Catherine M. Kelly

Selective serotonin reuptake inhibitors and breast cancer mortality in women receiving tamoxifen: a population based cohort study

Objective To characterise whether some selective serotonin reuptake inhibitor (SSRI) antidepressants reduce tamoxifen’s effectiveness by inhibiting its bioactivation by cytochrome P450 2D6 (CYP2D6). Design Population based cohort study. Participants Women living in Ontario aged 66 years or older treated with tamoxifen for breast cancer between 1993 and 2005 who had overlapping treatment with a single SSRI. Main outcome measures Risk of death from breast cancer after completion of tamoxifen treatment, as a function of the proportion of time on tamoxifen during which each SSRI had been co-prescribed. Results Of 2430 women treated with tamoxifen and a single SSRI, 374 (15.4%) died of breast cancer during follow-up (mean follow-up 2.38 years, SD 2.59). After adjustment for age, duration of tamoxifen treatment, and other potential confounders, absolute increases of 25%, 50%, and 75% in the proportion of time on tamoxifen with overlapping use of paroxetine (an irreversible inhibitor of CYP2D6) were associated with 24%, 54%, and 91% increases in the risk of death from breast cancer, respectively (P<0.05 for each comparison). By contrast, no such risk was seen with other antidepressants. We estimate that use of paroxetine for 41% of tamoxifen treatment (the median overlap in our sample) would result in one additional breast cancer death within five years of cessation of tamoxifen for every 19.7 (95% confidence interval 12.5 to 46.3) patients so treated; the risk with more extensive overlap would be greater. Conclusion Paroxetine use during tamoxifen treatment is associated with an increased risk of death from breast cancer, supporting the hypothesis that paroxetine can reduce or abolish the benefit of tamoxifen in women with breast cancer.

Estrogen and HER-2 Receptor Discordance Between Primary Breast Cancer and Metastasis

Discordance in estrogen receptor and human epidermal growth factor receptor 2 receptor status between the primary tumor and recurrence is frequently reported in the literature. This is frequently interpreted as evidence for a change in the biology of breast cancer during the course of the disease. This commentary discusses some of the caveats of this interpretation. Discordant receptor results can be caused by any of 3 factors: (a) a genuine switch in the biology of the disease, (b) sampling error in focally receptor-positive cancers, and (c) limited accuracy and reproducibility of receptor assays. The relative contribution of each of these factors to discordant results is unknown. A switch in molecular class between primary and recurrent cancer (or residual cancer after therapy) appears to be a rare event based on the available limited molecular profiling data. Small pockets of strongly focally receptor-positive tumor nests in a larger receptor-negative cancer are also relatively infrequently seen. Discordance resulting from inherent limitations in assay reproducibility is evident from the frequently discordant receptor results even when the same samples are assessed in different laboratories (e.g., central versus local laboratory). A repeat tumor biopsy is clearly justified when it is suspected, on clinical grounds, that the original receptor results may have been false negative or when the diagnosis of metastatic disease is in question. However, routine repeat biopsy for receptor re-evaluation does not necessarily improve diagnostic accuracy and have a potential to harm through a false-negative result. For patients with clinical courses consistent with hormone responsiveness, or with prior positive hormone receptor results, a course of endocrine therapy is reasonable regardless of the most recent hormone receptor assay result.

Cost-Effectiveness Analysis of Recurrence Score-Guided Treatment Using a 21-Gene Assay in Early Breast Cancer

PURPOSE Most guidelines for hormone receptor (HR)-positive early breast cancer recommend addition of adjuvant chemotherapy for most women, leading to overtreatment, which causes considerable morbidity and cost. There has been recent incorporation of gene expression analysis in aiding decision making. We evaluated the cost-effectiveness of recurrence score (RS)-guided treatment using 21-gene assay as compared with treatment guided by the Adjuvant! Online program (AOL). PATIENTS AND METHODS A Markov model was developed to compare the cost-effectiveness of treatment guided either by 21-gene assay or by AOL in a 50-year-old woman with lymph node-negative HR-positive breast cancer over a lifetime horizon. We assumed that women classified to be at high risk all received chemotherapy followed by tamoxifen and those classified to be at low risk received tamoxifen only. The model took a health care payers perspective with results reported in 2008 Canadian dollars (

Utility of oncotype DX risk estimates in clinically intermediate risk hormone receptor-positive, HER2-normal, grade II, lymph node-negative breast cancers

). Event rates, costs, and utilities were derived from the literature. Both costs and benefits were discounted at 5%. Outcome measures were life years gained, quality-adjusted life years (QALYs), lifetime costs, and incremental cost-effectiveness ratios (ICERs). RESULTS For a 50-year-old woman, RS-guided treatment was associated with an incremental lifetime cost of

Randomized Controlled Trial of a Computerized Decision Aid on Adjuvant Radioactive Iodine Treatment for Patients With Early-Stage Papillary Thyroid Cancer

4,102 and a gain in 0.065 QALY, with an ICER of

Systematic antibody generation and validation via tissue microarray technology leading to identification of a novel protein prognostic panel in breast cancer

63,064 per QALY compared with AOL-guided treatment. ICER increased with increasing cost of 21-gene assay and increasing age of patients. Results were most sensitive to probabilities relating to risk categorization and recurrence rate. CONCLUSIONS The 21-gene assay appears cost-effective from a Canadian health care perspective.

Phase III Trial Evaluating Weekly Paclitaxel Versus Docetaxel in Combination With Capecitabine in Operable Breast Cancer

Oncotype DX breast cancer assay (Genomic Health, Redwood City, Calif) stratifies patients with early breast cancer according to risk of distant recurrence. The authors hypothesized that the test is ordered when clinicopathological variables yield equivocal risk estimates. The current study also showed how often the test clarifies clinically ambiguous risk status.

Proliferation and estrogen signaling can distinguish patients at risk for early versus late relapse among estrogen receptor positive breast cancers.

PURPOSE Decision-making on adjuvant radioactive iodine (RAI) treatment for early-stage papillary thyroid cancer (PTC) is complex because of uncertainties in medical evidence. Using a parallel, two-arm, randomized, controlled trial design, we examined the impact of a patient-directed computerized decision aid (DA) on the medical knowledge and decisional conflict in patients with early-stage PTC considering the choice of being treated with adjuvant RAI or not. The DA describes the rationale, possible risks and benefits, and the medical evidence uncertainty relating to the choice. PATIENTS AND METHODS We recruited 74 patients with early-stage PTC after thyroidectomy. Participants were assigned by using 1:1 central computerized randomization to either the DA group with usual care (intervention) or usual care alone (control). Medical knowledge about PTC and RAI treatment (the primary outcome), as well as decisional conflict (a secondary outcome), were measured by using validated questionnaires, and the respective scores were compared between groups. RESULTS Consistent with PTC epidemiology, 83.8% (62 of 74) of the participants were women, and the mean age was 45.8 years (range, 19 to 79 years). Medical knowledge about PTC and RAI treatment was significantly greater and decisional conflict was significantly reduced in the DA group compared with the control group (respective P values < .001). The use of adjuvant RAI treatment was not significantly different between groups (DA group, 11 of 37 [29.7%]; controls, seven of 37 [18.9%]; P = .278). CONCLUSION A computerized DA improves informed decision making in patients with early-stage PTC who are considering adjuvant RAI treatment. DAs are useful for patients facing decisions subject to medical evidence uncertainty.

Coping with uncertainty: T1a,bN0M0 HER2-positive breast cancer, do we have a treatment threshold?

BackgroundAlthough omic-based discovery approaches can provide powerful tools for biomarker identification, several reservations have been raised regarding the clinical applicability of gene expression studies, such as their prohibitive cost. However, the limited availability of antibodies is a key barrier to the development of a lower cost alternative, namely a discrete collection of immunohistochemistry (IHC)-based biomarkers. The aim of this study was to use a systematic approach to generate and screen affinity-purified, mono-specific antibodies targeting progression-related biomarkers, with a view towards developing a clinically applicable IHC-based prognostic biomarker panel for breast cancer.MethodsWe examined both in-house and publicly available breast cancer DNA microarray datasets relating to invasion and metastasis, thus identifying a cohort of candidate progression-associated biomarkers. Of these, 18 antibodies were released for extended analysis. Validated antibodies were screened against a tissue microarray (TMA) constructed from a cohort of consecutive breast cancer cases (n = 512) to test the immunohistochemical surrogate signature.ResultsAntibody screening revealed 3 candidate prognostic markers: the cell cycle regulator, Anillin (ANLN); the mitogen-activated protein kinase, PDZ-Binding Kinase (PBK); and the estrogen response gene, PDZ-Domain Containing 1 (PDZK1). Increased expression of ANLN and PBK was associated with poor prognosis, whilst increased expression of PDZK1 was associated with good prognosis. A 3-marker signature comprised of high PBK, high ANLN and low PDZK1 expression was associated with decreased recurrence-free survival (p < 0.001) and breast cancer-specific survival (BCSS) (p < 0.001). This novel signature was associated with high tumour grade (p < 0.001), positive nodal status (p = 0.029), ER-negativity (p = 0.006), Her2-positivity (p = 0.036) and high Ki67 status (p < 0.001). However, multivariate Cox regression demonstrated that the signature was not a significant predictor of BCSS (HR = 6.38; 95% CI = 0.79-51.26, p = 0.082).ConclusionsWe have developed a comprehensive biomarker pathway that extends from discovery through to validation on a TMA platform. This proof-of-concept study has resulted in the identification of a novel 3-protein prognostic panel. Additional biochemical markers, interrogated using this high-throughput platform, may further augment the prognostic accuracy of this panel to a point that may allow implementation into routine clinical practice.

Enzalutamide for the Treatment of Androgen Receptor–Expressing Triple-Negative Breast Cancer

PURPOSE We investigated whether capecitabine and docetaxel followed by fluorouracil, epirubicin, and cyclophosphamide (FEC) or weekly paclitaxel (WP) followed by FEC would improve relapse-free survival (RFS) in operable breast cancer. PATIENTS AND METHODS In this single-institution study, patients with clinical stages I to IIIC breast cancer were randomly assigned on a 1:1 basis to WP 80 mg/m(2) for 12 weeks followed by fluorouracil 500 mg/m(2), epirubicin 100 mg/m(2), and cyclophosphamide 500 mg/m(2) (FEC-100) every 3 weeks for four cycles or docetaxel 75 mg/m(2) on day 1 and capecitabine (XT) 1,500 mg/m(2) on days 1 through 14 every 3 weeks for four cycles followed by FEC for four cycles and stratified by timing of chemotherapy (preoperative v adjuvant). Accrual was stopped short of 930 patients on the basis of a Bayesian predictive calculation that additional accrual would be unlikely to change the qualitative comparison of the two regimens. RESULTS After enrollment of 601 patients and a median follow-up of 50 months, we observed no improvement in RFS between XT (87.5%; 95% CI, 82.7% to 91.1%) and WP (90.7%; 95% CI, 86.4% to 93.7%; P = .51). In the preoperative group, the pathologic complete response rate was 19.8% and 16.4% in the XT and WP arms, respectively (P = .45). Rates of breast-conserving surgery were similar between the two groups (P = .48). The XT arm had a significantly higher incidence of stomatitis (P < .001), hand-foot syndrome (P < .001), and neutropenic infection (P < .001). CONCLUSION There was no difference in efficacy between WP and XT as used in this randomized phase III trial. XT was associated with higher GI, skin, and neutropenic-related toxicities.