pN0(i+) Breast Cancer: Treatment Patterns, Locoregional Recurrence, and Survival Outcomes

Does the Presence of Cytokeratin Positive Individual Tumor Cells (N0(I+)) in Sentinel Lymph Nodes Affect Clinical Outcomes in Breast Cancer Patients Treated with Accelerated Partial Breast Irradiation

Purpose

To report a primary objective clinical outcome of ipsilateral breast cancer recurrence following accelerated partial breast irradiation (APBI) with N_0(i+) (single tumor cells or clusters <2mm) in sentinel lymph nodes. The secondary objective was to observe any incidence of ipsilateral breast failure.

Patients and Methods

Between March 2004 and April 2016, a total of 747 patients were enrolled in one of two APBI (Accelerated Partial Breast Irradiation) breast protocols (Phase II NCT01185145 and Phase III NCT01185132). Nineteen patients with N_0(i+) disease were treated between February 2005 and December 2015. Patient eligibility included a primary invasive or DCIS tumor size <3 cm, N0(i+) disease, and margin width of >2 mm. All enrolled patients presented in this report had sentinel lymph node examinations. Clinical outcomes of ipsilateral breast, axillary and combined regional (breast or axillary) recurrences were analyzed.

Results

Median follow-up for all patients was 5 years (1–8 years). No patient experienced either ipsilateral breast or axillary recurrence.

Conclusion

There has been scarce information/reporting of the treatment of patients with cytokeratin positive individual tumor cells N_0(i+) with APBI. The authors have presented data which suggest that the successful outcomes of these patients might warrant further study.

Axillary Micrometastases and Isolated Tumor Cells Are Not an Indication for Post-mastectomy Radiotherapy in Stage 1 and 2 Breast Cancer

BACKGROUND

Randomized trials demonstrate equivalent locoregional control with sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND) for T1-2 micrometastatic breast cancer, but include few mastectomy patients. Consensus is lacking on indications for post-mastectomy radiotherapy (PMRT) in this population. Herein, we evaluate locoregional recurrence (LRR) in an unselected, modern cohort of T1-2 breast cancer patients with micrometastases or isolated tumor cells (ITCs; N0i+/N1mi) having a mastectomy.

METHODS

We identified patients with T1-2N0i+/N1mi breast cancer treated with mastectomy from January 2006 to December 2011. Recurrent, bilateral, and neoadjuvant cases were excluded. The primary outcome of interest was LRR.

RESULTS

Overall, 352 patients [211 (60%) with ITCs and 141 (40%) with micrometastases] were identified. 162 (46%) patients had SLNB alone and one node was positive in 295 (84%) cases; 31 (9%) patients had PMRT and 95% had systemic therapy. At a median 6 years of follow-up, the overall crude LRR rate was 2.8% (n = 9), with no axillary recurrences, and the crude LRR rate was 3.9% among those who had SNB alone. Those with LRR had a median age of 55 years, median tumor size of 1.7 cm, and ductal histology; the majority were high-grade (89%) and estrogen receptor positive (78%), with one positive node (89%). There was no association between LRR and receipt of PMRT (p = 0.4), SLNB versus ALND (p = 0.2), or number of positive nodes (p = 0.7) using the log-rank test.

CONCLUSIONS

LRR was infrequent among T1-2N0i+/N1mi patients treated with mastectomy without PMRT, with no axillary failures, suggesting that PMRT or nodal radiotherapy are not routinely indicated in this population.

Occult metastases in node-negative breast cancer: A Surveillance, Epidemiology, and End Results-based analysis

INTRODUCTION

The role of immunohistochemistry (IHC) for detecting occult lymph node disease in patients initially found to be node-negative by routine pathology is controversial. In this study, we evaluated trends associated with overall survival in node-negative breast cancer patients staged by IHC.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for all patients with invasive breast adenocarcinoma and negative lymph nodes on routine pathology between 2004 and 2011 who underwent IHC to evaluate for occult nodal disease. Overall survival stratified by N-stage was compared with Kaplan-Meier analysis. Multivariate analysis was performed using a Cox proportional hazards model.

RESULTS

Overall, 93,070 patients were identified, including 4,657 patients with isolated tumor cells (<0.2 mm diameter or <200 cells) and 6,720 patients with micrometastases (0.2-2 mm diameter). Kaplan-Meier curves demonstrated a difference in overall survival across all groups (P < .0001). On multivariate analysis, micrometastases remained an independent predictor for survival compared with IHC-negative patients (hazard ratio 1.40, 95% confidence interval 1.28-1.53), whereas isolated tumor cells were not a significant predictor (hazard ratio 1.05, 95% confidence interval 0.92-1.20).

CONCLUSION

Patients with occult micrometastases in axillary lymph nodes found via IHC demonstrated a significant overall survival difference, but isolated tumor cells have no prognostic significance.

The impact of isolated tumor cells on loco-regional recurrence in breast cancer patients treated with breast-conserving treatment or mastectomy without post-mastectomy radiation therapy

To compare the outcome of patients with invasive breast cancer, who had isolated tumor cells (ITC) in sentinel lymph nodes, pN0(i+), to patients with histologically negative nodes, pN0. We retrospectively studied 1,273 patients diagnosed with T1-T3 breast cancer from 1999 to 2009. Patients were divided into 2 populations: 807 patients treated with breast-conserving surgery (BCS) and radiotherapy (RT), 85(10.5 %) with pN0(i+) and 722(89.5 %) with pN0. And the other population had 466 patients treated with mastectomy without post-mastectomy radiation therapy (PMRT), 80(17.2 %) with pN0(i+),and 386(82.8 %)with pN0. All patients underwent sentinel node biopsy, and the presence of ITC was determined. Patients with axillary dissection only or neoadjuvant chemotherapy were excluded. Among the 1,273 patients studied; 87.3 % received adjuvant systemic therapy. Kaplan-Meier, Cox regression, and log-rank statistical tests were used. Median patient age was 55.7 years. Median follow-up was 69.5 months. The 5- and 10-year cumulative incidence of Loco-regional recurrence (LRR) for patients treated with BCS and RT was 1.6 and 3.5 % for 85 pN0(i+) patients, and 2.4 and 5 % for 722 pN0 patients, respectively. For patients treated with mastectomy without PMRT, 5- and 10-year LRR rates were 2.8 and 2.8 % for 80 pN0(i+) patients, and 1.8 and 3 % for 386 pN0 patients, respectively. There were no statistically significant differences in LRR (p = 0.9), distant recurrence (p = 0.3) ,and overall survival (p = 0.5) among all groups. On multivariate analysis, ITC were not associated with increased risk of LRR, distant recurrence and overall survival. Grade (p = 0.003) and systemic therapy (p = 0.02) were statistically significantly associated with risk of LRR. Sentinel node ITC have no significant impact on LRR, distant recurrence and overall survival in breast cancer patients. Additional treatments such as axillary dissection, chemotherapy, or regional radiation should not be given solely based on the presence of sentinel node ITC.

DEGRO practical guidelines: radiotherapy of breast cancer III--radiotherapy of the lymphatic pathways

AIM

The purpose of this work is to update the practical guidelines for adjuvant radiotherapy of the regional lymphatics of breast cancer published in 2008 by the breast cancer expert panel of the German Society of Radiation Oncology (DEGRO).

METHODS

A comprehensive survey of the literature concerning regional nodal irradiation (RNI) was performed using the following search terms: "breast cancer", "radiotherapy", "regional node irradiation". Recent randomized trials were analyzed for outcome as well as for differences in target definition. Field arrangements in the different studies were reproduced and superimposed on CT slices with individually contoured node areas. Moreover, data from recently published meta-analyses and guidelines of international breast cancer societies, yielding new aspects compared to 2008, provided the basis for defining recommendations according to the criteria of evidence-based medicine. In addition to the more general statements of the German interdisciplinary S3 guidelines updated in 2012, this paper addresses indications, targeting, and techniques of radiotherapy of the lymphatic pathways after surgery for breast cancer.

RESULTS

International guidelines reveal substantial differences regarding indications for RNI. Patients with 1-3 positive nodes seem to profit from RNI compared to whole breast (WBI) or chest wall irradiation alone, both with regard to locoregional control and disease-free survival. Irradiation of the regional lymphatics including axillary, supraclavicular, and internal mammary nodes provided a small but significant survival benefit in recent randomized trials and one meta-analysis. Lymph node irradiation yields comparable tumor control in comparison to axillary lymph node dissection (ALND), while reducing the rate of lymph edema. Data concerning the impact of 1-2 macroscopically affected sentinel node (SN) or microscopic metastases on prognosis are conflicting.

CONCLUSION

Recent data suggest that the current restrictive use of RNI should be scrutinized because the risk-benefit relationship appears to shift towards an improvement of outcome.

Ex vivo Evans blue assessment of the blood brain barrier in three breast cancer brain metastasis models

The limited entry of anticancer drugs into the central nervous system represents a special therapeutic challenge for patients with brain metastases and is primarily due to the blood brain barrier (BBB). Albumin-bound Evans blue (EB) dye is too large to cross the BBB but can grossly stain tissue blue when the BBB is disrupted. The course of tumor development and the integrity of the BBB were studied in three preclinical breast cancer brain metastasis (BCBM) models. A luciferase-transduced braintropic clone of MDA-231 cell line was used. Nude mice were subjected to stereotactic intracerebral inoculation, mammary fat pad-derived tumor fragment implantation, or carotid artery injections. EB was injected 30 min prior to euthanasia at various timepoints for each of the BCBM model animals. Serial bioluminescent imaging demonstrated exponential tumor growth in all models. Carotid BCBM appeared as diffuse multifocal cell clusters. EB aided the localization of metastases ex vivo. Tumor implants stained blue at 7 days whereas gross staining was not evident until day 14 in the stereotactic model and day 28 for the carotid model. EB assessment of the integrity of the BBB provides useful information relevant to drug testing in preclinical BCBM models.