Breast cancer is one of the most common malignancies in women. According to information, about one million women worldwide develop breast cancer each year and more than 400,000 women die from it. One in eight women in the United States will develop breast cancer in their lifetime. The incidence of breast cancer in China has been on the rise in recent years. A survey data recently released by China Cancer Research Foundation shows that breast cancer has become the most threatening malignant tumor to women in cities such as Shanghai, Beijing and Guangzhou. How patients can correctly understand breast cancer and choose the best treatment plan that suits them is the key to breast cancer treatment nowadays. Two choices: mastectomy or breast preservation? Previously, the surgical treatment for breast cancer was mainly radical surgery. In recent years, breast-conserving surgery has become one of the main treatment methods for early-stage breast cancer in Europe and the United States, with about 20-50% of early-stage breast cancer patients receiving this treatment each year in the United States. The vast majority of patients with early-stage breast cancer have the opportunity to choose a surgical procedure of their choice if they wish. Radical breast cancer surgery refers to the surgical removal of all the breast tissue, nipple areola and axillary lymph nodes on the affected side. Simple mastectomy is the removal of all the breast tissue, nipple areola, and axillary lymph nodes on the affected side in patients with early stage breast cancer without axillary lymph node metastasis. Both of these procedures cause the patient to lose the entire breast on the affected side, which has a significant impact on the appearance and the patient’s psychological well-being. Breast-conserving surgery for breast cancer is a procedure in which only the cancerous tissue is removed, but not the entire breast. The surgery includes lumpectomy, segmental excision (removal of the breast tissue around the cancerous tissue and the muscle envelope in the corresponding area), and quadrant excision (removal of a quarter of the breast). When patients learn that they have breast cancer, the first thing that occurs is the fear of cancer and the eagerness to have surgery to remove all the cancer cells from the body. However, there is only one chance to choose, and the patient needs to be given enough time to carefully consider the surgical option. Do the benefits of preserving the breast outweigh the disadvantages or do the disadvantages outweigh the benefits? Once patients understand some basic medical issues, it will be easier for them to make a choice based on their wishes. If you keep the breast, is the tumor not cleanly cut? Most patients must want both to be able to completely remove the cancerous tissue and to preserve the appearance of the breast. Their main concern is: if they keep their breasts, will the tumor not be clean? If the tumor is not clean, will the survival time be reduced? To answer this question, we need to clarify the following points first: First of all, not all patients have the chance of breast preservation. In other words, there are conditions for breast preservation. When these conditions are met, breast-conserving treatment is safe and effective. Several types of patients are currently recognized as not being able to preserve the breast (absolute contraindication): 1. previous radiation therapy to the breast or chest wall 2. need for radiation therapy during pregnancy (radiation therapy has an effect on the fetus) 3. mammography or MRI showing diffuse suspicious lesions 4. extensive lesions that cannot be cleanly excised through a single incision 5. previous excision of the mass or failure to achieve a better breast after excision of the lesion Positive pathological margins (the tissue at the margins of the mass is also diseased and cannot be excised cleanly). Some patients are not recommended for breast preservation (relative contraindication): 1) tumor larger than 5 cm and not shrinking after pre-surgical chemotherapy (neoadjuvant chemotherapy) 2) active diffuse connective tissue disease involving the skin (especially scleroderma or lupus), making the skin more sensitive to radiotherapy and prone to radiotherapy complications 3) focal positive cut margins. The core of the above requirements can be summarized as follows: firstly, it can ensure clean removal of cancerous lesions while taking into account the shape of the breast: for example, the cancerous lesions should be small in proportion to the patient’s breast, mammogram and MRI should be performed before surgery to determine that the lesions are small and limited, and rapid pathological examination of the cut edge tissue should be performed during surgery to ensure that there are no cancerous cells at the cut edge. Second, the majority of patients must undergo postoperative radiotherapy to kill any microscopic lesions that may be present in the preserved breast tissue. These requirements ensure that patients can preserve their breast while cutting away the maximum amount of cancerous tissue. Second, breast preservation does not affect survival time. A randomized clinical trial in the United States with a 20-year follow-up period showed that overall survival was equal for patients with early-stage breast cancer who underwent total mastectomy and breast conservation plus radiation therapy. NSABP B-06 is a landmark prospective randomized clinical trial that illustrates the need for radiotherapy after breast-conserving surgery. NSABP B-21 builds on the results of NSABP B-06, in which 1009 patients with invasive breast cancer ≤1 cm and negative lymph nodes underwent breast-conserving surgery and axillary lymph node dissection, followed by randomization to tamoxifen therapy, radiotherapy, or tamoxifen combined with radiotherapy. The cumulative 8-year ipsilateral tumor recurrence rates were 16.5%, 9.3% and 2.8% for the three groups, respectively. This result has been confirmed by an additional European trial. These trials have mainly confirmed the safety and efficacy of breast-conserving treatment for early-stage breast cancer. Finally, the issue of local recurrence rates in breast-conserving patients. Breast-conserving treatment may have a higher rate of ipsilateral breast cancer recurrence compared to total mastectomy. Patients with recurrence are unable to undergo breast-conserving surgery again because most of them have already undergone lumpectomy and radiotherapy. However, probably due to the advancement of chemotherapy and endocrine therapy, targeted therapy and other treatments, the overall survival of patients treated with both approaches is the same. Therefore, the patient’s choice regarding whether to conserve the breast or not often depends on her age, size, shape requirements, survival expectations and tumor concerns. For example, patients who choose breast conservation often have high cosmetic requirements, while patients who choose total mastectomy often want the lesion to be completely removed, sparing them the agony of radiation therapy and reoperation. Some other common questions Whether radiotherapy is always necessary. Although all patients with invasive breast cancer have a reduced rate of local recurrence after breast radiotherapy, the degree of patient benefit is also proportional to the level of local recurrence risk. For patients with breast cancer older than 70 years of age, tumor size less than 2 cm, better histological type, negative lymph nodes, and positive estrogen receptors, the risk of local recurrence is very low and may be considered without adjuvant radiotherapy. For older breast cancer patients, it is important to evaluate their disease and expected survival, and their risk of breast cancer recurrence needs to be weighed against other possible causes of death. Timing of radiotherapy. Postoperative radiotherapy can reduce the rate of local tumor recurrence, but the appropriate timing and sequence of postoperative radiotherapy and chemotherapy is controversial. For patients who do not require postoperative chemotherapy, the best interval between surgical radiotherapy is within 8 weeks. For patients with positive axillary lymph nodes and other high-risk patients, postoperative adjuvant chemotherapy should be administered first, but radiotherapy should not be delayed beyond 7 months postoperatively. Simultaneous radiotherapy can ensure efficacy without delaying radiotherapy, but an effective and low-toxic chemotherapy regimen should be selected to reduce acute toxicity and late complications associated with treatment. If the surgical margins are positive, radiotherapy should be started as early as possible. In summary, for patients with early-stage breast cancer and other eligible breast-conserving conditions, the use of breast-conserving surgery supplemented by radiation therapy is relatively safe and reliable. For larger primary breast cancers, neoadjuvant chemotherapy can also be used to increase the rate of surgical resection and the proportion of breast-conserving surgery. Breast-conserving treatment is more respectful of patients’ psychological needs than traditional surgery, which makes breast cancer surgery less harmful and treatment more rational and individualized.