The activity of letrozole in patients with advanced or recurrent endometrial cancer and correlation with biological markers--a study of the National Cancer Institute of Canada Clinical Trials Group

Int J Gynecol Cancer. Jul-Aug 2004;14(4):650-8. doi: 10.1111/j.1048-891X.2004.14419.x.


A multicenter phase II trial was conducted to define the activity of letrozole in postmenopausal women with recurrent or advanced endometrial carcinoma, who had no more than one prior line of progestins and never had chemotherapy (except adjuvant). Archival paraffin-embedded tumor samples were retrieved to determine the expression level of estrogen (ER) and progesterone receptor (PgR), p53, HER-2, bcl-2 and PTEN protein, and phosphorylation status of protein kinase B (PKB/Akt). Thirty-two eligible patients were treated with letrozole at 2.5 mg daily continuously, of whom 10 (31%) had prior progestins. Of the 28 patients evaluated for response, one complete and two partial responses were noted; overall response was 9.4% (95% confidence interval 2-25%). Eleven patients had stable disease for a median duration of 6.7 months (range 3.7-19.3 months). Amongst 22 patients who had tumor blocks available, the proportion showing positive expression of the following markers includes: PgR (86%), ER (86%), PTEN (82%), phosphorylated PKB/Akt (59%), bcl-2 (45%), p53 (32%), and HER-2 (0%). None of these markers correlated with response to letrozole or disease progression. In conclusion, letrozole is well tolerated but has little overall activity in this cohort of women with endometrial cancer.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Agents / therapeutic use*
  • Biomarkers, Tumor / metabolism*
  • Disease Progression
  • Endometrial Neoplasms / drug therapy*
  • Endometrial Neoplasms / metabolism
  • Endometrial Neoplasms / pathology
  • Female
  • Genes, bcl-2 / physiology
  • Genes, erbB-2 / physiology
  • Humans
  • Letrozole
  • Middle Aged
  • Neoplasm Recurrence, Local*
  • Neoplasm Staging
  • Nitriles / therapeutic use*
  • PTEN Phosphohydrolase
  • Phosphoric Monoester Hydrolases / biosynthesis
  • Postmenopause
  • Protein-Serine-Threonine Kinases / biosynthesis
  • Proto-Oncogene Proteins / biosynthesis
  • Proto-Oncogene Proteins c-akt
  • Triazoles / therapeutic use*
  • Tumor Suppressor Protein p53 / biosynthesis
  • Tumor Suppressor Proteins / biosynthesis


  • Antineoplastic Agents
  • Biomarkers, Tumor
  • Nitriles
  • Proto-Oncogene Proteins
  • Triazoles
  • Tumor Suppressor Protein p53
  • Tumor Suppressor Proteins
  • Letrozole
  • AKT1 protein, human
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Phosphoric Monoester Hydrolases
  • PTEN Phosphohydrolase
  • PTEN protein, human