Breast Cancer Subtypes and Response to Docetaxel in Node-Positive Breast Cancer: Use of an Immunohistochemical Definition in the BCIRG 001 Trial

PurposeTo investigate the prognostic and predictive significance of subtyping node-positive early breast cancer by immunohistochemistry in a clinical trial of a docetaxel-containing regimen.MethodsPathologic data from a central laboratory were available for 1,350 patients (91%) from the BCIRG 001 trial of docetaxel, doxorubicin, and cyclophosphamide (TAC) versus fluorouracil, doxorubicin, and cyclophosphamide (FAC) for operable node-positive breast cancer. Patients were classified by tumor characteristics as (1) triple negative (estrogen receptor [ER]–negative, progesterone receptor [PR]–negative, HER2/neu [HER2]–negative), (2) HER2 (HER2-positive, ER-negative, PR-negative), (3) luminal B (ER-positive and/or PR-positive and either HER2-positive and/or Ki67high), and (4) luminal A (ER-positive and/or PR-positive and not HER2-positive or Ki67high), and assessed for prognostic significance and response to adjuvant chemotherapy.ResultsPatients were subdivided into triple negative (14.5%), HER2 (8.5%), luminal B (61.1%), and luminal A (15.9%). Three-year disease-free survival (DFS) rates (P values with luminal B as referent) were 67% (P < .0001), 68% (P = .0008), 82% (referent luminal B), and 91% (P = .0027), respectively, with hazard ratios of 2.22, 2.12, and 0.46. Improved 3-year DFS with TAC was found in the luminal B group (P = .025) and a combined ER-positive/HER2-negative group treated with tamoxifen (P = .041), with a marginal trend in the triple negatives (P = .051) and HER2 (P = .068) subtypes. No DFS advantage was seen in the luminal A population.ConclusionA simple immunopanel can divide breast cancers into biologic subtypes with strong prognostic effects. TAC significantly complements endocrine therapy in patients with luminal B subtype and, in the absence of targeted therapy, is effective in the triple-negative population.

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Prognostic factor Ki67 for breast cancer patients in each subgroup.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.565 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. 565-565

Author(s):

Naoki Niikura ◽

Shinobu Masuda ◽

Mizuho Terada ◽

Mayako Terao ◽

Nobue Kumaki ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Patients ◽

Triple Negative ◽

Predictive Marker ◽

Rank Test ◽

Breast Cancer Patients ◽

Luminal A ◽

Her2 Positive ◽

Luminal B ◽

Er Positive

565 Background: Immunohistochemical (IHC) Ki67 has described it as a prognostic and predictive marker for breast cancer. The St. Gallen Consensus Meeting determined that Ki67 labeling index is chiefly important for distinguishing between “Luminal A” and “Luminal B (HER2 negative)” subtypes and is a predictive marker for chemotherapeutic efficacy. However, the high and low cutoff points remain controversial. Our objective is to compare survival in patients with low, intermediate, and high Ki67 levels in each subgroup. Methods: We retrospectively identified all the patients in the Tokai University breast cancer database for whom IHC Ki67 data were available between January 1, 2000, and December 31, 2010. Ki67 was defined as low if <10% Ki67 was detected, as Intermediate if 10–20% Ki67 was detected, and as high if >20% Ki67 was detected. To assess Ki67 levels and survival outcomes, survival curves were calculated using the Kaplan–Meier method and compared using the log-rank test. Results: We identified 1331 primary breast cancer patients without metastasis, of whom 686 received neoadjuvant or adjuvant chemotherapy. Patients with high Ki67 had poorer relapse-free survival (RFS) than patients with intermediate (p = 0.009) and low Ki67 (p < 0.001). Patients with intermediate Ki67 had poorer RFS than patients with low Ki67 (p < 0.001). In ER-positive cases (n = 1059), patients with high and intermediate Ki67 had poorer RFS than patients with low Ki67 (p < 0.001 and p = 0.002, respectively). In HER2-positive and ER-negative cases (n = 103), patients with high Ki67 had poorer RFS than patients with low Ki67 (p = 0.002). In triple-negative cases (n = 164), patients with high Ki67 tended to have poorer RFS than patients with low Ki67 (p = 0.064). Conclusions: Our data demonstrated that low, intermediate, and high Ki67 levels may be used to differentiate prognosis in ER-positive cancer patients as well as HER2-positive and triple-negative cancer patients.

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Inflammatory Breast Cancer: Clinical Characteristics and Influence of Molecular Subtypes on Treatment Response

Tumori Journal ◽

10.1177/03008916211012341 ◽

2021 ◽

Vol 107 (1_suppl) ◽

pp. 12-12

Author(s):

D Aissaoui ◽

M Bohli ◽

R Ben Amor ◽

J Yahyaoui ◽

A Hamdoun ◽

...

Keyword(s):

Breast Cancer ◽

Treatment Response ◽

Inflammatory Breast Cancer ◽

Hormone Receptor ◽

Triple Negative ◽

Molecular Subtypes ◽

Luminal A ◽

Her2 Positive ◽

Luminal B ◽

Significant Difference

Introduction: Inflammatory Breast Cancer (IBC) is a rare and very aggressive breast cancer with poor prognosis. The prevalence is different from a country to another. In Tunisia, it is about 5 to 7% of breast cancer. The aim of this study is to describe the epidemiological and histopathological features of patients with inflammatory breast cancer and to evaluate the treatment response according to the molecular subtypes. Methods: This retrospective review identified 31 patients with no metastatic IBC treated in our radiotherapy department between December 2019 and November 2020. IBC was confirmed using the clinical criteria. Baseline clinic-pathological and treatment information was retrieved from medical records. Statistical analysis was performed with IBM SPSS V.20. Results: Median age was 51.3 years [27-68]. 48% of tumors were grade 3. The average tumor size was 36mm [10-90]. The histological type was ductal carcinoma in 97%. Vascular invasion was noted in 24 patients (77%). Thirty patients were classified as stage IIIB and one patient was IIIC. 74% were hormone receptor positive and 45% were HER2 positive. Luminal B was the predominant subtype (52%) followed by Her2 positive (32%), Luminal A (23%), and triple negative (3%) All patients had chemotherapy: neoadjuvant for 26 patients (84%) and adjuvant for 5 patients (16%). Nine patients (29%) had tumor pathological complete response (pCR). Partial response was observed in 18 patients (58%). Lymph node pCR was noted in 16% of cases (n=5). Endocrine therapy and trastuzumab were given to 76% and 45% of patients, respectively. The influence of the molecular subtype was not statistically significant on the response to neoadjuvant treatment. The highest rate of pCR were 43% for Her2positive, then 27%, 21% and 9% for Luminal B, Luminal A and Triple negative, respectively (p=0.2). Conclusion: Our study showed a high percentage of hormone receptor and Her2+ (74% and 45% respectively) in IBC. Luminal B was the most frequent subtype. Anthracycline-based chemotherapy and trastuzumab improved the pCR rate: 44% for Her2positive. Triple negative showed poorer pCR than other breast cancer subtype without a significant difference. A larger study is warranted to confirm our findings.

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Trends in breast cancer mortality according to molecular subtypes: A population-based study.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.572 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. 572-572

Author(s):

Yunan Han ◽

Shuai Xu ◽

Graham A. Colditz ◽

Adetunji T. Toriola

Keyword(s):

Breast Cancer ◽

Cancer Mortality ◽

Triple Negative ◽

Molecular Subtypes ◽

Breast Cancer Mortality ◽

Treatment Strategies ◽

Luminal A ◽

Her2 Positive ◽

Mortality Trends ◽

Luminal B

572 Background: Breast cancer is the second leading cause of cancer death in U.S. women. On the molecular level, breast cancer is a heterogeneous disease. Heterogeneous expressions of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) are etiologically and clinically meaningful, as they map to distinct risk factors and different treatment strategies. Although breast cancer mortality has been declining since 1990, little is known about mortality trends according to molecular subtypes at the population level. Methods: We examined the incidence-based mortality rates and trends among women who were diagnosed with invasive breast cancer from 2010 through 2017 using the Surveillance, Epidemiology, and End Results (SEER) database. We defined incidence-based mortality using a moving 5-year calendar period starting in 2014. We further assessed mortality according to breast cancer molecular subtypes: luminal A (ER and/or PR positive, HER2 negative), luminal B (ER and/or PR positive, HER2 positive), HER2-enriched (HER2 over-expressed or amplified, ER and PR negative) and triple-negative (ER and PR negative, HER2 negative) tumors. We calculated annual percent changes (APC) in incidence-based mortality using joinpoint regression models. Results: Overall, incidence-based mortality for breast cancer significantly decreased by 1.5% annually from 2014 through 2017 (APC, -1.5%; 95% coefficient interval [CI], -2.3% to -0.7%; p<0.001). Incidence-based mortality decreased annually by 2.0% for luminal A breast cancer (APC, -2.0%; 95% CI, -3.7% to -0.3%; p<0.001), 2.1% for luminal B breast cancer (APC, -2.1%; 95% CI, -5.4% to 1.4%; p=0.1), 1.1% for triple-negative breast cancer (TNBC) (APC, -1.1%; 95% CI, -2.1% to -0.0%; p<0.001). However, incidence-based mortality for HER2-enriched breast cancer increased 2.3% annually during the study period (APC, 2.3%; 95% CI, -2.4% to 7.2%; p=0.2). Conclusions: Between 2014 and 2017, incidence-based mortality for luminal A, luminal B, and TNBC decreased among U.S. women, with a larger decrease observed for luminal tumors. However, incidence-based mortality for HER2-enriched breast cancer increased. The favorable incidence-based mortality trends for luminal tumors and TNBC are likely due to the continuing improvement in treatments and early detection. The increasing trend of incidence-based mortality for HER2-enriched breast cancer constitutes a priority for cancer control activities and further research.

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Analysis of prolactin receptor expression in breast cancer subtypes

Biomeditsinskaya Khimiya ◽

10.18097/pbmc20206601089 ◽

2020 ◽

Vol 66 (1) ◽

pp. 89-94

Author(s):

T.S. Kalinina ◽

V.V. Kononchuk ◽

S.V. Sidorov ◽

L.F. Gulyaeva

Keyword(s):

Breast Cancer ◽

Triple Negative ◽

Prolactin Receptor ◽

Mrna Level ◽

Receptor Expression ◽

Mrna Levels ◽

Luminal A ◽

Her2 Positive ◽

Tissue Samples ◽

Luminal B

Breast cancer (BC) is the most common cancer among women. It is known that the prolactin receptor (PRLR) may play a role in breast carcinogenesis, but the available data are often contradictory. To get a more complete picture of the relationship between the receptor and mammary gland carcinogenesis, we examined the association between changes in PRLR expression level and tumor subtype (and its main characteristics). To do this, using real-time PCR, we evaluated the level of PRLR mRNA in BC tissue samples and untransformed adjoining tissue samples (89 pairs). Since the androgen receptor (AR) has begun to be seen as a prognostic marker in breast cancer, we also evaluated the association between mRNA levels of AR and PRLR. We found a significant increase in PRLR expression in luminal subtypes; the highest level of PRLR mRNA was detected in luminal A subtype. In HER2-positive ER-, PR-negative BC, the PRLR mRNA level decreases in tumor tissues compared with untransformed tissues. High PRLR expression is also associated with smaller tumor size in luminal B HER2-negative subtype. In ER-, PR-negative tumors, PRLR expression is associated with AR expression: PRLR mRNA level is increased when AR mRNA level is reduced by more than 8 times in triple-negative tumors; in contrast, in HER2-positive subtype it decreases more significantly when AR expression is reduced by more than 3 times. A tendency towards an increase in PRLR expression with an increase in the AR mRNA level was also discovered in luminal subtypes. The level of PRLR expression depends on the age of patients. In luminal A, PRLR expression is higher in patients under 65 years. In contrast, in luminal B HER2-negative and triple-negative BC, reduced PRLR expression was observed in patients under the age of 40 years and under the age of 50 years, respectively. In this group of patients under the age of 40 years with luminal B HER2-negative BC, ER expression was also reduced (0-4 score according to the IHC assay). Thus, PRLR probably plays a different role in the development and progression of BC: in luminal A and luminal B HER2-positive subtypes PRLR may act as an oncogen, and in luminal B HER2-negative and ER-, PR-negative subtypes can play a tumor suppressor role.

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Androgen receptor signaling pathways as a target for breast cancer treatment

Endocrine Related Cancer ◽

10.1530/erc-16-0190 ◽

2016 ◽

Vol 23 (10) ◽

pp. R485-R498 ◽

Cited By ~ 43

Author(s):

Elisabetta Pietri ◽

Vincenza Conteduca ◽

Daniele Andreis ◽

Ilaria Massa ◽

Elisabetta Melegari ◽

...

Keyword(s):

Breast Cancer ◽

Androgen Receptor ◽

Signaling Pathways ◽

Triple Negative ◽

Pubertal Development ◽

Her2 Positive ◽

Age Related ◽

Clinical Scenarios ◽

Er Positive ◽

Positive Breast Cancer

The androgen receptor (AR) is a ligand-dependent transcription factor, and its effects on breast range from physiological pubertal development and age-related modifications to cancer onset and proliferation. The prevalence of AR in early breast cancer is around 60%, and AR is more frequently expressed in ER-positive than in ER-negative tumors. We offer an overview of AR signaling pathways in different breast cancer subtypes, providing evidence that its oncogenic role is likely to be different in distinct biological and clinical scenarios. In particular, in ER-positive breast cancer, AR signaling often antagonizes the growth stimulatory effect of ER signaling; in triple-negative breast cancer (TNBC), AR seems to drive tumor progression (at least in luminal AR subtype of TNBC with a gene expression profile mimicking luminal subtypes despite being negative to ER and enriched in AR expression); in HER2-positive breast cancer, in the absence of ER expression, AR signaling has a proliferative role. These data represent the rationale for AR-targeting treatment as a potentially new target therapy in breast cancer subset using androgen agonists in some AR-positive/ER-positive tumors, AR antagonists in triple-negative/AR-positive tumors and in combination with anti-HER2 agents or with other signaling pathways inhibitors (including PI3K/MYC/ERK) in HER2-positive/AR-positive tumors. Only the ongoing and future prospective clinical trials will allow us to establish which agents are the best option in every specific condition, keeping in mind that there is evidence of opposite androgens and AR agonist/antagonist drug effects on cell proliferation particularly in AR-positive/ER-positive tumors.

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Breast cancer in Angola, molecular subtypes: The first preliminary study.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.e13075 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. e13075-e13075

Author(s):

Lúcio Lara Santos ◽

Fernando Miguel ◽

Lygia Vieira Lopes ◽

Julio Oliveira ◽

Eduardo Ferreira ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative ◽

Molecular Subtypes ◽

Molecular Subtype ◽

Locally Advanced ◽

Luminal A ◽

Her2 Positive ◽

Luminal B ◽

Therapeutic Decisions ◽

Ihc Markers

e13075 Background: Women in sub-Saharan African countries, as Angola, are experiencing an increasing burden of aggressive breast cancer. Breast cancer molecular subtypes may enable more accurate diagnoses and support therapeutic decisions, however several studies have suggested that African breast cancers are predominantly hormone receptor poor. We conduct a study, to correlate the clinical pathological profiles and molecular subtypes, according its surrogate immunohistochemistry (IHC) markers, of breast cancer in Luanda, Angola. Methods: From Jan. 2011 to Dec. 30, 2014, 179 consecutive cases of microscopically confirmed invasive breast carcinoma that were evaluable for histology and IHC (ER, PR, HER2, and Ki-67) were classified. However, 21.8% (n = 39) of cases were poorly preserved, therefore it was only possible to study IHC in 140 cases. Results: All patients were female, the median age was 47 years (24-84 years). Invasive ductal carcinoma was the most common type, 91.4% (n = 128), grade 2 (moderately differentiated) was prevalent, 67.1%. Most of the tumours were locally advanced, stage III 65% (n = 91) and stage IV 3.6% (n = 5). In 140 cases studied, 53.2% (n = 74 ) of malignancies were hormone receptors positive, whence 25.7% were luminal A like, 19.3% luminal B like/ HER2 negative, 7.9% luminal B like/HER2 positive, 15.7% HER2 positive and 31,4% were triple-negative. Conclusions: Woman with breast cancer in Luanda-Angola were caracterized by advance stage and younger age at diagnosis of disease. The two predominant molecular subtypes are triple negative and luminal A like. Therefore, determining the molecular subtype using surrogate IHC markers has important treatment and prognostic implications for Angola women with breast cancer.

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Age, Breast Cancer Subtype Approximation, and Local Recurrence After Breast-Conserving Therapy

Journal of Clinical Oncology ◽

10.1200/jco.2011.36.1105 ◽

2011 ◽

Vol 29 (29) ◽

pp. 3885-3891 ◽

Cited By ~ 255

Author(s):

Nils D. Arvold ◽

Alphonse G. Taghian ◽

Andrzej Niemierko ◽

Rita F. Abi Raad ◽

Meera Sreedhara ◽

...

Keyword(s):

Breast Cancer ◽

Local Recurrence ◽

Systemic Therapy ◽

Cumulative Incidence ◽

Triple Negative ◽

Multivariable Analysis ◽

Breast Conserving Therapy ◽

Luminal A ◽

Her2 Positive ◽

Luminal B

Purpose Prior results of breast-conserving therapy (BCT) have shown substantial rates of local recurrence (LR) in young patients with breast cancer (BC). Patients and Methods We studied 1,434 consecutive patients with invasive BC who received BCT from December 1997 to July 2006. Ninety-one percent received adjuvant systemic therapy; no patients received trastuzumab. Five BC subtypes were approximated: estrogen receptor (ER) or progesterone receptor (PR) positive, HER2 negative, and grades 1 to 2 (ie, luminal A); ER positive or PR positive, HER2 negative, and grade 3 (ie, luminal B); ER or PR positive, and HER2 positive (ie, luminal HER2); ER negative, PR negative, and HER2 positive (ie, HER2); and ER negative, PR negative, and HER2 negative (ie, triple negative). Actuarial rates of LR were calculated by using the Kaplan-Meier method. Results Median follow-up was 85 months. Overall 5-year cumulative incidence of LR was 2.1% (95% CI, 1.4% to 3.0%). The 5-year cumulative incidence of LR was 5.0% (95% CI, 3.0% to 8.3%) for age quartile 23 to 46 years; 2.2% (95% CI, 1.0% to 4.6%) for ages 47 to 54 years; 0.9% (95% CI, 0.3% to 2.6%) for ages 55 to 63 years; and 0.6% (95% CI, 0.1% to 2.2%) for ages 64 to 88 years. The 5-year cumulative incidence of LR was 0.8% (95% CI, 0.4% to 1.8%) for luminal A; 2.3% (95% CI, 0.8% to 5.9%) for luminal B; 1.1% (95% CI, 0.2% 7.4%) for luminal HER2; 10.8% (95% CI, 4.6% to 24.4%) for HER2; and 6.7% (95% CI, 3.6% to 12.2%) for triple negative. On multivariable analysis, increasing age was associated with decreased risk of LR (adjusted hazard ratio, 0.97; 95% CI, 0.94 to 0.99; P = .009). Conclusion In the era of systemic therapy and BC subtyping, age remains an independent prognostic factor after BCT. However, the risk of LR for young women appears acceptably low.

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HER2 FISH ratio cut-points and pathologic complete response (pCR), residual tumor (RT), HER2 status, and survival prediction in HER2-positive breast cancer (BC)

Journal of Clinical Oncology ◽

10.1200/jco.2009.27.15_suppl.e22033 ◽

2009 ◽

Vol 27 (15_suppl) ◽

pp. e22033-e22033

Author(s):

R. S. Mehta ◽

D. Jackson ◽

T. Schubbert ◽

D. Hsiang

Keyword(s):

Breast Cancer ◽

Pathologic Complete Response ◽

Endocrine Resistance ◽

Disease Free Survival ◽

Survival Prediction ◽

Her2 Positive ◽

Cut Point ◽

Her2 Positive Breast Cancer ◽

Er Positive ◽

Positive Breast Cancer

e22033 Background: We demonstrated that pCR is correlated with increasing HER2-FISH ratio, while disease-free survival (DFS) with pCR and ER-positivity in HER2-positive breast cancer treated with trastuzumab (SABCS 2008). It is known that quantitative HER2-FISH ratio correlates with ER levels and HER2-positivity imparts a higher grade in ER-positive BC. Collectively, we hypothesized that combined ER (≥10) and a HER2 ratio cut-point may subdivide HER2-positive BC into pCR predictive subtypes.Methods: Of the 80 HER2-positive (IHC3+/FISH+) BC, quantitative HER2 FISH ratio (widely spread over 1–18.3) and ER correlation was noted (r=0.34, p=0.002). Moreover, HER2 ratio (>4) correlated with higher Ki-67 (r= 0.5, p=0.01) and grade (p trend=0.05) in ER-positive subtype, inferring a biologic cut-point. Results: Of patients with stage I-IV BC treated neoadjuvantly (92% trastuzumab-based), pCR was 0% (0/13) in ER-positive-low-HER2 compared to 77% (10/13, p=0.0001), 75% (24/32, p<0.0001) and 37.5% (3/8, p=0.043) in ER-positive-high-HER2, ER-negative-high-HER2 and ER-negative-low-HER2, respectively. DFS was 100, 90, 80% and 60% (logrank-trend p<0.05) in these 4 subtypes (excluding stage IV), respectively, at a median follow-up of 38 months (range 6–72). In ER-negative subtypes, DFS was 97% and 29% (logrank p=0.0001) in patients with or without pCR; of the six with RT, 0% DFS was noted in four with HER2-negative/HER2-reduced (HER2-R) RT, compared to 100% in the two with unchanged HER2 (p=<0.05, logrank test). In ER-positive subtypes, DFS is 95% overall, and 100% in patients with RT; 7 of 10 tested RT were HER2- R. Conclusions: pCR is crucial and high in ER-negative-high-HER2 and is crucial (but low) in ER-negative-low-HER2-positive BC for improved outcome. Improved DFS is associated with high pCR in ER-positive-high-HER2 BC, but is independent of the low pCR in ER-positive-low-HER2-subtype. Thus, combined HER2 and ER offer improved prediction. In hypothesis generating analysis, HER2-R may underlie relapse in ER-negative subtypes (HER2-basal-transitional-residual), while it may be beneficial in ER-positive subtypes (luminal-B- A-transitional) by reducing HER2-pathway mediated endocrine resistance. [Table: see text]

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Breast cancer subtype and screening sensitivity in the Quebec Mammography Screening Program

Journal of Medical Screening ◽

10.1177/0969141318816736 ◽

2018 ◽

Vol 26 (3) ◽

pp. 154-161

Author(s):

Linda Perron ◽

Sue-Ling Chang ◽

Jean-Marc Daigle ◽

Nathalie Vandal ◽

Isabelle Theberge ◽

...

Keyword(s):

Breast Cancer ◽

Mammography Screening ◽

Triple Negative ◽

Screening Program ◽

Luminal A ◽

Her2 Positive ◽

Cancer Subtypes ◽

Luminal B ◽

Mammography Screening Program ◽

Screening Sensitivity

Objective In mammography screening, interval cancers present a problem. The metric ‘screening sensitivity’ monitors both how well a programme detects cancers and avoids interval cancers. To our knowledge, the effect of breast cancer surrogate molecular subtypes on screening sensitivity has never been evaluated. We aimed to measure the 2-year screening sensitivity according to breast cancer subtypes. Methods We studied 734 women with an invasive breast cancer diagnosed between 2003 and 2007 after participating in one regional division of Quebec’s Mammography Screening Program. They represented 83% of all participating women with an invasive BC diagnosis in that region for that period. Tumours were categorized into ‘luminal A-like’, ‘luminal B-like’, ‘triple-negative’ and ‘HER2-positive’ subtypes. We used logistic regression and marginal standardization to estimate screening sensitivity, sensitivity ratios (SR) and sensitivity differences. We also assessed the mediating effect of grade. Results Adjusted 2-year screening sensitivity was 75.4% in luminal A-like, 66.1% in luminal B-like, 52.9% in triple-negative and 45.3% in HER2-positive, translating into sensitivity ratios of 0.88 (95% confidence interval [CI] = 0.78–0.98) for luminal B-like, 0.70 (CI = 0.56–0.88) for triple-negative and 0.60 (CI = 0.39–0.93) for HER2-positive, when compared with luminal A-like. Grade entirely mediated the subtype-sensitivity association for triple negative and mediated it partly for HER2-positive. Screening round (prevalent vs. incident) did not modify results. Conclusion There was substantial variation in screening sensitivity according to breast cancer subtypes. Aggressive phenotypes showed the lowest sensitivity, an effect that was mediated by grade. Tailoring screening according to women’s subtype risk factors might eventually lead to more efficient programs.

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