Abstract P3-03-03: Sentinel node biopsy (SNB) vs Low axillary sampling (LAS) in predicting nodal status of post-chemotherapy axilla in women with breast cancer

Introduction

There is no safe method of avoiding complete axillary lymph node dissection in women with breast cancer after neo-adjuvant chemotherapy. sentinel node biopsy (SNB) has had prohibitively high false negative rate. We tested low axillary sampling (LAS) and SNB performed in same patient to predict axillary lymph node status in clinically node negative women undergoing breast conservation or modified radical mastectomy after neo-adjuvant chemotherapy.

Methodology

Post neo-adjuvant chemotherapy 751 women who had no palpable axillary lymph node underwent LAS (all lymph nodes below intercosto-brachial nerve). Of these 751 women, 730 also underwent SNB by dual technique after injection of blue dye as well as radio-isotope. SN was identified within and outside axillary sampling specimen. SN as well as LAS specimens were distinctly examined for nodal metastasis. The rest of the axillary dissection was completed in all patients. Post NACT 292/751(38.9%) had residual positive lymph nodes on pathology. The identification rate, false negative rate (FNR), and negative predictive value (NPV) of SNB and LAS were compared for predicting negative axillary lymph node status.

Results

The median clinical tumor size was 5cm (1-15cm) and 533(71%) patients were N1 or N2 at presentation. The SNB identification rate was 87.1% (636 of 730), with a median of 5 nodes and node positive in 238 of 636 (37.4%). LAS identification rate was 98% (736 of 751), with a median of 7 nodes and node positive in 292 of 736 (39.6%). In all but one case, the SN was found within the LAS specimen. The FNR of SNB (blue, hot and adjacent palpable nodes) was 19.7% (47 of 238, one sided 95% upper CI 24.0) compared to LAS with FNR of 9.9% (29 of 292, one-sided 95% upper CI 12.8) (p<0.001). Comparative NPV for SNB and LAS were 89.4% and 93.9% respectively. If SNB was confined to blue/hot node excluding adjacent palpable nodes, FNR was 31.6% (74 of 234, 95% upper CI 36.6).

Conclusions

LAS is superior to SNB in identification rate, FNR and NPV in predicting node negative axilla post-neoadjuvant chemotherapy. LAS can be safely used to predict negative axilla with less than 10% chance of leaving residual disease.

Citation Format: Parmar V, Nair NS, Vanamali V, Hawaldar RW, Siddique S, Shet T, Desai SB, Rangarajan V, Patil A, Gupta S, Badwe RA. Sentinel node biopsy (SNB) vs Low axillary sampling (LAS) in predicting nodal status of post-chemotherapy axilla in women with breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-03.

Abstract P4-16-08: Neoadjuvant depot hydroxy-progesterone and vitamin D3 in large operable and locally advanced breast cancer: Planned safety and response analysis of a phase III randomized controlled trial

Background- The active metabolite of Vitamin D, 1,25-dihydroxycholecalciferol (Arachitol), and D3 analogs are known to be cytotoxic, anti-proliferative, pro-apoptotic[2] and potentiate responsiveness to cytotoxic agents such as doxorubicin.[3] Depot hydroxy-progesterone caproate (DHPC) has shown benefit in disease-free and overall survival when given as a single dose prior to definitive surgery in women with node positive operable breast cancer. [1] We undertook a factorial randomized controlled phase III study to evaluate the safety and efficacy of these interventions in the neoadjuvant setting in patients with operable and locally advanced breast cancer (NCT01608451).

Methods- The study was planned as a phase III, 2×2 factorial, randomized controlled trial with a sample size of 800. Women with high-risk (clinically T2N2, T3N1-3, all M0) operable or locally advanced breast cancer who were planned for neoadjuvant chemotherapy prior to surgery, were recruited in the study. Patients were randomized (2×2) to one of the following 4 arms: patients in Arm A received standard 4 cycles of anthracycline-based neoadjuvant chemotherapy followed by surgery, those in Arm B received 500 mg of DHPC 5-14 days prior to each cycle of chemotherapy and prior to surgery, those in Arm C received intramuscular injection of 300,000 IU Arachitol, and those in Arm D received a combination of both the experimental interventions at similar time points. The primary endpoint was disease-free survival and the secondary endpoints were overall survival, pathological complete response (pCR, defined as absence of invasive cancer in breast and axillary lymph nodes in the surgical specimen), and toxicity (defined by NCI Common Toxicity Criteria). We are reporting here a planned analysis of the secondary endpoints, after recruitment of 1/6th of total sample size, on toxicity and responses in the study arms.

Results- From September 2007 to December 2010, 120 patients were recruited in the study, 27 in Arm A, 33 in Arm B, 29 in Arm C and 31 in Arm D. The arms were balanced with respect to known prognostic variables including age, clinical tumor size, clinical nodal status and ER/PR and HER2 status. Of the 120 patients, 44(36.6%) were ER &/or PR positive with HER2 negative tumors, 27(22.3%) triple negative, 41(33.9%) ER &/or PR any with HER2 positive, and receptor status was unknown in 6.6%. The rates of all grades and grade III-IV febrile neutropenia, hepatic dysfunction, renal dysfunction and dyselectrolytemia were not different between the 4 arms. Surgery was performed in 114 of 120 patients(95.0%). The pCR rates in DHPC arm vs no DHPC was 5/51(9.8%) and 5/59(8.5%) respectively. The pCR rates in Arachitol versus no Arachitol arms were 5/55(9.0%) in both arms.

Conclusions- The addition of depot hydroxy-progesterone and vitamin D3 in neoadjuvant setting were found to be safe and well tolerated. Further details of toxicity, response and the ongoing study will be presented at the Symposium.

References:

1. Badwe RA et al. J Clin Oncol.2011 Jul 20;29(21):2845-51

2. James SY et al. J Steroid Biochem Mol Biol.1996 Jul;58(4):395-401

3. Chaudhary M et al. Cancer Chemother Pharmacol.2001;47(5):429-36.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-08.