Staging breast cancer--screening for occult metastases

The authors report on 1,017 consecutive breast cancer cases without symptomatic metastases staged by means of chest X-ray (CXR), skeletal survey (BXR) and bone scintigraphy (BS). Occult metastases (DM) detection rate was 0.88%: 0.29% for lung and 0.59% for bone DM. The detection rate was correlated with clinical stage: 0.36% for stage I, 0.20% for stage II, 0.26% for stages I and II, and 2.77% for stage III cases. The sensitivity based on DM cases prevalent or surfacing within 6 months of follow-up was 0.30 for CXR, 0.22 for BXR and 0.55 for BS; specificity was 0.99, 0.98 and 0.90, respectively. The study confirms the possibility of early detection of DM with preoperative staging, but the extremely low detection rates in stage I and II cancers do not advise such a routine procedure. The higher detection rate of DM may suggest adoption of the routine staging procedure in stage III cancers. In these cases, although no evidence is available of a favorable prognostic impact of early detection and treatment of DM, an unnecessary mastectomy could be avoided in about 3% of cases in the presence of DM detected by the staging procedure.