There are various reasons why breast nodules grow again half a year after surgery, which may be due to the influence of individual endocrine disorders, unclean nodules or malignant nodules. 1. Endocrine disorders: when the estrogen level in the patient’s body increases, it is possible to have a recurrence of breast nodules after mastectomy. 2. Unclear nodule: there are some differences in the examination conducted by doctors, some nodules in the breast may not be found in time and may recur within six months after mastectomy. 3. Malignant nodules: Some breast nodules may be malignant and have a certain risk of recurrence after surgery. If a patient’s breast nodule recurs after mastectomy, it is recommended that he or she undergoes standardized treatment as soon as possible to minimize the adverse effects of the disease.