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BACKGROUND: Activation of the PI3K/MAPK pathways results in anti-estrogen resistance in vitro, however a biomarker that can predict clinical resistance has not yet been identified. Common drivers of these pathways are PIK3CA mutations, loss of PTEN and over-expression of HER2 and IGF-1R. We aimed to test the prognostic and predictive value of PI3K/MAPK pathway drivers as well as downstream activated proteins in postmenopausal breast cancer patients. METHODS: We collected primary tumor tissue from 563 ERα positive breast cancer patients who were randomized between tamoxifen (1-3 years) versus no adjuvant systemic therapy. PIK3CA hotspot mutations were assessed by Sequenom Mass Spectrometry. Immunohistochemistry was performed for expression of PTEN, IGF-1R and the downstream markers p-AKT(Thr308), p-AKT(Ser473), p-mTOR, p-p706SK and p-ERK1/2. Cox proportional hazard models for recurrence free interval were used to assess hazard ratios and interaction between these markers and treatment. RESULTS: No significant interaction between any of the tested PI3K/MAPK pathways drivers and tamoxifen was found. [/bold]However, interactions were identified between tamoxifen and the downstream activated proteins (p-AKT(Thr308), p- mTOR, p-p70S6K and p-ERK1/2). After correcting for multiple testing, p-p70S6K remained significantly associated with tamoxifen resistance. Patients whose tumor did not express p-p70S6K did derive significant benefit from tamoxifen (HR 0.24, 95 % CI= 0.12-0.47, p < 0.0001), while patients whose tumor did express p-p70S6K did not (multivariate HR=1.02, 95% CI=0.48-2.21, p = 0.95), p for interaction 0.003. CONCLUSION: We conclude that the downstream marker of PI3K/MAPK activation p-p70S6K predicts tamoxifen resistance in ERα positive postmenopausal breast cancer patients. [ABSTRACT FROM AUTHOR]

Background: In the absence of prognostic biomarkers, most patients with early-stage triple-negative breast cancer (eTNBC) are treated with combination chemotherapy. The identification of biomarkers to select patients for whom treatment de-escalation or escalation could be considered remains an unmet need. We evaluated the prognostic value of histopathologic traits in a unique cohort of young, (neo)adjuvant chemotherapy-naïve patients with early-stage (stage I or II), node-negative TNBC and long-term follow-up, in relation to stromal tumor-infiltrating lymphocytes (sTILs) for which the prognostic value was recently reported., Materials and Methods: We studied all 485 patients with node-negative eTNBC from the population-based PARADIGM cohort which selected women aged <40 years diagnosed between 1989 and 2000. None of the patients had received (neo)adjuvant chemotherapy according to standard practice at the time. Associations between histopathologic traits and breast cancer-specific survival (BCSS) were analyzed with Cox proportional hazard models., Results: With a median follow-up of 20.0 years, an independent prognostic value for BCSS was observed for lymphovascular invasion (LVI) [adjusted (adj.) hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.49-3.69], fibrotic focus (adj. HR 1.61, 95% CI 1.09-2.37) and sTILs (per 10% increment adj. HR 0.75, 95% CI 0.69-0.82). In the sTILs <30% subgroup, the presence of LVI resulted in a higher cumulative incidence of breast cancer death (at 20 years, 58%; 95% CI 41% to 72%) compared with when LVI was absent (at 20 years, 32%; 95% CI 26% to 39%). In the ≥75% sTILs subgroup, the presence of LVI might be associated with poor survival (HR 11.45, 95% CI 0.71-182.36, two deaths). We confirm the lack of prognostic value of androgen receptor expression and human epidermal growth factor receptor 2 -low status., Conclusions: sTILs, LVI and fibrotic focus provide independent prognostic information in young women with node-negative eTNBC. Our results are of importance for the selection of patients for de-escalation and escalation trials., Competing Interests: Disclosure PJvD has advisory relationships with Paige, Pantarei and Samantree, paid to the institution, and research grants paid to the institute from Pfizer. NS received institutional research funding from Pfizer. ZV has a consulting role for Roche. CHMvD received institutional research funding from AstraZeneca/Daiichi Sankyo. SMW has a consulting role for Roche, and received institutional research funding from Roche, Pfizer, Bayer, MSD, AstraZeneca/Merck and Amgen. SMW has a consulting role for IDDI, Sensorion, Biophytis, Servier, Yuhan, Amaris Consulting and Roche. JW received institutional research funding from Cancer Research UK and KWF Dutch Cancer Society. AR has a consulting role for MSD Oncology, Amgen, Roche, AstraZeneca/Daiichi Sankyo and Bristol Myers Squibb/Pfizer. SCL reports grants from ZonMw and A Sister’s Hope during the conduct of the study; has been an advisory board member for AstraZeneca, Cergentis, IBM, Novartis, Pfizer, Sanofi and Roche; and received institutional research grants from Agendia, AstraZeneca, Eurocept-pharmaceuticals and Merck and Pfizer. In addition, SCL received institutional research grants and institutional non-financial support from Agendia, Genentech, Novartis, Roche, Tesaro and Immunomedics and other institutional support from AstraZeneca, Pfizer, Cergentis, Daiichi Sankyo, IBM and Bayer outside the submitted work. MK is an advisory board member and/or received speakers’ fee for/from Alderaan, Bristol Myers Squibb (BMS), Domain Therapeutics, Gilead, Roche, Medscape, MSD and AZ/Daiichi and received institutional research support from AstraZeneca/Daiichi, BMS and Roche outside the submitted work. RS reports non-financial support from Merck and BMS, research support from Merck, Puma Biotechnology and Roche, and personal fees from Roche, BMS and Exact Sciences for advisory boards. IRK received research grants from Novartis and Gilead. RHTK is an advisory board member for Amgen, AstraZeneca, Bayer, BMS, MSD, Novartis, Pfizer, Pierre Fabre Sante, Sanofi and Servier. All other authors have declared no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Histopathological examination of possible metastasis; indispensable or diagnostic excess?

Background: In 2007 the St. Gallen consensus panel defined three endocrine response classes: highly endocrine responsive (ER-H), incomplete endocrine responsive (ER-I) and non-endocrine responsive tumours (ER-N). However, it is uncertain whether ER-I tumours are less responsive than ER-H tumours. We investigated whether recurrence rates vary over time between response classes. Additionally, we investigated the most predictive response class definition for tamoxifen benefit., Patients and Methods: We recollected tumours from 646 patients who participated in a randomized trial of adjuvant tamoxifen vs., Observation: Estrogen receptor (ER), progesterone receptor (PgR), HER2 status and tumour grade were revised centrally. St. Gallen classes were evaluated for recurrence free interval (RFI). Change in hazards over time was assessed. Subsequently, 6 alternative response class definitions were compared to optimize the cut-off for PgR and ER., Results: Schoenfeld residuals indicate a failure of proportional hazards between the endocrine response groups (p = 0.0001). The HR for recurrence risk shifted over time with the ER-H group initially being at lower risk (HR ER-H vs. ER-I 0.5), but after six years the recurrence risk increased (HR 1.9). The cut-off values for ER and PgR that statistically best discriminated RFI in the first 4 years for lymph node positive patients were ER ≥ 50% and PgR ≥ 75%., Conclusion: We demonstrated a marked variability in endocrine therapy benefit. Patients with ER-H tumours have a larger benefit during adjuvant tamoxifen and in the first years after accomplishing of the therapy, but suffer from late recurrences. This might have implications for optimal treatment duration., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Clinical decision-making in patients with early stage breast cancer requires adequate risk estimation by medical oncologists. This survey evaluates the agreement among oncologists on risk estimations and adjuvant systemic treatment (AST) decisions and the impact of adding the 70-gene signature to known clinico-pathological factors., Methods: Twelve medical oncologists assessed 37 breast cancer cases (cT1-3N0M0) and estimated their risk of recurrence (high or low) and gave a recommendation for AST. Cases were presented in two written questionnaires sent 4 weeks apart. Only the second questionnaire included the 70-gene signature result., Results: The level of agreement among oncologists in risk estimation (κ=0.57) and AST recommendation (κ=0.57) was 'moderate' in the first questionnaire. Adding the 70-gene signature result significantly increased the agreement in risk estimation to 'substantial' (κ=0.61), while agreement in AST recommendations remained 'moderate' (κ=0.56). Overall, the proportion of high risk was reduced with 7.4% (range: 6.9-22.9%; p<0.001) and the proportion of chemotherapy that was recommended was reduced with 12.2% (range: 5.4-29.5%; p<0.001)., Conclusion: Oncologists' risk estimations and AST recommendations vary greatly. Even though the number of participating oncologists is low, our results underline the need for a better standardisation tool in clinical decision-making, in which integration of the 70-gene signature may be helpful in certain subgroups to provide patients with individualised, but standardised treatment., (Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.)

Aims: To report our clinical experience of panitumumab monotherapy as a second-line treatment for patients with metastatic colorectal cancer (mCRC)., Materials and Methods: This retrospective, descriptive study included a series of consecutive patients receiving panitumumab monotherapy (6 mg/kg 2 weekly) at a single centre in the Netherlands between June 2009 and November 2011. All patients had wild-type KRAS tumours, had progressed during first-line fluoropyrimidine-based therapy and were not candidates for, or refused, standard second-line therapy (usually irinotecan in the Netherlands). Prophylactic medication was given for epidermal growth factor receptor inhibitor-associated skin toxicities., Results: Thirty-one patients were treated during this period. The most commonly administered first-line mCRC regimen was capecitabine/oxaliplatin/bevacizumab (18/31 patients; 58.1%). Patients received a mean of 7.9 (range 1-18) panitumumab cycles. The median progression-free survival was 3.4 (95% confidence interval 2.4, 4.4) months. The median overall survival estimates were 11.4 (95% confidence interval 1.2, 21.6) months from the initiation of panitumumab monotherapy. Ten patients experienced partial responses according to Response Evaluation Criteria In Solid Tumors (RECIST; objective response rate: 32.3%); disease was controlled (objective response or stable disease) in 15 patients (48.4%). Carcinoembryonic antigen (CEA) responses (two consecutive ≥10% decreases from baseline) occurred in 11/29 patients (37.9%); all of whom had >50% decreases in CEA levels. All patients with an objective response at week 12 had CEA reductions at weeks 6 and 12. The only adverse events were grade 1/2 skin toxicities (61.3%) and gastrointestinal complaints (6.5%); three other patients (9.7%) experienced both skin and gastrointestinal complaints., Conclusion: Panitumumab monotherapy seems to be a safe and active second-line treatment for patients with wild-type KRAS mCRC, with activity in line with that seen for irinotecan monotherapy, but with less toxicity. CEA may provide a useful early indicator of response to panitumumab., (Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

The development and validation of a bioanalytical assay is described for the simultaneous analysis in human serum of tamoxifen, four of its main metabolites and three flavonoids, which are known constituents in alternative medicine and dietary supplements often used by breast cancer patients. The method has been fully validated at linear ranges covering steady-state serum concentrations in patients who receive therapeutic dosages of tamoxifen. The wide range also allows for quantification of large inter-patient fluctuations of flavonoid concentrations. The bioanalytical assay is based on reversed phase liquid chromatography coupled with tandem mass spectrometry in the positive ion mode using multiple reaction monitoring for drug (-metabolite) quantification. The sample pretreatment consists of a protein precipitation with acetonitrile using only 50 microL serum. The described method is simple, robust and reproducible with inter- and intra-assay accuracies within 85-115%. The applicability of the assay was demonstrated and it is now successfully used to study the in vivo pharmacokinetics of tamoxifen, its main metabolites and flavonoids in human serum of patients receiving tamoxifen.

Phosphorylation of oestrogen receptor alpha at serine 305 (ERalphaS305-P) induces tamoxifen resistance in experimental studies, but does not influence response to other endocrine agents, such as fulvestrant. We evaluated ERalphaS305-P using immunohistochemistry in 377 breast carcinomas from premenopausal participants of a randomized trial (n=248) and patients with advanced disease (n=129). Among the premenopausal patients, adjuvant tamoxifen improved recurrence-free survival (RFS) for ERalphaS305-P-negative tumours (multivariate HR=0.53, 95% CI 0.32-0.86, p=0.010), but not for ERalphaS305-P-positive tumours (multivariate HR=1.01, 95% CI 0.33-3.05, p=0.99) (interaction p=0.131). Notably, ERalphaS305-P was not significantly associated with RFS in patients not treated with tamoxifen (multivariate HR=0.64, 95% CI 0.30-1.37, p=0.248), indicating that ERalphaS305-P is a marker for treatment outcome rather than tumour progression. Given the direct experimental link between ERalphaS305-P and tamoxifen resistance and these first clinical data suggesting that premenopausal patients with ERalphaS305-P-positive breast cancer are resistant to adjuvant tamoxifen, further research is encouraged to study whether alternative endocrine treatment should be considered for this subgroup.