Using proliferative markers and Oncotype DX in therapeutic decision-making for breast cancer: the B.C. experience

BACKGROUND

Proliferative scoring of breast tumours can guide treatment recommendations, particularly for estrogen receptor (er)-positive, her2-negative, T1-2, N0 disease. Our objectives were to □ estimate the proportion of such patients for whom proliferative indices [mitotic count (mc), Ki-67 immunostain, and Oncotype dx (Genomic Health, Redwood City, CA, U.S.A.) recurrence score (rs)] were obtained.□ compare the indices preferred by oncologists with the indices available to them.□ correlate Nottingham grade (ng) and its subcomponents with Oncotype dx.□ assess interobserver variation.

METHODS

All of the er-positive, her2-negative, T1-2, N0 breast cancers diagnosed from 2007 to 2011 (n = 5110) were linked to a dataset of all provincial breast cancers with a rs. A 5% random sample of the 5110 cancers was reviewed to estimate the proportion that had a mc, Ki-67 index, and rs. Correlation coefficients were calculated for the rs with ng subcomponent scores. Interobserver variation in histologic grading between outside and central review pathology reports was assessed using a weighted kappa test.

RESULTS

During 2007-2011, most cancers were histologically graded and assigned a mc; few had a Ki-67 index or rs. The ng and mc were significantly positively correlated with rs. The level of agreement in histologic scoring between outside and central pathology reports was good or very good. Very few cases with a low mc had a high rs (1.8%).

CONCLUSIONS

Patients with low ng and mc scores are unlikely to have a high rs, and thus are less likely to benefit from chemotherapy. In the context of limited resources, that finding can guide clinicians about when a rs adds the most value.

Abstract P6-06-04: Breast cancer in young women: Have the prognostic and predictive implications of breast cancer subtypes changed over time?

Background:

Breast cancer (BC) occurring in very young women has a worse prognosis compared to older women, and is the leading cause of cancer death in women aged < 40 years. Over the last decade BC management has evolved to incorporate increased understanding of BC subtypes and new therapeutic agents such as taxanes and trastuzumab. Whether the previously observed poor prognosis associated with BC in young women persists in the context of modern adjuvant therapies and relative to the BC subtypes has not been widely investigated.

Methods:

We analyzed BC outcomes of young (40-49 years) and very young (<40 years) patients (pts) according to subtype defined by immune histochemistry (IHC) and evaluated for any changes over time by comparing 2 cohorts representative of different time periods. Data from 1,101 women aged < 50 diagnosed with invasive BC between 1986-1992, and 1,945 women diagnosed between 2004-2007 were abstracted from the British Columbia Cancer Agency's Breast Cancer Outcomes Database and analyzed according to two age categories (40 years and 40-49 years) and subtype (IHC was available on the earlier cohort from an established tumor repository for those years). Subtypes were defined as follows: Luminal: estrogen receptor (ER) and/or progesterone receptor (PR) positive, and HER2 negative, HER2: HER2 positive and any ER/PR, and Triple Negative (TN) (ie for ER,PR and HER2 negative). Survival analysis was performed using the Kaplan Meier method.

Results:

Median follow-up was 13.2 years and 6.2 years for the 1986-1992 and 2004-2007 cohorts respectively. Within both time cohorts, luminal subtype pts <40 demonstrated worse survival compared with those 40-49. This difference remained after accounting for grade in the contemporary cohort alone (Hazard ratio 0.50 p = 0.0001). Inferior survival was observed for pts <40 with HER2 BC in the 1986-1992 cohort, no impact of age was demonstrated in the HER2 2004-2007 cohort. No survival difference was seen between the age groups for TN BC in either time cohort. Across the HER2 and TN subtypes, and for luminal pts 40-49 a significant improvement was seen in 5-year RFS and OS between the 2 time cohorts. 5-year RFS but not OS improved over time for the luminal pts <40.

5 year overall survival  1986-1992  2004-2007   5-yr OS (%)  5-yr OS (%) p value  (95% CI)  (95% CI)  Luminalage < 4082 (76-89)  88 (84-93) 0.138 age 40-4990 (87-92)  95 (94-97) 0.001 p value0.055  <0.001          HER2age < 4049 (35-63)  89 (83-95) <0.001 age 40-4966 (57-75)  89 (83-94) <0.001 p value0.017  0.879          TNage < 40 (101)67 (58-77)  82 (73-90) 0.011 age 40-49 (182)74 (67-80)  84 (79-89) <0.001 p value0.909  0.759  

Conclusions:

We observed a significant improvement in survival over time for both HER2 and TN BC which may reflect improvements in adjuvant strategies based on subtype presentation. Inferior survival for pts <40 with luminal BC persists in the modern era and this group should be targeted for research.

5 year relapse free survival  1986-1992  2004-2007    5-yr RFS (%)  5-yr RFS (%) p value  (95% CI)  (95% CI)  Luminalage<4065(57-74)  79 (74-85) <0.001 age 40-4977 (72-80)  92 (91-94) <0.001 p value0.009  <0.001          HER2age<4039 (25-52)  81 (70-92) <0.001 age 40-4958 (48-67)  84 (80-88) <0.001 p value0.039  0.879          TNage<4060 (51-70)  78 (69-87) 0.014 age 40-4963 (56-70)  77 (71-82) 0.001 p value0.868  0.933  

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-04.

Abstract P4-08-01: Effects of exercise during adjuvant chemotherapy on clinical outcomes in early stage breast cancer

Background: Observational studies suggest that physical activity following a diagnosis of breast cancer may be associated with a lower risk of recurrence and death. Some studies also suggest possible effect modification by disease stage, body mass index, and receptor status. To date, however, there are no randomized trials examining the effects of exercise on disease outcomes in any cancer patient group. Here, we report an exploratory follow-up of disease outcomes from the Supervised Trial of Aerobic versus Resistance Training (START). Patients and Methods: The START Trial was a Canadian multicenter trial that randomized 242 breast cancer patients starting adjuvant chemotherapy to either usual care (n = 82) or supervised aerobic (n = 78) or resistance (n = 82) exercise for the duration of their chemotherapy. The primary efficacy endpoint for this exploratory analysis was disease-free survival (DFS). Secondary endpoints were overall survival (OS), distant disease-free survival (DDFS), and recurrence-free interval (RFI). The two exercise arms were combined for the analysis (n = 160) and selected subgroups were explored. Results: After a median follow-up of 89 months (IQR 81 to 96), there were 25/160 (15.6%) DFS events in the exercise groups and 18/82 (22.0%) in the control group (log-rank p = 0.21). Eight-year DFS was 82.7% for the exercise groups compared with 75.6% for the control group (Hazard ratio [HR] = 0.68, 95% CI = 0.37-1.24). There were 13/160 (8.1%) deaths in the exercise groups and 11/82 (13.4%) in the control group (log-rank p = 0.21). Eight-year OS was 91.2% in the exercise groups compared with 82.7% in the control group (HR = 0.60, 95% CI = 0.27 to 1.33. There were 20/160 (12.5%) DDFS events in the exercise groups and 16/82 (19.5%) in the control group (log-rank p = 0.15). Eight-year DDFS was 86.7% in the exercise groups compared with 78.3% in the control group (HR = 0.62, 95% CI = 0.32 to 1.19). Finally, there were 20/160 (12.5%) RFI events in the exercise groups and 17/82 (20.7%) in the control group (Gray's p = 0.095). Eight-year cumulative incidence of RFI was 12.6% in the exercise groups compared with 21.6% in the control group (HR = 0.58, 95% CI = 0.30 to 1.11). Subgroup analyses for DFS and RFI suggested stronger effects for women who were overweight/obese, had stage II/III cancer, receptor positive tumors, HER2 positive tumors, received taxane-based chemotherapies, and received at least 85% of their intended chemotherapy dose-intensity. The most notable subgroup effect was for patients who received optimal chemotherapy dosing with a borderline significant effect for DFS (HR = 0.50, 95% CI = 0.25 to 1.01) and a significant effect for RFI (HR = 0.38, 95% CI = 0.18 to 0.81). Conclusions: In this exploratory follow-up of the START Trial, there was a suggestion that exercise during adjuvant chemotherapy may improve several efficacy endpoints although none achieved statistical significance. Nevertheless, the magnitude of the effects appear to be meaningful with absolute 8-year survival differences between 7% and 9% and relative rate reductions between 30% and 40%. The START Trial provides the first randomized data to suggest that adding exercise to standard chemotherapy for breast cancer may improve outcomes. A definitive phase III trial is warranted.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-08-01.

Abstract P4-16-02: A survival benefit from locoregional radiotherapy for node-positive and CMF treated breast cancer is most significant in Luminal A tumors

Background: Between 1978–1986, 318 premenopausal women treated with mastectomy for lymph node positive breast cancer, were randomized to CMF chemotherapy alone vs. CMF chemotherapy and adjuvant radiotherapy (RT) to the chest wall and regional lymph nodes. After 15 years of follow-up, post-mastectomy RT was associated with a statistically significant 29% relative risk reduction in mortality. Recent evidence suggests that Luminal A tumors, identified using hormone receptors and Ki67, have a particularly favorable prognosis. We retrospectively identified the Luminal A tumors from this clinical trial cohort to determine if the response to postmastectomy RT differed among Luminal A and non-Luminal A tumors.

Methods: 203 archival breast tumor samples from this study were used to construct a tissue microarray. Luminal A tumors were identified using an immunopanel consisting of: estrogen receptor, progestorone receptor, Her2, and Ki67. Luminal A tumors were defined as either ER or PR positive, Her2 negative, and Ki67 < 14%. Kaplan-Meier estimates and the log-rank test were used to test the differences in locoregional relapse free survival (LRFS) and breast cancer specific survival (BCSS). Interaction between treatment and Luminal A/Non-luminal A were tested using Cox regression analysis.

Results: The intrinsic subtype was successfully determined in 144 breast tumors, and 49 were classified as Luminal A (34%). Survival outcomes at 10 years are summarized in Table 1:

Targeting triple-negative breast cancer: optimising therapeutic outcomes

BACKGROUND

Triple-negative breast cancer (TNBC) is a distinct subset of breast cancer (BC) defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2. It is highly heterogeneous and displays overlapping characteristics with both basal-like and BC susceptibility gene 1 and 2 mutant BCs. This review evaluates the activity of emerging targeted agents in TNBC.

DESIGN

A systematic review of PubMed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with targeted and platinum-based therapies.

RESULTS AND DISCUSSION

Our review identified TNBC studies of agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth, and survival pathways. Combining targeted agents with chemotherapy in TNBC produced only modest gains in progression-free survival, and had little impact on survival. Six TNBC subgroups have been identified and found to differentially respond to specific targeted agents. The use of biological preselection to guide therapy will improve therapeutic indices in target-bearing populations.

CONCLUSION

Ongoing clinical trials of targeted agents in unselected TNBC populations have yet to produce substantial improvements in outcomes, and advancements will depend on their development in target-selected populations.

The sequential use of endocrine treatment for advanced breast cancer: where are we?

BACKGROUND

Hormone receptor-positive advanced breast cancer is an increasing health burden. Although endocrine therapies are recognised as the most beneficial treatments for patients with hormone receptor-positive advanced breast cancer, the optimal sequence of these agents is currently undetermined.

METHODS

We reviewed the available data on randomised controlled trials (RCTs) of endocrine therapies in this treatment setting with particular focus on RCTs reported over the last 15 years that were designed based on power calculations on primary end points.

RESULTS

In this paper, data are reviewed in postmenopausal patients for the use of tamoxifen, aromatase inhibitors and fulvestrant. We also consider the available data on endocrine crossover studies and endocrine therapy in combination with chemotherapy or growth factor therapies. Treatment options for premenopausal patients and those with estrogen receptor-/human epidermal growth factor receptor 2-positive tumours are also evaluated.

CONCLUSION

We present the level of evidence available for each endocrine agent based on its efficacy in advanced breast cancer and a diagram of possible treatment pathways.

1st International consensus guidelines for advanced breast cancer (ABC 1)

The 1st international Consensus Conference for Advanced Breast Cancer (ABC 1) took place on November 2011, in Lisbon. Consensus guidelines for the management of this disease were developed. This manuscript summarizes these international consensus guidelines.

P2-12-27: Simply Adding Together the Diameters of Tumor Foci in Patients with Multicentric or Multifocal Disease Does Not Add Any Additional Prognostic Information: An Analysis from NCIC CTG MA.12 Randomized Placebo-Controlled Trial of Tamoxifen after Adjuvant Chemotherapy in Pre-Menopausal Women with Early Breast Cancer

Background: A common clinical conundrum in breast cancer management is whether pathologic T stage in women with multicentric or multifocal disease should be taken as the diameter of the largest focus or as the sum of all foci in the breast. Most staging systems, such as the American Joint Committee on Cancer (AJCC), simply use the largest tumor focus for staging. We examine here the impact of alternate methods of estimating tumour size including measures of total tumor size, volume and surface area.

Materials & Methods: NCIC CTG MA.12 is a randomized placebo-controlled trial of tamoxifen after adjuvant chemotherapy for pre-menopausal women with early breast cancer. Median follow up is 9.7 years. Pathologically reported patient tumor dimensions for up to 3 foci were utilized to examine the effects of tumor size on Breast-Cancer-Free-Interval (BCFI), defined as the time from randomization until recurrence (defined as first local, regional, distant, or contralateral invasive tumor or DCIS). Tumor size was estimated as 1) pathologic T stage as per AJCC criteria; 2) largest dimension of largest tumor focus (cm); 3) sum of largest dimension(s) of tumor foci (cm); 4) sum of surface area(s) of tumor foci (cm2), and 5) sum of volume of tumor foci (cm3). Step-wise forward unstratified Cox regression was used to assess the different effects of tumor size. Results: This study accrued 672 patients, 43% with T1 tumors, 51% with T2 tumors, and 6% with T3/T4 tumors; 25% were node negative and 56% had 1–3 positive lymph nodes. 75% were locally determined to have hormone receptor positive tumors. A higher number of involved lymph nodes was associated with significantly shorter BCFI (p<0.0001). None of pathologic T stage (p=0.14), largest dimension of largest tumor size (p=0.14), sum of largest dimensions of tumor foci (p=0.24), sum of surface area (p=0.38), and sum of volume of foci (p=0.51) were significantly associated with BCFI. Likewise, lymphovascular invasion (p=0.08), grade (p=0.14), nor administration of anthracycline therapy (p=0.08) were associated with BCFI.

Discussion: In the MA.12 population of pre-menopausal women randomized to either tamoxifen or placebo, the sole factor significantly associated with BCFI was nodal status. No measure of tumor size in unifocal or multicentric/multifocal tumors impacted BCFI. The findings of this mature data set suggest that simply adding together the diameters of tumors in patients with multicentric or multifocal disease did not add any additional prognostic information.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-27.

P2-12-23: How Should We Assess Tumour Size (T Stage) in Patients with Multicentric/Multifocal Breast Cancer? Results from the NCIC CTG MA.5 Randomized Trial of CEF vs. CMF in Pre-Menopausal Women with Node Positive Breast Cancer

Background

A common clinical conundrum in breast cancer management is whether pathologic T stage in women with multicentric or multifocal disease should be taken as the diameter of the largest focus or as the sum of all foci in the breast. Most staging systems, such as the American Joint Committee on Cancer (AJCC), simply use the largest tumour focus for staging. We examine here the impact of alternate methods of estimating tumour size including measures of total tumour size, volume and surface area.

Methods: NCIC CTG MA.5 is a randomized trial of CEF versus CMF in pre-menopausal women with node positive breast cancer.

Median follow up is 10 years. Pathologically reported patient tumour dimensions for up to 3 foci were utilized to examine the effects of tumour size on Breast-Cancer-Free-Interval (BCFI). BCFI is defined as the time from randomization until recurrence: first local invasive or DCIS, regional, distant, contralateral invasive or DCIS. Tumour size was estimated as 1) pathologic T stage as per AJCC criteria; 2) largest dimension of largest tumour focus (cm); 3) sum of largest dimension(s) of tumour foci (cm); 4) sum of surface area(s) of tumour foci (cm2), and 5) sum of volume of tumour foci (cm3). Step-wise forward unstratified Cox regression was used to assess the different effects of tumour size.

Results: This study accrued 710 patients, 37% with T1 tumours, 52% with T2 tumours and 9% with T3 tumours; 61% had 1 to 3 positive lymph nodes. 59% hormone receptor positive. Higher pathologic T stage (p=0.001) and greater surface area (p=0.02) were associated with shorter BCFI, as was lymphovascular invasion (p=0.03), and # of lymph nodes involved (p<0.0001). Administration of anthracycline therapy led to significantly longer BCFI (0.003). The sum of largest tumour sizes (p=0.33) and sum of tumour volume (p=0.34) were not significantly associated with BCFI. Additionally, when the less complete locally reported tumour grade data were included, higher tumour grade was associated with shorter BCFI (p<0.0001).

Conclusions: Consideration of multicentric and multifocal disease was an important adjunct to standard pathologic tumour size as was estimation of tumour surface area in this chemotherapy trial of node positive premenopausal women. However, simply adding together the diameters of tumours in patients with multicentric or multifocal disease did not add any additional prognostic information in this high risk patient population.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-23.

P5-14-17: Stage IV at Presentation – Are HER2 Positive Tumors Overrepresented?

Background: A minority of patients are diagnosed with Stage IV breast cancer at presentation. Recent studies (Dawood 2010) have suggested a better outcome for de novo vs. recurrent Stage IV but they did not account for the variation of molecular subtype. We questioned whether HER2 overexpressing tumors were over-represented in de novo Stage IV disease, and whether this impacted on survival compared to other subtypes. Further, if different subtypes are more likely to present with metastatic disease, then this factor may need to be considered when developing guidelines for staging. With such considerations in mind, the purpose of this study was to determine the breast cancer subtypes according to stage. The main hypothesis was that HER2 positive tumors would be more prevalent in stage IV presentations. Methods: Using the Breast Cancer Outcomes Unit database from the BC Cancer Agency (BCCA), patients referred to the BCCA with a new diagnosis of breast cancer between 2005 and 2010 were selected. Patients with a previous or synchronous contralateral breast cancer, male cases, and patients with referrals for reasons other than new disease were excluded. Four subtypes according to available markers were defined: ER+/HER2−, ER+/HER2+, ER-/HER2+, and ER-/HER2−.

Results: Using these criteria, 485 cases of de novo stage IV disease and 10,723 stages I — III cases were extracted. After excluding cases with missing data, our final cohort consisted of 10,186 stage I-III cases and 425 stage IV cases. Distribution by subtype is presented in the Table below.

BCL2 in breast cancer: a favourable prognostic marker across molecular subtypes and independent of adjuvant therapy received

BACKGROUND

Breast cancer is heterogeneous and the existing prognostic classifiers are limited in accuracy, leading to unnecessary treatment of numerous women. B-cell lymphoma 2 (BCL2), an antiapoptotic protein, has been proposed as a prognostic marker, but this effect is considered to relate to oestrogen receptor (ER) status. This study aimed to test the clinical validity of BCL2 as an independent prognostic marker.

METHODS

Five studies of 11 212 women with early-stage breast cancer were analysed. Individual patient data included tumour size, grade, lymph node status, endocrine therapy, chemotherapy and mortality. BCL2, ER, progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) levels were determined in all tumours. A Cox model incorporating the time-dependent effects of each variable was used to explore the prognostic significance of BCL2.

RESULTS

In univariate analysis, ER, PR and BCL2 positivity was associated with improved survival and HER2 positivity with inferior survival. For ER and PR this effect was time dependent, whereas for BCL2 and HER2 the effect persisted over time. In multivariate analysis, BCL2 positivity retained independent prognostic significance (hazard ratio (HR) 0.76, 95% confidence interval (CI) 0.66-0.88, P<0.001). BCL2 was a powerful prognostic marker in ER- (HR 0.63, 95% CI 0.54-0.74, P<0.001) and ER+ disease (HR 0.56, 95% CI 0.48-0.65, P<0.001), and in HER2- (HR 0.55, 95% CI 0.49-0.61, P<0.001) and HER2+ disease (HR 0.70, 95% CI 0.57-0.85, P<0.001), irrespective of the type of adjuvant therapy received. Addition of BCL2 to the Adjuvant! Online prognostic model, for a subset of cases with a 10-year follow-up, improved the survival prediction (P=0.0039).

CONCLUSIONS

BCL2 is an independent indicator of favourable prognosis for all types of early-stage breast cancer. This study establishes the rationale for introduction of BCL2 immunohistochemistry to improve prognostic stratification. Further work is now needed to ascertain the exact way to apply BCL2 testing for risk stratification and to standardise BCL2 immunohistochemistry for this application.

Elevated Tumor Markers in the Different Breast Cancer Subtypes; Percentage and Correlation with Outcome

Background: Tumor markers (TMs) are widely used in breast cancer to monitor patients with metastatic disease during active treatment in conjunction with diagnostic imaging, history and physical examination. Studies of CA15-3 and CEA in metastatic disease have yielded positivity rates of approximately 80% and 40%, respectively. There is less information regarding CA-125 and breast carcinoma. Recently, there has been a renewed interest in tumor markers and their potential as therapeutic targets, including vaccine development, in various cancers. Early studies have reported an association between CA 15-3 levels and ER positivity. As far as we are aware, this is the first study to report elevated TM levels in the different breast subtypes and their correlation with outcome in each subtype. Aim: To document the rate of elevated tumor markers (CEA, CA15-3, CA-125) in the different subtypes and correlate TM with outcome. Methods: Women with breast cancer diagnosed between 1986 and 1992 and referred to the British Columbia Cancer Agency with M1 disease at presentation or who later developed a distant relapse were included. Archival paraffin tissue blocks were used to construct a tissue microarray. Breast cancer subtypes were defined as Luminal A (ER/PR+, HER2- and Ki67 &lt;14%), Luminal B (ER/PR+ and HER2- and Ki67 ≥14%), Luminal HER2 (HER2+ and ER/PR+), HER2 (HER2+ and ER-and PR-), and Basal {HER2-, ER-PR- and (CK 5/6+ and/or EGFR+)} using immunohistochemical staining. In addition, we examined the triple negative (ER-, PR-, HER2-) non-basal subgroup. Levels of TM values (CA-15-3, CEA, CA-125) within 3 months of distant relapse date or anytime after were captured and percentage of elevated values (CA15-3&gt;28, CEA&gt;4, CA-125&gt; 35) among the different subtypes were reported. Kaplan Meier (KM) plots were created for cases with elevated TM versus non-elevated TM cases. Results: 1,656 cases with distant metastases were potentially eligible for inclusion. Excluded cases: 428 cases without any linkage to TM data, 16 cases with subsequent contaralateral breast cancer (CBC) and no TM between the time of distant relapse and CBC, 127 cases with TM &gt;3 months before distant relapse, and 187 cases where breast cancer subtype could not be determined. The percentage of TMs among the different breast cancer subtypes is shown in the table. Median duration of survival from time of diagnosis with metastatic disease was significantly shorter for patients with elevated TMs vs. those with normal TM values, p=0.003. Similar results were found when stratifying the results by subtype, with only Lum A and B attaining statistical significance, p=0.002 and p=0.016 respectively.Conclusion: Elevated TMs are documented in all breast cancer subtypes, with a significantly higher percentage of elevated TMs in luminal versus non-luminal groups. The lowest frequency of elevated TMs was documented in the non-basal TN cases. Elevated TMs in the metastatic setting predict worse outcome for Lum A/B subtypes.Table 1 : Percentage of elevated TMs among the different breast cancer subtypesSubtypeany TM %CA 15-3 %CEA %CA-125 %Lum A87816448Lum B88836054Lum Her2+86766339Her2+,ER-78705443Basal70642764Non Basal, Triple negative61582540p value&lt;0.0010.001&lt;0.0010.71 

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2125.

Using Ki67 To Improve and Simplify Outcome Modeling for Breast Cancer

Ki67 is a marker of proliferation which has several advantages over histological grade. Ki67 is determined less subjectively and is a continuous rather than a categorical variable. Many studies that have looked at Ki67 have been small and underpowered. A large population based tissue microarray was used to: A) test the prognostic value of Ki67 in testing and validation sets, and B) construct an improved model including Ki67 and conventional prognostic variables to predict patient outcome. Methods: The cohort included 2,780 patients with early breast cancer diagnosed in British Columbia and a median follow up of 14.5yrs. Variables included were: tumor size (T), number of positive nodes (N), grade, lymphovascular invasion (LVI), estrogen receptors (ER), progesterone receptors (PR), Her2, Ki67, local treatment (surgery, radiation) and systemic treatment (chemotherapy, hormonal). Prognostic factors were balanced between the training and validation sets. Prognostic variables were identified in the testing set among ER positive and ER negative cohorts using Cox Regression analysis and tested in the validation set. Results: The inclusion of Ki67 in the Cox Regression analysis resulted in the elimination of grade as a predictor. For ER positive disease independent predictors were T, N, LVI, PR, HER2, Ki67, local treatment, chemotherapy and hormonal therapy. Independent predictors among ER- cases were T, N, LVI, Ki-67, and chemotherapy. Predicted 10-yr Breast Cancer Specific Survival in the validation set was 72.0% versus 72.4% [SE: 1.2] observed. As subtle prognostic differences may result in very disparate treatment recommendations for Stage I breast cancers, we specifically reviewed this group. In analysis of stage I patients, there were no statistically significant deviations between predictions and observation; agreement between the predicted and observed 10-yr BCSS was excellent (86.0% vs 87.6% (SE: 1.6) p = 0.3169). As well, elevated Ki67 was common (53%) and was a powerful prognostic variable with causing more than a doubling of the 10-yr BrCa mortality (elevated ≥ 10% vs low &lt; 10%, 16.8% vs 6.8%) in this group (table). Conclusion: In this study the proliferation marker Ki67 replaced histologic grade as a predictor of outcome for patients with early breast cancer. Predictive models such as Adjuvant! could incorporate Ki67 as an input variable and this modification is being developed. If models that use Ki67 are validated they may be able to be used globally and be cost effective compared to more expensive genomic predictors.Table: Predicted versus observed 10yr BCSS, based on the new modelPatientsSubgroupNPredicted SurvivalObserved Survivalp-valueAll patientsOverall139772.072.40.75 ER+101277.276.40.56 ER-38558.461.20.27 HER2+19755.658.00.50 HER2-120074.874.80.99Stage IOverall45386.087.60.32 ER+35287.690.40.09 ER-10179.678.40.77 HER2+4378.882.40.55 HER2-41086.888.40.33 

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4042.

Pertuzumab and Trastuzumab: Re-Responses to 2 Biological Agents in Patients with HER2-Positive Breast Cancer Which Had Previously Progressed during Therapy with Each Agent Given Separately: A New Biological and Clinical Observation

Background: Pertuzumab, a fully humanised IgG1 monoclonal antibody, is a human epidermal growth factor receptor 2 (HER2)-dimerisation inhibitor directed to the dimerisation epitope of HER2 (trastuzumab binds to the juxta-membrane epitope). Pertuzumab has demonstrated promising activity when given with trastuzumab to patients with HER2-positive metastatic breast cancer (mBC) which had progressed during therapy with trastuzumab in a 2-step Phase II study.1Methods: The protocol was amended to include a 3rd cohort of patients to determine the activity of pertuzumab when given without trastuzumab.2 Patients recruited into this 3rd cohort were allowed to have trastuzumab re-introduced in combination with pertuzumab if there was inadequate response to pertuzumab alone or response followed by relapse.Results: Twenty-nine patients were recruited into this 3rd cohort. Patients had reached their 3rd line of treatment for mBC. To date, 15 patients have had trastuzumab re-introduced after disease progression on trastuzumab therapy and pertuzumab monotherapy. Among these 15 patients, at the time of this analysis there have been 3 patients with confirmed responses. There are also 4 patients who had not yet undergone 8 cycles of assessments to reach the overall best response end point, of which at least 2 were experiencing stablisation of disease. Updated data on activity and toxicity will be presented.Conclusions: We believe this is the first time that anti-tumour activity has been reported in patients when 2 biological agents have been used together after the disease has progressed during therapy with each agent alone. There are several mechanisms which might explain this phenomenon. Trastuzumab prevents proteolytic cleavage of the extracellular domain of HER2, keeping the receptor in situ. The addition of a second antibody to a separate epitope increases the potential for antibody-dependent cell-mediated cytotoxicity and prevents dimerisation between HER2 and other HER family members, such as HER1 and HER3. The combined antibodies might increase the efficiency of inhibition of signal transduction. There are wide-ranging and potentially significant biological and clinical implications.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5114.

Phase III randomized anastrozole exercise (RAE) trial: First planned interim analysis

e20674

Background: Adjuvant anastrozole (aA) is associated with arthralgias/myalgias (A/M), bone density loss, and hot flushes. Analgesics offer limited relief of musculoskeletal (MSK) symptoms and are associated with side effects of their own. The benefit of exercise on bone health, muscle strength, hot flushes, and quality of life (QOL) has been demonstrated; the objective of this trial is to determine if an exercise program improves anastrozole related A/M. Methods: This is a phase III, randomized trial of standard of care (observation) vs 48 weeks (wks) of exercise for women with BC on aA. Subjects in the control group receive literature about AIs (information on bone health, management of SEs of AIs). Subjects in the intervention group participate in a semi-supervised, individualized, and graduated 3x/wk exercise program (aerobic, resistance training, stretching) for 24 wks. From wks 25–48 independent exercise is recommended 3x/wk. The 10 endpoint is change in MSK symptoms as measured by 12 wk SF-36v2 bodily pain scores, NCI CTG toxicity, and visual analogue scale. 20 endpoints are QOL, hot flushes, bone density, and body mass. Physical activity and compliance with aA was monitored in both arms. The 1st interim analysis was planned after 10 patients were enrolled to evaluate accrual, compliance, and rate of discontinuation. Results: Accrual commenced December, 2007. Fourteen of a planned 72 patients have been enrolled (baseline data available for 13); 7 pts in the control arm (A) and 6 in the exercise arm (B). Median age was 59 (A) and 58 (B). Nine pts had baseline and 12 wk data available [5 (A), 4 (B)]. There were no withdrawals and compliance with scheduled exercise was 100%. Of the NCI CTG A/M deemed probably/definitely related to aA, there is no change in the number reported at baseline vs wk 12 in Arm A. In Arm B, 2 of 4 pts report a decrease in the number of A/M at wk 12. Mean norm-based wk 12 SF-36v2 bodily pain domain scores worsened by 4.1 in Arm A; an improvement of 1.9 in mean scores was observed in Arm B. Conclusions: Interim results show that a structured exercise program is well tolerated and compliance is high among women with aA related MSK symptoms. Early results point to a positive impact of exercise on MSK symptoms in women with early BC. Updated data will be presented.

[Table: see text]

Phase II trial of neoadjuvant sequential FEC100 followed by docetaxel and capecitabine for HER2-negative locally advanced breast cancer (LABC): A multicenter study from British Columbia

598

Background: Anthracyclines and taxanes are now standard of care for LABC. Phase III trials have demonstrated pathological complete responses of the breast (pCR) of 20–34% in studies of primary operable and LABC. Recent trials in the HER-2 negative population reported pCR rates of 20–29%.We have completed a multi-centre phase II trial of a neoadjuvant sequential anthracycline and taxane combination regimen in a HER-2 negative LABC population. Methods: Women with HER-2 negative stage IIB-IIIC breast cancer were enrolled. Treatment consisted of 4 cycles of FEC100 (5-FU 500 mg/m2, epirubicin 100 mg/m2, cyclophosphamide 500 mg/m2) followed by 4 cycles of XT (docetaxel 75 mg/m2 and capecitabine 1,000 mg/m2 PO BID x 14 days q3 weekly). Hormone receptor positive cases were prescribed standard endocrine therapy. A correlative translational component with baseline and interval biopsies and serum collection was also performed. Results: A total of 51 patients (27% stage IIB; 43% IIIA; 20% IIIB; and 10% IIIC) were accrued across 4 BCCA centres from November 2004-December 2007. Median age was 54 years (33–67 years). 59% of tumours were ER positive. There were no primary progressors on FEC100, though 2 patients had significant toxicities requiring early discontinuation. 3 patients (6%) developed clinical progression on XT. The majority of patients (79%) on XT required a dose reduction or delay. There were 5 episodes (10%) of febrile neutropenia. 15 patients (29%) underwent adjuvant radiotherapy prior to surgery. The pCR rate (breast and axilla) for the entire study population was 22% (11/51). In the ER+ and triple negative subtypes the pCR (breast and axilla) was 13% and 42%, respectively. Conclusions: This multi-centre phase II trial demonstrates activity for neoadjuvant anthracyclines followed by combination docetaxel/capecitabine in a HER-2 negative LABC population. Though the pCR rate was greater in the triple negative cohort, significant improvements are still required across the biological subtypes in HER-2 negative LABC.

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Pertuzumab monotherapy following trastuzumab-based treatment: Activity and tolerability in patients with advanced HER2- positive breast cancer

1022

Background: Pertuzumab binds to the dimerization epitope of the HER2 receptor, inhibits HER dimerization and signal transduction, and induces ADCC. In 2 cohorts of pts (n = 66) with HER2-positive metastatic breast cancer which had progressed during trastuzumab therapy after ≤3 lines of chemotherapy with or without trastuzumab, pertuzumab plus trastuzumab has been shown to be active (CR 7.6%, PR 16.7%, SD ≥6/12 25.8%) (Gelmon et al. ASCO 2008, Abs 1026). To assess the activity of pertuzumab monotherapy in this clinical setting, the protocol was amended to include a 3rd cohort of pts. Methods: Pt selection was not changed except that ≥1 month between the last dose of trastuzumab and study start was required. Pts received pertuzumab monotherapy. If the tumor failed to respond or responded and then progressed, trastuzumab could be added to pertuzumab. 27 pts were to be recruited to ensure that ≥24 were fully evaluable for objective response and stabilization of disease ≥6 months. Standard 21-day schedules of the antibodies were given. Results: 29 pts were recruited. Tolerability was good: the major adverse events were mild diarrhea and rash with no clinical cardiac events. To date, 2 responses have been reported, and several pts have ongoing stabilization of disease. 14 pts have received trastuzumab plus pertuzumab following inadequate response (or response then relapse) on pertuzumab monotherapy. Of these 14, 2, having progressed during trastuzumab, failed to respond to pertuzumab monotherapy but underwent confirmed response when trastuzumab was added to the pertuzumab –possibly the first report of such a phenomenon and providing good evidence of an enhanced effect when the antibodies are combined. Updated results will be presented. Conclusions: Pertuzumab monotherapy is active against HER2-positive breast cancer which has progressed during trastuzumab-based therapy. The combination of the two antibodies appears to be more active than either antibody alone. The combination is also active in patients that had failed both antibodies given separately. In clinical studies, the use of the two antibodies combined is justified.

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Phase II trial of neoadjuvant chemotherapy of sequential FEC100 followed by docetaxel, carboplatin and trastuzumab (TCH) for HER-2 over-expressing locally advanced breast cancer (LABC): a multi-centre study from British Columbia

Abstract #5118

Background: The role of trastuzumab either concurrent or sequential with adjuvant chemotherapy have clearly demonstrated significant benefits in early stage HER-2 positive breast cancer. There is now an accumulation of phase II and III trials also demonstrating improved pathological complete responses (pCR) in HER-2 positive breast cancer with neoadjuvant trastuzumab concurrent with chemotherapy. The number of patients on these trials are significantly fewer, and many of these trials are a mixture of primary operable and LABC. We have completed a multi-centre phase II trial of neoadjuvant chemotherapy and trastuzumab in HER-2 positive LABC.&#x2028; Methods: Women with HER-2 positive (IHC 3+ or FISH+) stage IIB-IIIC breast cancer were enrolled. Treatment consisted of 4 cycles of FEC100 (5-FU 500 mg/m2, epirubicin 100 mg/m2, cyclophosphamide 500 mg/m2) followed by 4 cycles of TCH (Docetaxel 75 mg/m2, carboplatin AUC 6, trastuzumab 8 mg/kg loading then 6 mg/kg q3 weekly). Trastuzumab was also continued adjuvantly for 9 months following chemotherapy and surgery. Cardiac monitoring every 3 months was mandated. A correlative translational component with baseline and interval biopsies and serum collection was also performed.&#x2028; Results: A total of 30 patients (3 stage IIB; 14 IIIA; 10 IIIB and 3 IIIC) over a 3 year time period in 4 centres were accrued. Median age was 49 years (26-77 years). 60% of tumours were ER negative. There was one clinical CHF and 2 asymptomatic falls in LVEF requiring early discontinuation of trastuzumab. There were 3 episodes (10%) of febrile neutropenia. Seven patients underwent adjuvant radiotherapy prior to surgery. The pCR rate (breast and axilla) for the entire study population was 60% (18/30). There have been 3 recurrences so far (all biopsy proven) – of which 2 were brain metastases only. Further details on toxicity and changes in LVEF will be presented.&#x2028; Conclusions: This multi-centre phase II trial clearly demonstrates significant activity (pCR 60%) for neoadjuvant anthracyclines followed by concurrent taxane, platinum and trastuzumab in a HER-2 positive LABC population. Overall the treatment regimen was well tolerated. Brain metastases however appear to be a common site of relapse in this high risk patient population and further treatment strategies directed at this site should be investigated.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5118.

Insulin like growth factor in breast cancer subtypes

Abstract #3048

Background: Insulin Like Growth Factor -1 Receptor (IGF-1R) is an important new therapeutic target expressed in all cancer types. IGF-1R supports cell survival pathways implicated in resistance to cancer therapy. Knowledge of the pattern of IGF-R1 expression among breast cancer subtypes and its impact on prognosis may enhance development of therapeutics targeting this pathway.&#x2028; Methods: Patients with early breast cancer cases, stage I-III, referred to the BC Cancer Agency from 1986 to 1992 were included. Archival paraffin tissue blocks were used to construct a tissue microarray. Among 4,046 patients with early stage on the TMA, 1,238 patients (30.6 %) were excluded due to missing subtype biomarkers, IGFR staining or both. Breast cancer subtypes were defined as Luminal A (ER/PR+, HER2- and Ki67 &lt;19%), Luminal B (ER/PR+,and HER2- and Ki67 &gt;19%), Luminal HER2+ (HER2+ and ER/PR+), HER2 (HER2+ and ER-and PR-), and Basal {HER2-,ER-PR- and (CK 5/6+ and/or EGFR+)}. IGF-1R staining was done with Santa Cruz antibody and was scored negative if there was no or weak staining and positive if staining was moderate or strong. Chi-square and Kaplan-Meier Survival analysis were done to compare IGF-1R expression among subtypes and determine impact on Breast Cancer Specific (BCSS) and Overall Survival (OS).&#x2028; Results: A total of 2,808 evaluable cases were included with a median follow-up of 12.5 years. IGF-1R staining was scored positive in 86.4%, and negative in 13.6%. Cases with Luminal A (1,676), Luminal B (426), Luminal HER2+ (199), HER2 (206 ) and Basal (301 ) had an IGF-1R+ rate of 89.9%, 94.4 %, 83.4%, 59.2% and 76.1%, respectively (p&lt;0.0001). 10 year BCSS was 68% (95% CI 66.0%-70.0%) in IGF-R1+ and 63% (95% CI 59.1%-66.9%) in IGF-R1 - group. Among subtypes, IGF-1R positivity was associated with improved BCSS only in Luminal A patients (p=0.015 ) and was not prognostic in other subtypes.&#x2028; Conclusion: Luminal breast cancer subtypes are associated with high rates of IGF1-R expression, while non-luminal groups have lower rates of expression. The prognostic impact of IGF-R1 expression supports the role of this pathway as a therapeutic target particularly among hormone receptor positive breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3048.