A case of metachronous cervical and early-stage breast cancer.

introductionCervical and breast cancer are among the most common malignancies in women, typically presenting independently. Their concurrent or metachronous occurrence is rare due to differing etiological factors. This report presents the case of a 53-year-old woman diagnosed with recurrent metastatic cervical cancer who subsequently developed early-stage breast cancer. CASE PRESENTATION: A 53-year-old postmenopausal woman with a history of cervical cancer, treated with radical hysterectomy and chemoradiotherapy in 2001, developed a pelvic wall recurrence with distant metastases in 2022. Despite treatment with chemotherapy in combination with checkpoint inhibitor pembrolizumab and subsequent Tisotumab Vedotin, her three-month follow-up in August 2024 revealed a new lesion in the right breast which turned out to be breast cancer. Biopsy confirmed a well-differentiated, hormone receptor-positive, HER2-negative breast cancer with a low proliferation index of 10%. DISCUSSION: The simultaneous or sequential presentation of cervical and breast cancer is rare, especially under systemic treatment. The patient's cervical cancer was aggressive, and the subsequent metachronous breast cancer highlights the complex, multifactorial nature of carcinogenesis. The development of a second primary malignancy while a patient is receiving treatment for a metastatic condition is a critical clinical scenario, necessitating individualized treatment strategies, as optimal management remains unclear due to the rarity of such cases.