Silicone Shell Breast Implants in Patients Undergoing Risk-Reducing Mastectomy With a History of Breast-Conserving Surgery and Adjuvant Radiotherapy: A Long-term Study.

BACKGROUND: Indications for breast-conserving surgery and adjuvant radiotherapy (BCSAR) in patients with breast carcinoma are increasing, as are indications for risk-reducing mastectomy (RRM) in healthy subjects. Most of these cases are reconstructed with silicone shell breast implants (SSBIs). OBJECTIVES: The aim of this work was to study complications of SSBIs in breast reconstruction in patients undergoing RRM with previous BCSAR. METHODS: A prospective cohort study was designed. The study group included cases of RRM reconstructed with SSBI in patients who had previously undergone BCSAR in the same breast. The control group consisted of patients with high-risk breast cancer who had undergone RRM and immediate SSBI reconstruction without previous BCSAR. RESULTS: There was a history of BCSAR in 15.8% of cases. The first SSBI used in immediate reconstruction after RRM was replaced in 51.5% of cases with a mean [standard deviation] survival of 24.04 [28.48] months. BCSAR was significantly associated with pathological capsular contracture (P = .00) with this first SSBI (37.5% vs 5.9%). Of the cases requiring the replacement of the first SSBI, 44.23% suffered failure of the second SSBI, with a mean survival of 27.95 [26.53] months. No significant association was found between the consecutive development of capsular contracture in the second SSBI and a previous history of BCSAR (P = .10). CONCLUSIONS: BCSAR prior to RRM reconstructed with an SSBI is associated with a significant increase in pathological capsular contracture. Patients should be warned of the high rate of SSBI complications and reconstruction failure. Polyurethane-coated implants may provide an alternative in cases in which alloplastic reconstruction is considered in patients with previous BCSAR.

A novel carbon-fibre adjustable reusable accessory (CARA) for supine breast positioning to reduce toxicity in breast adjuvant radiotherapy: a study protocol for a multicentre phase III randomized controlled trial.

BACKGROUND: A novel device for supine positioning in breast radiotherapy for patients with large or pendulous breasts has been developed and tested in phase II studies. This trial is designed to assess the efficacy of the device to reduce skin toxicity and unwanted normal tissue dose in comparison to the current clinical standard for supine breast support during breast radiotherapy. METHODS: Patients at high risk for moist desquamation, having infra-mammary fold or lateral ptosis, will be randomized into two arms. Patients in the control arm will receive breast radiotherapy with supine positioning using current standard of care. Patients in the experimental arm will be positioned supine with the novel device. The primary endpoint is the incidence of moist desquamation in the infra-mammary fold. We hypothesize a 20% reduction (from 50 to 30%) in the rate of moist desquamation in the study arm versus the control arm. For 80% power, two-tailed α = 0.05 and 10% loss to follow up, 110 patients will be assigned to each arm. The proportion of patients experiencing moist desquamation in the two arms will be compared using logistic regression adjusting for brassiere cup size, skin fold size, body mass index, smoking status, and dose fractionation schedule. An unadjusted comparison will also be made using the chi-square test, or Fisher's exact test, if appropriate. Secondary endpoints include dose-volume statistics for the lung and heart, skin dose and clinical parameters including setup time, reproducibility, and staff experience with setup procedures. Patient-reported pain, skin condition interference with sleep and daily activities, and comfort during treatment are also secondary endpoints. DISCUSSION: Based on results from earlier phase II studies, it is expected that the device-enabled elimination of infra-mammary fold should reduce toxicity and improve quality of life for this patient population. Earlier studies showed reduction in dose to organs at risk including lung and heart, indicating potential for other long-term benefits for patients using the device. This study is limited to acute skin toxicity, patient-reported outcomes, and clinical factors to inform integration of the device into standard breast radiotherapy procedures. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT04257396 . Registered February 6 2020.

Breast conserving surgery using oxidized regenerated cellulose as filling biomaterial: recommendations to improve clinical outcomes.

Oxidized regenerated cellulose is considered an optimal local hemostatic agent thanks to its favorable biocompatibility, absorption characteristics and ease-of-use. Recently, oxidized regenerated cellulose has also been used as a filler in breast conserving surgery with a reconstructive purpose in order to repair partial breast defects and improve aesthetic outcomes. However, some postoperative problems due to its use, such as allergic reactions, seroma, foreign-body reaction and misdiagnosis during the follow-up of breast cancer patients, have been shown. These possible surgical complications can undermine clinical outcomes and lead to delay the beginning of oncological treatments with a negative impact on patient quality of life and survival. An adequate surgical expertise and the compliance with some specific recommendations are crucial in order to minimize postoperative issues and optimise aesthetic outcomes.

Alveolar soft part sarcoma metastatic to the breast: a case report.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is an extremely rare neoplasm that tends to occur in the lower limbs of children and adolescents. Metastatic breast tumors constitute 0.5-2.0% of all malignant mammary neoplasms, and cases of ASPS with mammary metastases are very rare. CASE PRESENTATION: Three years ago, an 11-year-old girl presented to the hospital with pain in the right jaw after becoming aware of a mass in the right cheek. After detailed examination, the patient was diagnosed with ASPS with the primary tumor in the right cheek and multiple lung metastases, and chemotherapeutic treatment was initiated. One year later, accumulation of fluorodeoxyglucose (FDG) was observed in the right front of the skull (standardized uptake value (SUV)-max 2.8) and left breast (SUV-max 2.4) using FDG-positron emission tomography (PET) / computed tomography (CT). Ultrasonography revealed the mammary tumor as a hypoechoic, internally heterogeneous mass measuring 22.4 × 16.2 × 21.1 mm with a rich blood supply. Using pathological findings of core-needle biopsy, we diagnosed it as ASPS. Based on the above information, we made a diagnosis of ASPS with left mammary and cranial metastases. Due to chemoresistance, surgical excision was selected as the mode of treatment; resection of the metastatic cranial bone was performed first, and partial mastectomy of the left breast was performed in two stages. Postoperative conditions were good, and we are currently performing regular follow-ups (visual palpation every 3 months and semi-annual mammary gland ultrasonography). CONCLUSIONS: We have reported an extremely rare case of ASPS with mammary metastasis with some reference-based discussion. In our case, disease control was obtained by a combination of drug therapy and surgical treatment.

Prophylactically applied Hydrofilm polyurethane film dressings reduce radiation dermatitis in adjuvant radiation therapy of breast cancer patients.

PURPOSE: Radiation-induced skin injury represents one of the most common side effects in breast cancer patients receiving adjuvant whole-breast radiotherapy. Numerous systemic and topical treatments have been studied in the prevention and management of radiation-induced skin injury without providing sustainable treatment strategies. While superficial barrier-forming skin products such as dressings are the standard of care in wound care management, their utilization as preventive treatment approach in radiotherapy has barely attracted attention. METHODS: In this prospective, intra-patient randomized study, Hydrofilm polyurethane film dressings were applied prophylactically to either the medial or lateral breast half of 62 patients with breast cancer undergoing adjuvant radiation therapy following breast conserving surgery. The breast half contralateral to the film dressing was concurrently treated with 5% urea lotion as control skin care. Maximum severity of radiation dermatitis was assessed using RTOG/EORTC toxicity scores, photospectrometric erythema measurements and patient-assessed modified RISRAS scale. RESULTS: In the Hydrofilm compartments, mean maximum RTOG/EORTC radiation dermatitis severity grades were significantly reduced from 1.33 to 0.35 and photospectrometric measurements showed significantly reduced erythema severity, as compared to the control compartments, with an overall response rate of 89.3%. Hydrofilm completely prevented moist desquamation and significantly reduced patients' subjective experience of itching and pain. CONCLUSION: The obtained results along with a favorable cost-benefit ratio and an easy and quick application suggest a prophylactic application of Hydrofilm in adjuvant radiotherapy of breast cancer patients to reduce or even prevent radiation dermatitis.

Breast cancer in a patient with Kindlers syndrome.

Breast Cancer (BC) has associated risk factors and genetic factors like BRCA1, and BRCA2. Many benign and malignant disease processes are found concurrently with BC and believed to be additional risk factors like gall bladder stones (cholelithiasis), hypertension, diabetes mellitus, cerebrovascular lesions, arthritis, spine and spinal cord degenerative lesions, infertility, depression, sleep disturbances, obesity, autoimmune diseases (SLE), and thyroid diseases. There are some malignant disease associations like synchronous or metachronous ovarian, colonic and endometrial tumours with Breast cancer. Kindler Syndrome (KS) is a rare autosomal recessive genetic disorder manifesting as generalized dermatoses, described in 1954 by Theresa Kindler. KS is associated with acral skin blistering inducible by trauma, mucosal inflammation, photosensitivity, progressive pigmentation, telangiectasia, and skin atrophy (Poikiloderma). Repeated and progressive inflammation and subsequent fibrosis leads to ectropion, esophageal, anal, urethral, and vaginal stenosis and dryness. About 100 cases of Kindler syndrome have been reported in literature so far some from Arab World as well. Pathobiology of Kindler syndrome is not well understood. There are defects in KIND1 gene on chromosome 20. This gene expresses itself in basal keratinocytes, where it encodes a protein, called Kindlin 1. We report the second only case of Kindler's syndrome having breast cancer. These very very rare combinations have diagnostic issues, management restrictions, prognostic and follow up implications.

[Diagnosis and treatment for Paget's breast cancer: state of the art].

Breast cancer is the most common cancer in women. According to WHO experts in the world each year there are revealed from 800,000 up to 1 million new cases of breast cancer. In the structure of malignant tumors morbidity among female population, in Russia in 2012 breast cancer ranked the first place (20.7%) and remained the leading malignant pathology in women. Paget's breast cancer is a rare form of breast cancer that occurs in the mouth of the excretory ducts of the nipple, which characterized by lesion of the nipple and large ducts, often with the formation of tumor in the breast. This rare abnormality occurs in 0.5-5% of all cases of breast cancer.

Cell-free biomimetic polyurethane-based scaffold for breast reconstruction following non-malignant lesion resection. A first-in-human study.

BACKGROUND: Based on the volume of tissue removed, conservative surgery (BCS) cannot always guarantee satisfactory cosmetic results, unless resorting to more complex oncoplastic approaches. Investigating an alternative to optimize aesthetic outcomes minimizing surgical complexity, was the purpose of this study. We assessed an innovative surgical procedure based on the use of a biomimetic polyurethane-based scaffold intended for regenerating soft-tissue resembling fat, in patients undergoing BCS for non-malignant breast lesions. Safety and performance of the scaffold, and safety and feasibility of the entire implant procedure were evaluated. METHODS: A volunteer sample of 15 female patients underwent lumpectomy with immediate device positioning, performing seven study visits with six-month follow-up. We evaluated incidence of adverse events (AEs), changes in breast appearance (using photographs and anthropomorphic measurements), interference with ultrasound and MRI (assessed by two independent investigators), investigator's satisfaction (through a VAS scale), patient's pain (through a VAS scale) and quality of life (QoL) (using the BREAST-Q© questionnaire). Data reported are the results of the interim analysis on the first 5 patients. RESULTS: No AEs were device related nor serious. Breast appearance was unaltered and the device did not interference with imaging. High investigator's satisfaction, minimal post-operative pain and positive impact on QoL were also detected. CONCLUSIONS: Albeit on a limited number of patients, data showed positive outcomes both in terms of safety and performance, paving the way to an innovative breast reconstructive approach with a potential remarkable impact on clinical application of tissue engineering. TRIAL REGISTRATION: ClinicalTrials.gov (NCT04131972, October 18, 2019).

Tumor-targeting semiconducting polymer nanoparticles: efficient adjuvant photothermal therapy using ultra-low laser power inhibits recurrences after breast-conserving surgery.

The need for adjuvant therapy to inhibit local recurrence after breast-conserving surgery with minimal side effects is great. Adjuvant photothermal therapy (aPTT) has the potential to replace radiotherapy and eliminates its inherent damage to healthy tissues. Herein, we functionalized semiconducting polymer nanoparticles (SPNs) with cRGD-peptide and silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (NIR775) to target breast cancer and perform aPTT under an ultra-low laser power (0.2 W cm-2) after breast-conserving surgery (BCS). The synthesized RGD-SPNNIR775 showed an excellent photothermal conversion efficiency and biocompatibility and was demonstrated to accumulate in tumors specifically. The BCS could be performed with confidence under the guidance of preoperative and postoperative fluorescence imaging. Notably, the aPTT completely inhibited the local recurrence after the BCS without compromising the cosmetic effect of the BCS. These results indicate the prospect of RGD-SPNNIR775 as a theranostic nanoplatform for efficient aPTT using an ultra-low laser power to control recurrence after BCS.

Feasibility of eradication of breast cancer cells remaining in postlumpectomy cavity and draining lymph nodes following intracavitary injection of radioactive immunoliposomes.

Most diagnosed early stage breast cancer cases are treated by lumpectomy and adjuvant radiation therapy, which significantly decreases the locoregional recurrence but causes inevitable toxicity to normal tissue. By using a technique of preparing liposomes carrying technetium-99m ((99m)Tc), rhenium-186 ((186)Re), or rhenium-188 ((188)Re) radionuclides, as well as chemotherapeutic agents, or their combination, for cancer therapy with real time image-monitoring of pharmacokinetics and prediction of therapy effect, this study investigated the potential of a novel targeted focal radiotherapy with low systemic toxicity using radioactive immunoliposomes to treat both the surgical cavity and draining lymph nodes in a rat breast cancer xenograft positive surgical margin model. Immunoliposomes modified with either panitumumab (anti-EGFR) or bevacizumab (anti-VEGF) were remote loaded with (99m)Tc diagnostic radionuclide, and injected into the surgical cavity of female nude rats with positive margins postlumpectomy. Locoregional retention and systemic distribution of (99m)Tc-immunoliposomes were investigated by nuclear imaging, stereofluorescent microscopic imaging, and gamma counting. Histopathological examination of excised draining lymph nodes was performed. The locoregional retention of (99m)Tc-immunoliposomes in each animal was influenced by the physiological characteristics of the surgical site of individual animals. Panitumumab- and bevacizumab-liposome groups had higher intracavitary retention compared with the control liposome groups. Draining lymph node uptake was influenced by both the intracavitary radioactivity retention level and metastasis status. The panitumumab-liposome group had higher accumulation on the residual tumor surface and in the metastatic lymph nodes. Radioactive liposomes that were cleared from the cavity were metabolized quickly and accumulated at low levels in vital organs. Therapeutic radionuclide-carrying specifically targeted panitumumab- and bevacizumab-liposomes have increased potential compared to non-antibody targeted liposomes for postlumpectomy focal therapy to eradicate remaining breast cancer cells inside the cavity and draining lymph nodes with low systemic toxicity.

Evaluation of a hydrogel based breast biopsy marker (HydroMARK®) as an alternative to wire and radioactive seed localization for non-palpable breast lesions.

BACKGROUND AND OBJECTIVES: HydroMARK® is a newly available biopsy marker for image-guided needle biopsies of non-palpable breast lesions. Objective was to determine if the marker could be utilized independently for lesion localization using intra-operative ultrasound alone. METHODS: A single institution retrospective review identified patients who underwent surgical excision of breast lesions after placement of the HydroMARK®. Endpoints included intra-operative visualization of the marker, successful excision of the lesion, and presence of the marker on specimen radiograph. RESULTS: The study included 31 lesions in 25 patients. Twenty-nine (93.6%) HydroMARKSs® were adequately visualized by intra-operative ultrasound. Intra-operative ultrasound without pre-operative placement of a localizing device was successful for localization in six cases (19.4%). Intra-operative difficulties were encountered in 16 of 31 (51.6%) procedures. This included either extrusion of the marker when the biopsy tract was transected in 14 (45.2%) cases or migration of the marker prior to the procedure in two (6.4%) cases. The marker was visualized on specimen radiograph in 15 (48.4%) cases. CONCLUSIONS: While intraoperative sonographic visibility was excellent, a large number of excisions were associated with extrusion of the marker. Modifications are needed to improve acceptability of this marker for intra-operative localization independent of pre-operative wire or seed localization.

Outcomes of breast conserving surgery with immediate vicryl-mesh insertion: is it safe and effective?

Although breast-conserving surgery (BCS) has become a standard for breast-cancer surgery with improved cosmetic outcomes, there have been many attempts to achieve superior results. Vicryl-mesh insertion, one such method, is a simple technique involving a relatively short period of time. However, doubts regarding its safety and efficacy remain. Therefore, we attempted to analyze the aesthetic outcomes, patient satisfaction, and safety with respect to Vicryl mesh. From May 2007 to March 2009, 38 patients underwent BCS with immediate Vicryl-mesh insertion at Ewha Womans University Mokdong Hospital, Seoul, Korea. In the same period, 31 patients who underwent BCS for breast cancer were randomly selected as a control group. Five patients who underwent BCS with Vicryl-mesh insertion were excluded because they were lost to follow-up shortly after surgery. Retrospective analysis of patient records and oral interviews were performed. We analyzed patients' overall satisfaction, postoperative satisfaction with breast shape, pain, and postoperative complications in the two groups. The mean age, body mass index, follow-up period, specimen size, and ratio of benign to malignant tumors did not differ significantly between the two groups. With regard to tumor location, more tumors were in the upper and lower inner portions of the breast among patients who underwent BCS with Vicryl mesh. There were no significant differences in overall satisfaction or satisfaction with breast shape (p > 0.05), but differences in pain scores were significant (p = 0.016). In terms of the complication rate, four cases with complications (11.8%) were observed in the Vicryl-mesh group and no complications in the BCS-only group. Vicryl-mesh insertion showed a higher complication rate and no cosmetic gain. Therefore, we believe that Vicryl-mesh insertion should be performed carefully. In addition, studies involving many more cases and longer follow-up periods are needed.

A pilot multi-institutional study to evaluate the accuracy of a supine MRI based guidance system, the Breast Cancer Locator™, in patients with palpable breast cancer.

BACKGROUND: Evaluate whether the Breast Cancer Locator™ (BCL), a novel guidance system based on supine MRI images, can be safely and effectively deployed by several surgeons at multiple sites. METHODS: Patients with palpable breast cancer underwent supine MRI at their local institution. A three dimensional (3D) digital image of the tumor in the breast was derived from supine MRI images and used to generate 1) an interactive 3D virtual image of the tumor in the breast (Visualizer) and 2) a plastic bra-like form that allowed the surgeon to place a central wire and bracketing wires in the breast (BCL). The primary objective was to determine the proportion of patients who had the central localization wire deployed within the cancer on specimen mammogram. RESULTS: Fourteen patients were enrolled at 4 different sites by 6 surgeons. BCLs were successfully manufactured for all patients. The central wire was deployed within the tumor on specimen mammogram in 12 of the 13 patients who had a central wire placed (92%). The cancer was excised with negative margins in 14/14 cases (100%). No adverse events occurred. CONCLUSIONS: Supine MRI image acquisition was accomplished successfully across multiple sites. Multiple surgeons utilized the BCL system to localize cancers accurately and safely.

Post-lumpectomy intracavitary retention and lymph node targeting of (99m)Tc-encapsulated liposomes in nude rats with breast cancer xenograft.

Liposomes are recognized drug delivery systems with tumor-targeting capability. In addition, therapeutic or diagnostic radionuclides can be efficiently loaded into liposomes. This study investigated the feasibility of utilizing radiotherapeutic liposomes as a new post-lumpectomy radiotherapy for early-stage breast cancer by determining the locoregional retention and systemic distribution of liposomes radiolabeled with technetium-99m ((99m)Tc) in an orthotopic MDA-MB-231 breast cancer xenograft nude rat model. To test this new brachytherapy approach, a positive surgical margin lumpectomy model was set up by surgically removing the xenograft and deliberately leaving a small tumor remnant in the surgical cavity. Neutral, anionic, and cationic surface-charged fluorescent liposomes of 100 and 400 nm diameter were manufactured and labeled with (99m)Tc-BMEDA. Locoregional retention and systemic distribution of (99m)Tc-liposomes injected into the post-lumpectomy cavity were determined using non-invasive nuclear imaging, ex vivo tissue gamma counting and fluorescent stereomicroscopic imaging. The results indicated that (99)Tc-liposomes were effectively retained in the surgical cavity (average retention was 55.7 ± 24.2% of injected dose for all rats at 44 h post-injection) and also accumulated in the tumor remnant (66.9 ± 100.4%/g for all rats). The majority of cleared (99m)Tc was metabolized quickly and excreted into feces and urine, exerting low radiation burden on vital organs. In certain animals (99m)Tc-liposomes significantly accumulated in the peripheral lymph nodes, especially 100 nm liposomes with anionic surface charge. The results suggest that post-lumpectomy intracavitary administration of therapeutic radionuclides delivered by 100-nm anionic liposome carrier is a potential therapy for the simultaneous treatment of the surgical cavity and the draining lymph nodes of early-stage breast cancer.

Progress of radiotherapy after breast-conserving surgery combined with silicone prosthesis reconstruction.

Breast cancer is the malignant tumor with the highest incidence in women. The standard treatment for early breast cancer is radical surgery combined with radiotherapy, but many studies have shown that adjuvant radiotherapy after breast-conserving surgery combined with silicone prosthesis reconstruction is gradually expected to become the new standard treatment because this method can obtain a good local tumor control rate, and has a cosmetic effect. Compared with myocutaneous flap reconstruction, silicone prosthesis implantation has the advantages of less trauma, simple operation, beautiful appearance, and no overlap of donor areas during reconstruction. It is a safe and feasible surgical method without worrying about necrosis and atrophy of myocutaneous flap. This emerging combination therapy may become the best mode of early breast cancer treatment.

Method to prevent the target volume from escaping out of the field in breast irradiation: Forming a "fall-off margin".

OBJECTIVES: We aimed to obtain data that would enable the selection of the appropriate radiotherapy technique for whole breast irradiation (WBI) based on patients' physical characteristics and to evaluate the benefit of the new fall-off (FO) margin technique. MATERIALS AND METHODS: Ten patients with left-sided breast-conserving surgery, treated for breast carcinoma between August 2016 and September 2017, were included. The FO margin was created in five different plans of which two were formed by expanding the target volume out of the skin. The dose evaluation planning was statistically compared by calculating the target volume dosimetric parameters and the doses received by the organs at risk (OARs) for each technique. The volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy plans were considered ideal for WBI homogeneity and conformity indices, while the three-dimensional conformal radiotherapy (3DCRT) plan was considered nonideal. RESULTS: The increase in the breast x-axis length values and equivalent spherical diameter (ESD) dimension decreased the ideal value, whereas the increase in y-axis length values and ESD dimension correlated significantly with the D98 increase. The techniques were significantly correlated with OARs, such as V5, heart max, left anterior descending artery maximum, ipsilateral lung V5 and V20, and contralateral breast V5. Monitor unit values were significantly low in the 3DCRT and VMAT plans. CONCLUSION: The new FO margin structure will have benefits for practical application because the head designs of linear accelerators and collimators and the target-Jaw/MLC distance are adjacent to the breast tissue, which moves during treatment.

Fibrin glue reduces the duration of lymphatic drainage after lumpectomy and level II or III axillary lymph node dissection for breast cancer: a prospective randomized trial.

This randomized prospective study investigated the effect of fibrin glue use on drainage duration and overall drain output after lumpectomy and axillary dissection in breast cancer patients. A total of 100 patients undergoing breast lumpectomy and axillary dissection were randomized to a fibrin glue group (N=50; glue sprayed onto the axillary dissection site) or a control group (N=50). Outcome measures were drainage duration, overall drain output, and incidence of seroma. Overall, the fibrin glue and control groups were similar in terms of drainage duration, overall drain output, and incidence of seroma. However, subgroup analysis showed that fibrin glue use resulted in a shorter drainage duration (3.5 vs. 4.7 days; p=0.0006) and overall drain output (196 vs. 278 mL; p=0.0255) in patients undergoing level II or III axillary dissection. Fibrin glue use reduced drainage duration and overall drain output in breast cancer patients undergoing a lumpectomy and level II or III axillary dissection.

Injectable hydrogels for the sustained delivery of a HER2-targeted antibody for preventing local relapse of HER2+ breast cancer after breast-conserving surgery.

A high risk of local relapse is the main challenge of HER2+ breast cancer after breast-conserving surgery. We aimed to develop a long-acting delivery system for Herceptin, a HER2-targeting antibody, using injectable and thermosensitive hydrogels as the carrier to prevent the local relapse of HER2+ breast tumors while minimizing systemic side effects, especially cardiotoxicity. Methods: Two poly(lactic acid-co-glycolic acid)-b-poly(ethylene glycol)-b-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers with different PEG/PLGA proportions were synthesized. Their mixtures with rational mix proportions displayed sol-gel transitions in water with rising of temperature and the Herceptin-loaded hydrogel systems were then prepared. Both the in vivo antitumor and anti-relapse efficacies were evaluated after hypodermic injection of the Herceptin-loaded hydrogel, and the cardiotoxicity was also detected. Results: The gel performance, degradation rate and drug release kinetics of hydrogels were easily adjustable by simply varying the mix proportion. The hydrogel matrix with a specific mix proportion not only avoided initial burst release but also achieved sustained release of Herceptin in vitro for up to 80 days, which is the longest period of Herceptin delivery that has ever been reported. In vivo biodistribution studies performed in SK-BR-3 tumor-bearing mice revealed that a single hypodermic administration of the Herceptin-loaded hydrogel adjacent to the tumor tissue promoted the intratumoral antibody accumulation. This resulted in a better antitumor efficacy compared to weekly hypodermic injections of Herceptin solution for 28 days. A tumor relapse model was also established by imitative breast-conserving surgery on tumor-bearing mice, and both the single injection of the Herceptin-loaded hydrogel and the weekly injection of the Herceptin solution achieved superior anti-relapse efficacy. Furthermore, both antitumor and anti-relapse experiments demonstrated that the weekly pulsed administration of the Herceptin solution caused cardiotoxicity; however, the sustained release of Herceptin from the hydrogel effectively prevented this side effect. Conclusion: The Herceptin-loaded hydrogel has great potential for preventing the relapse of HER2+ breast tumors after breast-conserving surgery with enhanced therapeutic efficacy, improved patient compliance and significantly reduced side effects.