Addition of zoledronic acid to neoadjuvant chemotherapy does not enhance tumor response in patients with HER2-negative stage II/III breast cancer: the NEOZOTAC trial (BOOG 2010-01)

BACKGROUND

The role of zoledronic acid (ZA) when added to the neoadjuvant treatment of breast cancer (BC) in enhancing the clinical and pathological response of tumors is unclear. The effect of ZA on the antitumor effect of neoadjuvant chemotherapy has not prospectively been studied before.

PATIENTS AND METHODS

NEOZOTAC is a national, multicenter, randomized study comparing the efficacy of TAC (docetaxel, adriamycin and cyclophosphamide i.v.) followed by granulocyte colony-stimulating factor on day 2 with or without ZA 4 mg i.v. q 3 weeks inpatients withstage II/III, HER2-negative BC. We present data on the pathological complete response (pCR in breast and axilla), on clinical response using MRI, and toxicity. Post hoc subgroup analyses were undertaken to address the predictive value of menopausal status.

RESULTS

Addition of ZA to chemotherapy did not improve pCR rates (13.2% for TAC+ZA versus 13.3% for TAC). Postmenopausal women (N = 96) had a numerical benefit from ZA treatment (pCR 14.0% for TAC+ZA versus 8.7% for TAC, P = 0.42). Clinical objective response did not differ between treatment arms (72.9% versus 73.7%). There was no difference in grade III/IV toxicity between treatment arms.

CONCLUSIONS

Addition of ZA to neoadjuvant chemotherapy did not improve pathological or clinical response to chemotherapy. Further investigations are warranted in postmenopausal women with BC, since this subgroup might benefit from ZA treatment.

Abstract P1-08-19: Changes in circulating vitamin D levels as a predictor for pathological response to neoadjuvant chemotherapy (NAC) in breast cancer (BC): A Dutch breast cancer trialists group (BOOG) side-study

Background:

Vitamin D (vit D) status is suggested to be of prognostic value for treatment outcome in women with breast cancer. However, there are no data of the predictive value of vit D status and changes of vit D levels for response to neoadjuvant chemotherapy (NAC).

Methods:

A subset of patients (pts) from the NEOZOTAC trial in whom vit D data were available was evaluated. NEOZOTAC is a randomized phase III study comparing the efficacy of NCT with or without zoledronic acid (ZA) in pts with stage II/III, measurable, HER2-negative BC. Vit D deficiency and severe deficiency were defined as vit D levels of ≤ 50 and ≤25 nmol/L, respectively. Baseline vit D levels were available for correlation to pathological response of 165 pts (83 ZA-arm), while 67 pts (35 ZA arm) could be evaluated for changes in vit D levels between baseline and cycle 6. Pts who were allocated to the ZA arm should by protocol receive daily supplements of calcium/vit D 500/400 IU. Pathological response was assessed using the Miller and Payne scoring system; pathological complete response (pCR) was defined as absence of tumor cells in the tumor bed and good response was defined as ≥90% decrease of tumor cellularity.

Results:

Vit D was measured in 168 pts and was done in 75% of pre/perimenopausal pts and 51.3% of postmenopausal pts. There was no significant relation between baseline vit D deficiency (< 50 nmol/L) and pCR (pCR 25.8% for deficient pts vs. 14.1% for non-deficient pts, P = 0.06). Pts with severe vit D deficiency (<25 nmol/L) tended to respond less (pCR 10.5 vs 19.9%, p = 0.53). At the end of chemotherapy, good pathological responders seemed to have a slight increase in vit D levels compared to non-responders who rather showed a decrease (mean 1.11 vs. -9.71, P = 0.08). After multivariate analysis correcting for menopausal status and treatment arm, this result was significant (P = 0.03, 95% C.I. 1.004-1.055). When pts in the ZA arm were analyzed separately, again, good response was rather associated with an increase than a decrease (mean = 9.8 vs. -1.6, P = 0.12). From 17 out of 35 ZA treated pts who were vit D deficient at baseline, only 5 (29.4%) reached levels >50 nmol/L at the end of treatment.

Conclusions:

Baseline vit D status was not predictive for pCR. However, increase in vit D levels during therapy tended to be associated with better pathological response. Therefore, achieving higher vit D levels can be important. Daily suppletion with calcium/ vitamin D 500/400 might be inadequate for achieving sufficient levels after NAC.

Contact information:

Dr. J.R. Kroep, M.D., Ph.D., Department of Medical Oncology, email:j.r.kroep@lumc.nl or A. Charehbili, BSc. Department of Surgery and Medical Oncology, email: a.charehbili@lumc.nl or LUMC datacenter, Department of Surgery, phone +31(0)71-5263500, fax +31(0)71-5266744, email: datacenter@lumc.nl, Leiden University Medical Center (LUMC), Leiden, The Netherlands.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-19.

Abstract P1-06-04: The predictive value of tumor-stroma ratio for radiological and pathological response to neoadjuvant chemotherapy in breast cancer (BC): A Dutch breast cancer trialists’ group (BOOG) side-study

Background

Intra-tumoral stroma interacts with tumor cells and has a profound effect on tumor behavior. The tumor-stroma ratio (TSR) is of prognostic value in BC and other types of solid tumors. However, the predictive value of this parameter for achieving pathological complete response (pCR) after neoadjuvant chemotherapy is unknown.

Methods

We evaluated the relation between TSR and neoadjuvant treatment response in a retrospective cohort of 69 patients (pts) treated with various regimens of neoadjuvant chemotherapy at our institution who were diagnosed with BC between 1991 and 2007 and of whom radiological response was recorded. The percentage of intra-tumoral stroma was visually estimated on diagnostic sections from primary tumor tissue by two observers. The cut-off point between stroma-rich and stroma-poor tumors was set to 50% (as determined in previous investigations). These results were validated in a cohort from the NEOZOTAC trial: a national, multicenter, randomized study comparing the efficacy of TAC (docetaxel, adriamycin and cyclophosphamide i.v. day 1) chemotherapy with or without zoledronic acid 4 mg i.v., q 3 weeks, 6 times in 250 pts with stage II/III, measurable, HER2-negative BC. Radiological response (complete or partial) was evaluated following RECIST 1.1 criteria. pCR was centrally revised and defined as absence of residual tumor cells in the original tumor bed.

Results

In the retrospective cohort (n = 69) 62.3% of the specimens were classified as stroma-rich. In univariate analysis TSR was significantly associated with radiological response (76.0% stroma-poor vs. 48.8% stroma-rich, P = 0.03). This finding persisted after multivariate analysis for T-status, N-status and ER-status (Odds Ratio [OR] 0.17, 95% C.I.: 0.04-0.78). In the validation set, in which 47.9% of the specimens were stroma-rich (211 cases evaluated), TSR did not predict for radiological response (79.5% stroma-poor vs. 79.2%, P = 0.96). However, when validation data were split on basis of ER-status, TSR was a significant and independent predictor for radiological response in ER-negative pts. (89.5% vs. 50%, P = 0.048, 95% C.I.: 0.01 - 0.98). In the validation set, TSR predicted for pCR with greater pCR rates in stroma-poor tumors (P = 0.03, 22.7% vs 10.3%). Final response results of the pilot and the enlarged sample size of all 250 pts of the validation set will be presented.

Conclusions

TSR might be a marker for radiological and pathological response to neoadjuvant chemotherapy, especially for the ER- tumor subgroup. Considering the simplicity and low cost of TSR assessment, it should be further evaluated and will be prospectively studied in the next neoadjuvant chemotherapy trial of the BOOG.

Contact information:

Dr. J.R. Kroep, M.D., Ph.D., Department of Medical Oncology, email:j.r.kroep@lumc.nl or T.J.A. Dekker, MSc. Department of Surgery and Medical Oncology, email: t.j.a.dekker@lumc.nl or LUMC datacenter, Department of Surgery, phone +31(0)71-5263500, fax +31(0)71-5266744, email: datacenter@lumc.nl, Leiden University Medical Center (LUMC), Leiden, The Netherlands.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-04.

Abstract PD07-06: NEO-ZOTAC: Toxicity data of a phase III randomized trial with NEOadjuvant chemotherapy (TAC) with or without ZOledronic acid (ZA) for patients with HER2-negative large resectable or locally advanced breast cancer (BC)

Background: The role of bisphosphonates (BP) when added to the (neo)adjuvant treatment of BC in enhancing the efficacy of therapy is still unknown. NEOZOTAC investigates the efficacy of ZA added to neoadjuvant chemotherapy in patients with HER2-negative BC.

Trial design: NEOZOTAC is a Dutch multicenter study. Patients are 1:1 randomized to 3-weekly TAC (docetaxel 75mg/m2, adriamycin 50 mg/m2 and cyclophosphamide 500 mg/m2 i.v., day 1) chemotherapy supported by pegfilgrastim (6 mg sc), day 2 with or without ZA (4 mg i.v. within 24 hr after chemotherapy) q3 weeks.

Eligibility criteria: Main inclusion criteria: stage II or III, measurable, HER2-negative BC, age ≥18 years, WHO 0–2, adequate bone marrow-, renal-, and liver function, absence of prior BP usage and absence of active dental problems.

Study endpoint: The primary endpoint is the pathologic complete response (pCR) rate. Secondary endpoints are toxicity, clinical response, tumor heterogeneity in core biopsy vs. operation specimen, and (disease free) survival. Optional side studies include fluorescent imaging (SoftScan®), changes in bone markers, single nucleotide polymorphisms and the insulin-like growth factor pathway, circulating tumor and endothelial cells and the false-negative rate of the sentinel node biopsy after neoadjuvant chemotherapy.

Statistical Methods: Using a 5% significance level based on the two-sided Fishers exact test with a power of 80%, 250 patients (125/arm) are needed to show an improvement of the pCR-rate from 17% to 34% in the experimental arm. Randomization was done according to the Pococks minimisation technique stratified by cT, cN, and estrogen receptor status. Toxicity is analyzed using the Exact (2-sided) Chi-Square test.

Results: From July 2010 to April 2012, 250 patients from 25 participating sites were randomized. Toxicity data of 173 patients are currently available and data of all 250 patients will be presented at SABCS. Patient characteristics are presented in table 1.

Relevant impact of central pathology review on nodal classification in individual breast cancer patients

BACKGROUND

In the MIRROR study, pN0(i + ) and pN1mi were associated with reduced 5-year disease-free survival (DFS) compared with pN0. Nodal status (N-status) was assessed after central pathology review and restaging according to the sixth AJCC classification. We addressed the impact of pathology review.

PATIENTS AND METHODS

Early favorable primary breast cancer patients, classified pN0, pN0(i + ), or pN1(mi) by local pathologists after sentinel node procedure, were included. We assessed the impact of pathology review on N-status (n = 2842) and 5-year DFS for those without adjuvant therapy (n = 1712).

RESULTS

In all, 22% of the 1082 original pN0 patients was upstaged. Of the 623 original pN0(i + ) patients, 1% was downstaged, 26% was upstaged. Of 1137 patients staged pN1mi, 15% was downstaged, 11% upstaged. Originally, 5-year DFS was 85% for pN0, 74% for pN0(i + ), and 73% for pN1mi; HR 1.70 [95% confidence interval (CI) 1.27-2.27] and HR 1.57 (95% CI 1.16-2.13), respectively, compared with pN0. By review staging, 5-year DFS was 86% for pN0, 77% for pN0(i + ), 77% for pN1mi, and 74% for pN1 + .

CONCLUSION

Pathology review changed the N-classification in 24%, mainly upstaging, with potentially clinical relevance for individual patients. The association of isolated tumor cells and micrometastases with outcome remained unchanged. Quality control should include nodal breast cancer staging.

PD02-07: Models Predicting Non-Sentinel Node Involvement in Breast Cancer Also Predict for Regional Recurrence If the Axilla Is Not Treated

Background

Series on breast cancer patients with sentinel node (SN) isolated tumor cells or micrometastases show low recurrence rates in the presence of SN isolated tumor cells, and varying recurrence rates in the presence of SN micrometastases. Non-SN prediction models are frequently used as a decision aid to identify patients that may not need axillary treatment, but this still needs to be validated in respect to regional recurrence.

Patients and Methods

We followed a cohort of 486 patients in the MIRROR-study of whom none received axillary treatment with favorable primary tumor characteristics and pN0(i+)(sn) or pN1(mi)(sn) for a median of 5 years. The patients were categorized into low or high-risk subgroups based on several published non-SN prediction models (cut-off levels between models varied from 3 to 10%), i.e. the Tenon Scoring system, MSKCC nomogram, Stanford nomogram and a Dutch model (Bolster et al.). The primary endpoint was 5-year regional recurrence-free survival.

Results

The overall 5-year regional recurrence rate was 3.0% (+/− 0.1%). Using the Tenon scoring system, we identified 438 patients with a low risk score of 3.5 or lower with a 5-year regional recurrence rate of 2.3% (+/− 0.8%), compared to a recurrence rate of 10.1% (+/− 0.4%) in 48 patients with a score above 3.5. For the MSKCC nomogram a low risk score of 0.10 or lower identified 300 patients with a 5-year recurrence rate of 2.8% (+/− 1.1%), and a score above 0.10 identified 166 patients with a recurrence rate of 3.4% (+/− 1.5%) (20 patients not assessable). By the Stanford nomogram a low risk cutoff level of 10% identified 21 patients without recurrence, whereas 465 patients had a 3.2% (+/−0.9%) recurrence rate. Using a Dutch model, a low risk cutoff score of 20 discriminated between 384 patients with a 5-year recurrence rate of 2.2% (+/− 0.8%) and 102 patients with a recurrence rate of 6.3% (+/− 2.9%). Further analyses with different cut-off values and subgroups will be presented at the conference.

Conclusion

Using several published non-SN prediction models for predicting regional recurrence, the Tenon scoring system outperformed the other models in that it identified the largest subgroup of patients with a low recurrence rate. We would recommend axillary treatment in patients classified as high risk according to the Tenon score.

Funding: Netherlands Organization for Health Research and Development (ZonMw 945-06-509).

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD02-07.