Very Late Recurrence in Breast Cancer: Is Breast Cancer a Chronic Disease?

Although breast cancer treatments have made great strides in recent decades, there are still many recurrences. Late recurrence is one of the characteristics of breast cancer. Here, we present four cases of recurrence more than 10 years after the initial diagnosis. The time from diagnosis to recurrence was 13 to 20 years in our four cases, which were all estrogen receptor (ER)-positive, and one was also human epidermal growth factor receptor 2-positive. Long-term hormone therapy for 10 years is necessary to prevent late recurrence of breast cancer, but we need to know that late recurrence remains common. Risk factors for late recurrence include ER positivity, progesterone receptor positivity, and low Ki67. The most common sites of recurrence are the lungs/pleura and bones, which was also the case in our experience. It is no exaggeration to say that breast cancer is a chronic disease similar to hypertension and diabetes. This is because breast cancer is not completely cured by surgery alone and lasts for a long time, with patients requiring long-term hormone therapy. Moreover, it can recur even after 10 years or more.