Surveillance After Stage II – III Breast Cancer: Routine Vs. Symptomatic Imaging
Current guidelines recommend only clinician visits to detect breast cancer recurrence following initial treatment. Imaging is only recommended for those patients demonstrating signs or symptoms of recurrence. These guidelines apply to all locoregional breast cancer patients regardless of stage or molecular subtype. In the 1980s clinical trials supported these guidelines. The largest and most often quoted trial is a 2005 Cochrane review which showed no difference in disease-free and overall survival with intensive systemic imaging compared with annual physician visits alone (Rojas et al., Cochrane Database Syst Rev. 2005). Since these trials were completed, much has changed in imaging, treatment, and molecular risk evaluation. “To that end, the authors assessed survival in patients with distant recurrence after locoregional breast cancer detected by a symptomatic imaging vs signs and/or symptoms, stratified by molecular subtype.” Imaging varied among patients, but included chest CT, abdominal CT, pelvic CT, MRI, head CT and MRI, bone scan, PET or PET/CT. The data source was medical records from the National Cancer Database, a national registry. The authors used overall survival as the primary outcome which they defined as the number of days from the initial cancer diagnosis to death. The researchers chose overall survival as opposed to distant recurrence detection to reduce the potential for lead-time bias.
Results
The cohort consisted of 9560 women with locoregional breast cancer. In the entire cohort, 1220 recurrences were detected. The unadjusted five-year distant recurrence rate was 12.8% (21.9% for patients with triple-negative, 13.9% for HER-2 positive, and 10.1% for ER-positive or PR-positive, HER2 negative cancers.) Recurrences were detected by signs and or symptoms in 76.7% (936 of 1220) and asymptomatic imaging and 23.3% (284 of 1220). Using propensity weighting and other statistical methodology, patients with asymptomatic as compared with signs and or symptoms detected recurrences had a statistically significantly lower risk of death at five and nine years if they were triple negative or HER2 positive (HR = 0.66 at 5 years and 0.73 at 9 years for triple-negative: HR = 0.40 at 5 years and 0.51 at 9 years). This is in distinction to ER-positive or PR-positive, HER2-negative cancers in which there was no significant statistical association. According to the authors, this translated to an absolute between-group difference in weighted median survival of approximately five months for triple-negative and 12 months for HER2-positive tumors.
Conclusions
The researchers noted that this study found no survival advantage with asymptomatic detection of distant recurrence for women with ER-positive or PR-positive, HER2-negative disease. This is significant in that approximately two-thirds of all newly diagnosed breast cancers are this molecular subtype. Consequently, this subtype would likely not benefit from routine imaging on follow-up surveillance. However, it may be that going forward the use of imaging in patients of this molecular subtype with high recurrence scores may be suitable for routine imaging. This will clearly take randomized trial to determine. This study however did clearly demonstrate a survival advantage with the use of routine periodic imaging in patients with stage II and III breast cancer that are HER2-positive or triple negative.
Dr. Alan Stolier, MD, FACS, clinical breast oncologist, shares his expert medical perspective with a series of educational and scientific articles.
