Successful treatment of a large-sized triple-negative breast cancer: A case report.

RATIONALE: Triple-negative breast cancer (TNBC) is defined as the absence of estrogen receptor and progesterone receptor expression, along with a lack of human epidermal growth factor receptor 2 overexpression or amplification. Patients with TNBC exhibit a poorer prognosis, characterized by a higher propensity for metastasis to the lungs, liver, and brain, and a lower overall survival rate than other breast cancer subtypes. Primary treatment modalities for TNBC include surgery, chemotherapy, and radiotherapy. Although stereotactic body radiotherapy (SBRT) has been reported for the treatment, there is a paucity of comprehensive research in this field. PATIENT CONCERNS: We report a case of successful treatment of a 38-year-old female patient with TNBC who experienced recurrence after surgery. The tumor occurred 1 year after surgery. The tumor showed rapid progression and growth. DIAGNOSES: Stage Ⅳ TNBC with lung metastasis. INTERVENTIONS: After visiting multiple hospitals, the patient finally underwent SBRT combined with chemotherapy. During SBRT implementation, an ultrahigh-dose radiotherapy modality was adopted, which is a rarely reported approach in previous studies. Subsequently, a conventional fractionated radiotherapy regimen was administered. Concurrent with radiotherapy, the patient received 2 cycles of chemotherapy. OUTCOMES: The patient's tumor shrank rapidly, with minimal adverse reactions. Nine months later, the tumor remained well controlled. LESSONS: Treatment of TNBC remains challenging. Given the aggressive progression of the tumor, a new radiotherapy regimen was adopted. Given that such an approach has scarcely been documented in the published literature, this case may offer novel implications for clinical practitioners.