1.What is McMurdo? It is a minimally invasive biopsy system developed by Johnson & Johnson. It consists of two major devices: a rotary cutter and a vacuum suction pump, which can repeatedly cut suspicious lesions in the breast to obtain histological specimens of the breast, and also provides a technical basis for minimally invasive excision of benign tumors. Here, first of all, let’s be clear: the McMerton is a device for diagnosis and not for treatment. On this point, it is clear in the user manual of McMerton. However, both businessmen and physicians are intentionally or unintentionally highlighting the therapeutic role of McMerton when promoting it. This is because: (1) the diagnostic advantages of Mamertone are not as great as advertised; (2) it takes advantage of the patient’s avoidance of surgery and the demand for cosmetic treatment. The greatest advantage of McMurdo is that when the mass is not clinically accessible and the patient is psychologically stressed about the lesion, McMurdo can be used for biopsy under ultrasound localization. If the pathological diagnosis is benign, it can be removed together for therapeutic purposes (clinically inaccessible masses usually do not exceed 1.0 cm or the patient has a relatively large breast). However, a rapid pathological examination must be performed during the operation, and if it is malignant, the cutting should be stopped and the patient should be admitted to the hospital for systemic treatment such as radical treatment. 2. Indications for the McMerton system: (1) histopathological biopsy; (2) excision of benign breast tumors (e.g. fibroadenoma). The selling point of McMerton for excision of benign breast tumors is minimally invasive. However, this method is only minimally invasive on the skin surface, and in practice it can cause significant damage to the breast tissue, so it is not recommended for women before childbearing age because it may damage the structure of the milk ducts and lead to breast milk accumulation and mastitis during breastfeeding. Moreover, the removal of benign breast tumors with Maimerton directly contradicts the basic principle of surgical oncology, which is the principle of non-contact tumor-free surgery, because the surgeon’s concern is not only whether the tumor can be cut down, but whether it can be cut cleanly. One of the reasons for the high recurrence rate of benign tumors resected by Maimerton is that the process of Maimerton spinning into the inside of the tumor is easily accompanied by shedding of tumor cells, which is invisible by ultrasound when the debris of the tumor is too small. Therefore, although McMurdo is guided by ultrasound, it is impossible to ensure that the swelling is removed intact, unless there is no bleeding and no cell shedding during the swelling cutting process – and this is simply not possible. As a result, more and more patients have been coming into the clinic recently with recurrences after McMurdo surgery. These patients were fine at the time, with minimal skin incisions, but relapsed in about a year, in effect delaying the direct vision surgery for a year. And at this point, the inside of the breast is already unevenly soft, so if you want to make a small incision, you don’t dare, you have to open a large incision – and the final damage is actually greater. There is another very important reason, McMurdo can deal with small fibroids would not have to be operated, especially small multiple fibroids, and relatively large fibroids that must be operated McMurdo can not deal with – in fact he can only cut the tumors that do not need to be cut. For an oncologic surgeon, the norm requires that all neoplastic disease should be removed in its entirety; removing a piece of it will encourage tumor cells to enter the bloodstream, potentially promoting metastasis. For tumor pathology, the most important information lies in the junction between tumor and normal tissues. All the tumor pathology taking generally does not take the center of the tumor, but the edge of the tumor, and McMurdo surgery often destroys this part of the basic information. As an oncologist when considering treatment options, we definitely need more information than just cancer or not cancer, we need more information such as histological classification. When differentiating various invasive ductal carcinomas, when grading histology, when considering the invasive characteristics of the tumor, we also need to observe the invasion of cell basement membrane, the formation of glandular ducts, the heterogeneity of the tumor tissue (especially when doing immunohistochemistry), the invasion of surrounding soft tissues, the formation of microvessels and lymphatic vessels…all these information, only when the tissue is intact These information can only be judged if the tissue is intact. The scope of resection of McMurdo is definitely not enough, and McMurdo only removes the tumor, which is obviously far from enough. In addition, McMurdo is done under ultrasound surveillance, when the residual mass is less than 0.5cm, the credibility of ultrasound saying no is very low, even if ultrasound says no tumor residue, we still find it unbelievable. Because the tumor is infiltrative growth, it is simply impossible to cut cleanly with just a rotary cutter. Even if the whole piece is excised for biopsy, it should be removed together with the normal glandular tissues around 0.5-1cm of the tumor to ensure that the tumor is not contacted and squeezed during the surgery (to prevent medical metastasis) and the tumor is not exposed (to prevent recurrence). The principle of non-contact is an important principle to prevent tumor recurrence and metastasis, and is the first principle of surgical oncology. Still, McMurdo has a unique advantage in the diagnosis of isolated, small masses (especially those that are not clinically palpable) with a high risk of breast cancer with localized biopsy. All we need to do is to build on our strengths and avoid our weaknesses, and properly guide our patients to the most appropriate screening and treatment.