Abstract P2-08-06: Initial systemic treatment choices by subtype of advanced breast cancer in 2007-2017, a study of the southeast Netherlands advanced breast cancer (SONABRE) registry

Background The aim of this study was to determine the subtype conversion rate and the initial systemic treatment choices by subtype for patients diagnosed with advanced breast cancer since 2007 who were included in the SONABRE Registry. Patients and methods Patients diagnosed with advanced breast cancer in 2007-2017 in six (one academic, three teaching, two non-teaching) hospitals in the Netherlands were selected from the ongoing SOutheast Netherlands Advanced BREast Cancer (SONABRE) Registry (NCT-03577197). We registered patient, primary tumor, recurrent and metastatic disease characteristics, and (neo-)adjuvant and palliative treatment choices. Follow-up was collected until September 2018. To determine the subtype, we assessed the hormone receptor (HR) and the human epidermal growth factor receptor (HER)-2 status from the initial metastatic site(s). If not available, biopsy results from the locoregional recurrence or the primary breast cancer were used. Initial systemic treatment choices were presented by subtype (HR+/HER2-, HER2+, and triple negative (TN) disease). In this abstract, we present the findings for the period 2007-2017, at the SABCS 2019, we will present the results for the period 2007-2018. Results Of the 2288 patients included, 67% had HR+/HER2-, 16% HER2+, 15% TN disease and 2% of patients had unknown subtype. The HR and HER2 status were based on pathology of the metastasis in 48% and 40% of patients, respectively. In 41% and 25% of patients, the HR and HER2 status was determined for both the primary tumor and the initial metastatic sites. Of these latter patients, HR status changed from HR+ to HR- in 10% of patients and from HR- to HR+ in 2% of patients. HER2 status changed from HER2+ to HER2- in 6% of patients and from HER2- to HER2+ in 4% of patients. Among patients with HR+/HER2- disease, 78% received endocrine-based and 17% received chemotherapy-based therapy as initial systemic therapy, and 5% of patients deceased without receiving any systemic therapy. For patients with HER2+ disease, 57% received HER2-targeted based therapy as initial systemic treatment, 22% received endocrine monotherapy, 8% received chemotherapy alone and 13% deceased without receiving systemic therapy. In patients with TN disease, 71% received chemotherapy as initial systemic treatment, 4% received endocrine therapy and 25% received no systemic therapy. Overall, 6% of patients received initial systemic therapy as part of a clinical trial. Conclusions For only half of the patients, HR and HER2 receptor status of the metastasis were determined at initiation of initial systemic therapy. Since one in ten tested patients showed a conversion of subtype, and thus impacting treatment decisions, it is important to reassess subtype upon diagnosis of metastatic disease whenever possible. With a few exceptions, initial systemic treatment choices were in line with guideline recommendations. Only 6% of patients were treated as part of a clinical trial, confirming the highly selected patient population included in these trials, highlighting the importance of real life studies to evaluate the outcomes of systemic treatment for advanced breast cancer.

Citation Format: Sandra M.E. Geurts, Khava IE Ibragimova, Frans Erdkamp, Birgit EPJ Vriens, M. Wouter Dercksen, Marien O den Boer, Manon JAE Pepels, Dominique Tilli, Maaike de Boer, Vivianne CG Tjan-Heijnen. Initial systemic treatment choices by subtype of advanced breast cancer in 2007-2017, a study of the southeast Netherlands advanced breast cancer (SONABRE) registry [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-08-06.

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 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.