Pathologic Changes in Breast Cancer After Anti-Estrogen Therapy

The Breast Journal, 05/25/2012

These findings indicate increased differentiation of the tumor cells in response to anti–estrogen therapy and that may correlate with clinical response.


  • Authors reviewed a cohort of patients who received preoperative anti–estrogen therapy after baseline biopsy and then had a repeat biopsy after several weeks on treatment.
  • Patients with estrogen receptor positive tumors received anastrozole and fulvestrant in combination with gefitinib.
  • Core needle biopsies were performed at day 1 and 21, and tumors were completely excised if operable at day 112.
  • All patients were postmenopausal.


  • Following treatment, tumors had degenerative changes including smudged nuclei, decreased nuclear size, intranuclear vacuoles, vacuolated cytoplasm, and increased cellular discohesion.
  • In addition, increased tubule formation and intracytoplasmic lumina were seen in 6/9 cases (66.7%) and decreased mitotic rate was demonstrated in 7/9 cases (77.8%).

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