Abstract 2034
Background
The degree of oestrogen receptor (ER) expression in ovarian cancer correlates well with its endocrine sensitivity. However, the use of endocrine therapy (ET) in relapsed disease is variable in part due to the lack of phase III data. It is thus unlicensed and not a standard of care. Here we describe the endocrine sensitivity of high grade serous ovarian carcinoma (HGSOC) in a large retrospective cohort.
Methods
Patients were eligible if they had HGSOC treated with prior chemotherapy, and received at least 4 weeks of ET. Exclusion criteria included: ET as a maintenance treatment and unknown duration of therapy (DOT). The best CA125 response across the DOT was recorded as per modified GCIG criteria. Stable CA125 response had to be maintained for at least 12 weeks. The primary endpoint was DOT. Secondary endpoints were time to next therapy (TTNT) from treatment initiation, CA125 objective response rate (ORR) and clinical benefit rate (CBR).
Results
593 patients were identified from the Edinburgh Ovarian Cancer Database between January 1974 and December 2015. 267 patients met the eligibility criteria (78.3% letrozole, 19.5% tamoxifen, 2.2% megestrol acetate). Median DOT and TTNT were 122.5 days (range 28-1427 days) and 161 days (range 41-2345 days), respectively. 33.2% and 14.6% of patients received ET for ≥ 180 and ≥ 365 days, respectively. Of 38 patients on ET for ≥ 365 days, 29 (76%) received ET as 2nd line therapy, 9 (24%) as 3rd line therapy and none as 4th line or later. The CA125 ORR and CBR in evaluable pts was 11.4% (20/175) and 48.6% (85/175), respectively. The CA125 CBR, median DOT and TTNT between different ER histoscore ranges are compared in Table. In early (2nd line) vs late (3rd line onwards) use of ET, the median DOT and TTNT was 140 vs 98 days (HR = 0.68 [95% CI 0.53-0.87]) and 167 vs 138 days (p = 0.022), respectively.Table:
951P
| ER histo-score | CA125 CBR (%) | DOT (days) | Median TTNT (days) | |||
|---|---|---|---|---|---|---|
≥150 vs ConclusionsThe endocrine sensitivity of HGSOC is significantly influenced by the degree of ER expression and line of treatment that ET is used in. Early introduction of ET in the management of relapsed HGSOC should be considered particularly in tumours with an ER histoscore of ≥ 200. Clinical trial identificationNot applicable. Legal entity responsible for the studyProfessor Charlie Gourley FundingNone DisclosureM. MacKean: For the last 10 years; Ad boards: Tessaro, Bristol-Myers Squibb, Roche, Boehringer Ingelheim, Eli Lily and Glaxo Smith Kline. F. Nussey: Has been the local principle investigator for the SOLO 2 trial (randomised phase III trial of maintenance Olaparib in BRCA mutant patients). C. Gourley: AstraZeneca (advisory board, lecture fees, research funding); Clovis (advisory board); Tesaro (advisory board, lecture fees), Roche (advisory board); Novartis (research funding), Nucana (advisory board, research funding) and Aprea (research funding). All other authors have declared no conflicts of interest. Resources from the same session3660 - Tumor-stroma interactions and response to targeted agents in preclinical models of colorectal cancer (CRC)Presenter: Chiara Bazzichetto Session: Poster display session Resources: Abstract 2831 - Molecular profiling of colorectal tumors stratified by the histological tumor-stroma ratioPresenter: Tessa Sandberg Session: Poster display session Resources: Abstract 4988 - The Characteristics and Prognostic Factors in Colorectal Cancer Containing Signet Ring CellPresenter: Xiang Quan Kong Session: Poster display session Resources: Abstract 1844 - Effect of lateral lymph node dissection for lower rectal cancer: An ad hoc analysis of the ACTS-RC randomized clinical trialPresenter: Eiji Oki Session: Poster display session Resources: Abstract 4371 - Effects of mesorectal fascia (MRF) status for locally advanced rectal cancer: Results of a multicenter, randomized, controlled, phase II trial (FDRT-002）Presenter: Ji Zhu Session: Poster display session Resources: Abstract 2018 - Planned organ preservation for selected T2, T3 rectal cancer. French experience using chemo radiotherapy and Contact X Ray boostPresenter: Jean-Pierre Gérard Session: Poster display session Resources: Abstract 2891 - Comparison between magnetic resonance imaging (MRI) and pathology in the assessment of tumour regression grade (TRG) in rectal cancer (RC)Presenter: Francesco Sclafani Session: Poster display session Resources: Abstract 4031 - FOLFIRINOX as induction treatment in rectal cancer patients with synchronous metastases (RCSM): final results of the FFCD 1102 phase II trial.Presenter: Jean-Baptiste BACHET Session: Poster display session Resources: Abstract 3864 - Neoadjuvant treatment with mFOLFOXIRI alone versus chemoradiotherapy in locally advanced rectal cancer: A Propensity Score Analysis from two prospective trialsPresenter: JianWei Zhang Session: Poster display session Resources: Abstract 1429 - Updated survival results of FACT trial: Multicenter phase II trial of neoadjuvant chemotherapy with mFOLFOX6 for stage II/III rectal cancer with a T3/T4 tumor.Presenter: Hirotoshi Hasegawa Session: Poster display session Resources: Abstract This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used. For more detailed information on the cookies we use, please check our Privacy Policy.
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