Effect of continuous statistically standardized measures of estrogen and progesterone receptors on disease-free survival in NCIC CTG MA.12 Trial and BC Cohort.

INTRODUCTION: We hypothesized improved inter-laboratory comparability of estrogen receptor (ER) and progesterone receptor (PgR) across different assay methodologies with adjunctive statistical standardization, akin to bone mineral density (BMD) z-scores. We examined statistical standardization in MA.12, a placebo-controlled pre-menopausal trial of adjuvant tamoxifen with locally assessed hormone receptor +/- tumours, and in a cohort of post-menopausal British Columbia (BC) tamoxifen-treated patients. METHODS: ER and PgR were centrally assessed for both patient groups with real time quantitative reverse transcription polymerase chain reaction (qPCR) and immunohistochemistry (IHC). Effects on disease-free survival (DFS) were investigated separately for 345 MA.12 and 673 BC patients who had both qPCR and IHC assessments. Comparisons utilized continuous laboratory units and statistically standardized z-scores. Univariate categorization of ER/PgR was by number of standard deviations (SD) above or below the mean (z-score ≥1.0 SD below mean; z-score <1.0 SD below mean; z-score ≤1.0 SD above mean; z-score >1.0 SD above mean). Exploratory multivariate examinations utilized step-wise Cox regression. RESULTS: Median follow-up for MA.12 was 9.7 years; for BC patients, 11.8 years. For MA.12, 101 of 345 (29%) patients were IHC ER-PgR-. ER was not univariately associated with DFS (qPCR, P = 0.19; IHC, P = 0.08), while PgR was (qPCR, P = 0.09; IHC, P = 0.04). For BC patients, neither receptor was univariately associated with DFS: for ER, PCR, P = 0.36, IHC, P = 0.24; while for PgR, qPCR, P = 0.17, IHC, P = 0.31. Multivariately, MA.12 patients randomized to tamoxifen had significantly better DFS (P = 0.002 to 0.005) than placebo. Meanwhile, jointly ER and PgR were not associated with DFS whether assessed by qPCR or by IHC in all patients, or in the subgroup of patients with IHC positive stain, for pooled or separate treatment arms. Different results by type of continuous unit supported the concept of ER level being relevant for medical decision-making. For postmenopausal BC tamoxifen patients, higher qPCR PgR was weakly associated with better DFS (P = 0.06). CONCLUSIONS: MA.12 pre-menopausal patients in a placebo-controlled tamoxifen trial had similar multivariate prognostic effects with statistically standardized hormone receptors when tumours were assayed by qPCR or IHC, for hormone receptor +/- and + tumours. The BC post-menopausal tamoxifen cohort did not exhibit a significant prognostic association of ER or PgR with DFS. Adjunctive statistical standardization is currently under investigation in other NCIC CTG endocrine trials.

Prognostic and predictive value of epidermal growth factor receptor tyrosine kinase domain mutation status and gene copy number for adjuvant chemotherapy in non-small cell lung cancer.

PURPOSE: Patients with non-small cell lung carcinoma with epidermal growth factor receptor (EGFR) mutations may have a more favorable prognosis and greater response to chemotherapy. The effect of EGFR mutation and gene copy on patients with early-stage non-small cell lung carcinoma receiving adjuvant chemotherapy has not been reported. PATIENTS AND METHODS: Tumor samples from NCIC Clinical Trials Group JBR.10, an adjuvant trial of vinorelbine/cisplatin adjuvant chemotherapy [ACT] versus observation (OBS), were analyzed for EGFR mutation by multiple sensitive methods and copy number by fluorescent in situ hybridization. Their prognostic and predictive roles were explored in correlation with survival. RESULTS: Mutation results were available in 221 OBS and 215 ACT and fluorescent in situ hybridization results in 159 OBS and 163 ACT patients. Mutations were identified in 43 (27 OBS and 16 ACT) patients (36 sensitizing exon 19 deletions or L858R mutations). Compared with wild-type, sensitizing mutations were not significantly prognostic in OBS patients (hazard ratio [HR]: 0.79, 95% confidence interval [CI]: 0.38-1.63, p = 0.53). Although the presence of sensitizing mutations resulted in relatively greater benefit in ACT patients (HR: 0.44, 95% CI: 0.11-1.70, p = 0.22) compared with wild-type patients (HR: 0.78, 95% CI: 0.58-1.06, p = 0.12), this quantitative difference was not significant (interaction p = 0.50). Similarly, high EGFR copy was neither significantly prognostic nor predictive, although quantitatively it was associated with greater benefit from ACT. CONCLUSIONS: Trends toward longer survival and a greater benefit from chemotherapy were observed in patients with exon 19/21 mutations and high EGFR copy, although the differences were not statistically significant. The interpretation of the results was limited by the low EGFR mutation rate in this study of mainly white patients.