Long-Term Ultrasound Twinkling Detectability and Safety of a Polymethyl Methacrylate Soft Tissue Marker Compared to Conventional Breast Biopsy Markers-A Preclinical Study in a Porcine Model

OBJECTIVE

We have studied the use of polymethyl methacrylate (PMMA) as an alternative biopsy marker that is readily detectable with ultrasound Doppler twinkling in cases of in vitro, ex vivo, or limited duration in vivo settings. This study investigates the long-term safety and ultrasound Doppler twinkling detectability of a PMMA breast biopsy marker following local perturbations and different dwell times in a 6-mo animal experiment.

METHODS

This study, which was approved by our Institutional Animal Care and Use Committee, involved three pigs and utilized various markers, including PMMA (Zimmer Biomet), 3D-printed, and Tumark Q markers. Markers were implanted at different times for each pig. Mesh material or ethanol was used to induce a local inflammatory reaction near certain markers. A semiquantitative twinkling score assessed twinkling for actionable localization during monthly ultrasounds. At the primary endpoint, ultrasound-guided localization of lymph nodes with detectable markers was performed. Following surgical resection of the localized nodes, histomorphometric analysis was conducted to evaluate for tissue ingrowth and the formation of a tissue rind around the markers.

RESULTS

No adverse events occurred. Twinkling scores of all markers for all three pigs decreased gradually over time. The Q marker exhibited the highest mean twinkling score followed by the PMMA marker, PMMA with mesh, and Q with ethanol. The 3D-printed marker with mesh and PMMA with ethanol had the lowest scores. All wire-localized lymph nodes were successfully resected. Despite varying percentages of tissue rind around the markers and a significant reduction in overall twinkling (p < 0.001) over time, mean PMMA twinkling scores remained clinically actionable at 6 and 5 mo using a General Electric C1-6 probe and 9L-probe, respectively.

CONCLUSIONS

In this porcine model, the PMMA marker demonstrates an acceptable safety profile. Clinically actionable twinkling aids PMMA marker detection even after 6 mo of dwell time in porcine lymph nodes. The Q marker maintained the greatest twinkling over time compared to all the other markers studied.

Assessment of the effect of the American Society of Breast Surgery guidelines on contralateral prophylactic mastectomy rates for unilateral breast cancer

BACKGROUND

In July 2016, the American Society of Breast Surgeons published guidelines discouraging contralateral prophylactic mastectomy for average-risk women with unilateral breast cancer. We incorporated these into practice with structured patient counseling and aimed to assess the effect of this initiative on contralateral prophylactic mastectomy rates.

METHODS

We evaluated female patients with unilateral breast cancer undergoing mastectomy at our institution from January 2011 to November 2022. Variables associated with contralateral prophylactic mastectomy and trends over time were analyzed using the Wilcoxon rank sum test or χ2 analysis as appropriate.

RESULTS

Among 3,208 patients, (median age 54 years) 1,366 (43%) had a unilateral mastectomy, and 1,842 (57%) also had a concomitant contralateral prophylactic mastectomy. Across all patients, contralateral prophylactic mastectomy rates significantly decreased post-implementation from 2017 to 2019 (55%) vs 2015 to 2016 (62%) (P = .01) but increased from 2020 to 2022 (61%). Immediate breast reconstruction rate was 70% overall (81% with contralateral prophylactic mastectomy and 56% without contralateral prophylactic mastectomy, P < .001). Younger age, White race, mutation status, and earlier stage were also associated with contralateral prophylactic mastectomy. Genetic testing increased from 27% pre-guideline to 74% 2020 to 2022, as did the proportion of patients with a pathogenic variant (4% pre-guideline vs 11% from 2020-2022, P < .001), of whom 91% had a contralateral prophylactic mastectomy. Among tested patients without a pathogenic variant and patients not tested, contralateral prophylactic mastectomy rates declined from 78% to 67% and 48% to 38% pre -and post-guidelines, respectively, P < .001.

CONCLUSION

Implementation of specific patient counseling was effective in decreasing contralateral prophylactic mastectomy rates. While recognizing that patient choice plays a significant role in the decision for contralateral prophylactic mastectomy, further educational efforts are warranted to affect contralateral prophylactic mastectomy rates, particularly in the setting of negative genetic testing.

Neoadjuvant cobimetinib and atezolizumab with or without vemurafenib for high-risk operable Stage III melanoma: the Phase II NeoACTIVATE trial

Both targeted therapies and immunotherapies provide benefit in resected Stage III melanoma. We hypothesized that the combination of targeted and immunotherapy given prior to therapeutic lymph node dissection (TLND) would be tolerable and drive robust pathologic responses. In NeoACTIVATE (NCT03554083), a Phase II trial, patients with clinically evident resectable Stage III melanoma received either 12 weeks of neoadjuvant vemurafenib, cobimetinib, and atezolizumab (BRAF-mutated, Cohort A, n = 15), or cobimetinib and atezolizumab (BRAF-wild-type, Cohort B, n = 15) followed by TLND and 24 weeks of adjuvant atezolizumab. Here, we report outcomes from the neoadjuvant portion of the trial. Based on intent to treat analysis, pathologic response (≤50% viable tumor) and major pathologic response (complete or near-complete, ≤10% viable tumor) were observed in 86.7% and 66.7% of BRAF-mutated and 53.3% and 33.3% of BRAF-wild-type patients, respectively (primary outcome); these exceeded pre-specified benchmarks of 50% and 30% for major pathologic response. Grade 3 and higher toxicities, primarily dermatologic, occurred in 63% during neoadjuvant treatment (secondary outcome). No surgical delays nor progression to regional unresectability occurred (secondary outcome). Peripheral blood CD8 + TCM cell expansion associated with favorable pathologic responses (exploratory outcome).

Changes in Surgical Management of the Axilla Over 11 Years - Report on More Than 1500 Breast Cancer Patients Treated with Neoadjuvant Chemotherapy on the Prospective I-SPY2 Trial

BACKGROUND

Axillary surgery after neoadjuvant chemotherapy (NAC) is becoming less extensive. We evaluated the evolution of axillary surgery after NAC on the multi-institutional I-SPY2 prospective trial.

METHODS

We examined annual rates of sentinel lymph node (SLN) surgery with resection of clipped node, if present), axillary lymph node dissection (ALND), and SLN and ALND in patients enrolled in I-SPY2 from January 1, 2011 to December 31, 2021 by clinical N status at diagnosis and pathologic N status at surgery. Cochran-Armitage trend tests were calculated to evaluate patterns over time.

RESULTS

Of 1578 patients, 973 patients (61.7%) had SLN-only, 136 (8.6%) had SLN and ALND, and 469 (29.7%) had ALND-only. In the cN0 group, ALND-only decreased from 20% in 2011 to 6.25% in 2021 (p = 0.0078) and SLN-only increased from 70.0% to 87.5% (p = 0.0020). This was even more striking in patients with clinically node-positive (cN+) disease at diagnosis, where ALND-only decreased from 70.7% to 29.4% (p < 0.0001) and SLN-only significantly increased from 14.6% to 56.5% (p < 0.0001). This change was significant across subtypes (HR-/HER2-, HR+/HER2-, and HER2+). Among pathologically node-positive (pN+) patients after NAC (n = 525) ALND-only decreased from 69.0% to 39.2% (p < 0.0001) and SLN-only increased from 6.9% to 39.2% (p < 0.0001).

CONCLUSIONS

Use of ALND after NAC has significantly decreased over the past decade. This is most pronounced in cN+ disease at diagnosis with an increase in the use of SLN surgery after NAC. Additionally, in pN+ disease after NAC, there has been a decrease in use of completion ALND, a practice pattern change that precedes results from clinical trials.

Long-term outcomes of intraoperatively-placed applicator brachytherapy for rapid completion of breast conserving treatment: An analysis of a prospective registry data

Background and purpose

To evaluate the long-term outcome of accelerated partial breast irradiation utilizing intraoperatively placed applicator-based brachytherapy (ABB) in early-stage breast cancer.

Materials and methods

From our prospective registry, 223 patients with pTis-T2, pN0/pN1mic breast cancer were treated with ABB. The median treatment duration including surgery and ABB was 7 days. The prescribed doses were 32 Gy/8 fx BID (n = 25), 34 Gy/10 fx BID (n = 99), and 21 Gy/3 fx QD (n = 99). Endocrine therapy (ET) adherence was defined as completion of planned ET or ≥ 80% of the follow-up (FU) period. Cumulative incidence of ipsilateral breast tumor recurrence (IBTR) was estimated and influencing factors for IBTR-free survival rate (IBTRFS) were analyzed.

Results

218/223 patients had hormone receptor-positive tumors, including 38 (17.0%) with Tis and 185 (83.0%) with invasive cancer. After a median FU of 63 months, 19 (8.5%) patients had recurrence [17 (7.6%) with an IBTR]. Rates of 5-year IBTRFS and DFS were 92.2% and 91.1%, respectively. The 5-year IBTRFS rates were significantly higher for post-menopausal women (93.6% vs. 66.4%, p = 0.04), BMI < 30 kg/m2 (97.4% vs. 88.1%, p = 0.02), and ET-adherence (97.5% vs. 88.6%, p = 0.02). IBTRFS did not differ with dose regimens.

Conclusions

Postmenopausal status, BMI < 30 kg/m2, and ET- adherence predicted favorable IBTRFS. Our results highlight the importance of careful patient selection for ABB and encouragement of ET compliance.

Using US Twinkling Artifact to Identify Breast Biopsy Markers: Brief Report

Breast biopsy markers play an essential role in the surgical management of patients with clinically node-positive breast cancer. Marking a pathology-proven lymph node ensures accurate imaging assessment of response to neoadjuvant systemic therapy and decreased false-negative rates in sentinel lymph node biopsy. There is a clinically unmet need to make breast biopsy markers, particularly in the axilla, more sonographically visible or identifiable for preoperative localization purposes. Previously described color Doppler US twinkling artifact of some breast biopsy markers in in vitro gel phantoms and in ex vivo cadaveric breasts suggests that twinkling of such markers can be leveraged for improved in vivo detection. In this retrospective case series of eight female patients (mean age, 58.6 years ± 12.3 [SD]), conventional B-mode US imaging failed to identify the biopsy marker associated with a surgical target in the breast or in an axillary lymph node. However, in each patient, the marker was successfully identified with the help of color Doppler US twinkling. Keywords: Breast, Ultrasound, Color Doppler US, Lymphatic, Artifacts, Biopsy Marker Published under a CC BY 4.0 license.

Overuse of Axillary Surgery in Patients with Ductal Carcinoma In Situ: Opportunity for De-escalation

BACKGROUND

Ductal carcinoma in situ (DCIS) is noninvasive breast cancer and therefore nodal staging is not routinely recommended. We evaluated the use of and factors associated with axillary surgery in DCIS in the National Cancer Database (NCDB).

METHODS

DCIS cases were identified from the NCDB 2012-2018. Use of axillary surgery was evaluated over time, and factors associated with axillary surgery were assessed for breast-conserving surgery (BCS) and mastectomy groups.

RESULTS

We identified 178,762 patients, median age of 60 years. Majority of DCIS (87%) was ER-positive, and 14% low, 43% intermediate, and 44% high grade. Median DCIS size was 1.1 cm. BCS was performed in 72%, whereas 28% had mastectomy. Overall axillary surgery was performed in 38% and was higher in patients undergoing mastectomy compared with patients undergoing BCS (88% vs. 19%, p < 0.001). At axillary surgery, the vast majority (92%) had 1-5 nodes examined, whereas 8% had >5 nodes examined. Over time, axillary surgery decreased in BCS patients (21% in 2012 to 17% in 2018, p < 0.001) but increased slightly in mastectomy patients (86% in 2012 to 90% in 2018, p < 0.001). On multivariable analysis, factors significantly associated with axillary surgery were younger patient age, larger tumor size, higher grade, and ER-negative status.

CONCLUSIONS

Factors associated with axillary surgery reflect higher risk disease for upstage to invasive cancer, indicating surgeon judgment. However, despite axillary surgery being overtreatment of DCIS, it is common in mastectomy and is performed for one in five patients undergoing BCS. This provides opportunity for improvement in breast cancer care delivery.

Surgeon Assessment of the Technical Impact of Neoadjuvant Systemic Therapy on Operable Stage III Melanoma

INTRODUCTION

The effect of neoadjuvant systemic therapies (NST) on technical aspects of operation for resectable stage III melanoma is unknown. Prospective capture of the estimated and actual degree of difficulty of therapeutic lymphadenectomy at presentation and after NST may inform the relative merits of NST versus surgery followed by adjuvant therapy.

METHODS

We designed surgeon survey tools to capture key impressions at baseline prior to NST and postoperatively. We conducted a sub-study within a multi-institutional clinical trial for high-risk operable stage III melanoma (NeoACTIVATE, NCT03554083) which enrolls clinically node-positive patients to 12 weeks of combinatorial NST determined by BRAF status. Survey data were analyzed.

RESULTS

Surveys were completed for 24 of 25 patients (96%). Affected nodal basins were cervical (3, 13%) axillary (9, 38%), inguinal ± pelvic (14, 58%); 2 (8%) involved ≥ 2 basins. Baseline estimates included largest affected node size (median/range 4/1.4-11 cm), number of involved nodes (median/range 3/1-10) and tumor fixation (present in 12, 50%). At operation, actual degree of difficulty increased from the baseline estimate in 4 (17%) and decreased in 6 (25%). Surgery was less difficult, average, or more difficult versus usual operation in 4, 9, and 11 cases (17%, 38%, 46%), respectively.

CONCLUSIONS

Although many operations were judged to be more difficult than the usual therapeutic lymphadenectomy, operation following NST was more often perceived as easier than more difficult versus baseline impression. Engaging surgical oncologists to perform similar structured assessments across clinical trials will permit cross-study analysis of the effect of NSTs on the technical conduct of lymphadenectomy.

Locoregional Management of the Axilla in Mastectomy Patients with One or Two Positive Sentinel Nodes: The Role of Intraoperative Pathology

INTRODUCTION

Controversy exists regarding optimal management of the axilla in clinically node-negative (cN0) mastectomy patients with one or two positive sentinel lymph nodes (+SLNs). We evaluated the influence of frozen-section pathology on axillary management and recurrence.

PATIENTS AND METHODS

We studied cN0 breast cancer patients treated from 2008 to 2018 with mastectomy and SLN surgery with one or two +SLNs. Patients with one or two +SLNs identified on frozen-section intraoperatively (FS+SLN) were compared to those with one or two +SLNs not detected by frozen section (FS-SLN). Recurrence rates were estimated using the Kaplan-Meier method.

RESULTS

Of 2295 cN0 mastectomy patients, 338 patients had one or two +SLNs: 108 (32%) FS-SLN and 230 (68%) FS+SLN. In the FS+SLN cases, completion axillary lymph node dissection (cALND) was more frequent (97% vs. 39%; P < .001), and median SLN metastasis size (5 vs. 1.3 mm; P < .001) and likelihood of positive non-SLNs (31% vs. 14%; P = .02) were greater compared with FS-SLN cases. Across all 338 patients, 40% had SLN surgery alone, and 47% of cALND patients received post-mastectomy radiation therapy (PMRT). At a median follow-up of 61 months, no axillary recurrences were observed among FS-SLN patients. Among FS+SLN patients, 97% proceeded to cALND but 49% avoided PMRT; three regional nodal recurrences were observed (all in patients treated with cALND, of whom two received PMRT).

CONCLUSION

Mastectomy patients with one or two FS+SLNs have a higher nodal disease burden than FS-SLN patients. The majority of FS+SLN patients underwent cALND, and 51% received PMRT with very low 5-year regional nodal recurrence rates. A substantial proportion of FS-SLN patients successfully avoided both cALND and PMRT. Frozen-section pathology analysis can guide de-escalation of axillary management.

Use of the Twelve-Gene Recurrence Score for Ductal Carcinoma in Situ and Its Influence on Receipt of Adjuvant Radiation and Hormonal Therapy

BACKGROUND

Tumor genomic prognostic assays estimate 10-year local recurrence risk in ductal carcinoma in situ (DCIS) and can guide treatment decisions. This study aimed to evaluate which DCIS patients treated with breast-conserving surgery (BCS) underwent DCIS score genomic testing and the influence of the results on adjuvant treatment recommendations.

METHODS

The study identified patients from the National Cancer Database (NCDB) who had DCIS treated with BCS from 2010 to 2016.

RESULTS

Of 141,047 patients, 4255 (3%) had a DCIS score assessed, 0.3% in 2010 increasing to 5.8% in 2016 (p < 0.001). The patients most likely to undergo DCIS score assessment had more favorable tumor features in the multivariable analysis. The DCIS score result was documented for 91.4% of the tested patients (n = 3888): 70.5% of the low-risk, 14.9% of the intermediate-risk, and 14.6% of the high-risk patients. The patients with low-risk scores were less likely to have radiation than those with intermediate- or high-risk scores among the patients with either ER + (35.0% vs 71.0% or 81.1%) or ER- disease (48.1% vs 77.0% or 85.5%) (each p ≤ 0.001). The patients who had ER + disease with high- and intermediate-risk scores were most commonly treated with both radiation and hormone therapy (HT) (57.1% and 52.2%), whereas the most common treatment for those with a low-risk DCIS score was HT alone without radiation (37.1%). Comparison of genomic testing with clinicopathologic features showed an independent influence of genomic testing on treatment.

CONCLUSIONS

Use of the DCIS score increased over time, predominantly for favorable DCIS. Patients with a low-risk score were significantly less likely to receive radiation, supporting an impact of the DCIS score on treatment de-escalation.

Oncologic Outcomes of Sentinel Lymph Node Surgery After Neoadjuvant Chemotherapy for Node-Positive Breast Cancer

BACKGROUND

Sentinel lymph node (SLN) surgery after neoadjuvant chemotherapy (NAC) has been well studied. However, outcomes data addressing the oncologic safety of this technique are sparse. This study aimed to evaluate use of SLN surgery versus axillary lymph node dissection (ALND) for clinically node-positive patients treated with NAC and to report outcomes.

METHODS

The study identified patients at the authors' institution with biopsy proven clinically node-positive (cN1-cN3) breast cancer undergoing axillary surgery after NAC from 2009 to 2019. Practice patterns and outcomes were evaluated.

RESULTS

Of 602 patients, 52.3% underwent SLN surgery. Use of SLN surgery increased significantly over time, reaching 75.3% during 2015-2019. For 52.5% of the patients who had an SLN identified, ALND was not used. Use of ALND (± SLN surgery) decreased from 100% in 2009 to 57.2% in 2015-2019. The nodal positivity rate of patients who proceeded directly to ALND was 64.5% (185/287), increasing significantly over time. Factors significantly associated with performing SLN surgery on multivariable analysis were lower presenting clinical T category, lower presenting clinical N category (cN1 vs cN2-3) and HER2-positive status. During the median 34-month follow-up period, 17 regional recurrences were observed (16/443 with ALND; 1/159 with SLN surgery alone), for a 2-year freedom-from-regional-recurrence rate of 99.1% among the SLN surgery patients and 96.4% among the ALND patients (p = 0.10).

CONCLUSIONS

For cN1-3 breast cancer treated with NAC, SLN surgery has been incorporated into clinical practice at the authors' institution. In this study, selection for SLN surgery was based on clinical factors and tumor biology. More than half of the patients who were selected for SLN surgery were spared ALND, with a low nodal failure rate and no recurrence-free survival disadvantage at 2 years.

Performance and Clinical Utility of Models Predicting Eradication of Nodal Disease in Patients with Clinically Node-Positive Breast Cancer Treated with Neoadjuvant Chemotherapy by Tumor Biology

INTRODUCTION

Prediction models are useful to guide decision making. Our goal was to compare three published nomograms predicting axillary response to neoadjuvant chemotherapy (NAC), clinically node-positive breast cancer.

METHODS

Patients with cT1-T4, cN1-N3 breast cancer treated with NAC and surgery from 2008 to 2019 were reviewed. The predicted probability of pathologic node-negative (ypN0) status was estimated for each nomogram. Area under the curve (AUC) was compared across models, overall and by biologic subtype.

RESULTS

Of 581 patients, 253 (43.5%) were ypN0. ypN0 status varied by subtype: 23.9% for estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-), 68.9% for HER2-positive (HER2+), and 47.2% for ER-negative (ER-)/HER2-. The three nomograms had similar AUC values (0.761-0.769; p = 0.80). The Mayo model-predicted probability was significantly lower (p < 0.001) than the observed probability of ypN0 status, while the MD Anderson Cancer Center (MDACC) 1- and 2-predicted probabilities were similar to the observed probability. At a predicted probability threshold of 50%, the Mayo model had the highest sensitivity (89.6%) for detecting ypN+ patients compared with MDACC models 1 and 2 (76.5%; p < 0.001). However, both MDACC models had higher specificity in identifying ypN0 status among HER2+ (81.7%) and ER-/HER2- (75.9-77.6%) patients compared with the Mayo model (59.5% and 43.1%; each p < 0.001). None of the models identified the ER+/HER2- patients with ypN0 status well at the ≥ 50% threshold (specificity 0-9.4%).

CONCLUSION

All three models predicting nodal response to NAC performed well overall with respect to discrimination, but differed with respect to calibration and performance at a 50% probability threshold. However, none of the models performed well at the 50% threshold for ER+/HER2- patients.

QIM19-139: Reflex Testing of Oncotype DX Recurrence Score: A Single Institution Review of a Quality Improvement Protocol

Background: Implementation of genomic assays has led to treatment of early-stage breast cancers with high risk of recurrence with adjuvant systemic chemotherapy while sparing those with a low risk of recurrence from systemic therapy with minimal benefit. Genomic assays are becoming a more widely used tool, evident by the eighth edition of the American Joint Committee on Cancer (AJCC) Breast Cancer Staging System, which includes recurrence score as part of the treatment algorithm in certain subgroups of tumors. Our institution identified the time to assay result as a quality improvement opportunity. We instituted a protocol to have a reflex testing of Oncotype DX based on certain criteria to decrease time to assay results and ultimately time to treatment. Methods: Our Multidisciplinary Breast Leadership Committee instituted a policy for reflex Oncotype DX testing on patients under the age of 70 with estrogen receptor positive, HER2-neu protein–negative, and node-negative invasive breast cancers measuring between 0.5 cm to 5 cm in January 2018. We compared our data available from pre- and postimplementation using the single factor analysis of variance (ANOVA) as well as an independent t-test and a post-hoc Tukey-Kramer test. Results: We have observed 45 cases that met the criteria for reflex Oncotype Dx testing since the initiation of this quality improvement protocol. The recurrence scores ranged from 0 to 55. There was a statistically significant difference in the number of days from operation to result day from 2016 to 2018 (55 days vs 18 days; P<.001). The number of days from the test order date to result date also saw a significant improvement from 2016 to 2018 (12 vs 9 days; P<.05). Conclusions: Breast cancer treatment options continue to evolve, particularly with the use of genomic assays. Our single institution review confirms the utility of our reflex Oncotype DX protocol with a decreased time to result with reflex testing of patients in the appropriate clinical setting. Further development of similar pathways may be necessary to streamline our patients’ care in the treatment of breast cancer.