Multi-center Investigation of the Clinical and Pathological Characteristics of Inflammatory Breast Cancer Based on Chinese Society of Breast Surgery (CSBrs-007)
Inflammatory breast cancer (IBC) is a rare and highly aggressive form of breast cancer, accounting for only 2% of all breast cancer cases according to the Surveillance, Epidemiology, and End Results (SEER) registry. Despite its low incidence, IBC is associated with poor prognosis and outcomes due to its aggressive nature. The disease is characterized by clinical signs such as diffuse erythema and edema (peau-d’orange) in the absence of a clinically evident underlying mass. These signs are attributed to the invasion of tumor emboli into the dermal lymphatic vessels, which may or may not be visible on skin biopsy. The diagnosis of IBC is challenging, and the disease is often excluded from studies of early-stage breast or metastatic cancer due to its rarity. Consequently, there is a lack of comprehensive data on the clinicopathological features, molecular characteristics, and treatment outcomes of IBC, particularly in the Chinese population.
This multi-center study aimed to investigate the clinicopathological features, molecular characteristics, and treatment status among Chinese patients diagnosed with IBC. The study was conducted by members of the Chinese Society of Breast Surgery and included data from 95 patients treated between January 2017 and December 2018. The data were collected using a uniform electronic questionnaire and included demographic characteristics, pathological findings, surgical methods, systemic treatment plans, and follow-up information. The study provides valuable insights into the clinical and pathological characteristics of IBC in China and offers a basis for further research and treatment optimization.
The demographic and clinical characteristics of the study participants revealed that the mean age at diagnosis was 50.55 ± 13.0 years, with 54.4% of patients being pre-menopausal. The mean body mass index (BMI) was 25.4 ± 4.1 kg/m2, with 23.2% of patients classified as obese based on Chinese criteria (BMI ≥28.0 kg/m2). A family history of malignant tumors was reported in 8.5% of patients. The majority of patients presented with stage III (80%) or stage IV (20%) disease, with bone being the most common site of distant metastasis. Pathological findings indicated that invasive ductal carcinoma was the most common histological type, accounting for 86.8% of cases, followed by invasive lobular carcinoma (5.3%). The most common biologic subtypes were hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) (41.5%) and HR-/HER2+ (20.1%), followed by HR+/HER2+ (19.1%) and HR-/HER2- (19.1%).
Lymph node metastasis was observed in 75.8% of patients, while distant metastasis was noted in 21.4%. The mean tumor size at diagnosis was 6.2 ± 3.7 cm, with 49.4% of patients having tumors larger than 5 cm. This pattern is consistent with previous studies, which have reported that IBC is often diagnosed at an advanced stage with large tumor sizes. The high BMI observed in this study is also consistent with previous findings, as obesity is a known risk factor for the development of IBC and is associated with poorer outcomes.
The treatment and outcomes among patients with IBC were also analyzed in this study. Among the 76 patients without distant metastases, 65 underwent preoperative neoadjuvant systemic therapy, with 64 receiving neoadjuvant chemotherapy and one receiving neoadjuvant endocrine therapy. The majority of patients (87.7%) with stage III IBC were treated with preoperative neoadjuvant chemotherapy, predominantly using anthracycline and taxane-based regimens. Surgical treatment was performed in 91.9% of patients, with 77.0% undergoing modified radical mastectomy. Immediate breast reconstruction was performed in 8.1% of patients, which is higher than the rates reported in previous studies, suggesting that immediate reconstruction may be an increasingly viable option for patients with IBC.
The efficacy of neoadjuvant chemotherapy was evaluated using the Miller-Payne method, which classifies the response to chemotherapy based on the reduction in tumor cellularity. Among the 50 patients without distant metastases who were evaluated, 14% achieved a pathologic complete response (pCR), which is slightly higher than the rates reported in previous studies. The Kruskal-Wallis test revealed significant differences in Ki-67 expression and the efficacy of chemotherapy among different molecular subtypes. Specifically, Ki-67 expression was significantly higher in HR-/HER2- tumors compared to HR+/HER2- tumors, and the efficacy of chemotherapy was significantly different between HR+/HER2- and HR-/HER2- tumors.
The study also highlighted the importance of HER2-targeted therapy in the treatment of IBC. All patients with HER2 overexpression were treated with trastuzumab, which is consistent with current treatment guidelines. The combination of neoadjuvant chemotherapy, surgery, and adjuvant locoregional radiotherapy (trimodal therapy) has been shown to improve survival outcomes in patients with IBC. In this study, 63.5% of patients with stage III IBC were treated with anthracycline and taxane-based neoadjuvant chemotherapy, and supplemental postoperative chemotherapy was provided as needed.
The findings of this study provide novel insights into the clinicopathological characteristics and treatment status of IBC in China. The high rates of lymph node and distant metastasis, large tumor sizes, and advanced stage at diagnosis highlight the aggressive nature of IBC and the need for early detection and effective treatment strategies. The study also underscores the importance of molecular subtyping in guiding treatment decisions and predicting outcomes. The higher rates of immediate breast reconstruction observed in this study suggest that reconstructive surgery may be an increasingly viable option for patients with IBC, although further research is needed to determine the optimal timing and approach for reconstruction.
In conclusion, this multi-center study provides valuable insights into the clinical and pathological characteristics of IBC in China and offers a basis for further research and treatment optimization. The findings highlight the importance of early detection, molecular subtyping, and multimodal therapy in improving outcomes for patients with IBC. Future studies should focus on identifying additional prognostic factors and developing targeted therapies to further improve survival outcomes in this aggressive form of breast cancer.
doi.org/10.1097/CM9.0000000000001104
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