For young female breast cancer patients, we should pursue breast-conserving treatment with better local control in the long term, and should reasonably formulate a treatment plan under the premise of full communication with patients. Local recurrence of breast-conserving surgery should be controlled mainly through local management of breast cancer lesions in the initial treatment and postoperative adjuvant therapy, i.e. reasonable selection of suitable breast-conserving population, excluding multicentric or multifocal lesions; ensuring negative intraoperative margins; postoperative breast radiotherapy with additional irradiation to the tumor bed; postoperative adjuvant chemotherapy and endocrine therapy according to adjuvant therapy guidelines; insisting on long-term follow-up for early detection local recurrence and treatment. One of the characteristics of female breast cancer incidence in China is different from that in the West, one of which is the forward shift of the peak age of incidence, with an increase in breast cancer incidence already after the age of 40. According to the WHO definition of youth, those under 45 years of age belong to the young population; therefore, there is a significant proportion of young people with breast cancer in China, who have a more active social life and a higher demand for their image. Since the 1990s, with the increasing understanding of breast cancer and a series of large prospective randomized controlled clinical studies confirming that breast-conserving surgery plus postoperative radiotherapy has similar efficacy to traditional modified radical surgery, breast-conserving treatment has gradually been accepted by physicians and patients. Breast-conserving treatment indications and contraindications Currently, there are differences in the indications for breast-conserving treatment. The NSABP B06 trial defines the indications for breast-conserving treatment as: the largest diameter of the tumor is ≤4 cm; the tumor is confined to the breast or involves only the ipsilateral lymph nodes; the mass is movable; there is no adhesion between the mass and the skin and pectoral muscle; the tumor is in moderate proportion to the breast and the mass has an acceptable appearance after excision. The appearance of the tumor after excision is acceptable. In 2008, the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines for Breast Cancer summarized the contraindications to breast-conserving treatment: absolute Absolute contraindications include prior breast or chest wall radiotherapy, radiotherapy during pregnancy, mammography suggestive of diffuse suspicious or malignant calcifications, extensive lesions that cannot be resected locally with a single incision to achieve negative margins and good profile, and pathologically confirmed positive margins; relative contraindications include active connective tissue disease involving the skin, tumors >5 cm, focal positive margins, premenopausal women with known BRCA1/2 mutations, and young women ≤35 years of age. women, and young women ≤35 years of age. Although some researchers believe that breast-conserving treatment is more important for this population, young women have their own characteristics and breast-conserving treatment should be chosen with caution in this population. Characteristics of young breast cancer Young breast cancer has its own characteristics, such as large tumors, negative estrogen/progesterone receptors, poor tissue differentiation, high risk of axillary lymph node involvement and vascular invasion, and susceptibility to carry mutations in the breast cancer susceptibility gene BRCA1/2. Breast cancer is difficult to detect early in young women, and patients often have large masses at the time of presentation and are at a relatively higher risk of local recurrence after breast-conserving surgery. The reasons for the difficulty in early detection may include the low diagnostic rate of dense mammograms and the lack of regular and effective breast cancer screening in young women. Some studies suggest that breast ultrasound and magnetic resonance imaging (MRI) can detect young breast cancer early and provide insight into the extent of tumor infiltration and the presence of multicentric or multifocal lesions, which can help determine whether a patient is suitable for breast-conserving treatment. In young breast cancer patients, adequate breast imaging should be performed prior to breast-conserving surgery to assess tumor size, exclude multicentric lesions, and design the extent of surgical gland removal. Breast MRI can be a good adjunct to the decision of breast-conserving surgery. The younger the age of onset of breast cancer tends to indicate a greater likelihood of carrying a breast cancer susceptibility gene. the risk of developing breast cancer is 20% for BRCA1 mutation carriers by age 40 and 80% by age 70. For young breast cancer patients with BRCA1 or BRCA2 mutations, modified radical surgery of the affected breast and prophylactic simple mastectomy of the contralateral breast combined with breast reconstruction is feasible because of the risk of later recurrence or new breast cancer in the residual breast and contralateral breast. This treatment may be more appropriate than breast-conserving surgery in terms of treatment and prevention of breast cancer. Local recurrence after breast-conserving treatment Some studies suggest that young women with breast cancer tend to have a longer survival time after breast-conserving treatment, but the risk of local recurrence of breast cancer increases by 1% for each additional year of survival time, which suggests that we should pay attention to the problem of local recurrence after breast-conserving surgery in young women. The aim of breast-conserving treatment is to improve the quality of life of patients, but if breast-conserving treatment is accompanied by a higher risk of local recurrence, the choice of breast-conserving treatment should be carefully considered. The risk of local recurrence after breast-conserving treatment in young women is not only related to the characteristics of the tumor itself, but also to the treatment factors. One of these treatment factors is surgery, including the extent of surgery, the condition of the incision margins, and the surgeon’s proficiency. Adequate and appropriate surgical excisional extent is fundamental to reducing local recurrence after breast-conserving surgery. Breast-conserving surgical mastectomy procedures include lumpectomy, segmental resection, and quadrant resection. The quadrant resection has the lowest risk of local recurrence, but the postoperative breast appearance is poor; the mass resection has the least impact on the breast appearance, but the risk of local recurrence is increased. Therefore, appropriate segmental resection can provide a better balance between local surgical radical treatment and postoperative cosmetic results. A safe border of at least 2 cm should be ensured for segmental resection in young breast cancer patients, and intraoperative frozen pathology should be performed to ensure negative margins. Veronesi et al. showed that the risk of local recurrence in patients with positive margins for breast-conserving surgery was one times higher than in those with negative margins (17.4% vs. 8.6%). In a Dutch study, the 10-year local recurrence rate after breast-conserving surgery for breast cancer patients under 40 years of age was 58% for those with positive margins compared with 15% for those with negative margins, suggesting that breast-conserving surgery for young breast cancer patients should always be performed with negative margins, otherwise the risk of local recurrence is greatly increased. Another therapeutic factor that affects local recurrence is the combination of postoperative treatment. The role of radiotherapy as an important component of breast-conserving treatment has been confirmed in several large clinical trials, and whole-breast radiotherapy after breast-conserving surgery has been written as a norm in various guidelines. As the risk of local recurrence is higher in younger breast cancer patients than in older patients, radiotherapy is indispensable as an important tool for local control in younger patients. The European Organization for Research and Treatment of Cancer (EORTC) 22881/10882 trial studied local recurrence after breast-conserving surgery in 5569 patients with stage I and II breast cancer, and the results of a median follow-up of 5.1 years showed that the local recurrence rate was significantly higher in breast cancer patients under 40 years of age compared to patients over 40 years of age, and that additive irradiation to the tumor bed reduced the local The recurrence rate was reduced from 20% to 10% in patients under 40 years of age. Currently, post-breast-conserving radiotherapy mainly uses three-dimensional conformal and intensity-modulated techniques, which result in more uniform irradiation of the target area and less impact on surrounding tissues. The EORTC 10854 trial included 2795 breast cancer patients, who were randomized into breast-conserving surgery alone and breast-conserving surgery combined with CAF (cyclophosphamide + doxorubicin + 5-fluorouracil) chemotherapy within 36 hours after surgery. The results showed that age <43 years was an independent risk factor for local recurrence, and the risk of local recurrence was greatly reduced in patients aged <43 years after combined 1 cycle of chemotherapy. In receptor-positive young female breast cancer patients, 5 years of endocrine therapy reduced the risk of systemic metastasis or local recurrence. Psychological concerns after breast-conserving treatment Psychological changes in young women before and during postoperative follow-up should not be ignored. In particular, it should be noted that the psychological status of patients in the first month after breast-conserving surgery, such as anxiety, depression, and control of self-emotion, is better than that of patients who underwent mastectomy. However, as the time lengthens, breast-conserving patients often become anxious due to the risk of local recurrence, which makes it more important for professional doctors to provide guidance to enable the patients to make a full physical and psychological recovery.