TC-99M SESTAMIBI - AN INDICATOR OF BREAST-CANCER INVASIVENESS

As recently shown, angiogenesis is the most reliable marker of breast cancer invasiveness. Unfortunately it must be assessed by immunohistoc hemistry on tissue specimens. We have used technetium-99m sestamibi, a marker of regional blood flow in other organs that often but not alwa ys images breast cancer, to assess the invasiveness of this tumour. Ni neteen patients, ten with nodal metastases and nine without any metast ases, were studied with Tc-99m-sestamibi scintigraphy before operation . Angiogenesis was quantitatively assessed by immunohistochemical stai ning of endothelia for factor VIII. All the node-positive (N+) patient s at surgical revision showed a positive Tc-99m-sestamibi scan of the primary tumour and all the N-patients were negative. Nine out of ten N + and sestamibi-positive tumours showed more than 135 microvessels/mm( 2) and one showed 99 microvessels/mm(2); by contrast there were 71.6+/ -12.1 microvessels/mm(2) in the nine N- and sestamibi-negative tumours . Our study suggests that Tc-99m-sestamibi is a marker of breast cance r invasiveness: its uptake is related to angiogenesis and, possibly, t o oxidative metabolism of the tumour.