Detection of isolated ipsilateral regional lymph node recurrences by F18-fluorodeoxyglucose positron emission tomography-CT in follow-up of postoperative breast cancer patients.

Imaging diagnostic methods except for mammograms are not recommended for follow-up of postoperative breast cancer patients in order to detect small recurrences because of the poor survival improvement in earlier randomized trials. However, the use of new imaging modalities may improve survival by detection of small isolated regional lymph node recurrences which are potentially curable. Between April 2006 and December 2008, we used PET-CT to find small recurrences in follow-up of 1,907 postoperative breast cancer patients. A total of 3,280 PET-CT imagings were performed. The median age at PET-CT imaging was 58 years, with a median 48-month interval from definitive surgery to the PET-CT imaging. Twenty-two patients were found to have isolated ipsilateral regional recurrences only by PET-CT (axillary node recurrences in 6, infraclavicular node recurrences in 5, supraclavicular node recurrences in 6, and parasternal node recurrences in 5). All of those recurrences were missed by palpation or were nonpalpable. The pathological lymph node status at the definitive surgery for the primary breast cancer of 22 patients with the isolated ipsilateral regional lymph node recurrences was positive in 17 patients. If patients are limited to those who had pathologically positive node(s) at definitive surgery, the incidence of patients with isolated regional lymph node recurrences found only by PET-CT would be 2.6% (17/663 patients). Seventeen other asymptomatic cancers including contralateral breast cancers were found only by PET-CT. Early detection of isolated loco-regional recurrences of breast cancer is suggested to result in improved survival. Therefore, the use of PET-CT in follow-up of postoperative node-positive breast cancer patients may improve their survival because of early detection of isolated regional lymph node recurrences which are still potentially curable, and screening of other asymptomatic cancers.