Introduction to the standard treatment of sentinel lymph node biopsy and breast cancer surgery
1.The development of sentinel lymph node biopsy in breast cancer surgery
Breast cancer surgical treatment has gone through the course of radical breast cancer surgery, modified radical breast cancer surgery (mastectomy + axillary lymph node dissection), breast-conserving treatment (extended tumor resection + axillary lymph node dissection), breast cancer axillary-conserving surgery (sentinel lymph node biopsy), and minimally invasive breast-conserving treatment (non-surgical ablation of primary tumor ± sentinel lymph node biopsy). While traditional axillary lymph node dissection completely clears the suspicious positive lymph nodes in the axilla, it also inevitably brings various complications, including pain in the axilla, impaired drainage, reduced ability to work, abnormal sensation, fluid accumulation, infection, limited shoulder movement, etc.
Axillary lymph node dissection (ALND) is an important part of radical breast cancer surgery; however, complications of ALND, especially upper limb lymphedema on the affected side, affect the quality of life of patients. The incidence is 5% after surgery alone, and up to 30% for those who combine axillary radiotherapy. In severe cases, upper limb dysfunction also occurs, and lymphedema of the affected upper limb is also a difficult problem in clinical treatment at home and abroad.
With the popularization of mammography and the development of breast cancer screening in countries with high prevalence, the staging ratio of breast cancer has changed and the number of early stage cases is increasing, and the routine axillary lymph node dissection has been questioned in the breast surgery community. In 1992, Morton first published an article on SLNB in melanoma; in 1993, Alex reported an animal test of SLNB in breast cancer; in the same year, Krag reported a study of 22 breast cancer patients who underwent SLNB with radiocolloid as a tracer. In 1994, Giuliano reported the method of SLNB with blue dye as tracer, and since then, SLNB of breast cancer has become a hot spot in breast cancer surgery.
2. Clinical development of anterior lymph node biopsy in breast cancer surgery
Axilary Lymph Node Dissection (ALND) is a routine procedure for breast cancer surgery, and ALND is performed simultaneously with all kinds of breast-conserving surgery. In recent years, many scholars have questioned the necessity of ALND for early stage breast cancer and have begun to explore the challenge of replacing conventional ALND with Sentinel Lymph Node Biopsy (SLNB), which was proposed by Beechey-Newman as another “revolution” in the history of surgical treatment of breast cancer.
The sentinel lymph node (SLN) is the first lymph node through which the lymphatic drainage of the tumor must metastasize. SLNB biopsy will make the treatment of breast cancer more rational and individualized. Many useful explorations have been conducted at home and abroad, showing a broad prospect of clinical use. The theoretical basis includes: lymphatic drainage of axillary negative patients is unnecessary; lymphatic drainage of the breast has specific regularity, and the sentinel lymph node is the first station lymph node of breast cancer drainage. At present, biopsy of sentinel lymph nodes has become a routine surgical procedure in foreign countries, and the long-term follow-up confirms that the compliance rate is high and does not affect the prognosis.
The SLNB has been used clinically in some hospitals in Europe and the United States, and if SLN(+), ALND or axillary radiotherapy will be performed; if SLN(-), the axilla will not be treated; Smillie et al. have suggested that SLNB should be accurate >90% and false negative ≤5% before the technique can be used clinically. At present, most hospitals in China are still in the research stage, that is, SLNB is performed while ALND is still performed, and the reliability and accuracy of this technique continue to be prospectively studied. A small number of T1 patients and those who strongly requested by themselves were selected from the Cancer Hospital of the Academy of Medical Sciences, and frozen sections were performed immediately after excision of SLN, and ALND was not done if they were negative, totaling 19 cases. The results were 3 cases of SLN (+) and 16 cases of SLN (-), all 16 cases did not have ALND and were not included within this group of cases because there was no histological information of axillary lymph nodes to be counted by formula. The clinical study and follow-up analysis of SLNB in breast cancer will eventually clarify whether SLN can reflect the status of axillary lymph nodes, whether the injection of SLN tracer has any effect on tumor spread and metastasis, and whether SLNB in early breast cancer can replace conventional ALND. clinical testing of anterior lymph nodes has been started in foreign countries since the 1990s and in China only in recent years. However, only a few central hospitals in China are able to carry out this technique. The advantages of this technology are: it can accurately detect the lymph nodes that may metastasize; for patients with negative sentinel lymph nodes, it can avoid the complications caused by axillary lymph node dissection, such as dysfunction of the affected limb, swelling of the affected limb, and subcutaneous fluid accumulation, which can significantly improve the quality of life of patients; like breast-conserving surgery, it can significantly improve the quality of life of patients after surgery without reducing the efficacy.
3.Technical problems of anterior lymph nodes of breast cancer
The sentinel lymph node (SLN) is the first lymph node to receive lymphatic drainage within the tumor area and the first station of tumor metastasis. If this lymph node does not metastasize, the chance of metastasis in other lymph nodes is very small, estimated at 5% or less. Predicting the presence of metastasis in axillary lymph nodes by biopsy of anterior lymph nodes can avoid surgical clearance of axillary lymph nodes without metastasis, reduce postoperative complications such as lymphatic reflux obstructive edema and pain in the affected limb, simplify the surgical procedure, shorten the operative time, and significantly improve the quality of life of breast cancer patients. The American Society of Clinical Oncology (ASCO) has done a clinical study of more than 10,000 cases, and the results showed that the sensitivity of SLNB was 71%-100%, with an average false-negative rate of 8.4% (0%-29%). As a minimally invasive biopsy technique for accurate staging of the axilla, SLNB represents the state of the art in surgical treatment of breast cancer.
I. Indications and contraindications for sentinel lymph node biopsy (SLNB)
The indications for routine SLNB include: early invasive breast cancer, axillary lymph nodes that are not significantly enlarged on palpation, and solitary tumors. Patient age, gender and obesity are not restricted, and the type of biopsy of the previous primary breast tumor is not restricted, including needle aspiration cytology, hollow-core needle biopsy or excisional biopsy.
Contraindications include: patients with biopsied axillary lymph nodes, lactating breast cancer, tracer allergy, inflammatory breast cancer, previous major breast or axillary surgery that disrupted lymphatic return in this area, multicentric breast cancer, and clinically detected axillary lymph node metastasis.
II. SLNB method
The identification and localization of SLN is the key to the success of SLN biopsy. The combination of isotope tracer and blue dye can significantly improve the detection rate of SLN. The commonly used tracers for the nuclide method are: 99mTc (99mTc) labeled sulfur colloid, macromolecular dextrose, tritoxan monoclonal antibody, and melphalan, etc. Blue dyes are mainly methylene blue (Melan), patent blue, isothiocarbon blue and nanocarbon suspensions.
Nuclear tracer injection can be performed 2-6 hours before surgery with subcutaneous injection around the tumor (or areola) and lymphatic imaging 1 hour before surgery. 5-10 minutes before the start of surgery, 2-4 ml of blue dye is injected subcutaneously into the tumor (or areola), and a hand-held γ-detector is used to locate the “hot spot” in conjunction with the lymphatic imaging results and to localize it on the body surface. On the surface of the “hot spot”, 3-5cm incision was made along the skin line, and the “hot spot” and blue-stained lymph nodes were searched under the guidance of γ-detector, and the lymph nodes were taken out and sent to pathological examination alone. If the anterior lymph nodes are negative by intraoperative freezing, axillary lymphatic clearance is not performed, and if positive, axillary lymphatic clearance is performed.
The SLNB technique is simple, safe, and reliable, and can avoid complications caused by axillary dissection. A large number of studies at home and abroad have shown that SLNB for primary breast cancer has a high success rate and a low false-negative rate, and is expected to become one of the standardized procedures for the treatment of breast cancer. SLNB should be preferred for axillary staging in patients with indications for SLNB, and it is no longer ethical to not offer SLNB to patients.
4. Routine implementation of sentinel lymph node biopsy in breast cancer surgery in our hospital
Traditional radical breast cancer surgery is extensive, traumatic, with slow postoperative recovery and many postoperative complications, which may produce permanent dysfunction of the affected upper limb, such as upper limb pain, limited shoulder joint movement and irreversible upper limb edema, which seriously affects patients’ postoperative survival quality. In addition, in clinical treatment, there are quite a number of patients with no metastasis in axillary lymph nodes, but still undergo lymph node dissection, which brings unnecessary pain and injury to patients. How to detect the presence of metastasis in axillary lymph nodes before surgery, so as to avoid excessive surgery, has been a frontier issue explored by breast surgeons. The advent of anterior lymph node biopsy technique has filled this gap in breast cancer treatment.
Following breast-conserving surgery, sentinel lymph node biopsy has also become a routine procedure in breast surgery.
Traditionally, one of the purposes of axillary lymph node dissection after radical breast cancer surgery is to determine the stage, to see if there are metastases and how many metastases there are, so as to judge the prognosis. But clinically, especially in early stage breast cancer, the rate of lymph node metastasis is about 10% for cancer less than 2 cm, and about 30% for 2-3 cm, which means that 70% or more of patients do not have lymph node metastasis, so if all patients undergo axillary lymph node dissection, it is not only over-treatment, but also affects patients’ quality of life, with complications such as upper limb bleeding, fluid accumulation, edema, pain, and some Some of them are so distended and painful at night that they cannot sleep, have a foreign body feeling in their armpits, and even affect their working life. The axillary lymph nodes play a key role in lymphatic return to the upper limbs of the body. In the past, due to the immaturity of breast cancer diagnosis and treatment technology, coupled with breast cancer patients’ eagerness to save their lives psychologically and economically, most patients would not give much consideration to the quality of life after surgery, and often choose to completely remove their breasts and axillae. About 20% of patients would have hand edema, pain, numbness and sensory disorders six months after surgery, which seriously affect the quality of life. According to statistics, at least 50% of breast cancer patients in our province have been subjected to unnecessary axillary clearance, resulting in serious damage to the body.
The Department of Breast Surgery of Nanchang III Hospital has successfully completed thirty cases of in situ breast cancer and early breast cancer sentinel lymph node biopsy using a combination of isotope tracer and blue dye. These patients recovered well after surgery, with significantly fewer surgical complications, and have all been discharged from the hospital. Dr. Yang Shixin introduced the sentinel lymph node dissection for breast cancer, in which the first lymph nodes that may metastasize in early stage breast cancer patients (i.e. sentinel lymph nodes) are marked by Melanoma combined with radionuclide, and then the group of lymph nodes is found by using nuclear detector combined with early blue-stained lymph nodes, and the sentinel lymph nodes are removed through a small incision or from the breast surgery incision for pathological examination. If there is no metastasis in this group of lymph nodes, traditional radical breast cancer surgery can be avoided without further axillary lymph node dissection. This preserves the function of the affected limb of the breast cancer patient to the greatest extent possible, avoiding edema of the affected limb and permanent functional impairment, thus improving the patient’s quality of life.
Currently, breast cancer sentinel lymph node biopsy has been written into the “Chinese Anti-Cancer Association Guidelines and Specifications for Breast Cancer Diagnosis and Treatment” and “Breast Cancer Clinical Practice Guidelines NCCN 2010”. At present, based on breast-conserving surgery, the hospital has successfully carried out the technique of preserving the axilla with sentinel lymph node biopsy, which marks that the level of breast surgery in our hospital follows the international frontier in breast cancer surgical treatment and ranks among the forefront in China, and this technique is routinely carried out to relieve the pain of breast cancer patients and at the same time ensure the perfect shape and good quality of life.