Extensive intraductal carcinoma of the breast refers to a type of breast cancer in which ≥ 25% of ductal carcinoma in situ is present in invasive tumors and there is a scattered distribution of ductal carcinoma in situ (DCIS) in or around the invasive carcinoma. Studies have shown that patients with DCIS positive for extensive intraductal component have more residual tumors than patients with DCIS negative for extensive intraductal component. There are still many subclinical tumors in the residual mammary gland after removal of the main invasive tumor foci. This provides the condition for tumor recurrence after breast-conserving surgery, and the risk of tumor recurrence in DCIS positive for extensive intraductal component is 2.52 times that in DCIS negative for extensive intraductal component. Compared with DCIS negative for extensive intraductal component, DCIS positive for extensive intraductal component is not sensitive to radiotherapy.
Mckissock surgery is originated from a breast reduction surgery developed by American doctors in 1970, which can remove glands to the maximum extent. This technique was applied to breast-conserving surgery in 2016, which initiated the application of this operation in malignant tumors. Jianyi Li and the team members (Shengjing Hospital of China Medical University, Shenyang, China) first applied expanded Mckissock surgery in breast-conserving surgery with the nipple-areola complex preserved. This surgical technique is suitable for low-grade malignant tumors. This surgical technique has been performed in 30 patients and results showed that the expanded Mckissock surgery has better prognosis than radical mastectomy. Therefore, this prospective cohort study will compare the postoperative disease-free survival and quality of life between modified radical mastectomy and expanded Mckissock surgery.
