The West German Study Group Breast Cancer Intrinsic Subtype study: a prospective multicenter decision impact study utilizing the Prosigna assay for adjuvant treatment decision-making in estrogen-receptor-positive, HER2-negative early-stage breast cancer

PURPOSE

The West German Study Group (WSG) Breast Cancer Intrinsic Subtype (BCIST) study was designed to assess the influence of Prosigna gene signature assay results on physicians' adjuvant treatment recommendations by determining the extent of change in pre-test treatment recommendations following assay results. Secondary objectives were to assess the influence of Prosigna results on physicians' confidence in their therapeutic recommendations and on patients' decisional conflict status, anxiety levels, and functional status.

METHODS

This prospective, observational, decision impact study enrolled consecutive postmenopausal patients with estrogen-receptor (ER)-positive, HER2-negative, lymph-node-negative early-stage breast cancer in 11 centers in Germany. Physicians based their pre-test adjuvant treatment recommendations on standard clinico-pathological parameters. Tumor specimens were assayed using the Prosigna test in a WSG central pathology laboratory following manufacturer's guidelines. An independent pathology laboratory performed subsequent Prosigna assays on tumor sections to assess assay result concordance with the central laboratory. Physicians completed treatment confidence questionnaires prior to and after receiving Prosigna test results. Patients completed standardized questionnaires on decisional conflict, anxiety, and health status both before and after Prosigna testing.

RESULTS

The present study population consisted predominantly of low-to-intermediate risk patients (N = 198). Prosigna had 29.3% discordance in intrinsic subtyping with local immunohistochemistry test results. After Prosigna test results, a change in the adjuvant therapy recommendation occurred in 36 (18.2%) patients; 22 (11.1%) patients switched from no chemotherapy to chemotherapy. After Prosigna test results, physicians expressed increased confidence in their prognostic assessment in 87.9% of patients, and increased confidence in their treatment recommendation in 89.4%. Patients reported improved anxiety and emotional/functional well-being after receiving Prosigna test results.

CONCLUSIONS

Use of the Prosigna assay led to a change in 18.2% of adjuvant treatment decisions. Prosigna testing was associated with increased patient and physician confidence in treatment decisions, and with decreased patient anxiety and improved well-being. Any comparison of the therapeutic decision-making impacts of different genomic assays must account for potential confounding factors.

A randomized multicenter phase III trial of topotecan monotherapy versus topotecan + etoposide versus topotecan + gemcitabine for second-line treatment of recurrent ovarian cancer

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Background: Topotecan combined with etoposide (GINECO 1998) and gemcitabine (NOGGO 2001) proved effective for second-line treatment of recurrent ovarian cancer. It is, however, unclear whether combined treatment improves survival and tumor control compared to topotecan alone. Methods: Women with recurrent ovarian cancer after primary surgery and platinum therapy were enrolled in an open-label randomized phase-III trial at 93 German institutions. Stratifying for treatment-free intervals (TFI) of less or more than 12 months, subjects were centrally allocated to topotecan 1.25 mg/m2/d (TM), topotecan 1.0 mg/m2/d plus oral etoposide 50 mg/d (TE) on day 6–12, or topotecan 0.5 mg/m2/d plus gemcitabine (TG) 800 mg/m2/d1 and 600 mg/m2/d8 every three weeks. Local institutional review boards approved this study, and all patients provided written informed consent. With 145 subjects each arm, this study yielded 90% power to detect a Hazard Ratio (HR) of 0.60 in overall survival (OS) at a two-sided alpha of 0.01. We employed Cox regression for primary endpoint analysis, and addressed progression-free survival (PFS) and toxicity descriptively. Results: Between September 1999 and November 2004, 3036 courses were administered to 505 patients (mean age 60.4 [SD 11.3] years), 208 of whom had a TFI <12 months. Women assigned to TM, TE, and TG received a median of 6.7 (range, 0–10), 6.2 (0–9), and 5.4 (1–42) cycles. Median OS after TM, TE, and TG was 17.8, 17.8, and 15.3 months. Setting TM as the reference, HRs for OS with TE and TG were 1.13 (95% confidence interval [CI] 0.87–1.47) and 1.07 (95% CI 0.80–1.43, p = 0.590). HRs for PFS with TE and TG versus TM were calculated at 0.84 (95% CI 0.66–1.07) each. Subgroup analysis suggested enhanced PFS among subjects with TFI ≥12 months who received TE (HR 0.62, 95% CI 0.42–0.91) or TG (HR 0.68, 95% CI 0.46–1.01) rather than TM. TE produced higher CTC grade 3/4 hematotoxicity than TM or TG, with cumulative incidences of 24.4% (95% CI 20.2–29.0%), 16.0% (95% CI 11.9–20.9%), and 14.7% (10.6–19.5%). Conclusions: This large RCT does not provide evidence that combined treatment performs generally better than topotecan monotherapy in recurrent ovarian cancer.

No significant financial relationships to disclose.