels were identified at an average distance of 2.72 cm (range, 0.25-5 cm) caudal to the axillary vein. On average, 1.7 channels were bypassed per patient. Eleven anastomoses were performed to the accessory branch of the axillary vein and 1 to a lateral branch. In 1 patient, a bypass was not performed due to poor lymphatic caliber and inadequate length of the harvested vein tributary. No intraoperative adverse events were noted. Fluorescein isothiocyanate is a safe and effective method for intra-operative lymphatic mapping. Fluorescein isothiocyanate imaging allows for simultaneous dissection and lymphatic visualization, making it an ideal agent for lymphatic mapping and dissection in open surgical fields, such as in the LYMPHA procedure.

Ultrasound-Guided Segmental Mastectomy and Excisional Biopsy Using Hydrogel-Encapsulated Clip Localization as an Alternative to Wire Localization.

BACKGROUND: Wire localization is currently the most widely used localization strategy for excision of nonpalpable breast lesions. Its disadvantages include patient discomfort, wire-related complications such as wire displacement/fracture, and operating room delays related to difficulties during wire placement. We have implemented the technique of intraoperative ultrasound-guided excision using hydrogel-encapsulated (HydroMARK) biopsy clips for lesion localization. We hypothesize that this method is as effective as wire localization for breast conserving therapy. METHODS: This is a retrospective review of 220 consecutive patients who underwent segmental mastectomy or excisional biopsy using wire localization or hydrogel-encapsulated clip localization from January 2014 to July 2015. Data were collected and analyzed. Statistical analyses for differences between groups were performed using t tests and Mann-Whitney rank-sum analyses. RESULTS: A total of 107 excisions were performed using hydrogel-encapsulated clip localization, and 113 excisions were performed using the traditional wire localization technique; 68 % of our patients underwent excision for malignant pathology. Wire placement took a mean of 46 minutes (range 20-180 min), compared with 5 minutes for ultrasound localization (p <  .001). Successful intraoperative ultrasound localization and excision was performed on 100 % of patients. There was no difference in re-excision rates for positive margins or overall specimen size between the two groups. CONCLUSIONS: Intraoperative ultrasound-guided excision of nonpalpable breast lesions using a hydrogel-encapsulated biopsy clip for breast conserving therapy is a safe and feasible alternative to the traditional preoperative wire localized excision. This technique will lead to improvement in patient experience, operative efficiency, and alleviate wire-related complications.

Calciphylaxis of the Breast: A Case Report and Literature Review.

Calciphylaxis, or calcific uremic arteriolopathy, is a rare but particularly morbid condition involving systemic medial calcification of arterioles causing ischemia and subsequent tissue necrosis. Although most commonly occurring over the abdomen and proximal extremities, calciphylaxis can present on nearly any skin surface with a tendency toward areas of increased adiposity. We report a case of a 53-year-old female with end-stage renal disease who presented with bilateral palpable breast masses and overlying skin changes. Diagnostic mammography and percutaneous biopsy of the lesion facilitated the diagnosis of calciphylaxis and she was treated with medical therapy, local wound care, and eventual tissue extirpation. Due to the morbidity attributed to calciphylaxis and associated wound complications, surgical extirpation is at times unavoidable. Once malignancy has been excluded, we recommend nonoperative management with prompt referral to Nephrology for medical optimization, reserving surgical debridement for nonhealing wounds and superinfection.

A Case of a Giant Borderline Phyllodes Tumor Early in Pregnancy Treated with Mastectomy and Immediate Breast Reconstruction.

Breast tumors in pregnancy are often times diagnosed at advanced stages secondary to difficulty distinguishing between pathologic from normal physiologic changes. Often benign, phyllodes tumors are rare fibroepithelial stromal tumors of the breast, most commonly diagnosed in the 4th and 5th decades of life. However, these tumors may be characterized by malignancy with metastases in 10% of cases. In this paper, we report a novel case of a young woman presenting at 8 weeks gestation with a large borderline phyllodes tumor. An exceedingly rare condition, with only nine previously reported cases, phyllodes tumors in pregnancy frequently display more aggressive characteristics with larger median tumor size, more malignant potential, and more rapid growth rate. Here, we describe our experience safely and effectively treating this rare condition in a young gravid women with mastectomy and immediate breast reconstruction in the second trimester.

Surgical excision versus clinical follow-up: Outcomes of benign intraductal papillomas diagnosed on core needle biopsy.

OBJECTIVE: To compare outcomes between benign intraductal papillomas diagnosed on core need biopsy that were excised (BIP-E) versus those that were followed-up (BIP-F) at our institution. METHODS: Patients were identified by an electronic data base search from January 2010 to October 2016. After exclusions, clinical, radiological and histologic variables were evaluated and biopsy and excision slides reviewed. RESULTS: 110 BIP from 104 females were analyzed. 84 BIP were excised and 26 BIP were followed up (mean 43.3 months, range 7-93 months).11 patients in BIP-E group had atypia on excision. There were no statistically significant differences between BIP-E with atypia and BIP-E without, except for clinical presentation with pain/discomfort (p â€‹= â€‹0.015) in the former. There were no true upgrades to malignancy in both groups on follow up. One patient from each group developed a new breast cancer distant from IP site after nearly 4 years of uneventful follow-up. CONCLUSION: Clinical follow up is an oncologically safe alternative for radiologically concordant BIP. Excision may be considered if a diagnosis of atypia would impact surveillence and chemoprevention recommendations.

Evaluation of an Artificial Intelligence System for Detection of Invasive Lobular Carcinoma on Digital Mammography.

Introduction Early breast cancer detection with screening mammography has been shown to reduce mortality and improve breast cancer survival. This study aims to evaluate the ability of an artificial intelligence computer-aided detection (AI CAD) system to detect biopsy-proven invasive lobular carcinoma (ILC) on digital mammography. Methods This retrospective study reviewed mammograms of patients who were diagnosed with biopsy-proved ILC between January 1, 2017, and January 1, 2022. All mammograms were analyzed using cmAssist® (CureMetrix, San Diego, California, United States), which is an AI CAD for mammography. The AI CAD sensitivity for detecting ILC on mammography was calculated and further subdivided by lesion type, mass shape, and mass margins. To account for the within-subject correlation, generalized linear mixed models were implemented to investigate the association between age, family history, and breast density and whether the AI detected a false positive or true positive. Odds ratios, 95% confidence intervals, and p-values were also calculated. Results A total of 124 patients with 153 biopsy-proven ILC lesions were included. The AI CAD detected ILC on mammography with a sensitivity of 80%. The AI CAD had the highest sensitivity for detecting calcifications (100%), masses with irregular shape (82%), and masses with spiculated margins (86%). However, 88% of mammograms had at least one false positive mark with an average number of 3.9 false positive marks per mammogram. Conclusion The AI CAD system evaluated was successful in marking the malignancy in digital mammography. However, the numerous annotations confounded the ability to determine its overall accuracy and this reduces its potential use in real-life practice.

COVID-19 Associated Micro-Anastomotic Thrombosis After Abdominal Free Tissue Transfer: A Case Report and Literature Review.

The hypercoagulable state of COVID-19 infection presents a challenge to microsurgeons. While the American Society of Anesthesiologists recommends deferring surgery for 4-10 weeks for COVID-19-infected patients, little else is known regarding how to mitigate thrombotic complications for patients undergoing free tissue transfer. Here, we present a presumed COVID-19-induced hypercoagulable state in a patient undergoing abdominally based free tissue transfer for breast reconstruction as a brief review of the literature to guide clinical decision making.

L'état d'hypercoagulabilité de l'infection par le virus de la COVID-19 représente un défi pour la micro-chirurgie. L'American Society of Anesthesiologists recommande de retarder la chirurgie de 4 à 10 semaines chez les patients infectés par la COVID, mais on sait peu de choses sur comment réduire les complications thrombotiques chez les patients subissant un transfert de tissu libre. Nous présentons ici un état d'hypercoagulabilité présumé induit par la COVID chez un patient subissant un transfert de tissu libre d'origine abdominale pour reconstruction mammaire comme brève revue des publications pour guider la prise de décision clinique.

The Incidence of Retained Objects in Intraoperative X-rays for Missing Counts in Plastic Surgery: We Should Do Better.

Background: In the event of incorrect surgical counts, obtaining X-rays to rule out retained surgical items (RSI) is standard practice. However, these safeguards also carry risk. This study investigates the actual incidence of RSI in plastic reconstructive surgery (PRS) cases as measured on intraoperative X-rays and its associated modifiable risk factors. Methods: X-rays with indication of "foreign body" in PRS procedures from 2012 to 2022 were obtained. Reports with "incorrect surgical counts" and associated perioperative records were retrospectively analyzed to determine the incidence of retained surgical items. Results: Among 257 X-rays, 21.4% indicated incorrect counts during PRS operations. None were positive for RSIs. The average number of staff present was 12.01. This correlated to an average of 6.98 staff turnovers. The average case lasted 8.42 hours. X-rays prolonged the time under anesthesia by an average of 24.3 minutes. Free flap surgery had 49.1% prevalence of missing counts (lower extremity 25.5%, breast 20%, craniofacial 3.6%), followed by hand (14.5%), breast (10.9%), abdominal reconstruction (10.9%), craniofacial (9.1%), and cosmetic (5.4%). Conclusions: Although X-rays for incorrect counts intend to prevent catastrophic sequela of inadvertent RSIs, our results suggest the true incidence of RSI in PRS is negligible. However, intraoperative X-rays have potentially detrimental and pervasive consequences for patients, including increased anesthesia time, radiation exposure, and higher overall cost. Addressing modifiable risk factors to minimize unnecessary intraoperative X-rays is imperative while also considering whether this modality is an effective and appropriate tool in PRS procedures with incorrect surgical counts.

The Novel Use of Magtrace in Chest Masculinizing Transgender Top Surgery.

Chest masculinization is the most common surgery performed in transgender men, and although incidence of occult cancer is lower than in cis-gender women receiving mastectomy or reduction mammoplasties, the incidence of high-risk lesions is comparable. In patients with concerns for occult malignancy, Magtrace is a nonradioactive tracer available to assist management for its delayed sentinel lymph node mapping capabilities. We present the first case report using Magtrace before masculinizing mastectomies in a transgender man.

Comparison of Aesthetic Outcomes of Epidermal Staples vs Sutures in Deep Epigastric Perforator Flap Breast Reconstruction.

Background: A secondary benefit of abdominally based autologous breast reconstruction may be improving the abdominal contour; however, poor scaring can lead to aesthetic dissatisfaction and complications. Although studies have demonstrated favorable aesthetic results and decreased operative time using dermal or subcuticular stapling (Insorb), no reports exist regarding epidermal stapling. Objectives: The aim of this study is to compare the aesthetic abdominal scar outcomes, closure time, and postoperative complications of abdominally based breast reconstruction patients who have undergone suture closure vs epidermal staple closure. Methods: A total of 217 patients who underwent abdominally based autologous breast reconstruction from 2011 to 2022 were included and retrospectively analyzed (staples = 41, suture = 176). Twenty-four patients' postoperative abdominal scar photographs were randomly chosen (staples = 12, sutures = 12) and assessed by 3 board-certified plastic surgeons using a modified patient observer scar assessment scale (POSAS) and visual analog scale (VAS). Closure time (minutes per centimeter) using staples or sutures was also analyzed. Results: The assessment of abdominal scars closed by epidermal staples revealed significant improvements in thickness (P = .033), relief (P = .033), surface area (P = .017), overall opinion (P = .033), POSAS score (P = .034), and VAS scar score (P = .023) in comparison with scars closed by sutures. Closing the abdominal wound with staples was significantly faster than closing with sutures (P < .0001). Staple and suture closure had similar postoperative complication rates. Conclusions: Abdominal donor-site scar quality may be superior and faster using the epidermal staple compared to traditional suture closure.

Closed Incision Negative Pressure Therapy in Oncoplastic Surgery Prevents Delays to Adjuvant Therapy.

Breast reductions, including oncoplastic breast surgery (OBS), have high postoperative wound healing complication (WHC) rates, ranging from 17% to 63%, thus posing a potential delay in the onset of adjuvant therapy. Incision management with closed incision negative pressure therapy (ciNPT) effectively reduces postoperative complications in other indications. This retrospective analysis compares postoperative outcomes and delays in adjuvant therapy in patients who received ciNPT on the cancer breast versus standard of care (SOC) after oncoplastic breast reduction and mastopexy post lumpectomy. Methods: Patient demographics, ciNPT use, postoperative complication rates, and time to adjuvant therapy were analyzed from the records of 150 patients (ciNPT = 29, SOC = 121). Propensity score matching was used to match patients based on age, body mass index, diabetes, tobacco use, and prior breast surgery. Results: In the matched cohort, the overall complication rate of ciNPT-treated cancerous breasts was 10.3% (3/29) compared with 31% (9/29) in SOC-treated cancerous breasts (P = 0.096). Compared with the SOC-treated cancerous breasts, the ciNPT breasts had lower skin necrosis rates [1/29 (3.4%) versus 6/29 (20.7%); P = 0.091] and dehiscence rates [0/29 (0%) versus 8/29 (27.6%); P = 0.004]. In the unmatched cohort, the total number of ciNPT patients who had a delay in adjuvant therapy was lower compared to the SOC group (0% versus 22.5%, respectively; P = 0.007). Conclusion: Use of ciNPT following oncoplastic breast reduction effectively lowered postoperative wound healing complication rates and, most importantly, decreased delays to adjuvant therapy.

Young Adult Caregiving Daughters and Diagnosed Mothers Navigating Breast Cancer Together: Open and Avoidant Communication and Psychosocial Outcomes.

For many diagnosed mothers and their daughters, breast cancer is a shared experience. However, they struggle to talk about cancer. This is particularly true when the daughter is in adolescence or young adulthood, as they tend to be more avoidant, which is associated with poorer biopsychosocial outcomes. When daughters are their mother's caregivers, daughters' burden and distress are heightened. Young adult caregiving daughters (YACDs) are the second most common family caregiver and encounter more distress and burden than other caregiver types. Yet, YACDs and their diagnosed mothers receive no guidance on how to talk about cancer. Thirty-nine mother/YACD pairs participated in an online survey to identify challenging topics and strategies for talking about cancer, and to explore associations between openness/avoidance and psychosocial outcomes. YACDs and mothers reported the same challenging topics (death, treatment-related issues, negative emotions, relational challenges, YACDs' disease risk) but differed on why they avoided the topic. YACDs and mothers identified the same helpful approaches to navigate conversations (openness, staying positive, third-party involvement, avoidance). Avoidance was correlated with more distress whereas openness was correlated with better psychosocial outcomes. These results provide a psychosocial map for a mother-YACD communication skills intervention, which is key to promoting healthy outcomes.

Proton Therapy for Bilateral Breast Cancer Maximizes Normal-Tissue Sparing.

Purpose: Treatment for bilateral breast cancer with radiation therapy is technically challenging. We evaluated the clinical and dosimetric outcomes of a small series of patients with synchronous bilateral breast cancer, including a photon dosimetric comparison, to identify optimal treatment planning approaches. Materials and Methods: We reviewed a registry of patients (simultaneously) diagnosed with synchronous bilateral breast cancers who underwent postoperative definitive adjuvant proton therapy at our institution between 2012 and 2021. All patients were treated with double-scattered proton or pencil-beam scanning therapies. For comparison, intensity-modulated radiation therapy photon plans optimized for organ sparing and coverage were generated after treatment. Results: Six patients were included. The median patient age was 66 years; all were female with no history of breast cancer or radiation therapy. Two (33%) patients received breast/chest wall-only treatments, 1 (17%) required breast plus level I axillary treatment to one side and breast plus regional nodal irradiation (RNI) to the other, and 3 (50%) received bilateral breast/chest plus RNI; dosimetric results are reported for each group's median. Analysis showed clinical target coverage was comparable between proton and photon techniques (V95% of 96.4% with proton, 97.8% with photon). However, protons could deliver superior organ sparing at clinically relevant dose metrics for virtually all structures: a 6.7 Gy absolute reduction in the mean heart dose (7.5 Gy with photons to 0.7 Gy with protons), a 47% to 57% relative reduction in D0.1cm3 to coronary arteries, a 54% relative reduction in lung V20 Gy, and an absolute 7.6 Gy reduction to the brachial plexus. There was also greater esophagus and spinal cord sparing. The overall survival rate was 100% at 1.5 years of median follow-up (0.5-4.9), and all patients were free of disease. For toxicity, all patients had some form of acute side effects: 66% experienced grade 2 breast/chest pain or soreness; 100% had grade 2 radiation dermatitis or skin induration; 33% had grade 2 fatigue; and 17% had grade 2 esophagitis (per the Common Terminology Criteria for Adverse Events [CTCAE] version 5.0; US National Cancer Institute, Bethesda, Maryland). Subacute toxicity (within 6 months) was observed for 17% of patients with delayed onset of grade 3 dermatitis in the setting of preexisting lupus, 17% with a delayed surgical wound complication, and 17% with grade 2 soft tissue fibrosis. No grade 4 or 5 events were observed. Conclusions: Substantial dose reductions to multiple organs at risk while maintaining target coverage make proton the preferred modality for bilateral breast cancer treatment when available.