Dormancy of mammary carcinoma after mastectomy

Background: The longest interval between primary treatment of breast cancer and tumor recurrence, i.e., the limit of breast cancer dormancy, defines t he appropriate length of follow-up, the effectiveness of treatment, and cur ability (no excess mortality risk for patients relative to the general popu lation) for the disease. To determine this limit, we analyzed long-term fol low-up data from patients who underwent a radical mastectomy during a four- decade period at the University of Chicago Hospitals. Methods: For 1547 pat ients operated on during the period from 1945 through mid-1987, the number of recurrences and deaths occurring within each postoperative year were tab ulated, and the hazard rate for first recurrence or death from breast cance r was estimated by use of the actuarial method. The excess mortality rate w as calculated for successive 5-year intervals, beginning at the time of mas tectomy, by use of U.S. life tables and matching on the basis of age, race, and sex. Results: Most recurrences occurred within the first 10 years afte r mastectomy, Recurrences were rare after 20 years; only one recurrence was reported among 192 patients followed for 26-45 years. Patients who had a r ecurrence within 5 years following mastectomy had shorter subsequent surviv al times than those whose recurrence appeared after 5 years (two-sided P = .0001), The excess death rate increased with pathologic stage of the primar y tumor, Overall, there was evidence of excess mortality up to 20 years pos tsurgery (two-sided P = .009), Conclusions: The limit of breast cancer dorm ancy in this patient population appears to be between 20 and 25 years. Afte r this time, recurrences were rare, and the mortality rate was no longer st atistically significantly different from that of the general population, Pa tients surviving to this time without evidence of recurrence or contralater al breast cancer are probably cured.