Abstract P1-01-22: The utility of axillary ultrasound and sentinel lymph node biopsy in the management of metaplastic breast carcinoma

Background: Metaplastic breast carcinoma (MBC) accounts for <5% of all breast malignancies. This entity represents a heterogenous group of tumors in which the adenocarcinomatous element is admixed with one or more neoplastic mesenchymal (spindle, squamous, chondroid, or osseous) elements. Patients typically present with large triple negative tumors and have a poor prognosis. The likelihood of lymph node (LN) involvement has been reported to be low in MBC patients. Due to the paucity of data, we undertook this study to explore the role of axillary ultrasound (US) and sentinel LN biopsy (SLNB) in the management of MBC.

Methods: With IRB approval, we retrospectively identified patients diagnosed with MBC from 2001–2011 from the surgical pathology database. Histopathology and imaging were reviewed. Demographic, treatment and outcome data were obtained by clinical chart review. Data were analyzed using JMP 9.0 software.

Results: We identified 41 women with MBC. Median age was 60 years (range 33–90). Histologic subtypes were spindle cell (46%), mixed adenocarcinoma and mesenchymal elements (20%), squamous cell (17%) chondroid/osseous (10%) and adenosquamous (7%). Tumor stage was T1 (24%), T2 (44%), T3 (12%) and T4 (20%). 26 patients (63%) were treated by mastectomy and 15 (37%) by wide excision. Of the 38 patients who underwent LN surgery (6 low-grade MBC, 32 intermediate/high-grade MBC), 10 (26%) were LN positive. All low-grade MBC patients were LN negative while 10 of 32 intermediate/high-grade MBC patients (31%) had LN metastasis. 22 patients had a preoperative axillary US. 14 patients had a negative axillary US and none had LN metastasis. 4 of 8 patients with suspicious axillary US findings had a preoperative axillary LN fine needle aspiration biopsy (FNAB) and 3 were positive for cancer. These patients proceeded directly to axillary LN dissection (ALND). 24 patients had a SLNB of whom one was SLN positive and underwent completion ALND. LN metastasis was associated with larger tumor size (p = 0.003), higher tumor grade (p = 0.04), angioinvasion (p = 0.07) and abnormal axillary US (p = 0.003). Surviving patients were followed for a mean (median) of 41 (30) months during which 13 (32%) recurred at a median of 6 months (IQR 3–17 months) and 11 (27%) subsequently died of disease. One SLN negative patient developed an axillary recurrence at 8 months, was successfully treated by ALND and is disease-free at 38 months. There were no axillary LN relapses after ALND.

Conclusions: For clinically node-negative MBC patients, our contemporary data series suggests the incidence of occult LN metastasis is sufficiently high to warrant LN staging especially for patients with intermediate and high-grade tumors. This can be accomplished in a minimally invasive fashion with reasonable accuracy (∼97%) with axillary US, FNAB of sonographically suspicious LNs, and SLNB for patients with negative axillary US or FNAB. Axillary LND should be performed for patients with clinically and/or FNAB-positive LN for enhanced disease control.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-22.

Erosive potential of sports beverages

BACKGROUND

Dental erosion is an increasingly prevalent problem in Australia, with the consumption of sports beverages suggested as a risk factor. The aim of this study was to compare the erosive potential of Australian sports beverages.

METHODS

Ten beverages were selected and analysed to determine their pH, titratable acidity and apparent degree of saturation with respect to apatite. The erosive potential of the beverages was measured by human enamel surface loss and surface softening following a 30-minute exposure. A taste testing panel was established to determine the palatability of the sports beverages.

RESULTS

All sports beverages except Sukkie and Endura produced substantial surface loss and surface softening. Compared with the other sports beverages, Sukkie and Endura had a higher pH, lower titratable acidity and higher calcium content. However, Sukkie and Endura were deemed to be less palatable than the other more acidic sports beverages.

CONCLUSIONS

The majority of the sports beverages tested produced dental erosion in this in vitro model. However, two new products Sukkie and Endura have lower erosive potential but also lower palatability.

Effect of casein phosphopeptide-amorphous calcium phosphate added to acidic beverages on enamel erosion in vitro

BACKGROUND

To investigate, in vitro, the effect on enamel erosion of the addition of 0.2% w/v casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) to four commercially-available soft drinks, two of which were carbonated.

METHODS

Enamel specimens (n=27) were sectioned from sound extracted human third molar teeth and polished to a mirror finish. Exposed enamel windows of 1 mm2 were created by painting the surface with acid-resistant nail varnish. Four citric flavoured soft drinks (pH range 2.2 to 2.4) and distilled deionized water (DDW) were tested. Each drink was tested with and without 0.2% CPP-ACP w/v. The specimens were placed into 50 mL of solution at 37 °C for 30 minutes, rinsed and varnish removed. The samples were profiled with a white light profilometer and erosive depths recorded.

RESULTS

All soft drinks tested caused enamel erosion but adding 0.2% w/v CPP-ACP significantly reduced (p<.05) erosive depth in all test solutions in comparison with the solutions without CPP-ACP. The erosive depths for all solutions with 0.2% CPP-ACP did not differ significantly from those of DDW.

CONCLUSIONS

Adding CPP-ACP at 0.2% w/v significantly decreased the erosivity of all four soft drinks. The erosivity of the soft drinks with 0.2% CPP-ACP added did not differ significantly from that of distilled water.

Abstract P5-10-07: TACT2 Randomised Adjuvant Trial in Early Breast Cancer (EBC): Tolerability and Toxicity of Standard 3 Weekly Epirubicin (E) Versus Accelerated Epirubicin (aE) Followed by Capecitabine (X) or CMF in 129 UK Hospitals (CRUK/05/019)

Introduction: TACT2, a multicentre phase III trial with E-CMF as control (NEAT Poole NEJM 2006), tests 2 hypotheses in a 2x2 factorial design: A) accelerating chemotherapy (CT) offers superior benefits (CALGB9741 Citron JCO 2003); B) the oral 5FU prodrug X gives similar efficacy but preferential side-effect profile to CMF. Here, focus is on hypothesis B with results for compliance, QL & acute toxicities (physician & patient (pt) reported) during CMF vs. X

Materials &

Methods: 4391 pts (4371 women, 20 men) with node+ve/high risk node-ve invasive EBC were recruited between Dec 2005-08. Treatment was E(100mg/m2 x 4) q3wk vs q2wk aE(100mg/m2 x 4 + pegfilgrastim 6mg d2) followed by classical CMF q4wk x 4 vs X(2500mg/m2/day x 14) q3wk x 4. Detailed CTCAE toxicity was assessed in a subset (38 centres, 2086 pts receiving ≥1 cycle CMF or X). 1279/2086 also participated in substudy of pt-reported outcomes (EORTC QLQ-C30 and TACT2-specific toxicities). 826 had complete dataset (baseline, cycles 4&8). P-values are trend tests across all grades & %grade 3+ are reported. QL assessed via linear regression models adjusted for baseline, end cycle 4 score, & aE vs E. P&lt;0.01 classed as significant

QL in cycles 5-8 was better with X than CMF for global QL& fatigue (P&lt;0.001). Pts reporting clinically meaningful deterioration (&gt;10 points): global QL CMF 106/398 (27%), X 79/428 (18%); fatigue CMF 164/398 (41%), X 122/428 (29%)).

Conclusion: TACT2, the largest adjuvant EBC trial with X, confirms that X has preferential side-effect profile and global QL compared to CMF, with no evidence that prior aE compromised treatment delivery. Dose delivery data are consistent with advanced disease observations that for some pts, 2000mg/m2/day may be correct dose.

Results: 4264 (97%) pts continued on CT beyond cycle 4. 3726 completed all 8 cycles (E-CMF 951 (85%), aE-CMF 938 (86%), E-X 932 (84%), aE-X 905 (83%). For cycles 5-8, %RDI &gt; 85% was 69% after E and 68% after aE. Cycles delivered on time CMF 59%, X 63%; cycles without dose reduction CMF 75%, X 62%. 15 deaths in total within 30 days of CT: 9 on CMF, 6 on X. Worst grade toxicities which differed between CMF & X during cycles 5-8:

Estimation of Risk of Recurrence of Early Stage Estrogen Receptor Positive Breast Carcinoma by Surgical and Medical Oncologists and Pathologists Compared to the Oncotype Dx® Recurrence Score

Background: The decision to use adjuvant chemotherapy in patients with early stage breast cancer is based in part on the estimation of risk of tumor recurrence by physicians, which traditionally relies heavily on tumor size, nodal status and a set of biologic tumor characteristics such as hormone receptor and HER2 expression. The Oncotype DX® assay is a 21-gene expression profile aiming to improve risk stratification, recurrence prediction and optimize selection of patients for adjuvant chemotherapy.Methods: We selected 154 consecutive patients with early stage estrogen receptor (ER) positive breast cancer and available Oncotype Dx® recurrence score (RS) for the study. Clinicopathologic data, including patient age, menopausal status, tumor size, histologic type, grade, mitotic activity, presence of lymphatic invasion (LVI), nodal status, hormone receptor and HER2 status on all patients were provided to four surgical oncologists, four medical oncologists and three pathologists, specializing in breast cancer diagnosis and management. Participants were asked to estimate the risk of recurrence of tumors based on available clinicopathologic data and to provide the three most important tumor features their risk estimates were based on. Risk estimates of participants were compared with RS results.Results: Based on the Oncotype Dx® results, 95 (61.7%), 45 (29.2%) and 14 (9.1%) tumors were of low (RS &lt;18), intermediate (RS 18-30) and high (RS ≥31) risk, respectively. RS values showed a highly significant correlation with tumor grade, mitotic activity, LVI, hormone receptor and HER2 status, while no correlation with patient age, menopausal status, tumor size and histologic type was found. Participants' risk estimates agreed with those of the Oncotype Dx® assay in 54.2 ± 2.3 % (mean ± SEM, range 41.6 - 63.0%) of cases, while the risk of recurrence was over- and underestimated compared to RS results in 31.8 ± 3.1% (16.2 - 43.5%) and 14.1 ± 1.4% (7.1 - 22.7%), respectively. The rates of overestimation were significantly higher than those of underestimation (p = 0.0003). Although medical oncologists tended to overestimate the risk more frequently (38.1 ± 2.0%) compared to surgeons (28.7 ± 5.9%) and pathologists (27.5 ± 7.8%), the difference did not reach statistical significance. Estimation of the agreement of participants' risk assessment with RS results showed a mean kappa value of 0.2955 (range 0.1506 - 0.4123). No statistically significant difference in overall concurrence with RS results was found between surgeons, medical oncologists and pathologists. Participants ranked tumor stage/nodal status, hormone receptor status and tumor size to be the most important features when estimating recurrence risk.Conclusions: Based on traditional clinicopathologic features alone, surgeons, medical oncologists and pathologists tend to overestimate the risk of tumor recurrence as compared to Oncotype Dx® assay results. The RS may provide additional information regarding the intrinsic biological features of ER positive breast cancers and help tailoring treatment recommendations.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4061.

The Effect of Oncotype Dx® Recurrence Score on Treatment Recommendations for Patients with Early Stage Estrogen Receptor Positive Breast Cancer

Background: Current guidelines recommend administration of chemotherapy for patients with breast carcinomas &gt;1 cm in size, with consideration for patient age, comorbidities and tumor grade. However, it is unknown which patients actually benefit from therapy and overtreatment of a significant proportion of patients is a major concern. We investigated the impact of the Oncotype Dx® Recurrence Score (RS) on chemotherapy recommendations in early stage estrogen receptor (ER) positive breast cancer patients.Methods: We selected 154 patients with early stage ER positive breast cancer and available RS for the study. Clinicopathologic data, including age, menopausal status, tumor size, type, grade, mitotic activity, presence of lymphatic invasion, nodal status, hormone receptor and HER2 status on all patients were provided to four surgical oncologists, four medical oncologists and three pathologists, specializing in breast cancer diagnosis and management. Assuming that all patients were in good general health and would receive endocrine therapy, participants were asked whether they would also advovate adjuvant chemotherapy based on clinicopathologic data with and without knowledge of the RS, and to provide the three salient clinicopathologic features on which their recommendations were based. Changes in recommendations of participants following inclusion of RS data were compared.Results: Based on RS results, 95 (61.7%), 45 (29.2%) and 14 (9.1%) tumors were of low (RS &lt;18), intermediate (RS 18-30) and high (RS ≥31) risk, respectively. The results are summarized in Table 1. Assuming that the hypothesis previously put forward that patients with low to intermediate risk RS are not likely to benefit from chemotherapy, 82.3 ± 1.3% (75.5 - 89.0%) and 69.0 ± 6.9% (5.9 - 85.7%) of patients for whom chemotherapy was recommended by the participants would be "overtreated" without and with the use of RS results (p = 0.0322). No statistically significant difference was found among surgeons, medical oncologists and pathologists. Participants ranked patient age/menopausal status, hormone receptor status and tumor stage/nodal status to be the most important features when recommending chemotherapy.Conclusions: Although current recommendations for adjuvant chemotherapy for early stage ER positive breast cancer patients are largely in line with published guidelines, inclusion of RS alters recommendations in about 25% of cases. While medical oncologists recommended chemotherapy more frequently compared to surgeons and pathologists, they were more likely to change recommendations in light of RS results.Table 1. Summary of results SurgeonsMedical oncologistsPathologistsp* Mean ± SEMRangeMean ± SEMRangeMean ± SEMRange Chemo without RS (%)29.2 ± 1.824.0 - 31.859.0 ± 5.046.8 - 70.846.8 ± 3.741.6 - 53.90.0156Chemo with RS (%)27.0 ± 5.611.0 - 36.438.6 ± 9.517.5 - 63.644.4 ± 5.833.8 - 53.90.1794No change (%)75.3 ± 7.054.5 - 85.766.7 ± 6.851.3 - 83.885.9 ± 6.478.6 - 98.70.3682Add chemo (%)11.2 ± 4.13.2 - 22.76.5 ± 1.93.2 - 11.75.8 ± 3.20.6 - 11.70.6882Avoid chemo (%)13.5 ± 3.94.5 - 22.726.8 ± 7.94.5 - 41.68.2 ± 4.50.6 - 16.20.2186*Kruskal-Wallis test

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4058.

Tamoxifen, HER2, and Endoxifen: The Role of CYP2D6 as a Predictor of Tamoxifen Resistance in ER+/HER2+ Breast Cancer

Background: Endoxifen, the active metabolite of tamoxifen (Tam), is currently being developed as a drug for the treatment of estrogen receptor (ER) + breast cancer (BC). HER2 expression in ER+ BC is associated with Tam resistance, and in vivo Tam administration to mice bearing ER+/HER2+ xenografts stimulates BC growth (Shou, JNCI 2004). In humans, endoxifen is the most important Tam metabolite responsible for inhibiting estrogen induced BC growth (Wu, Cancer Research 2009). CYP2D6 metabolism affects the concentrations (conc) of endoxifen (Stearns, JNCI, 2003) and associated with worse disease free survival (DFS) in Tam treated BC (Goetz, JCO, 2005). We sought to determine the activity of Tam and its metabolites in ER+/HER2+ BC cell lines and to evaluate the role of CYP2D6 metabolism in Tam-treated patients (pts) with ER+/HER2+ BC. Additionally, we sought to determine endoxifen conc in mice administered oral Tam.Methods: MCF7 (parental and HER2-expressing) and BT474 (ER+/HER2+) cells were used to compare the activity of Tam, 4HT, and endoxifen on estrogen- stimulated growth. Oral tam PK were characterized in mice treated with standard dose of Tam (4 mg/kg; 100 μg). Clinical data were obtained via a retrospective analysis of Tam-treated pts with ER+/ HER2+ BC randomized to receive 5 years of Tam (NCCTG 89-30-52). CYP2D6 metabolism (extensive or decreased) was based on CYP2D6 genotype (*3, 4, 6, 10, 17, 41) and co-administration of a CYP2D6 inhibitor (yes/no). HER2 was determined by immunohistochemistry (IHC) or FISH (tumors 0, 1, or 2+ by IHC). The association between CYP2D6 and DFS was assessed using the log-rank test and proportional hazards modeling.Results: Compared to Tam, endoxifen potently inhibited the growth of estrogen- stimulated BT474 cells. In MCF7 cells, expression of HER2 shifted the conc of endoxifen required for 50% inhibition of growth (IC50) from 54 nM (parental) to 131 nM (HER2 expressing). Using the range of conc of Tam and its metabolites observed in humans (Tam, 300-500 nM; 4HT, 5-10 nM; and endoxifen, 10-200 nM), only endoxifen potently inhibited estrogen- stimulated growth of MCF7HER2+ cells and only at conc achievable in CYP2D6 extensive metabolizers (&gt;50nM). In mice, conc of 4HT and endoxifen were below 15 nM following an oral dose of 4 mg/kg. In NCCTG 89-30-52, both CYP2D6 phenotype and HER2 status was determined in 201/256 randomized pts. HER2 was expressed in 23/215 (11%) but not associated with DFS overall (p=0.62). In the HER2+ subset, pts with decreased CYP2D6 metabolism (n=10) had significantly shorter DFS compared to extensive metabolizers (n=9) (HR 9.5, p=0.03; 95% CI 1.16-76.9).Conclusions: Our in vitro and clinical data provide a simple pharmacological model for understanding HER2 resistance in Tam-treated breast cancer. Mice, which lack the CYP2D6 enzyme, may not be an appropriate model for understanding tam resistance given low conc of both 4HT and endoxifen. Given that the in vitro conc of endoxifen needed to inhibit the growth of ER+/HER-2+ BC are achievable in only a subset of humans (CYP2D6 extensive metabolizers), the primary administration of endoxifen could overcome de novo Tam resistance in ER+/HER2+ BC.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2006.

Ki67: A Time-Varying Biomarker of Risk of Breast Cancer in Atypical Hyperplasia

Background: Uncontrolled proliferation is a defining feature of the malignant phenotype. Ki67 is a marker for proliferating cells and is overexpressed in many breast cancers. Atypical hyperplasia is a premalignant lesion of the breast (relative risk ∼ 4.0). Here we asked if Ki67 expression could stratify risk in women with atypia.Methods: Ki67 expression was assessed immunohistochemically by digital image analysis in archival sections from 192 women with atypia diagnosed at the Mayo Clinic 1/1/67-12/31/91. Risk factor and follow-up data were obtained via study questionnaire and medical records. Observed breast cancer events were compared to population expected rates (Iowa SEER) using standarized incidence ratios (SIRs). We examined both short-term (within 10 years) and long-term (after 10 years) risk of breast cancer (BC) following atypia biopsy.Results: The median value for percent positive cells for Ki67 was 1.0%; the 75th percentile value was 2.3%. Based on the empirical distribution of staining values in our cohort, we selected a cutoff of 2% cells positive to separate high from low staining. There were no differences in Ki67 levels by age at biopsy, type of atypia (ADH, ALH, or both), number of foci of atypia, or family history. 32 women developed BC over a median of 14.6 years. Among them, those with ≥2% Ki67 expression had a shorter time to breast cancer (median 5.5 years, IQR=3.2-7.2) than those with &lt;2% cells positive (median=13.8 years, IQR=11.6-20.3). There was a positive association between Ki67 overexpression (≥2% of cells positive) and risk of BC in the first 10 years of follow-up (SIR=4.42 [95% CI 2.21-8.84]). This excess risk resulted in a 10-year cumulative incidence of 14.1%. In contrast, in the women with low Ki67 expression, we found no increased risk of BC in the first 10 years, with SIR 1.01 (95% CI 0.38-2.70), which was significantly lower than the women with high expression (p=0.01). The 10-year cumulative incidence of BC was 3% for the low Ki67group, in line with population averages. After 10 years, risk increased significantly in the low Ki67 group [SIR 5.69 (3.63-8.92)] vs. no increased risk in the high Ki67 group [SIR 0.78 (0.11-5.55)]. We formally examined this apparent time-dependent difference in incidence patterns by Ki67 staining levels via Poisson regression analysis, and found a statistically significant interaction between pre- vs. post-10 years incidence and high vs. low staining levels (p&lt;0.001).Conclusions: Ki67 appears to be a time-varying biomarker of risk of breast cancer in women with atypical hyperplasia. Women whose atypias show higher proliferation rates have an increased risk for an earlier BC (within 10 years). Those with lower proliferation rates tend to develop BCs later, after 10 years. Ki67 levels may help to define the time period of greatest risk for women with atypia.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 909.

Lobular Involution and Mammographic Density: Independent Contributors to Breast Cancer Risk

Background: Women with benign breast disease are at elevated breast cancer risk. In order to accurately predict a woman's individual risk of breast cancer, a breast cancer risk-prediction model is needed that incorporates significant breast cancer risk factors. This report describes two factors: tissue based assessment of lobular involution, and radiological marker- mammographic density (MD). Lobular involution, or physiologic atrophy of the breast glandular epithelium, is inversely associated with breast cancer risk. MD is a strong positive risk factor for breast cancer. With increasing age, the extent of lobular involution increases while MD decreases. However, it is unclear whether involution and MD represent independent breast cancer risk factors. We examined breast cancer risk associated with lobular involution and MD in women with benign breast disease (BBD) to determine whether these features are independently associated with breast cancer risk.Methods: Using the Mayo Clinic Surgical and Pathology Indices, 9376 women ages 18 to 85 with benign excisional breast biopsy between January 1, 1967 and December 31, 1991 were identified and formed the Mayo BBD cohort. We studied a sub-cohort of women diagnosed with BBD between 1985 and 1991 (when MD was clinically assessed and recorded) who had a mammogram within 6 months of the BBD diagnosis. Breast cancer outcomes were determined through the Mayo medical records and a study-specific questionnaire. Lobular involution extent was assessed in background tissue as 'none' (0% lobules involuted), 'partial' (1-74% lobules involuted) or 'complete' (≥75% lobules involuted). MD was classified as Wolfe's parenchymal pattern (PP) as N1/ fatty; P1; P2; and DY/ homogenously dense. Hazard ratios and confidence intervals were calculated using Cox regression analyses, adjusting for confounders: age, parity, BMI, BBD histology, menopausal status, family history, PP and involution extent.Results: A total of 2666 women in the Mayo BBD cohort, with biopsies between 1985 and 1991, had a mammogram within 6 months of the breast biopsy. The mean age at biopsy was 54.6 years. After a mean follow-up of 13.3 years, 172 (6.5%) women developed breast cancer. After adjustment for PP and other confounders, women with no or partial involution had elevated risk compared to women with complete involution (HR 2.62 [95% CI 1.39, 4.94] for no involution and 1.61 [95% CI 1.03, 2.53] for partial involution; complete involution as reference group; p for trend 0.003). Moreover, women with dense breasts were at greater risk compared to women with nondense breasts (HR 1.67 [95% CI 1.0, 2.73] for DY pattern, 1.96 [95% CI 1.2 – 3.21] for P2, 1.23 [95% CI 0.67, 2.26] for P1; N1 category as reference group; p for trend 0.02). Multivariate analyses also showed that women with the combination of no involution and dense breasts had greater risk compared to those with complete involution and nondense breasts (HR 4.08 [95% CI 1.72, 9.68]).Conclusion: Lobular involution and MD are both risk factors for breast cancer; this report is the first to demonstrate that each provides unique information about breast cancer risk. These findings emphasize the potential for inclusion of both these factors in future breast cancer risk-prediction models.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6064.

Evaluation of the Tyrer-Cuzick Model in Women with Atypical Hyperplasia

Background: Risk prediction models are important clinical tools for counseling and decision making for women with an elevated risk of breast cancer, such as women with atypical lobular or ductal hyperplasia (atypia). The Gail model has been shown to underestimate the risk of breast cancer in women with atypia. We sought to evaluate the performance of the Tyrer-Cuzick model in a well-defined cohort of women with atypia.Methods: The Mayo Benign Breast Disease (BBD) Cohort includes 9,376 women aged 18 to 85 who had an open breast biopsy with benign pathological findings between 1967 and 1991. The subset of women with atypia was identified by our study pathologists. Risk factor data required by the Tyrer-Cuzick model were collated for each woman, and the model was used to predict each woman's risk of developing invasive breast cancer within ten years. The predicted numbers of breast cancers were compared to the observed numbers to assess overall model calibration, and the concordance between breast cancer outcomes and predicted probabilities was used to measure the accuracy of the model on the individual level. Subset analysis of women with strong family history was performed. Strong family history was defined as: at least one first-degree relative with breast cancer before the age of 50 years or two or more relatives with breast cancer, at least one being a first degree relative.Results: Three hundred and thirty one women with atypia were identified. Over a mean follow up of 13.7 years, 62 (19%) women have developed invasive breast cancer. Thirty one women developed invasive cancer in the first ten years after biopsy. The Tyrer-Cuzick model predicted that 64.6 invasive breast cancers would occur in the first ten years after biopsy. Thus, the predicted to observed ratio was 2.08 [95% CI: 1.47 – 2.96], p &lt; 0.001).The concordance statistic was 0.51, revealing that the Tyrer-Cuzick model did not accurately distinguish, on an individual level, between women who were diagnosed with invasive breast cancer within ten years of biopsy and those who were not.Performance was somewhat better in the subset of 68 women with a strong family history of breast cancer. The model predicted 12.3 invasive breast cancers, and 7 were observed, for a predicted to observed ratio of 1.76 [95% CI: 0.84 – 3.70]. The concordance statistic was 0.57.Conclusion: The Tyrer-Cuzick model significantly overestimated the risk of breast cancer in the first ten years after biopsy for this group of women with atypia. Individual risk estimates showed poor concordance. Performance was slightly improved in women with a strong family history of breast cancer. Physicians should be cautious when using the Tyrer-Cuzick model to predict ten-year risk in patients with atypia.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6063.