BackgroundA second primary malignant tumor is one of the most important factors affecting the long-term survival of young women with breast cancer (YWBC). As one of the main treatments for breast cancer YWBC patients. postoperative radiotherapy (PORT) may increase the risk of second primary malignancy (SPM). MethodsMachine learning components. https://unitedssports.shop/product-category/bike-parts-tires-27/