One of the main clinical goals for patients with early-stage breast cancer is to reduce the risk of disease recurrence and death. Clinical practice guidelines suggest use of endocrine therapy in the adjuvant setting to reduce these risks. However, many women diagnosed with hormone receptor–positive, human epidermal growth factor receptor 2–negative, node-positive, early-stage breast cancer will experience disease recurrence despite the effectiveness of standard endocrine therapy.

Recurrence data from clinical trials can be confusing. Clinical trials of breast cancer therapies can select different recurrence endpoints, including distant disease-free survival, disease-free survival, progression-free survival, recurrence-free survival, recurrence-free interval, and local recurrence rates.

In some helpful cases, study investigators will report the incidences and locations of recurrence events. However, even these outcome terms may not share the same definition between studies. A few examples from different trials define recurrence-free survival as either locoregional or distant recurrence, distant relapse, or recurrence and death . This illustrates how different measures or changing measurement definitions can make it challenging to analyze data between studies, as well as to highlight why recurrence endpoints require explanation whenever they’re presented.

What is the most important measure of recurrence to you and your patients? How do you counsel your patients on their risk of recurrence and plan future therapeutic decision-making?