Abstract P3-04-01: Molecular determinants of post-mastectomy breast cancer recurrence

Introduction

The management of breast cancer (BC) patients who undergo mastectomy in the setting of 1-3 positive lymph nodes has been controversial. This retrospective Translational Breast Cancer Research Consortium study evaluated the molecular aberrations associated with locoregional recurrence (LRR) or distant metastasis (DM) compared to controls in an effort to identify molecular predictors associated with recurrence.

Methods/Materials

We identified 115 HER2 negative, therapy naïve, T 1-3 and N 0-1 BC patients treated with mastectomy and no post mastectomy radiation therapy from 1997 to present with available FFPE tissue blocks. The cohort included 32 patients with LRR, 34 with DM, and 49 controls (without recurrence) who were matched for stage, grade, hormone receptor status, age ≤ or > 50, chemotherapy receipt, and margin status. Matched primary and recurrent LRR samples were available for 3 patients. Hybrid capture next generation sequencing (NGS) of 142 cancer related genes and RNAseq were performed to identify DNA/RNA alterations associated with LRR or DM. The frequency of common alterations on NGS was compared with Fisher's exact test. Expression of each gene from mRNA-Seq was treated as an explanatory variable. Immunohistochemistry (IHC) was performed for PTEN, Ki-67 and cleaved caspase 3 (CC3). PTEN loss and percentage of Ki-67 and CC3 positive cells were compared between groups with Fisher's exact test and nonparametric methods, respectively.

Results

RNAseq was performed on 115 patients; there was no difference in RNA expression levels between the groups. DNA analysis was performed on 57 patients (17 LRR, 15 DM and 25 controls), NF1 mutation rate was significantly elevated in both the LRR (24%) and DM (27%) samples compared to controls 0%; (p=0.0070). The mitogen activated protein kinase (MAPK) pathway was significantly mutated in both LRR (47%) and DM (40%) samples compared to the controls 0%; (p<0.0001). There was no significant difference in the rate of alterations of the PI3K/Akt/mTOR pathway among the three groups. Of three patients with matched primary vs LRR samples, one had concordant mutations. The second patient had additional mutations in the LRR, including gain of a NF1 mutation. The third patient had complete discordance of mutations identified in primary and LRR and had gain of HER2 amplification, suggestive of a new primary. There was no significant association between the groups and the loss of PTEN expression or CC3 expression. There was a significant difference between Ki 67 positive cells in patients with LRR (mean 29%), DM (mean 26%) versus controls (mean 14%, p= 0.0011). HR+ patients were significantly more likely to have a positive PTEN, lower Ki-67 and lower CC3 expression, p=0.0004, p<0.0001, and p<0.0001 respectively.

Conclusions

In this matched cohort analysis, mutations in the MAPK pathway, specifically NF1, were associated with both LRR and DM, suggesting that alterations in this pathway are associated with a more aggressive tumor phenotype. However, there were no molecular features that discriminated between those likely to recur locally alone versus distantly. Further study is needed to validate these findings, and to determine whether targeting alterations in this pathway could decrease the risk of recurrence.

Citation Format: Keene KS, King T, Hwang ES, Peng B, McGuire K, Tapia C, Zhang H, Bae S, Nakhlis F, Klauber-Demore N, Meszoely I, Sabel MS, Willey SC, Eterovic KA, Hudis C, Wolff A, De Los Santos J, Thompson A, Mills GB, Meric-Bernstam F. Molecular determinants of post-mastectomy breast cancer recurrence [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-04-01.

A multi-institutional analysis of intraoperative radiotherapy for early breast cancer: Does age matter?

BACKGROUND

Single-session intraoperative radiation therapy (IORT) minimizes treatment demands associated with traditional whole breast radiation therapy (WBRT) but outcomes on local disease control and morbidity among the elderly is limited.

METHODS

A multi-institutional retrospective registry was established from 19 centers utilizing IORT from 2007 to 2013. Patient, tumor, and treatment variables were analyzed for ages <70 and ≥70.

RESULTS

We evaluated 686 patients (<70 = 424; ≥70 = 262) who were margin and lymph node negative. Patients <70 were more likely to have longer operative time, oncoplastic closure, higher rates of IORT used as planned boost, and receive chemotherapy and post-operative WBRT. Wound complication rates were low and not significantly different between age groups. Median follow-up was 1.06 (range 0.51-1.9) years for < 70 and 1.01 (range 0.5-1.68) years for ≥ 70. There were 5 (0.73%) breast recurrences (4 in <70 and 1 ≥ 70, p = 0.65) and no axillary recurrences during follow-up.

CONCLUSIONS

IORT was associated with a low rate of wound complication and local recurrence on short-term follow-up in this cohort.

Abstract P2-18-07: Nipple sparing mastectomy-infectious complication risk. A preliminary assessment of the American Society of Breast Surgeons nipple sparing mastectomy registry

Objectives: The American Society of Breast Surgeons (ASBS) Nipple Sparing Mastectomy Registry (NSMR) is a prospective, IRB approved, non-randomized, multi-institutional registry assessing surgical techniques, utilized metrics, oncologic outcome, and aesthetic outcome of nipple sparing mastectomies. The registry has been open for enrollment for 26 months. The target accrual is 1000 individuals. This abstract specifically analyzes rates of post-operative infection in NSMs.

Methods: Fifty two investigators from 41 institutions are participating in the ASBS NSMR. A total of 373 patients underwent 631 mastectomies, with indications of prophylaxis (365), cancer (248), and unknown (18). We assessed a sub group of 449 mastectomies, with indications of prophylaxis (253) and cancer (196) that had all data sets completed. We assessed infection rates(characterized as needing oral or iv antibiotics with or without removal of implant/expander and/or debridement) in the entire group as well as by indication (cancer vs. prophylaxis). Factors such as smoking history, previous radiation therapy, previous surgery, incision type, reconstruction technique, and flap dissection technique were analyzed.

Results: In a subgroup of 449 mastectomies (253 prophylactic and 196 cancer):

Post operative infections were reported in 22 (4.9%) of patients: 7 (3.6%) of mastectomies with an indication of cancer and 15 (5.9%) of prophylactic mastectomies (p-value 0.3140). Infections were characterized as: treatment with oral antibiotics alone, treatment with i.v. antibiotics alone, iv antibiotics with washout or debridement, or antibiotics and implant/ tissue expander removal. No correlation was found in smoking history (p-value 1.000), previous breast surgery (p-value 0.1277) or previous radiation (p-value 0.6024). No correlation was found in incision utilized, reconstruction technique, or method of flap dissection either.

Conclusion:

The rate of postoperative infections in nipple sparing mastectomies is comparable if not lower than non-nipple sparing mastectomies. No statistically significant difference in infection rate was found between mastectomies completed for prophylaxis or cancer. No correlation was found between factors such as smoking history, history of radiation therapy, prior breast surgery, incision utilized, reconstruction technique, or method of flap dissection. Improved aesthetics with a nipple sparing approach (technically more demanding and typically through a smaller incision) does not come at the cost of a higher rate of infectious complications.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-07.

Naloxone potentiates epinephrine's pressor actions in endotoxemic rats

Naloxone's pressor effects in shock may be mediated through antagonism of endogenous opioid inhibition of sympathoadrenal catecholaminergic systems. Since circulating catecholamine levels are not further elevated by naloxone in endotoxemic animals, it is possible that naloxone acts upon opiate receptors to enhance catecholamine actions at the receptor or postreceptor level. To investigate this hypothesis, we sought to determine whether naloxone treatment would augment the pressor actions of exogenous catecholamines (epinephrine) in normal and endotoxemic rats. Naloxone (3 mg/kg intravenous [i.v.] bolus followed by 3 mg/ml/hr infusion) significantly augmented the pressor response to 10, 20, and 50 micrograms/kg of i.v. epinephrine by 69%, 48% and 14%, respectively, in endotoxin (5 mg/kg, LD20, i.v.) -treated rats but not in normal rats. Likewise, the duration of the pressor response to epinephrine was significantly increased by naloxone. These findings suggest that the coadministration of naloxone and epinephrine may be of benefit in the treatment of shock.

Glucagon's chronotropic action is calcium dependent

Evidence is increasing that many anesthetics and cardiovascular agents alter cellular Ca kinetics and flux. In prior work we demonstrated that the tachycardic effects of glucagon were significantly blunted by Ca channel blockade, but not by beta adrenergic receptor blockade. Thus, the chronotropic effects of glucagon may be dependent upon extracellular Ca levels. Based upon these observations, we tested the hypothesis that changes in circulating ionized Ca concentrations may alter glucagon's ability to increase heart rate in rats. In conscious normocalcemic rats, glucagon's tachycardic actions were dose related with peak effects obtained at 1 to 2 min and persisting approximately 10 min after 1.0 mg/kg of glucagon. The effects of altered Ca levels on glucagon tachycardia were evaluated in three groups of rats: 1) rats rendered hypercalcemic by the infusion of Ca chloride (10, 50 or 100 mg/ml/hr); 2) rats rendered hypocalcemic by infusion of the Ca chelator EDTA (15 or 30 mg/ml/hr); and 3) normocalcemic rats infused with saline. Normocalcemic rats had a mean ionized Ca level of 4.73 mg/dl. In rats, increasing Ca chloride doses resulted in increasing mean serum ionized Ca levels (5.24, 8.35 and 15.2 mg/dl, respectively), whereas increasing doses of EDTA produced progressive decreases in mean ionized Ca (3.62 and 2.13 mg/dl, respectively). Severe hypo (2.13 mg/dl)- or hypercalcemia (15.2 mg/dl) significantly blunted glucagon's chronotropic action (51 and 44%, respectively). From these data, we conclude that glucagon has its maximal tachycardic action at physiologic Ca levels (being blunted by both hyper- and hypocalcemia), indicating that this effect of glucagon is Ca dependent.(ABSTRACT TRUNCATED AT 250 WORDS)