Construction and validation of a novel nomogram for prediction of lymph node metastasis in HER2-positive breast cancer: based on the optimal number of examined lymph nodes for accurate nodal staging

PURPOSE

This study aimed to construct and validate a novel nomogram for prediction of lymph node metastasis in HER2-positive breast cancer based on the optimal number of examined lymph nodes (ELNs) for accurate nodal staging.

METHODS

We included 4,040 patients diagnosed with HER2-positive breast cancer from the SEER database, randomly allocating them into training and validation cohorts in a 7:3 ratio. The optimal number of ELNs was identified via piecewise linear regression. The association of ELNs count with nodal migration was evaluated through Logistic Regression (LR) analysis and Random Forest (RF). The nomogram was constructed, and its' performance was evaluated by the receiver operating characteristic curves, calibration curve and Decision curve analysis curves.

RESULTS

The optimal number of ELNs was 13. LR and RF identified the optimal number of ELNs, radiotherapy status, chemotherapy status, T stage, and grade as independent predictive variables for node metastasis, which were used in the nomogram's construction. And the area under the curve values for the nomogram were 0.829 (95% confidence interval (CI): 0.813-0.845) and 0.833 (95% CI:0.808-0.858) in the training and test split respectively, surpassing those of the optimal number of ELNs (0.649, 95% CI: 0.631-0.667 and 0.676, 95% CI:0.648-0.704). Calibration plots exhibited low Brier scores (0.150 for training split, 0.145 for test split).

CONCLUSION

This study developed a novel nomogram that integrates the optimal number of ELNs with other independent risk factors, facilitating individualized prediction of lymph node metastasis in patients with HER2-positive breast cancer.

Nodal Burden and Oncologic Outcomes in Patients With Residual Isolated Tumor Cells After Neoadjuvant Chemotherapy (ypN0i+): The OPBC-05/ICARO Study

PURPOSE

The nodal burden of patients with residual isolated tumor cells (ITCs) in the sentinel lymph nodes (SLNs) after neoadjuvant chemotherapy (NAC) (ypN0i+) is unknown, and axillary management is not standardized. We investigated rates of additional positive lymph nodes (LNs) at axillary lymph node dissection (ALND) and oncologic outcomes in patients with ypN0i+ treated with and without ALND.

METHODS

The Oncoplastic Breast Consortium-05/ICARO cohort study (ClinicalTrials.gov identifier: NCT06464341) retrospectively analyzed data from patients with stage I to III breast cancer with ITCs in SLNs after NAC from 62 centers in 18 countries. The primary end point was the 3-year rate of any axillary recurrence. The rate of any invasive recurrence was the secondary end point.

RESULTS

In total, 583 patients were included, of whom 182 (31%) had completion ALND and 401 (69%) did not. The median age was 48 years. Most patients (74%) were clinically node-positive at diagnosis and 41% had hormone receptor-positive/human epidermal growth factor receptor 2-negative tumors. The mean number of SLNs with ITCs was 1.2. Patients treated with ALND were more likely to present with cN2/3 disease (17% v 7%, P < .001), have ITCs detected on frozen section (62% v 8%, P < .001), have lymphovascular invasion (38% v 24%, P < .001), and receive adjuvant chest wall (89% v 78%, P = .024) and nodal radiation (82% v 75%, P = .038). Additional positive nodes were found at ALND in 30% of patients, but only 5% had macrometastases. The 3-year rates of any axillary and any invasive recurrence were 2% (95% CI, 0.95 to 3.6) and 11% (95% CI, 8 to 14), respectively, with no statistical difference by type of axillary surgery.

CONCLUSION

The nodal burden in patients with ypN0(i+) was low, and axillary recurrence after ALND omission was rare in patients selected for this approach. These results do not support routine ALND in all patients with ypN0(i+).

Is Axillary Lymph Node Dissection Needed? Clinicopathological Correlation in a Series of 224 Neoadjuvant Chemotherapy-Treated Node-Positive Breast Cancers

BACKGROUND

Axillary lymph node status is valuable in determining systemic and radiation therapy. Following neoadjuvant therapy for patients with clinically involved axillary nodes, the role of axillary lymph node dissection (ALND) following a positive sentinel lymph node biopsy (SLNB) is a subject of controversy.

MATERIALS AND METHODS

We retrospectively analyzed 224 neoadjuvant chemotherapy-treated node-positive breast cancer cases and evaluated the role of ALND in optimizing staging accuracy and treatment outcomes.

RESULTS

About 63 (27.8%) underwent ALND based on post neoadjuvant persistent positive lymph nodes on exam /imaging. SLNBs were performed in 161 (71.9%) patients as initial surgical planning; 67 (41.6%) patients had positive SLNB results, and 51 (76.1%) underwent further ALND. In patients with 1 positive sentinel lymph node, follow-up ALND yielded additional positive lymph nodes in 10.5% of cases, whereas in patients with 2 or more positive sentinel lymph nodes, follow-up ALND yielded additional positive lymph nodes in 87.5% of cases. The presence of 2 positive macro-metastatic sentinel lymph nodes significantly predicts additional nodal involvement, especially in patients without a pathologic complete response.

CONCLUSION

De-escalation of axillary surgery to SLNB alone in this context may be safely considered in neoadjuvant-treated clinical node positive patient with <2 positive sentinel lymph nodes. Our findings help guide surgeons to appropriately select patients who can potentially benefit from ALND for locoregional control and recommendation for adjuvant radiation.

Predicting Additional Metastases in Axillary Lymph Node Dissection After Neoadjuvant Chemotherapy: Ratio of Positive/Total Sentinel Nodes

BACKGROUND/OBJECTIVES

The aim of the study was to determine the clinical value of the sentinel lymph node ratio (SLN-R) in predicting additional positive lymph nodes during axillary lymph node dissection (ALND) in breast cancer patients following neoadjuvant chemotherapy (NAC).

METHODS

A cross-sectional study was performed at a single institution evaluating data from 1521 BC patients. Inclusion criteria comprised cT1/cT4, cN0/cN1 status with positive post-NAC axillary staging by SLN/TAD, respectively, and subsequent ALND.

RESULTS

The study included 118 patients, divided into two groups based on the presence or absence of additional node metastasis at ALND: 39 in the residual disease group (RD) and 79 in the non-residual disease group (nRD). Univariate logistic regression analysis of SLN-R was conducted to assess its predictive value, yielding an odds ratio (OR) of 7.79 (CI 1.92-29.5, p = 0.003). An SLN-R cut-off point of <0.35 was identified using ROC curve analysis, with a false-negative rate of 10.2%, as a predictor for no additional metastasis at ALND following post-NAC SLN/TAD positivity.

CONCLUSIONS

The study concludes that SLN-R is a valuable predictor for determining the omission of ALND in cases where SLN/TAD is positive after NAC. This metric, in combination with other clinical variables, could help develop a nomogram to spare patients from ALND.

Ultrasound-Based Deep Learning Radiomics Nomogram for the Assessment of Lymphovascular Invasion in Invasive Breast Cancer: A Multicenter Study

RATIONALE AND OBJECTIVES

The aim of this study was to develop a deep learning radiomics nomogram (DLRN) based on B-mode ultrasound (BMUS) and color doppler flow imaging (CDFI) images for preoperative assessment of lymphovascular invasion (LVI) status in invasive breast cancer (IBC).

MATERIALS AND METHODS

In this multicenter, retrospective study, 832 pathologically confirmed IBC patients were recruited from eight hospitals. The samples were divided into training, internal test, and external test sets. Deep learning and handcrafted radiomics features reflecting tumor phenotypes on BMUS and CDFI images were extracted. The BMUS score and CDFI score were calculated after radiomics feature selection. Subsequently, a DLRN was developed based on the scores and independent clinic-ultrasonic risk variables. The performance of the DLRN was evaluated for calibration, discrimination, and clinical usefulness.

RESULTS

The DLRN predicted the LVI with accuracy, achieving an area under the receiver operating characteristic curve of 0.93 (95% CI 0.90-0.95), 0.91 (95% CI 0.87-0.95), and 0.91 (95% CI 0.86-0.94) in the training, internal test, and external test sets, respectively, with good calibration. The DLRN demonstrated superior performance compared to the clinical model and single scores across all three sets (p < 0.05). Decision curve analysis and clinical impact curve confirmed the clinical utility of the model. Furthermore, significant enhancements in net reclassification improvement (NRI) and integrated discrimination improvement (IDI) indicated that the two scores could serve as highly valuable biomarkers for assessing LVI.

CONCLUSION

The DLRN exhibited strong predictive value for LVI in IBC, providing valuable information for individualized treatment decisions.

Residual Nodal Burden After Neoadjuvant Chemotherapy in cN1 Breast Cancer Patients with Positive Nodes at Targeted Axillary Dissection

BACKGROUND

Targeted axillary dissection (TAD) facilitates nodal staging in cN1 breast cancer after neoadjuvant chemotherapy (NAC). Completion axillary node dissection (cALND) remains the standard of care for TAD-positive patients. This study investigated factors associated with additional positive nodes at cALND (cALND+) and the impact on the residual cancer burden (RCB).

METHODS

Retrospective review of cN1 breast cancer patients treated with NAC and TAD was conducted from July 2013 to June 2023. The review defined cN1 status by ultrasound (US) and biopsy. Patient, tumor, and treatment characteristics were evaluated. Multivariate analysis was performed to identify factors associated with cALND+, and RCB was calculated.

RESULTS

Of 902 patients who underwent TAD, 554 (61.4%) were TAD-positive. 457 underwent cALND, and 124 (27%) were cALND+ (average 4.1 additional +nodes). The cALND+ patients had larger primary tumors at diagnosis (4 vs 3.5 cm; p = 0.04), more than three suspicious nodes on initial US (30% vs 13%; p ≤ 0.0001), larger residual primary tumors on pathology (median, 3 vs 2.1 cm; p = 0.0004), and more positive TAD nodes (median, 2 vs 1; p ≤ 0.0001). In the multivariate analysis, the factors associated with cALND+ were more than three suspicious nodes on initial US (odds ratio [OR], 2.9; p ≤ 0.0001), more positive TAD nodes (OR, 1.1; p ≤ 0.0001), larger clipped node metastasis (OR, 1.1; p ≤ 0.0001), and larger residual tumor on pathology (OR, 1.1; p = 0.006). Of 65 cALND+ patients with RCB class I or II, 29 (45%) had an increase in RCB based on cALND.

CONCLUSION

Of cN1 breast cancer patients treated with NAC who are TAD-positive, approximately 25% will have additional nodal disease on cALND. In these patients, positive cALND is associated with greater disease burden, which has potential implications for RCB status and prognosis.

Residual Axillary Metastases in Node-Positive Breast Cancer Patients After Neoadjuvant Treatment: A Register-Based Study

BACKGROUND

Lymph node (LN) metastasis after neoadjuvant chemotherapy (NACT) generally warrants axillary lymph node dissection, which opposes guidelines of upfront surgery in many cases. We investigated the risk of having additional metastases in the axilla when the LNs removed by targeted axillary dissection (TAD) harbored metastases after NACT. We aimed to identify subgroups suitable for de-escalated axillary treatment.

METHODS

This register-based study used data from the Danish Breast Cancer Cooperative Group database. Data were analyzed with logistic regression models. The primary outcome was the metastatic burden in non-TAD LNs in patients with positive TAD LNs after NACT.

RESULTS

Among 383 patients, < 66.6% positive TAD LNs (adjusted odds ratio [OR] 0.34, 95% confidence interval [CI] 0.17-0.62), only isolated tumor cells (ITCs) [OR 0.11, 95% CI < 0.01-0.82], and breast pathological complete response (pCR) [OR 0.07, 95% CI < 0.01-0.56] were associated with a low risk of having more than three positive non-TAD LNs. In 315 patients with fewer than three positive non-TAD LNs, the proportion of positive TAD LNs (OR 0.45, 95% CI 0.27-0.76 for 33.3-66.6% vs. > 66.6%), size of the TAD LN metastasis (OR 0.14, 95% CI 0.04-0.54 for ITC vs. macrometastasis), tumor size at diagnosis (OR 0.30, 95% CI 0.15-0.64 for 20-49 mm vs. ≥ 50 mm) and breast pCR (OR 0.38, 95% CI 0.15-0.96) were associated with residual LN metastases in the axilla.

CONCLUSIONS

Breast pCR or ITC only in TAD LNs can, with reasonable certainty, preclude more than three positive non-TAD LNs. Additionally, patients with only ITCs in the TAD LN had a low risk of having any non-TAD LN metastases after NACT. De-escalated axillary treatment may be considered in both subgroups.

Targeted axillary dissection reduces residual nodal disease in clinically node- positive breast cancer after neoadjuvant chemotherapy

BACKGROUND

Any advantage of performing targeted axillary dissection (TAD) compared to sentinel lymph node (SLN) biopsy (SLNB) is under debate in clinically node-positive (cN+) patients diagnosed with breast cancer. Our objective was to assess the feasibility of the removal of the clipped node (RCN) with TAD or without imaging-guided localisation by SLNB to reduce the residual axillary disease in completion axillary lymph node dissection (cALND) in cN+ breast cancer.

METHODS

A combined analysis of two prospective cohorts, including 253 patients who underwent SLNB with/without TAD and with/without ALND following NAC, was performed. Finally, 222 patients (cT1-3N1/ycN0M0) with a clipped lymph node that was radiologically visible were analyzed.

RESULTS

Overall, the clipped node was successfully identified in 246 patients (97.2%) by imaging. Of 222 patients, the clipped lymph nodes were non-SLNs in 44 patients (19.8%). Of patients in cohort B (n=129) with TAD, the clipped node was successfully removed by preoperative image-guided localisation, or the clipped lymph node was removed as the SLN as detected on preoperative SPECT-CT. Among patients with ypSLN(+) (n=109), no significant difference was found in non-SLN positivity at cALND between patients with TAD and RCN (41.7% vs. 46.9%, p=0.581). In the subgroup with TAD with axillary lymph node dissection (ALND; n=60), however, patients with a lymph node (LN) ratio (LNR) less than 50% and one metastatic LN in the TAD specimen were found to have significantly decreased non-SLN positivity compared to others (27.6% vs. 54.8%, p=0.032, and 22.2% vs. 50%, p=0.046).

CONCLUSIONS

TAD by imaging-guided localisation is feasible with excellent identification rates of the clipped node. This approach has also been found to reduce the additional non-SLN positivity rate to encourage omitting ALND in patients with a low metastatic burden undergoing TAD.

Axillary Surgery for Chemoresidual (ypN-Positive) Nodal Disease

This cohort study using pooled data from 2 randomized clinical trials examines whether removing more lymph nodes with axillary lymph node dissection improved outcomes over sentinel lymph node biopsy when most patients received adjuvant radiation therapy or regional nodal irradiation.

Personalizing Locoregional Therapy in Patients With Breast Cancer in 2024: Tailoring Axillary Surgery, Escalating Lymphatic Surgery, and Implementing Evidence-Based Hypofractionated Radiotherapy

The management of axillary lymph nodes in breast cancer is continually evolving. Recent data now support omitting axillary lymph node dissection (ALND) in most patients with metastases in up to two sentinel lymph nodes (SLNs) during upfront surgery and those with residual isolated tumor cells after neoadjuvant chemotherapy (NACT). In the upfront surgery setting, ALND is still indicated, however, in patients with clinically node-positive breast cancer or more than two positive SLNs and, after NACT, in case of residual micrometastases and macrometastases. Omission of the sentinel lymph node biopsy (SLNB) can be considered in many postmenopausal patients with small luminal breast cancer, particularly when axillary ultrasound is negative. Several randomized controlled trials (RCTs) are currently aiming at eliminating the remaining indications for ALND and also establishing omission of SLNB in a broader patient population. The movement to deescalate axillary staging is in part because of the association between ALND and lymphedema, which is swelling of an extremity because of lymphatic damage and obstructed lymphatic drainage. To reduce the risk of developing this condition, patients undergoing ALND can undergo reverse mapping of the axilla and immediate reconstruction or bypass of the lymphatics from the involved extremity. Decongestion and compression are the foundation of conservative treatment for established lymphedema, while lymphovenous bypass and lymph node transfer are surgical procedures to address the physiologic dysfunction. Radiotherapy is an essential component of breast locoregional therapy: more than three decades of radiation research has optimized treatment according to patient's risk of local recurrence while substantially reducing the number of treatment visits. High-quality RCTs have shown the efficacy and safety of hypofractionation-more than 2Gy radiation dose per treatment (fraction)-significantly reducing the burden of radiotherapy treatment for many patients with breast cancer. In 2024, guidelines recommend no more than 15-16 fractions for whole-breast and nodal radiotherapy, with some recommending five fractions for whole-breast radiotherapy. In addition, simultaneous integrated boost (SIB) has been shown to be noninferior to sequential boost with regards to ipsilateral breast tumor recurrence with similar or reduced long-term side effects, also reducing overall treatment length. Further RCTs are underway investigating other indications for five fractions, including SIB and regional node irradiation, such that, in future, it may be possible for the majority of breast radiotherapy patients to be treated with a 1-week course. This manuscript serves to outline the latest updates on axillary surgical staging, lymphatic surgery, and evidence-based radiotherapy in the treatment of breast cancer.

Axillary Surgery for Breast Cancer in 2024

Axillary surgery for patients with breast cancer (BC) in 2024 is becoming increasingly specific, moving away from the previous 'one size fits all' radical approach. The goal is to spare morbidity whilst maintaining oncologic safety. In the upfront surgery setting, a first landmark randomized controlled trial (RCT) on the omission of any surgical axillary staging in patients with unremarkable clinical examination and axillary ultrasound showed non-inferiority to sentinel lymph node (SLN) biopsy (SLNB). The study population consisted of 87.8% postmenopausal patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative BC. Patients with clinically node-negative breast cancer and up to two positive SLNs can safely be spared axillary dissection (ALND) even in the context of mastectomy or extranodal extension. In patients enrolled in the TAXIS trial, adjuvant systemic treatment was shown to be similar with or without ALND despite the loss of staging information. After neoadjuvant chemotherapy (NACT), targeted lymph node removal with or without SLNB showed a lower false-negative rate to determine nodal pathological complete response (pCR) compared to SLNB alone. However, oncologic outcomes do not appear to differ in patients with nodal pCR determined by either one of the two concepts, according to a recently published global, retrospective, real-world study. Real-world studies generally have a lower level of evidence than RCTs, but they are feasible quickly and with a large sample size. Another global real-world study provides evidence that even patients with residual isolated tumor cells can be safely spared from ALND. In general, few indications for ALND remain. Three randomized controlled trials are ongoing for patients with clinically node-positive BC in the upfront surgery setting and residual disease after NACT. Pending the results of these trials, ALND remains indicated in these patients.

Ultrasound radiomics-based nomogram to predict lymphovascular invasion in invasive breast cancer: a multicenter, retrospective study

OBJECTIVES

To develop and validate an ultrasound (US) radiomics-based nomogram for the preoperative prediction of the lymphovascular invasion (LVI) status in patients with invasive breast cancer (IBC).

MATERIALS AND METHODS

In this multicentre, retrospective study, 456 consecutive women were enrolled from three institutions. Institutions 1 and 2 were used to train (n = 320) and test (n = 136), and 130 patients from institution 3 were used for external validation. Radiomics features that reflected tumour information were derived from grey-scale US images. The least absolute shrinkage and selection operator and the maximum relevance minimum redundancy (mRMR) algorithm were used for feature selection and radiomics signature (RS) building. US radiomics-based nomogram was constructed by using multivariable logistic regression analysis. Predictive performance was assessed with the receiving operating characteristic curve, discrimination, and calibration.

RESULTS

The nomogram based on clinico-ultrasonic features (menopausal status, US-reported lymph node status, posterior echo features) and RS yielded an optimal AUC of 0.88 (95% confidence interval [CI], 0.84-0.91), 0.89 (95% CI, 0.84-0.94) and 0.95 (95% CI, 0.92-0.99) in the training, internal and external validation cohort. The nomogram outperformed the clinico-ultrasonic and RS model (p < 0.05). The nomogram performed favourable discrimination (C-index, 0.88; 95% CI: 0.84-0.91) and was confirmed in the validation (0.88 for internal, 0.95 for external) cohorts. The calibration and decision curve demonstrated the nomogram showed good calibration and was clinically useful.

CONCLUSIONS

The radiomics nomogram incorporated in the RS and US and the clinical findings exhibited favourable preoperative individualised prediction of LVI.

CLINICAL RELEVANCE STATEMENT

The US radiomics-based nomogram incorporating menopausal status, posterior echo features, US reported-ALN status, and radiomics signature has the potential to predict lymphovascular invasion in patients with invasive breast cancer.

KEY POINTS

• The clinico-ultrsonic model of menopausal status, posterior echo features, and US-reported ALN status achieved a better predictive efficacy for LVI than either of them alone. • The radiomics nomogram showed optimal prediction in predicting LVI from patients with IBC (ROC, 0.88 and 0.89 in the training and validation sets). • A nomogram demonstrated favourable performance (area under the receiver operating characteristic curve, 0.95) and well calibration (C-index, 0.95) in an independent validation cohort (n = 130).

Nonsentinel Axillary Lymph Node Status in Clinically Node-Negative Early Breast Cancer After Primary Systemic Therapy and Positive Sentinel Lymph Node: A Predictive Model Proposal

BACKGROUND

In clinically node-negative (cN0) early stage breast cancer (EBC) undergoing primary systemic treatment (PST), post-treatment positive sentinel lymph node (SLN+) directs axillary lymph node dissection (ALND), with uncertain impacts on outcomes and increased morbidities.

PATIENTS AND METHODS

We conducted an observational study on imaging-confirmed cN0 EBC, who underwent PST and breast surgery that resulted in SLN+ and underwent ALND. The association among baseline/postsurgical clinic-pathological factors and positive nonsentinel additional axillary lymph nodes (non-SLN+) was analyzed with logistic regression. LASSO regression (LR) identified variables to include in a predictive score of non-SLN+ (ALND-predict). The accuracy and calibration were assessed, an optimal cut-point was then identified, and in silico validation with bootstrap was undertaken.

RESULTS

Non-SLN+ were detected in 22.2% cases after ALND. Only progesterone receptor (PR) levels and macrometastatic SLN+ were independently associated to non-SLN+. LR identified PR, Ki67, and type and number of SLN+ as the most efficient covariates. The ALND-predict score was built based on their LR coefficients, showing an area under the curve (AUC) of 0.83 and an optimal cut-off of 63, with a negative predictive value (NPV) of 0.925. Continuous and dichotomic scores had a good fit (p = 0.876 and p = 1.00, respectively) and were independently associated to non-SLN+ [adjusted odds ratio (aOR): 1.06, p = 0.002 and aOR: 23.77, p < 0.001, respectively]. After 5000 bootstrap-adjusted retesting, the estimated bias-corrected and accelerated 95%CI included the aOR.

CONCLUSIONS

In cN0 EBC with post-PST SLN+, non-SLN+ at ALND are infrequent (~22%) and independently associated to PR levels and macrometastatic SLN. ALND-predict multiparametric score accurately predicted absence of non-SLN involvement, identifying most patients who could be safely spared unnecessary ALND. Prospective validation is required.

Surgical Management of the Axilla for Breast Cancer

This review discusses the contemporary surgical management of the axilla in patients with breast cancer. Surgical paradigms are highlighted by clinical nodal status at presentation and treatment approach, including upfront surgery and neoadjuvant systemic therapy settings. This review focuses on the increasing opportunities for de-escalating the extent of axillary surgery in the era of sentinel lymph node biopsy, while also reviewing the remaining indications for axillary clearance with axillary lymph node dissection.

Estimating the Benefit of Preoperative Systemic Therapy to Reduce the Extent of Breast Cancer Surgery: Current Standard and Future Directions

Once reserved for locally advanced tumors which were deemed inoperable at presentation, preoperative systemic therapy (PST) is nowadays increasingly used to treat early breast cancer. PST allows for in vivo assessment of tumor response, for tailoring of adjuvant systemic therapy and for de-escalation of breast and the axillary surgery. Increased rates of pathological complete response together with more accurate response assessment and surgical planning have led to a significant reduction in surgical morbidity. While surgical assessment remains the standard of care, ongoing studies are evaluating whether surgery can be omitted in patients who achieve a complete pathological response. In this chapter, I will review the impact of PST on surgical de-escalation and the data supporting the safety of this approach.

A Model Incorporating Axillary Tail Position on Mammography for Preoperative Prediction of Non-sentinel Lymph Node Metastasis in Patients with Initial cN+ Breast Cancer after Neoadjuvant Chemotherapy

RATIONALE AND OBJECTIVES

This study aimed to develop a model incorporating axillary tail position on mammography (AT) for the prediction of non-sentinel Lymph Node (NSLN) metastasis in patients with initial clinical node positivity (cN+).

METHODS AND MATERIALS

The study reviewed a total of 257 patients with cN+ breast cancer who underwent both sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) following neoadjuvant chemotherapy (NAC). A logistic regression model was developed based on these factors and the results of post-NAC AT and axillary ultrasound (AUS).

RESULTS

Four clinical factors with p<0.1 in the univariate analysis, including ycT0(odds ratio [OR]: 4.84, 95% confidence interval [CI]: 2.13-11.91, p<0.001), clinical stage before NAC (OR: 2.68, 95%CI: 1.15-6.58, p=0.025), estrogen receptor (ER) expression (OR: 3.29, 95%CI: 1.39-8.39, p=0.009), and HER2 status (OR: 0.21, 95%CI: 0.08-0.50, p=0.001), were independent predictors of NSLN metastases. The clinical model based on the above four factors resulted in the area under the curve (AUC) of 0.82(95%CI: 0.76-0.88) in the training set and 0.83(95% CI: 0.74-0.92) in the validation set. The results of post-NAC AUS and AT were added to the clinical model to construct a clinical imaging model for the prediction of NSLN metastasis with AUC of 0.87(95%CI: 0.81-0.93) in the training set and 0.89(95%CI: 0.82-0.96) in the validation set.

CONCLUSIONS

The study incorporated the results of post-NAC AT and AUS with other clinal factors to develop a model to predict NSLN metastasis in patients with initial cN+ before surgery. This model performed excellently, allowing physicians to select patients for whom unnecessary ALND could be avoided after NAC.

Factors Influencing Non-sentinel Lymph Node Involvement in Patients with Positive Sentinel Lymph Node(s) After Neoadjuvant Chemotherapy for Breast Cancer

BACKGROUND

When a positive sentinel lymph node (SLN) is identified after neoadjuvant chemotherapy (NAC), completion axillary lymph node dissection (cALND) is generally recommended. We sought to evaluate the rate of non-SLN positivity and factors influencing this in patients with a positive SLN following NAC.

METHODS

We identified all patients at our hospital between 2006 and 2021 with a positive SLN (> 0.2 mm) following NAC who underwent cALND. Rates of positive non-SLN (NSLN) on cALND were compared by nodal status. Chi-square tests and multivariable logistic regression were used to assess factors predictive of positive NSLN and overall nodal burden.

RESULTS

Overall, 229 cases (177 cN+, 52 cN0 prior to NAC) with positive SLN(s) after NAC underwent cALND. Additional NSLN involvement was found in 129/229 (56.3%) patients, including 24/52 (46.2%) cN0 and 105/177 (59.3%) cN+ patients (p = 0.09). There was a trend for patients with SLN micrometastases to be less likely to have positive NSLN(s) than those with SLN macrometastases (38.5% vs. 58.6%; p = 0.05). Subgroup analyses showed no clinicopathologic factors significantly associated with additional axillary involvement for initially cN0 patients. Factors found to significantly influence NSLN positivity in the initially cN+ subgroup were HER2 status, multicentricity/multifocality, number of positive SLNs, and size of SLN metastasis. SLN metastasis size > 5 mm and three or more positive SLNs exerted the greatest influence on NSLN positivity.

CONCLUSION

Rates of nodal positivity on cALND in the setting of positive SLN after NAC are high, supporting the current standard of routine cALND. In cN+ disease, NSLN positivity varies by tumor biology, multicentricity/multifocality, number of positive SLNs, and SLN metastasis size.

Is Residual Nodal Disease at Axillary Dissection Associated with Tumor Subtype in Patients with Low Volume Sentinel Node Metastasis After Neoadjuvant Chemotherapy?

BACKGROUND

In patients with a positive sentinel lymph node (SLN) after neoadjuvant chemotherapy (NAC), the likelihood of residual nodal disease at axillary dissection (ALND) is high. Whether non-SLN metastasis frequency varies based on tumor subtype and SLN metastasis size is uncertain. We examined the association between tumor subtype and frequency of non-SLN metastases in patients with SLN micro- vs macrometastases after NAC.

METHODS

Patients with invasive breast cancer and a positive SLN biopsy after NAC between July 2008 and July 2019 were identified. Associations between tumor subtype, SLN disease volume, and frequency of non-SLN metastases were examined.

RESULTS

Among 273 patients with ≥ 1 positive SLN and a completion ALND, mean age was 51 years, 87% of tumors were ductal, 80% were clinically node-positive at presentation, and 85% were cT2-3. The frequency of non-SLN metastases was non-significantly higher in HR+/HER2- (61%) vs. HER2+ (52%) and triple negative tumors (45%) (p = 0.09). Frequency of SLN micrometastasis was 9% for triple negative tumors compared with 17% for HR+/HER2- and 34% for HER2+ tumors (p = 0.015). Size of SLN metastasis (micro- vs. macrometastases) was not associated with non-SLN metastasis frequency or number within any subtype.

CONCLUSIONS

In patients with a positive SLN after NAC, the likelihood of non-SLN metastasis at ALND was high across all tumor subtypes and did not vary significantly for SLN micro- versus macrometastases. ALND is recommended for SLN micro- and macrometastases after NAC, irrespective of tumor subtype.

Optimal Management for Residual Disease Following Neoadjuvant Systemic Therapy

OPINION STATEMENT

Treatment sequencing in early-stage breast cancer has significantly evolved in recent years, particularly in the triple negative (TNBC) and human epidermal growth factor receptor 2 (HER2)-positive subsets. Instead of surgery first followed by chemotherapy, several clinical trials showed benefits to administering systemic chemotherapy (and HER2-targeted therapies) prior to surgery. These benefits include more accurate prognostic estimates based on the extent of residual cancer that can also guide adjuvant treatment, and frequent tumor downstaging that can lead to smaller surgeries in patients with large tumors at diagnosis. Patients with extensive invasive residual cancer after neoadjuvant therapy are at high risk for disease recurrence, and two pivotal clinical trials, CREATE-X and KATHERINE, demonstrated improved recurrence free survival with adjuvant capecitabine and ado-trastuzumab-emtansine (T-DM1) in TNBC and HER2-positive residual cancers, respectively. Patients who achieve pathologic complete response (pCR) have excellent long-term disease-free survival regardless of what chemotherapy regimen induced this favorable response. This allows escalation or de-escalation of adjuvant therapy: patients who achieved pCR could be spared further chemotherapy, while those with residual cancer could receive additional chemotherapy postoperatively. Ongoing clinical trials are testing this strategy (CompassHER2-pCR: NCT04266249). pCR also provides an opportunity to assess de-escalation of locoregional therapies. Currently, for patients with residual disease in the lymph nodes (ypN+), radiation therapy entails coverage of the undissected axilla, and may include supra/infraclavicular/internal mammary nodes in addition to the whole breast or chest wall, depending on the type of surgery. Ongoing trials are testing the safety of omitting post-mastectomy breast and post-lumpectomy nodal irradiation (NCT01872975) as well as omitting axillary lymph node dissection (NCT01901094) in the setting of pCR. Additionally, evolving technologies such as minimal residual disease (MRD) monitoring in the blood during follow-up may allow early intervention with "second-line systemic adjuvant therapy" for patients with molecular relapse which might prevent impending clinical relapse.

Development of a predictive score of axillary lymph node dissection based on targeted axillary dissection in patients with breast cancer diagnosis, affected lymph nodes, and neoadjuvant treatment

AIM

To determine predictive factors of axillary lymph node dissection (ALND) results in breast cancer (BC) patients undergoing neoadjuvant chemotherapy (NACT), and subsequent staging using Targeted Axillary Dissection (TAD).

MATERIAL AND METHOD

Case-control study between January 2016 and August 2019. Patients with BC, cN1 staging, marked with a metallic clip prior to NACT, and subsequently staged with TAD and ALND were included. They were divided into 2 groups: ALND patients with or without metastatic involvement (group 1 and group 2, respectively). We carried out a univariate analysis comparing clinical, radiological, surgical and pathological variables, and a logistic regression, (dependent variable: positive result of ALND; independent variables: number of suspicious lymph nodes in diagnostic ultrasound, positive hormone receptors, HER2 positive, complete clinical-radiological response to NACT, positive TAD, and biopsy of ≤2 nodes in TAD). A score for prediction of a metastatic ALND was proposed, with an internal validation study.

RESULTS

60 patients were included: Group 1: 33 (55.0%); Group 2: 27 (45.0%). Tumor size (Odds Ratio (OR) = 1.67; 95%CI 1.02-2.74), number of suspected nodes in ultrasound (OR = 2.20; 95%CI 1.01-4, 77), HER2 positive (OR 0.04; 95%CI 0.003-0.54), clinical-radiological response to NACT (OR = 0.07; 95%CI 0.01-0.75), and positive TAD (OR 15.48; 95%CI 1.68-142.78) were independent predictors of a positive result in ALND. We developed a "positive ALND predictive score", with good calibration (Hosmer-Lemeshow test: p = 0.65), and discrimination (AUC = 0.93; 95% CI 0, 87-0.99), with highest Youden index (0.7) at cut-off point of 17% risk of positive ALND (sensitivity = 100%; specificity = 70%).

CONCLUSION

Tumor size, number of suspected nodes, positive HER2, response to NACT, and metastatic TAD are independent predictors of ALND. The predictive score for positive ALND would be a good indicator to safely omit ALND.

Prognostic Impact of Extranodal Extension in Rectal Cancer Patients Undergoing Radical Resection After Preoperative Chemoradiotherapy

BACKGROUND

Extranodal extension (ENE) of nodal metastasis has emerged as an important prognostic factor in many malignancies, including rectal cancer. However, its significance in patients with rectal cancer receiving preoperative chemoradiotherapy (PCRT) has not been extensively investigated. We therefore assessed ENE and its prognostic impact in a large series of consecutive rectal cancer patients with lymph node metastasis after PCRT and curative resection.

PATIENTS AND METHODS

Between January 2000 and December 2014, a total of 1925 patients with rectal cancer underwent surgical resection after PCRT. Medical records of 469 patients with pathologic node positivity were retrospectively reviewed.

RESULTS

Of the 469 patients, 118 (25.2%) presented with ENE. ENE was observed more frequently in those with advanced tumor stage (higher ypT, ypN, and ypStage), lymphovascular invasion, and perineural invasion. Five-year disease-free survival rate was lower in patients with ENE-positive tumors than those with ENE-negative tumors (36.1% vs. 52.3%, P = .003). Similarly, 5-year overall survival rate was lower in patients with ENE-positive tumors than those with ENE-negative tumors (60.2% vs. 70.6%, P < .001). Multivariate analysis revealed that the presence of ENE was an independent poor prognostic factor for disease-free survival (hazard ratio = 1.412; 95% confidence interval, 1.074-1.857; P = .013) and overall survival (hazard ratio = 1.531; 95% confidence interval 1.149-2.039; P = .004).

CONCLUSION

The presence of ENE in patients with rectal cancer undergoing PCRT is a negative prognostic factor, reflecting poor survival outcome.

A nomogram to predict non-sentinel lymph node metastasis in patients with initial cN+ breast cancer that downstages to cN0 after neoadjuvant chemotherapy

BACKGROUND AND OBJECTIVES

This study mainly explored the factors that influence non-sentinel lymph node (NSLN) metastasis in patients with breast cancer (BC) whose axillary lymph nodal status changed from clinically node positive (cN+) to clinically node negative (cN0) after neoadjuvant chemotherapy (NAC).

METHODS

We retrospectively analyzed the clinicopathological factors affecting NSLN metastasis in a total of 179 patients with cN+ BC downstaged to cN0 (120 in the training set and 59 in the validation set) who underwent both sentinel lymph node (SLN) biopsy and axillary lymph node dissection following NAC.

RESULTS

Among 179 patients enrolled, the overall NSLN metastatic rate was 24.0% (95% confidence interval [CI]: 17.7%-30.3%). In multivariate logistic regression analysis, the number of positive SLNs achieving a pathological complete remission of the breast and clinical node staging was independent predictors of NSLN metastasis. A nomogram was established based on these factors and displayed a good discriminatory capability, with an area under the curve of 0.919 (95% CI: 0.865-0.973) for the training set and 0.900 (95% CI: 0.812-0.988) for the validation set and its clinical utility was confirmed by the decision curve analysis.

CONCLUSIONS

The nomogram established showed the ability to predict NSLN metastases in patients with initial cN+ BC that downstaged to cN0 after NAC.

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.

Establishment and Verification of a Bagged-Trees-Based Model for Prediction of Sentinel Lymph Node Metastasis for Early Breast Cancer Patients

Purpose: Lymph node metastasis is a multifactorial event. Several scholars have developed nomograph models to predict the sentinel lymph nodes (SLN) metastasis before operation. According to the clinical and pathological characteristics of breast cancer patients, we use the new method to establish a more comprehensive model and add some new factors which have never been analyzed in the world and explored the prospect of its clinical application.

Materials and methods: The clinicopathological data of 633 patients with breast cancer who underwent SLN examination from January 2011 to December 2014 were retrospectively analyzed. Because of the imbalance in data, we used smote algorithm to oversample the data to increase the balanced amount of data. Our study for the first time included the shape of the tumor and breast gland content. The location of the tumor was analyzed by the vector combining quadrant method, at the same time we use the method of simply using quadrant or vector for comparing. We also compared the predictive ability of building models through logistic regression and Bagged-Tree algorithm. The Bagged-Tree algorithm was used to categorize samples. The SMOTE-Bagged Tree algorithm and 5-fold cross-validation was used to established the prediction model. The clinical application value of the model in early breast cancer patients was evaluated by confusion matrix and the area under receiver operating characteristic (ROC) curve (AUC).

Results: Our predictive model included 12 variables as follows: age, body mass index (BMI), quadrant, clock direction, the distance of tumor from the nipple, morphology of tumor molybdenum target, glandular content, tumor size, ER, PR, HER2, and Ki-67.Finally, our model obtained the AUC value of 0.801 and the accuracy of 70.3%.We used logistic regression to established the model, in the modeling and validation groups, the area under the curve (AUC) were 0.660 and 0.580.We used the vector combining quadrant method to analyze the original location of the tumor, which is more precise than simply using vector or quadrant (AUC 0.801 vs. 0.791 vs. 0.701, Accuracy 70.3 vs. 70.3 vs. 63.6%).

Conclusions: Our model is more reliable and stable to assist doctors predict the SLN metastasis in breast cancer patients before operation.

Debating the Optimal Approach to Nodal Management After Pathologic Complete Response to Neoadjuvant Chemotherapy in Patients With Breast Cancer

Greater use of neoadjuvant chemotherapy in patients with breast cancer has led surgeons and radiation oncologists to have frequent encounters with women with upfront node-positive disease and a clinical complete response. These cases raise many important questions about what the optimal locoregional management should be to minimize recurrence risk while minimizing treatment-related toxicities. A particular point of debate is whether all patients who are known to have had node-positive disease before neoadjuvant chemotherapy should receive complete axillary lymph node dissection (ALND) if they have had a complete clinical and radiologic response. In this article, we present arguments and evidence in favor of and against axillary dissection after a complete response to neoadjuvant chemotherapy, followed by a brief data-driven review of implications for adjuvant radiotherapy in this context. We conclude that as trials continue to gather more evidence to guide decisions in the future, we must encourage patients to enroll in clinical trials when eligible, and otherwise support them to make decisions that are informed and congruent with their personal values in areas where there is clinical equipoise.