Annual hazard rates of recurrence
for breast cancer after primary therapy
T Saphner,
DC Tormey and R Gray
PURPOSE: To determine if the long-term increase of recurrence for breast
cancer is stable or slowly decreasing, or if it ever reaches zero; and
to determine the effect of prognostic factors on the hazard of
recurrence. METHODS: All patients entered onto the seven completed
and unblinded Eastern Cooperative Oncology Group (ECOG) coordinated
studies of postoperative adjuvant therapy for breast cancer were
analyzed in terms of annual hazard of recurrence of breast cancer.
RESULTS: For the entire group, the peak hazard of recurrence
occurred in the interval of 1 to 2 years. The hazard decreased
consistently in the interval of 2 to 5 years. Beyond 5 years, the
hazard of recurrence decreased very, very slowly through year 12.
The average hazard of recurrence between years 5 and 12 for
the entire population was 4.3% per year. The pattern of a peak hazard
of recurrence during the first 5 years with a slowly decreasing hazard
of recurrence beyond 5 years was also observed to varying degrees
in most subsets. Higher risk subsets such as patients with more
than three nodes positive had a higher hazard of recurrence at
all time intervals, while lower risk subsets such as patients with
negative nodes had a lower hazard of recurrence in all time periods.
CONCLUSION: Patients 5 years post-surgery for breast cancer appear
to have a very slowly decreasing hazard of recurrence. The mean
hazard of recurrence between years 5 to 12 post-surgery is 4.3%
per year. This group of patients may be well suited for trials evaluating
cytostatic drugs or differentiating agents.
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