Annual hazard rates of recurrence for breast cancer during 24 years of follow-up: results from the International Breast Cancer Study Group Trials I to V

Purpose: Predicting the pattern of recurrence can aid in the development of targeted surveillance and treatment strategies. We identified patient populations that remain at risk for an event at a median follow-up of 24 years from the diagnosis of operable breast cancer. Patients and Methods: International Breast Cancer Study Group clinical trials I to V randomly assigned 4,105 patients between 1978 and 1985. Annualized hazards were estimated for breast cancer-free interval (primary end point), disease-free survival, and overall survival. Results: For the entire group, the annualized hazard of recurrence was highest during the first 5 years (10.4%), with a peak between years 1 and 2 (15.2%). During the first 5 years, patients with estrogen receptor (ER) - positive disease had a lower annualized hazard compared with those with ER-negative disease (9.9% v 11.5%; P = .01). However, beyond 5 years, patients with ER-positive disease had higher hazards (5 to 10 years: 5.4% v 3.3%; 10 to 15 years: 2.9% v 1.3%; 15 to 20 years: 2.8% v 1.2%; and 20 to 25 years: 1.3% v 1.4%; P < .001). Among patients with ER-positive disease, annualized hazards of recurrence remained elevated and fairly stable beyond 10 years, even for those with no axillary involvement (2.0%, 2.1%, and 1.1% for years 10 to 15, 15 to 20, and 20 to 25, respectively) and for those with one to three positive nodes (3.0%, 3.5%, and 1.5%, respectively). Conclusion: Patients with ER-positive breast cancer maintain a significant recurrence rate during extended follow up. Strategies for follow up and treatments to prevent recurrences may be most efficiently applied and studied in patients with ER-positive disease followed for a long period of time