Optimal surveillance for postoperative metastasis in breast cancer patients

To establish an optimal surveillance schedule after surgery for breast cancer, patients included in an institutional database were retrospectively investigated with respect to the first metastatic site and timing of recurrence. We investigated 11,676 pT1-4pN0-2M0 breast cancer patients treated from 1985 to 2009 and followed up until June 2014. Our surveillance protocol included physician visits and examinations with bone scans, liver echography, chest roentgenography and laboratory tests. We evaluated the liver, bones, lungs and pleura as surveillance covering sites (SCS) in addition to parameters such as time points exceeding 80 % with respect to the accumulated percentage of patients of recurrence and the number of surveillance per one recurrence (NSR), calculated by dividing the number of patients at risk of recurrence at the start of a particular time frame by the number of patients of recurrence at SCS within that period. There were a total of 1,962 recurrent patients, including 601 patients with locoregional recurrence, nine patients with recurrence in the opposite breast, 1,349 patients with recurrence at distant sites and three unknown patients. The number of patients with the bones, lungs, liver and pleura as the first site of recurrence was 447, 324, 144 and 69, respectively, and 72.9 % of the distant metastatic lesions belonged to SCS. The five-year overall survival rate after recurrence among the patients with single recurrent site was longer than that observed among the patients with multiple sites of recurrence (43.3 vs 25.3 %; p < 0.0001). In addition, more than 80 % of the patients of liver metastasis were detected within 5 years after surgery, while 80 % of the patients of pleura metastasis were detected within 10 years. The NSR was below 200 for the 10-year period, as was the NSR of the patients with lymph node metastasis and a positive hormone receptor status. In contrast, the NSR of the patients with a negative hormone receptor status was above 200 after 5 years. In this study, the prognosis of the patients with a single site of recurrence was superior to that of the patients with multiple sites. Curable patients with distant metastases included those with single metastatic sites. The optimal surveillance schedule should be established taking into consideration that the incidence of metastasis differs among metastatic sites during follow-up.