A Propensity Score-matched Analysis of Long-term Oncologic Outcomes After Nipple-sparing Versus Conventional Mastectomy for Locally Advanced Breast Cancer.

OBJECTIVES: To compare the long-term oncologic outcomes of nipple-sparing mastectomy (NSM) with those of conventional mastectomy (CM) in patients with locally advanced breast cancer (LABC) receiving neoadjuvant chemotherapy (NACT). SUMMARY OF BACKGROUND DATA: NSM has been increasingly implemented in patients with breast cancer. However, oncologic efficacy of NSM in patients with LABC has not been sufficiently demonstrated. METHODS: The study group comprised 850 patients with clinical stage IIB to IIIC breast cancer who underwent NACT followed by either NSM and immediate breast reconstruction or CM alone. After propensity score-matching, 418 patients were included in the analysis. Local recurrence-free survival, disease-free survival (DFS), distant metastasis-free survival, and overall survival (OS) rates were calculated using the Kaplan-Meier method and compared using log-rank tests between the NSM and CM groups. RESULTS: After matching, the mean follow-up period was 70 ± 25 months for the NSM group and 74 ± 27 months for the CM group ( P = 0.181). There were no significant differences between the groups in terms of 6-year local recurrence-free survival (91.6% vs. 95.8%; P = 0.239), DFS (70.5% vs. 73.4%; P = 0.583), distant metastasis-free survival (79.8% vs. 77.4%; P = 0.320), or OS (87.6% vs. 84.8%; P = 0.465) rates. Additionally, we identified 30 patients in the NSM group who initially presented with tumor extension in the subareolar area; the nipple-areola complex was successfully preserved after NACT, and no recurrence at the nipple was observed in these patients. CONCLUSIONS: In this matched control study, we demonstrated comparable long-term oncologic outcomes between NSM with immediate reconstruction and CM alone after NACT for LABC. In patients who had tumors extending to the subareolar area before NACT, NSM can be tried if tumor involvement of the nipple-areola complex appears resolved on imaging studies after chemotherapy.

Oncologic Outcomes of Nipple-sparing Mastectomy and Immediate Reconstruction After Neoadjuvant Chemotherapy for Breast Cancer.

OBJECTIVES: To evaluate the oncologic outcomes and risk factors for locoregional recurrence (LRR) and nipple-areola complex recurrence (NR) in a large series of breast cancer patients who underwent nipple-sparing mastectomy (NSM) and immediate reconstruction after neoadjuvant chemotherapy (NACT). SUMMARY OF BACKGROUND DATA: The use of NSM and immediate reconstruction in breast cancer patients receiving NACT is increasing. However, the oncologic safety of this approach is unclear. PATIENTS AND METHODS: A total of 310 breast cancer patients (319 breasts) who underwent NACT and NSM between February 2010 and November 2016 were retrospectively analyzed. Clinical and pathologic factors associated with increased risks of LRR and NR were analyzed using univariate (Chi-square or Fisher exact test) and multivariate (Cox proportional hazard regression model) analyses. RESULTS: During a mean follow-up of 63 ± 22 months, 38 cases had LRR as the first event, including 6 cases of NR as the first event. The 5-year cumulative LRR and NR rates were 11.0% and 1.9%, respectively. In univariate analysis, clinical T stage, pathologic nodal status, histologic grade, lymphovascular invasion, and post-NACT Ki67 status were associated with increased LRR risk, and post-NACT Ki67 status was the only significant risk factor for NR. In multivariate analysis, post-NACT Ki67 ≥10% (hazard ratio, 4.245; 95% confidence interval, 1.865-9.663; P = 0.001) was an independent risk factor for LRR. CONCLUSIONS: NSM and immediate reconstruction seem to be oncologically safe with acceptable LRR and NR rates for appropriately selected breast cancer patients treated with NACT. Post-NACT Ki67 ≥10% was associated with increased risk of LRR or NR, and therefore, necessitates cautious follow-up.

Recurrence Outcomes After Nipple-Sparing Mastectomy and Immediate Breast Reconstruction in Patients with Pure Ductal Carcinoma In Situ.

BACKGROUND: Nipple-sparing mastectomy (NSM) has become increasingly prevalent for patients with ductal carcinoma in situ (DCIS) requiring mastectomy. However, few data regarding recurrence outcomes after NSM are available for this patient population. This study evaluated the locoregional recurrence (LRR) rate for patients with pure DCIS who underwent NSM followed by immediate breast reconstruction without adjuvant radiotherapy and investigated potential risk factors for LRR and/or nipple-areola complex recurrence (NR). METHODS: A retrospective chart review was performed for 199 consecutive patients with pure DCIS who underwent NSM and immediate breast reconstruction between March 2003 and December 2015. Risk factors for LRR and NR were analyzed using univariate (Chi square test) and multivariate (Cox model) methods. RESULTS: The median follow-up duration after surgery was 97 months (range, 39-186 months). At 10 years, the LRR rate was 4.5%, and the NR rate was 3%. The univariate analysis showed that high nuclear grade, negative receptor status, positive human epidermal growth factor receptor 2 (HER2) status, and negative hormone receptor/positive HER2 subtype were associated with increased risk for NR. The multivariate analysis demonstrated that negative progesterone receptor status was an independent risk factor for LRR. However, margin status and tumor-to-nipple distance (TND) were not associated with increased risk for either LRR or NR. CONCLUSIONS: The study findings suggest that NSM can be a feasible surgical option even for DCIS with a TND of 1 cm or less if the retroareolar resection margin is negative for malignancy. Determining the molecular subtype of DCIS might be helpful in identifying patients at high risk for recurrence.

A Secure and Efficient Group Key Management Protocol with Cooperative Sensor Association in WBANs.

The wireless body area network (WBAN) is considered as one of the emerging wireless techniques in the healthcare system. Typical WBAN sensors, especially implantable sensors, have limited power capability, which restricts their wide applications in the medical environment. In addition, it is necessary for the healthcare center (HC) to broadcast significant notifications to different patient groups. Considering the above issues, in this paper, the novel practical WBAN system model with group message broadcasting is built. Subsequently, a secure and efficient group key management protocol with cooperative sensor association is proposed. In the proposed protocol, the Chinese remainder theorem (CRT) is employed for group key management between HC and the personal controller (PC), which also supports batch key updating. The proposed sensor association scheme is motivated by coded cooperative data exchange (CCDE). The formal security proofs are presented, indicating that the proposed protocol can achieve the desired security properties. Moreover, performance analysis demonstrates that the proposed protocol is efficient compared with state-of-the-art group key management protocols.

An energy-efficient and compact clustering scheme with temporary support nodes for cognitive radio sensor networks.

A cognitive radio sensor network (CRSN) is a wireless sensor network whose sensor nodes are equipped with cognitive radio capability. Clustering is one of the most challenging issues in CRSNs, as all sensor nodes, including the cluster head, have to use the same frequency band in order to form a cluster. However, due to the nature of heterogeneous channels in cognitive radio, it is difficult for sensor nodes to find a cluster head. This paper proposes a novel energy-efficient and compact clustering scheme named clustering with temporary support nodes (CENTRE). CENTRE efficiently achieves a compact cluster formation by adopting two-phase cluster formation with fixed duration. By introducing a novel concept of temporary support nodes to improve the cluster formation, the proposed scheme enables sensor nodes in a network to find a cluster head efficiently. The performance study shows that not only is the clustering process efficient and compact but it also results in remarkable energy savings that prolong the overall network lifetime. In addition, the proposed scheme decreases both the clustering overhead and the average distance between cluster heads and their members.

Long-term Oncologic Outcomes of Immediate Breast Reconstruction vs Conventional Mastectomy Alone for Breast Cancer in the Setting of Neoadjuvant Chemotherapy.

Importance: An increasing number of patients with breast cancer receiving neoadjuvant chemotherapy (NACT) undergo immediate breast reconstruction (IBR) with nipple-sparing mastectomy (NSM) or skin-sparing mastectomy (SSM) as surgical treatment. However, the oncologic efficacy and safety of this treatment sequencing strategy is unclear. Objective: To compare the long-term oncologic outcomes of IBR with NSM/SSM and conventional mastectomy (CM) alone for breast cancer in the NACT setting. Design, Setting, and Participants: A retrospective, propensity score-matched case-control study was conducted at Asan Medical Center, Seoul, Korea. A total of 1266 patients with breast cancer who underwent NACT followed by mastectomy with or without breast reconstruction between January 1, 2010, and November 30, 2016, were included. Data analysis was performed from July 1, 2019, to January 24, 2020. After propensity score matching, 323 patients who underwent IBR with NSM/SSM and 323 who underwent CM alone were selected for comparison of long-term oncologic outcomes. Main Outcomes and Measures: The 5-year local recurrence-free survival, disease-free survival, distant metastasis-free survival, and overall survival rates were calculated using the Kaplan-Meier method and compared using log-rank tests. Hazard ratios (HRs) and 95% CIs were estimated using the Cox proportional hazards regression model. Results: After matching, the median follow-up periods were 67 (range, 17-125) months for the IBR group and 68 (range, 17-126) months for the CM-alone group. Median age of the women in the IBR group was 42 (range, 23-72) years; median age of those in the CM-alone group was 46 (range, 30-75) years. No significant differences were observed between the IBR and CM-alone groups in local recurrence (3.7% vs 3.4%; P = .83), regional recurrence (7.1% vs 5.3%; P = .33), or distant metastasis (17.3% vs 18.6%; P = .68) rates. There was also no significant difference between the IBR and CM-alone groups in 5-year local recurrence-free survival (95.6% vs 96.7%; HR, 1.124; 95% CI, 0.495-2.549; P = .78), disease-free survival (76.5% vs 79.9%; HR, 1.089; 95% CI, 0.790-1.500; P = .60), distant metastasis-free survival (82.5% vs 82.5%; HR, 0.941; 95% CI, 0.654-1.355; P = .74), or overall survival (92.0% vs 89.3%; HR, 0.847; 95% CI, 0.530-1.353; P = .49) rates. Conclusions and Relevance: The long-term oncologic outcomes of IBR with NSM/SSM for breast cancer in this study appeared to be comparable to those of CM alone after NACT, suggesting the feasibility of IBR with NSM/SSM in the NACT setting.

Breast Cancer Recurrence in the Nipple-Areola Complex After Nipple-Sparing Mastectomy With Immediate Breast Reconstruction for Invasive Breast Cancer.

Importance: The main concern associated with nipple-sparing mastectomy (NSM) is the risk of local breast cancer recurrence at the retained nipple-areola complex (NAC) consequent to occult nipple involvement. Long-term follow-up data regarding the oncologic safety of modern therapeutic NSM in terms of cancer recurrence at the NAC and survival are limited. Objective: To assess the incidence, risk factors, treatment, and long-term outcomes associated with cancer recurrence at the NAC in a large series of patients with invasive breast cancer who underwent NSM and immediate breast reconstruction. Design, Setting, and Participants: In this retrospective cohort study at a single institution (Asan Medical Center) in Seoul, Republic of Korea, 962 breasts from 944 patients who underwent NSM and immediate breast reconstruction for invasive breast cancer were analyzed between March 3, 2003, and December 31, 2015. Patients who underwent neoadjuvant systemic therapy or palliative surgery were excluded. Data analysis was performed from June 4, 2018, to August 31, 2018. Main Outcomes and Measures: Univariate and multivariate Cox proportional hazards regression models were used to analyze the association between clinicopathologic variables and cancer recurrence at the NAC. To evaluate the association between cancer recurrence at the NAC and prognosis, distant metastasis-free survival, and overall survival were estimated using the Kaplan-Meier method and compared using the log-rank test. Results: Among the 944 study patients (median age at diagnosis, 43 years [range, 23-67 years]) during a median follow-up of 85 months (range, 14-185 months), 39 cases (4.1%) of cancer recurrence at the NAC were identified as the first event after NSM. The 5-year cumulative incidence of cancer recurrence at the NAC was 3.5% (n = 34). In multivariate analyses, multifocality or multicentricity (hazard ratio [HR], 3.309; 95% CI, 1.501-7.294; P = .003), negative hormone receptor or ERBB2 (formerly HER2 or HER2/neu)-positive subtype (HR, 3.051; 95% CI, 1.194-7.796; P = .02), high histologic grade (HR, 2.641; 95% CI, 1.132-6.160; P = .03), and extensive intraductal component (HR, 3.338; 95% CI, 1.262-8.824; P = .02) were independently associated with cancer recurrence at the NAC after NSM. All 39 recurrent cases involved wide local excision. Patients with and without cancer recurrence at the NAC as the first event did not differ significantly with regard to distant metastasis-free survival (P = .95) or overall survival (P = .21). The 10-year distant metastasis-free survival rates were 89.3% among patients with cancer recurrence at the NAC and 94.3% among patients without recurrence. The 10-year overall survival rates were 100% among patients with cancer recurrence at the NAC and 94.5% among those without recurrence. Conclusions and Relevance: Patients had a low incidence of cancer recurrence at the NAC after NSM and immediate breast reconstruction in this study. The findings suggest that multifocal or multicentric disease, hormone receptor-negative/ERBB2-positive subtype, high histologic grade, and positive extensive intraductal component should be considered before determining the NSM procedure.