A patient with stage IIIB advanced breast cancer who is still alive 24 years after surgery: a case report and remarks on the treatment strategies.

Background: In recent years, a number of agents possessing novel mechanisms, such as cyclin-dependent kinase 4/6 (CDK 4/6) inhibitors and PIK3CA inhibitors, have been developed for the treatment of hormone receptor-positive (HR+) human epidermal growth factor receptor type negative (HER2-) advanced or recurrent breast cancer. As a result, the treatment strategies for advanced or recurrent breast cancer have changed significantly. The combination of CDK 4/6 inhibitors administration and endocrine therapy is now widely used in the treatment of HR+ HER2- recurrent breast cancer with improved outcomes. In 2021, abemaciclib was approved as post-operative adjuvant combination therapy with endocrine therapy for HR+ HER2- advanced breast cancer and is expected to suppress postoperative recurrence. A range of new agents are being developed in addition to CDK4/6 inhibitors that provided more options of treatment strategies for advanced or recurrent breast cancer, which in turn could improve outcomes. However, the prognosis for the recurrent HR+ HER2- breast cancer remains poor, overall survival (OS) is still very low and a complete cure is difficult even with the treatments.

Case Description: In 1998, 24 years ago, neoadjuvant chemotherapy (NAC) and the concept of subtypes were not even widespread, the number of available drugs was far fewer than today, the clinical treatment guidelines had not been established. Nevertheless, we experienced a case of HR+ HER2- advanced breast cancer, stage IIIB at the initial diagnosis, which was consistently treated with the aim of complete cure and with the various treatments available at the time, resulting in long-term survival. 24 years have passed since the initial surgery, the patient has continued to do well despite repeated recurrences and remissions.

Conclusions: We report here a case of long-term survival in advanced breast cancer of 24 years after surgery, and remark for future treatment strategies that not bound by the conventional treatment policy that emphasizes quality of life without aiming for complete cure.