Internal mammary nodes in breast cancer: diagnosis and implications for patient management -- a systematic review

Internal Mammary Lymphadenopathy Does Not Impact Oncologic Outcomes in Patients Treated with Neoadjuvant Chemotherapy: Results from the I-SPY2 Clinical Trial

BACKGROUND

Internal mammary lymphadenopathy (IML) plays a role in breast cancer stage and prognosis. We aimed to evaluate method of IML detection, how IML impacts response to neoadjuvant chemotherapy (NAC), and oncologic outcomes.

METHODS

We evaluated patients enrolled in the I-SPY-2 clinical trial from 2010 to 2022. We captured the radiographic method of IML detection (magnetic resonance imaging [MRI], positron emission tomography/computed tomography [PET/CT], or both) and compared patients with IML with those without. Rates of locoregional recurrence (LRR), distant recurrence (DR) and event-free survival (EFS) were compared by bivariate analysis.

RESULTS

Of 2095 patients, 198 (9.5%) had IML reported on pretreatment imaging. The method of IML detection was 154 (77.8%) MRI only, 11 (5.6%) PET/CT only, and 33 (16.7%) both. Factors associated with IML were younger age (p = 0.001), larger tumors (p < 0.001), and higher tumor grade (p = 0.027). Pathologic complete response (pCR) was slightly higher in the IML group (41.4% vs. 34.0%; p = 0.03). There was no difference in breast or axillary surgery (p = 0.41 and p = 0.16), however IML patients were more likely to undergo radiation (68.2% vs. 54.1%; p < 0.001). With a median follow up of 3.72 years (range 0.4-10.2), there was no difference between IM+ versus IM- in LRR (5.6% vs. 3.8%; p = 0.25), DR (9.1% vs. 7.9%; p = 0.58), or EFS (61.6% vs. 57.2%; p = 0.48). This was true for patients with and without pCR.

CONCLUSIONS

In this large cohort of patients treated with NAC, outcomes were not negatively impacted by IML. We demonstrated that IML influences treatment selection but is not a poor prognostic indicator when treated with modern NAC and multidisciplinary disease management.

Oncological outcomes in patients with residual triple-negative breast cancer after preoperative chemotherapy

PURPOSE

This study aimed to evaluate the clinical outcomes and prognostic implications of regional nodal irradiation (RNI) after neoadjuvant chemotherapy (NAC) in patients with residual triple-negative breast cancer (TNBC).

MATERIALS AND METHODS

We analyzed 152 patients with residual TNBC who underwent breast-conserving surgery after NAC between December 2008 and December 2017. Most patients (n = 133; 87.5%) received taxane-based chemotherapy. Adjuvant radiotherapy (RT) was administered at a total dose of 45-65 Gy in 15-30 fractions to the whole breast, with some patients also receiving RT to regional nodes. Survival was calculated using the Kaplan-Meier method, and prognostic factors influencing survival were analyzed using the Cox proportional-hazards model.

RESULTS

During a median follow-up of 66 months (range, 9 to 179 months), the 5-year disease-free survival (DFS) rate was 68.0%. The 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 83.6%, 72.6%, and 78.7%, respectively. In the univariate analysis, the cN stage, ypT stage, ypN stage, axillary operation type, and RT field were associated with DFS. Multivariate analysis revealed that higher ypT stage (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.00-3.82; p = 0.049) and ypN stage (HR = 4.7; 95% CI 1.57-14.24; p = 0.006) were associated with inferior DFS. Among clinically node-positive patients, those who received RT to the breast only had a 5-year DFS of 73.7%, whereas those who received RNI achieved a DFS of 59.6% (p = 0.164). There were no differences between the DFS and RNI.

CONCLUSION

In patients with residual TNBC, higher ypT and ypN stages were associated with poorer outcomes after NAC. RNI did not appear to improve DFS. More intensive treatments incorporating systemic therapy and RT should be considered for these patients.

Tumor Contact With Internal Mammary Perforator Vessels as Risk Factor for Gross Internal Mammary Lymph Node Involvement in Patients With Breast Cancer

PURPOSE

The identification of internal mammary lymph node metastases and the assessment of associated risk factors are crucial for adjuvant regional lymph node irradiation in patients with breast cancer. The current study aims to investigate whether tumor contact with internal mammary perforator vessels is associated with gross internal mammary lymph node involvement.

METHODS AND MATERIALS

We included 297 patients with primary breast cancer and gross internal mammary (IMN+) and/or axillary metastases as well as 230 patients without lymph node metastases. Based on pretreatment dynamic contrast-enhanced magnetic resonance imaging, we assessed contact of the tumor with the internal mammary perforating vessels (IMPV).

RESULTS

A total of 59 patients had ipsilateral IMN+ (iIMN+), 10 patients had contralateral IMN+ (cIMN+), and 228 patients had ipsilateral axillary metastases without IMN; 230 patients had node-negative breast cancer. In patients with iIMN+, 100% of tumors had contact with ipsilateral IMPV, with 94.9% (n = 56) classified as major contact. In iIMN- patients, major IMPV contact was observed in only 25.3% (n = 116), and 36.2% (n = 166) had no IMPV contact at all. Receiver operating characteristic analysis revealed that "major IMPV contact" was more accurate in predicting iIMN+ (area under the curve, 0.85) compared with a multivariate model combining grade of differentiation, tumor site, size, and molecular subtype (area under the curve, 0.65). Strikingly, among patients with cIMN+, 100% of tumors had contact with a crossing contralateral IMPV, whereas in cIMN- patients, IMPVs to the contralateral side were observed in only 53.4% (iIMN+) and 24.8% (iIMN-), respectively.

CONCLUSIONS

Tumor contact with the IMPV is highly associated with risk of gross IMN involvement. Further studies are warranted to investigate whether this identified risk factor is also associated with microscopic IMN involvement and whether it can assist in the selection of patients with breast cancer for irradiation of the internal mammary lymph nodes.

Oncoplastic Breast Conservation for Central Tumors: Definition, Classification, and the Analysis of Single Institution Experience

Background

Tumors in the central part of the breast are usually considered more aggressive and technically difficult, which limits breast conservation. The definition of central tumors from a surgical point of view, classification of the techniques for partial breast reconstruction, and conceptual algorithm of choice based on tumor and breast characteristics are proposed, along with the estimation of surgical and oncological safety.

Methods

This is a retrospective analysis of the single-institution experience, with a focus on the decision-making process for choosing the oncoplastic breast-conserving surgery technique. To evaluate the safety of breast conservation for central tumors, a comparative analysis of early surgical complications and oncological long-term results of treatment in patients with central breast tumor location and other breast tumor locations was performed.

Results

A total of 940 lumpectomies were performed in 926 patients during 15 years. The central breast tumor location group included 128 patients with 130 lumpectomies (13.8%), and the other breast tumor locations group included 798 patients with 810 lumpectomies (86.2%). We did not find any significant differences in the rate of early surgical complications and involved margins, local and systemic recurrence rates, time to progression, or overall survival between the groups.

Conclusions

Oncoplastic breast-conserving surgery is a safe procedure for the treatment of central tumors. In our opinion, the proposed classification of partial breast reconstruction techniques and an algorithm of their choice allow for effective restoration of the breast shape and volume according to the parameters of the tumor, breast, surgeon, and patient preferences.

The Japanese breast cancer society clinical practice guidelines for radiation treatment of breast cancer, 2022 edition

The Breast Cancer Clinical Practice Guidelines, organized by the Japanese Breast Cancer Society (JBCS), were published in 2022. We present the English version of the Radiation Therapy (RT) section of the guidelines. The JBCS formed a task force to update the 2018 version of the JBCS Clinical Practice Guidelines. The Background Questions (BQs) contain the standard treatments for breast cancer in clinical practice, whereas the Clinical Questions (CQs) address daily clinical questions that remain controversial. Future Research Questions (FRQs) explore the subjects that are considered important issues, despite there being insufficient data for inclusion as CQs. The task force selected the 12 BQs, 8 CQs, and 6 FRQs for the RT section. For each CQ, systematic literature reviews and meta-analyses were conducted according to the Minds Manual for Guideline Development 2020, version 3.0. The recommendations, strength of recommendation, and strength of evidence for each CQ were determined based on systematic reviews and meta-analyses, and finalized by voting at the recommendation decision meeting.

Internal mammary node abnormality in imaging studies and treatment outcomes in patients with breast cancer

The clinical significance of mild internal mammary node (IMN) enlargement (Mild-IMN) is uncertain. This study aimed to evaluate the relationship between treatment outcomes and IMN status in patients with breast cancer who underwent postmastectomy radiation therapy between January 2010 and December 2018. Overall, 250 patients were categorized based on IMN status: Clinically normal IMN (Normal-IMN; n=172), Mild-IMN (n=39) and clinically metastatic IMN (cMet-IMN; n=39). None of the patients in the Normal- or Mild-IMN groups received IMN irradiation. In the cMet-IMN group, 25 patients underwent IMN irradiation with an IMN boost (10 Gy in 5 fractions), while 14 patients did not. The median follow-up time was 80.0 months (range, 7.2-147.6 months). The 7-year overall survival (OS), disease-free survival (DFS) and IMN recurrence-free survival (IRF) rates were 80.2, 73.0 and 93.4%, respectively. Multivariate analyses indicated that only cMet-IMN had a significant impact on OS [hazard ratio (HR), 1.66; 95% CI, 1.01-3.68; P=0.05] and DFS (HR, 1.91; 95% CI, 1.08-3.39; P=0.03), while cMet-IMN did not have a significant impact on IRF (HR, 1.66; 95% CI, 0.41-6.78; P=0.48). Additionally, receiving an IMN boost had no influence on OS (HR, 1.11; 95% CI, 0.37-2.34; P=0.84), DFS (HR, 1.28; 95% CI, 0.51-3.22; P=0.60) or IRF (HR, 1.94; 95% CI, 0.22-17.47; P=0.55). In conclusion, the impact of Mild-IMN on clinical outcomes was small. Although irradiation for cMet-IMN is important, the impact of the cMet-IMN boost with 10 Gy in 5 fractions on clinical outcomes may also be limited.

A Questionnaire Survey of Current Practice in the Management of Internal Mammary Lymph Nodes in Breast Cancer

Nita S. NairBackground  Radiotherapy (RT) is an important modality in the management of breast cancers (BC). Large randomized trials have suggested that prophylactic regional nodal irradiation inclusive of internal mammary lymph nodes (IMLN) reduces BC-related mortality. However, the adoption of IMLN-RT has been variable due to relative benefits and toxicity concerns. Methods  A survey was emailed to radiation oncologists (ROs) across the country wherein they were asked about their practice regarding IMLN-RT in BC. Results  We received 128 responses, which included radiation oncologists across both private institutions (PIs) and government institutions (GIs). Fifty-six (43.8%) routinely offer prophylactic(p) IMLN-RT and an additional 15 (11.71%) suggested they would have offered it in the absence of logistic constraints. Almost all, 121 (94.5%) radiate the IMLN in case of radiologically positive lymph nodes (LNs). Fifty-six ROs (43.8%) offered prophylactic IMLN-RT in node-negative disease. Among those who did not offer IMLN-RT, most (84.72%) felt the clinical evidence was equivocal. Of the 56 who offered pIMLN-RT, 34/56 (60.71%) offered to locally advanced tumors, 20/56 (35.71%) offered to all inner and central tumors (ICQT), 29/56 (51.78%) to > 4 axillary LN-positive and 9/56 (16.07%) to any axillary LN-positive. The majority, i.e., 36/56 (64.28%) radiated upper three intercostal spaces, 9 (16.07%) radiated upper five intercostal spaces, and 6 (10.9%) decided based on tumor location, while 5 (9%) irradiated one space below the involved space. Overall, simulation-based planning was undertaken in 99% of PIs as opposed to 89% of GIs ( p  = 0.03). The majority of ROs, i.e., 92 (72.4%) preferred IMRT to IMLN-RT. In addition, the surgical approach to IMLN was practiced by surgeons at 18 (14%) centers, of which 13 (72.22%) operated the IMLN when radiologically evident. The IMLN dissection was preferentially performed for second and third intercostal spaces as suggested in 10 (55.55%) responses, while 8 (44.44%) performed thoracoscopic dissection of the IMLN chain. The distribution of prophylactic, definitive IMLN-RT, and IMLN dissection did not differ significantly between GI and PI ( p  = NS). Conclusion  pIMLN-RT is still not the standard protocol in most centers citing equivocal evidence in the literature. Logistics, though different in GIs and PIs, did not impact the decision of pIMLN-RT. Further efforts would be required to standardize practice in IMLN across India.

Treatment of Internal Mammary Nodes is Associated With Improved Overall Survival in Breast Cancer: A Meta-Analysis

INTRODUCTION

The role of internal mammary nodal irradiation (IMNI) as a component of regional nodal radiotherapy is a controversial issue in breast radiation oncology with conflicting results presented in recent landmark trials. We thus created a meta-analysis of available data to better ascertain the potential benefit of IMNI. We hypothesize that with the increased power available within a meta-analysis, IMNI will prove to improve overall survival (OS) in breast cancer.

METHODS

Literature search was conducted for prospective studies comparing IMNI to no IMNI. Primary endpoint was OS and secondary endpoints included local recurrence, regional recurrence, disease-free survival (DFS), breast cancer mortality (BCM), distant metastasis-free survival (DMFS), grade 2+ skin toxicity, cardiac events, and pneumonitis events. Subgroup analyses were performed for tumor location (medial/central vs. lateral), and nodal status (pN+ vs. pN0). Fixed-effect model was used if there was no heterogeneity, random-effects model otherwise.

RESULTS

Four studies with a total of 5258 patients (IMNI: n=2592; control: n=2666) were included in the study. Pooled results showed IMNI significantly improved OS for all-comers (hazard ratio [HR]=0.89; 95% CI 0.81-0.97; P =0.008), as well as subgroups of pN+ with medial/central tumor location (HR=0.84; 95% CI 0.73-0.96; P =0.01) and pN+ with lateral tumor location (HR=0.87; 95% CI 0.77-0.99; P =0.04). There was no significant difference in OS for subgroups of pN0 and medial/central tumor location. There was no difference in local recurrence, but regional recurrence was significantly improved ( P =0.04). Endpoints of DFS (HR 0.91, 95% CI 0.84-0.99 P =0.03), BCM (HR 0.87, 95% CI 0.77-0.98, P =0.03), and DMFS (HR=0.87; 95% CI, 0.78-0.98; P =0.02) were all improved with IMNI. Grade 2+ skin toxicity, cardiac events and pneumonitis events were not significantly different between patient in the IMNI and no IMNI groups.

CONCLUSION

Inclusion of IMN irradiation improves OS, DFS, BCM, and DMFS in breast cancer. Largest effect on OS was noted in the subgroup of patients with pN+ and medial/central tumor location.

Analysis of factors influencing the pathological complete remission (ipCR) in patients with internal mammary lymph node metastasis after neoadjuvant chemotherapy

Objective

To investigate the factors impacting pathological complete remission (ipCR) of the internal mammary lymph nodes in patients with internal mammary lymph node metastasis (IMLN) after adjuvant chemotherapy.

Methods

Sixty-five cases of primary breast cancer (BC) with IMLN metastasis who had received neoadjuvant chemotherapy (NAC) were retrospectively analyzed. Postoperative pathology was used to divide the patients into ipCR and non-ipCR groups. Univariate and multivariate analyses were performed on ipCR after NAC. A receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the factors related to ipCR and a Kaplan-Meier curve was used to analyze prognosis.

Results

Twenty-nine (44.62%) of the 65 female patients received ipCR after NAC. Significant differences in hormone receptor (HR) negative and axillary pathological complete response (apCR) rates between the ipCR and non-ipCR group (P < 0.05). Multivariate logistic regression analysis showed that HR (OR = 2.698) and apCR (OR = 4.546) were the most significant factors that influenced ipCR (P < 0.05). The ROC curves showed that the area under the curves (AUC) for HR and apCR for the prediction of ipCR were 0.744 and 0.735 respectively. The AUC for the combined detection was 0.905. The average disease free survival (DFS) for patients in the ipCR group was 94.0 months which was significantly longer compared to patients in the non-ipCR group (64.2 months) (χ2 = 4.265, P = 0.039). No significant difference in OS was detected between the two groups (P > 0.05).

Conclusions

ipCR after NAC is correlated with HR and apCR. HR combined with apCR has value in predicting ipCR. ipCR has prognostic value in patients with IMLN metastasis and may have the potential to inform clinical decision-making. Further validation of these findings is required through larger-scale prospective studies.

Development and validation of a nomogram for predicting internal mammary sentinel node metastasis in breast cancer patients

OBJECTIVE

Internal mammary nodes are important in breast cancer prognosis, but their diagnosis is often missed in clinical practice, leading to inaccurate staging and treatment. We developed a validated nomogram to predict the presence of internal mammary sentinel nodes (IMSN) metastasis.

METHODS

A total of 864 sequential IMSN biopsy procedures from a prospective studies database of 1505 cases were used for model development and validation. Multivariable logistic regression was performed on 519 sequential IMSN biopsy procedures from multi-center data between August 2018 and July 2022 to predict the presence of IMSN metastasis. A nomogram was developed based on the logistic regression model and subsequently applied to 345 sequential IMSN biopsy procedures from single-center data between November 2011 and July 2018. The model's discrimination was assessed using the area under the receiver operating characteristic curve.

RESULTS

The overall frequency of IMSN metastasis was 17.0% in our study. A predictive model for IMSN metastasis was constructed using tumor size, tumor location, lymphovascular invasion, the number of positive axillary nodes (P < 0.05 for all variables in multivariate analysis), and histological grade (P < 0.05 only in univariate analysis). The nomogram was accurate, with a concordance index of 0.84 in the bootstrapping analysis and an area under the receiver operating characteristic curve of 0.80 in the validation population.

CONCLUSION

Our nomogram provides an accurate and validated multivariable predictive model for estimating the individual likelihood of having IMSN metastasis. This may be useful for personalized treatment decisions regarding internal mammary radiotherapy in breast cancer patients.

Internal mammary node involvement in patients with axilla-negative early breast cancer: a narrative review

Early breast cancer staging involves radiological and pathological evaluation of the tumour and regional lymph nodes. The internal mammary nodes (IMN) are an important site of possible metastasis and influence disease stage and prognosis. However, the recommendation for routine IMN assessment remains unclear. Internal mammary sentinel lymph node biopsy (SLNB) is associated with increased morbidity and an unknown survival benefit. Furthermore, the IMN are traditionally thought to be involved only synchronous with, or following, axillary node (AXN) metastasis. The aim of this review is to determine the prevalence of IMN metastasis in patients with axilla-negative early breast cancer. A narrative review of studies assessing IMN metastasis was performed. The literature search was completed using the database Medline (Ovid). Twenty-two retrospective studies were identified. The studies included data from SLNB, US, MRI, PET/CT and opportunistic biopsy during free-flap reconstruction (FFR). The prevalence of isolated IMN metastasis ranged from 1.2% to 17.9%.

Risk factors to identify the indication for regional nodal irradiation in T1-2N1M0 breast cancer: A joint analysis of 4,243 real-world cases from two institutions

Purpose

The aim of this study is to evaluate the role of regional nodal irradiation (RNI) in patients with T1-2N1M0 breast cancer and to identify the subgroup that could benefit from RNI.

Methods and materials

A total of 4,243 women with pT1-2N1M0 breast cancer treated at two institutions in China were retrospectively reviewed. Survival rates were calculated by the Kaplan-Meier method and compared by the log-rank test. The association of risk factors with survival outcomes was evaluated using multivariable proportional hazards regression.

Results

A total of 932 patients (22.0%) received RNI. At a median follow-up of 5.9 years, the 5-year locoregional recurrence (LRR), distant metastasis (DM), disease-free survival (DFS), and overall survival (OS) rates were 4.0% and 7.2% (P = 0.001), 13.2% and 10.6% (P = 0.465), 85.0% and 84.7% (P = 0.131), and 93.9% and 92.8% (P = 0.004) in the RNI and non-RNI groups, respectively. Multivariate analysis revealed that RNI was an independent prognostic factor for lower LRR (P = 0.001) and longer DFS (P = 0.013). Patients were stratified into low-, intermediate-, and high-risk groups based on the eight non-therapeutic risk factors. RNI significantly decreased the 5-year LRR (2.2% vs. 7.0%, P = 0.001) and improved the 5-year DFS (88.8% vs. 84.9%, P = 0.015) and OS (95.8% vs. 93.9%, P = 0.010) in the intermediate-risk group. However, neither the low-risk group nor the high-risk group had survival benefit from RNI.

Conclusion

T1-2N1M0 breast cancer is a heterogeneous disease. We found that RNI only improved survival in the intermediate-risk group. It might be omitted in low-risk patients, and the role of RNI in high-risk patients needs further study.

Internal Mammary Node Irradiation in Patients With Node-Positive Early Breast Cancer: Fifteen-Year Results From the Danish Breast Cancer Group Internal Mammary Node Study

PURPOSE

The Danish Breast Cancer Group Internal Mammary Node study demonstrated improved 8-year overall survival (OS) with internal mammary node irradiation (IMNI) in patients with node-positive early breast cancer. Here, we present long-term results from the Danish Breast Cancer Group Internal Mammary Node study cohort.

PATIENTS AND METHODS

This nationwide, prospective cohort study allocated patients with node-positive early breast cancer to adjuvant radiotherapy with or without IMNI depending on cancer laterality. Patients with right-sided cancer received IMNI. Patients with left-sided cancer were treated without IMNI because of risk of radiation-induced heart disease. Other treatment was independent of laterality. The primary study end point was OS. Secondary end points were distant recurrence and breast cancer mortality. Analyses were by intention to treat.

RESULTS

During 2003-2007, 3,089 women were allocated to IMNI (right-sided, n = 1,491) or no IMNI (left-sided, n = 1,598). With a median follow-up of 14.8 years, 589 patients with and 701 patients without IMNI had died. The corresponding 15-year OS rates were 60.1% and 55.4%. The adjusted hazard ratio (HR) for death was 0.86 (95% CI, 0.77 to 0.96; P = .007) in favor of IMNI. The 15-year risk of developing distant recurrence was 35.6% (523 recurrences) and 38.6% (602 recurrences) with vs. without IMNI (adjusted HR, 0.88 [95% CI, 0.79 to 0.99; P = .04]). The 15-year breast cancer mortality with IMNI was 31.7% (467 deaths) compared with 33.9% (537 deaths) without IMNI (adjusted HR, 0.88 [95% CI, 0.78 to 1.00; P = .05]). The distribution of other deaths was similar across groups.

CONCLUSION

In patients with node-positive early breast cancer treated with IMNI or without IMNI depending on breast cancer laterality, IMNI reduced the risk of distant recurrence and death from breast cancer, thereby improving long-term survival.

Efficacy and Safety of the Addition of Internal Mammary Irradiation to Standard Adjuvant Radiation in Early-Stage Breast Cancer: A Systematic Review and Meta-Analysis

Background: Existing data on adding internal mammary nodal irradiation (IMNI) to the regional nodal fields are inconsistent. Methods: Randomized trials investigating the addition of IMNI to standard adjuvant radiation were identified. Hazard ratios (HRs) and 95% confidence intervals (CI) were extracted for overall-survival (OS), breast cancer specific-survival (BCSS), and disease-free survival (DFS) as well as distant-metastasis free survival (DMFS). The odds ratios (ORs) for regional and loco-regional recurrence, non-breast cancer mortality, secondary non-breast cancer, contralateral breast cancer, and cardiovascular morbidity and mortality were also extracted. Results: Analysis included five trials comprising 10,994 patients, predominantly with higher risk, lymph node positive disease. Compared to the control group, IMNI was associated with significant improvement in OS (HR = 0.91, p = 0.004), BCSS (HR = 0.84, p < 0.001), DFS (HR = 0.89, p= 0.01), and DMFS (HR = 0.89, p = 0.02). IMNI was also associated with reduced odds for regional (OR = 0.58, p < 0.001) and loco-regional recurrence (OR = 0.85, p = 0.04). The odds for cardiotoxicity were not statistically significantly higher (OR = 1.23, p = 0.07). There were comparable odds for cardiovascular mortality (OR = 1.00, p = 1.00), non-breast cancer mortality (OR = 1.05, p = 0.74), secondary cancer (OR = 0.95, p = 0.51), and contra-lateral breast cancer (OR = 1.07, 95% 0.77−1.51, p = 0.68). Conclusions: Compared to the control group, the addition of IMNI in high-risk patients is associated with a statistically significant improvement in survival, albeit with a magnitude of questionable clinical meaningfulness.

Dosimetric Evaluation of Incidental Irradiation to the Internal Mammary Chain After Surgery in Breast Cancer Patients

Background and Purpose

The low rate of internal mammary node (IMN) recurrence was attributed to systemic therapy and internal mammary chain (IMC) coverage by the tangential fields of irradiation. This study aimed to evaluate the incidental irradiation dose to the IMC in breast cancer patients after surgery and to estimate the clinical predictive parameters affecting the magnitude of the IMC.

Materials and Methods

A total of 138 patients treated with postmastectomy radiotherapy and 210 patients undergoing radiotherapy after breast-conserving surgery (BCS) in our hospital were retrospectively analyzed. The mean dose (Dmean) to the IMC and the first to third intercostal spaces of IMC levels (ICS1–3) were evaluated. We evaluated the IMC coverage according to the type of surgery and whether the ipsilateral supraclavicular fossa (SCF) was included in the irradiation field.

Results

The incidental radiation dose to the IMC was 29.69 Gy, and the dose delivered to the IMC, ICS1, and ICS2 showed a greater coverage in the modified radical mastectomy (MRM) group when compared with the BCS group (32.85 vs. 27.1 Gy, 26.6 vs. 12.5 Gy, 34.63 vs. 30.42 Gy). The dose delivered to ICS3 showed no difference between the MRM and BCS groups (37.41 vs. 36.24 Gy). Furthermore, 131 patients (37.64%) received radiotherapy to the chest wall and ipsilateral SCF. In the univariate analysis, both surgery type and SCF irradiation were parameters affecting the Dmean of incidental radiation to the IMC (r = −0.179, P = 0.001; r = −0.175, P = 0.001). In the multivariate analysis, surgery type was the only correlative factor that affected incidental radiation dose to the IMC (r = –3.534, P = 0.000).

Conclusion

The real influencing factor of incidental dose to the IMC was the surgery form rather than the accession of SCF irradiation.

Internal Mammary Lymph Node Biopsy during Microsurgical Breast Reconstruction: A Prospective Study

BACKGROUND

 Accurate assessment of regional lymph node basins is critical for oncological management of breast cancer. The internal mammary lymph node (IMLN) basin directly drains the medial pole of the breast, but biopsy is not commonly performed. While the axillary sentinel lymph node sample remains the standard of care, the majority of patients who have been found to have a positive IMLN biopsy have simultaneously had negative axillary sentinel lymph nodes. This study prospectively examines routine IMLN biopsy during microsurgical breast reconstruction.

METHODS

 An IRB-approved study of routine IMLN biopsies in 270 consecutive patients who underwent microsurgical breast reconstruction was performed from July 1, 2018, to June 1, 2021. Recorded data included unilateral or bilateral breast reconstruction, unilateral or bilateral IMLN sampling, patient demographics, disease stage, and pathologic findings of IMLN.

RESULTS

 The majority of patients, 240 of 270 patients (88.9%), had bilateral reconstruction. Overall, 5 out of 270 (1.9%) patients had positive IMLN; one of these patients had positive axillary sentinel lymph nodes. The IMLN biopsy results in two of the five patients affected the clinical course as they were upstaged and required chemoradiation.

CONCLUSION

 Direct visualization of the internal mammary lymph nodes during dissection of the recipient vessels for microsurgical breast reconstruction allows for convenient sampling, with minimal donor site morbidity and enhances the therapeutic management of patients in whom nodal involvement is present. As such, the authors recommend IMLN sampling.

Effect of Elective Internal Mammary Node Irradiation on Disease-Free Survival in Women With Node-Positive Breast Cancer: A Randomized Phase 3 Clinical Trial

IMPORTANCE

The benefit of internal mammary node irradiation (IMNI) for treatment outcomes in node-positive breast cancer is unknown.

OBJECTIVE

To investigate whether the inclusion of IMNI in regional nodal irradiation improves disease-free survival (DFS) in women with node-positive breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, phase 3 randomized clinical trial was conducted from June 1, 2008, to February 29, 2020, at 13 hospitals in South Korea. Women with pathologically confirmed, node-positive breast cancer after breast-conservation surgery or mastectomy with axillary lymph node dissection were eligible and enrolled between November 19, 2008, and January 14, 2013. Patients with distant metastasis and those who had received neoadjuvant treatment were excluded. Data analyses were performed according to the intention-to-treat principle.

INTERVENTIONS

All patients underwent regional nodal irradiation along with breast or chest wall irradiation. They were randomized 1:1 to receive radiotherapy either with IMNI or without IMNI.

MAIN OUTCOMES AND MEASURES

The primary end point was the 7-year DFS. Secondary end points included the rates of overall survival, breast cancer-specific survival, and toxic effects.

RESULTS

A total of 735 women (mean [SD] age, 49.0 [9.1] years) were included in the analyses, of whom 373 received regional nodal irradiation without IMNI and 362 received regional nodal irradiation with IMNI. Nearly all patients underwent taxane-based adjuvant systemic treatment. The median (IQR) follow-up was 100.4 (89.7-112.1) months. The 7-year DFS rates did not significantly differ between the groups treated without IMNI and with IMNI (81.9% vs 85.3%; hazard ratio [HR], 0.80; 95% CI, 0.57-1.14; log-rank P = .22). However, an ad hoc subgroup analysis showed significantly higher DFS rates with IMNI among patients with mediocentrally located tumors. In this subgroup, the 7-year DFS rates were 81.6% without IMNI vs 91.8% with IMNI (HR, 0.42; 95% CI, 0.22-0.82; log-rank P = .008), and the 7-year breast cancer mortality rates were 10.2% without IMNI vs 4.9% with IMNI (HR, 0.41; 95% CI, 0.17-0.99; log-rank P = .04). No differences were found between the 2 groups in the incidence of adverse effects, including cardiac toxic effects and radiation pneumonitis.

CONCLUSIONS AND RELEVANCE

This randomized clinical trial found that including IMNI in regional nodal irradiation did not significantly improve the DFS in patients with node-positive breast cancer. However, patients with medially or centrally located tumors may benefit from the use of IMNI.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04803266.

POstmastectomy radioThErapy in Node-posiTive breast cancer with or without Internal mAmmary nodaL irradiation (POTENTIAL): a study protocol for a multicenter prospective phase III randomized controlled trial

BACKGROUND

Various randomized trials have demonstrated that postmastectomy radiotherapy (RT) to the chest wall and comprehensive regional nodal areas improves survival in patients with axillary node-positive breast cancer. Controversy exists as to whether the internal mammary node (IMN) region is an essential component of regional nodal irradiation. Available data on the survival benefit of IMN irradiation (IMNI) are conflicting. The patient populations enrolled in previous studies were heterogeneous and most studies were conducted before modern systemic treatment and three-dimensional (3D) radiotherapy (RT) techniques were introduced. This study aims to assess the efficacy and safety of IMNI in the context of modern systemic treatment and computed tomography (CT)-based RT planning techniques.

METHODS

POTENTIAL is a prospective, multicenter, open-label, parallel, phase III, randomized controlled trial investigating whether IMNI improves disease-free survival (DFS) in high-risk breast cancer with positive axillary nodes (pN+) after mastectomy. A total of 1800 patients will be randomly assigned in a 1:1 ratio to receive IMNI or not. All patients are required to receive ≥ six cycles of anthracycline and/or taxane-based chemotherapy. Randomization will be stratified by institution, tumor location (medial/central vs. other quadrants), the number of positive axillary nodes (1-3 vs. 4-9 vs. ≥10), and neoadjuvant chemotherapy (yes vs. no). Treatment will be delivered with CT-based 3D RT techniques, including 3D conformal RT, intensity-modulated RT, or volumetric modulated arc therapy. The prescribed dose is 50 Gy in 25 fractions or 43.5 Gy in 15 fractions. Tiered RT quality assurance is required. After RT, patients will be followed up at regular intervals. Oncological and toxilogical outcomes, especially cardiac toxicities, will be assessed.

DISCUSSION

This trial design is intended to overcome the limitations of previous prospective studies by recruiting patients with pN+ breast cancer, using DFS as the primary endpoint, and prospectively assessing cardiac toxicities and requiring RT quality assurance. The results of this study will provide high-level evidence for elective IMNI in patients with breast cancer after mastectomy.

TRIAL REGISTRATION

ClinicalTrails.gov , NCT04320979 . Registered 25 Match 2020, https://clinicaltrials.gov/ct2/show/NCT04320979.

Excluding Lung Tissue from the PTV during Internal Mammary Irradiation. A Safe Technique for OAR-Sparing?

Simple Summary

The planning treatment volume (PTV) during internal mammary irradiation (IMNI) regularly overlaps with lung tissue and is often in close proximity to the heart. Thus, exclusion of lung tissue from the PTV is a potential technique to spare the organs at risk (OARs) during adjuvant breast cancer irradiation. Using an innovative dose recalculation and accumulation algorithm, we evaluated the safety of exclusion of lung tissue from the PTV. According to our data, exclusion of lung tissue from the PTV to spare the OARs leads to significant dose reduction in the target volume and can, therefore, not be recommended.

Abstract

The current study aims to determine whether exclusion of lung tissue from planning treatment volume (PTV) is a valid organ at risk (OAR)-sparing technique during internal mammary irradiation (IMNI). Twenty patients with left-sided breast cancer undergoing adjuvant radiotherapy including IMNI after mastectomy or lumpectomy with daily ConeBeam CT (CBCT; median n = 28) were enrolled in the current study. The daily dose distribution of the patients was estimated by recalculating treatment plans on CBCT-scans based on a standard PTV (PTV margin: 5mm-STD) and a modified PTV, which excluded overlapping lung tissue (ExLung). Using 3D-deformable dose accumulation, the dose coverage in the target volume was estimated in dependence of the PTV-margins. The estimated delivered dose in the IMN-CTV was significantly lower for the ExLung PTV compared to the STD PTV: ExLung: V95%: 76.6 ± 22.9%; V90%: 89.6 ± 13.2%, STD: V95%: 95.6 ± 7.4%; V90%: 99.1 ± 2.7%. Daily CBCT imaging cannot sufficiently compensate the anatomic changes and intrafraction movement throughout the treatment. Therefore, to ensure adequate delivery of the prescribed dose to the IMN-CTV, exclusion of lung tissue from the PTV to spare the OARs is not recommended.

Gated Radiotherapy Development and its Expansion

One of the most important challenges in treatment of patients with cancerous tumors of chest and abdominal areas is organ movement. The delivery of treatment radiation doses to tumor tissue is a challenging matter while protecting healthy and radio sensitive tissues. Since the movement of organs due to respiration causes a discrepancy in the middle of planned and delivered dose distributions. The moderation in the fatalistic effect of intra-fractional target travel on the radiation therapy correctness is necessary for cutting-edge methods of motion remote monitoring and cancerous growth irradiancy. Tracking respiratory milling and implementation of breath-hold techniques by respiratory gating systems have been used for compensation of respiratory motion negative effects. Therefore, these systems help us to deliver precise treatments and also protect healthy and critical organs. It seems aspiration should be kept under observation all over treatment period employing tracking seed markers (e.g. fiducials), skin surface scanners (e.g. camera and laser monitoring systems) and aspiration detectors (e.g. spirometers). However, these systems are not readily available for most radiotherapy centers around the word. It is believed that providing and expanding the required equipment, gated radiotherapy will be a routine technique for treatment of chest and abdominal tumors in all clinical radiotherapy centers in the world by considering benefits of respiratory gating techniques in increasing efficiency of patient treatment in the near future. This review explains the different technologies and systems as well as some strategies available for motion management in radiotherapy centers.

Staging for Breast Cancer With Internal Mammary Lymph Nodes Metastasis: Utility of Incorporating Biologic Factors

Purpose

To validate the 8th edition of the American Joint Committee on Cancer (AJCC) pathological prognostic staging system for breast cancer patients with internal mammary lymph nodes (IMN) metastasis (N3b disease, stage IIIC in 7th AJCC anatomical staging).

Methods

Breast cancer patients with IMN metastasis diagnosed between 2010 and 2014 were retrieved from the Surveillance, Epidemiology, and End Results program. Chi-squared test, Log-rank test, Kaplan-Meier method, and Cox proportional hazard analysis were applied to statistical analysis.

Results

We included 678 patients with N3b disease in this study. Overall, 68.4% of patients were downstaged to IIIA and IIIB diseases from the 7th anatomical staging to 8th pathological prognostic staging. The new pathological prognostic staging system had better discriminatory value on prognosis prediction among IMN-metastasized breast cancer patients, with a 5-year breast cancer-specific survival (BCSS) of 92.7, 77.4, and 66.0% in stage IIIA, IIIB, and IIIC diseases, respectively (P<0.0001), and the 5-year overall survival (OS) rates was 85.9, 72.1, and 58.7%, respectively (P<0.0001). The results of the multivariate prognostic analysis showed that the new pathological prognostic staging was the independent prognosis related to BCSS and OS, the 8th AJCC pathological prognostic stages showed worse BCSS and OS with gradually increased hazard ratios.

Conclusion

The 8th AJCC pathological prognostic staging system offers more refined prognostic stratification to IMN-metastasized breast cancer patients and endorses its use in routine clinical practice for this specific subgroup of breast cancer.

Evaluation of internal mammary lymph node biopsy during microsurgical breast reconstruction: An analysis of 230 consecutive patients

INTRODUCTION

Clinical significance of internal mammary (IM) lymph node biopsy during microvascular free flap breast reconstruction remains controversial. Some microsurgeons may choose to biopsy an IM lymph node during routine IM vessel dissection. The authors reviewed the results of IM lymph node biopsy during autologous breast reconstruction.

METHODS

A retrospective chart review of patients who underwent autologous breast reconstruction during a seven-year period (January 2010 to January 2017) was performed. Patient demographic data, disease staging, flap details, pathology reports, and adjuvant treatment were evaluated.

RESULTS

A total of 230 patients with a mean age of 52.1 (SD 9.3) underwent IM lymph node biopsy (n = 297). Single IM lymph node was removed in 169 patients, 2 nodes were removed in 56 patients, 3 nodes in 4 patients, and 4 nodes in a single patient. Histopathologic analysis demonstrated presence of IM lymph node metastasis in 16 patients (7.0%). Thirteen patients were found to have metastatic IM lymph nodes in the setting of immediate reconstruction. Three patients were found to have metastatic IM lymph nodes in the setting of delayed. Five out of 16 patients (31.3%) had negative axillary sentinel lymph node biopsy and IM lymph nodes were the only site of nodal metastases. All five of these patients were upstaged accordingly and received adjuvant therapy based on the discussion at the multidisciplinary breast tumor conference.

CONCLUSIONS

Opportunistic internal mammary lymph node sampling during autologous breast reconstruction can be performed with minimal morbidity and has significant impact on the disease staging and adjuvant treatment.

Sentinel node occult lesion localization technique for impalpable breast cancer

BACKGROUND

Mammographic screening has enabled earlier detection of breast cancer, with 25-35% of malignancies being non-palpable at diagnosis. Accurate removal and sentinel node biopsy for staging these lesions are crucial to successful management. Both these aspects are achieved by peritumoural localization with radioisotope and lymphoscintigraphy for sentinel lymph node (SN) mapping using the sentinel node and occult lesion localization (SNOLL) technique. This study reports SNOLL outcomes in a large cohort of women with non-palpable breast cancers to assess its performance and promote its logistic advantages.

METHODS

This retrospective cohort study used data from BreastSurgANZ Quality Audit supplemented with private case notes. Inclusion criteria were females >18 years, with invasive breast cancer that was asymptomatic and non-palpable at presentation, who underwent SNOLL (n = 450). Primary outcomes were proportion of successful lesion localization, proportion of patients requiring re-excision and volume of tissue excised. Secondary outcomes focused on lymphoscintigraphy success rate in detecting sentinel nodes and SN positivity rates.

RESULTS

Tumours were successfully removed with the initial SNOLL procedure in 449 cases (99.8%). The re-excision rate was 15.1% (n = 68). The mean total excision volume was 54.69 cm3 (95% CI 51.49-57.88 cm3 ; range 2.75-195.33 cm3 ), with a mean closest circumferential margin of 7.05 mm (95% CI 6.60-7.49 mm; range 0 to ≥10 mm). Lymphoscintigraphy was successful in 96.9% (n = 436) of cases. Sentinel nodes were successfully identified and removed in 99.6% (n = 448) of cases. SN positivity rate was 18.4%.

CONCLUSION

SNOLL is an efficient and effective technique for localizing non-palpable invasive breast lesions while simultaneously identifying sentinel nodes.

Risk stratification for prediction of locoregional recurrence in patients with pathologic T1-2N0 breast cancer after mastectomy

Background

Previous studies have revealed that nearly 15–20% of selected high-risk T1–2N0 breast cancers developed LRR after mastectomy. This study is aim to indentify the risk factors of locoregional recurrence (LRR) in patients with pathologic T1–2N0 breast cancer after mastectomy in a real-world and distinguish individuals who warrant postmastectomy radiotherapy (PMRT).

Methods

Female patients treated from 1999 to 2014 in National Cancer Center of China were retrospectively reviewed. A competing risk model was developed to estimate the cumulative incidence of LRR with death treated as a competing event.

Results

A total of 4841 patients were eligible. All underwent mastectomy plus axillary nodes dissection or sentinel node biopsy without PMRT. With a median follow-up of 56.4 months (range, 1–222 months), the 5-year LRR rate was 3.9%.Besides treatment era, age ≤ 40 years old (p < 0.001, hazard ratio [HR] = 2.262), tumor located in inner quadrant (p < 0.001, HR = 2.236), T2 stage (p = 0.020, HR = 1.419), and negative expressions of estrogen receptor (ER) and progesterone receptor (PR) (p = 0.032, HR = 1.485), were patients-related independent risk factors for LRR. The 5-year LRR rates were 1.7, 3.5, and 15.0% for patients with zero, 1–2, and 3–4 risk factors (p < 0.001).

Conclusions

Risk Stratification based on age, T stage, ER/PR status and tumor location can stratify patients with pT1–2 N0 breast cancer into subgroups with different risk of LRR. PMRT might be suggested for patients with 3–4 risk factors.

Imaging and Management of Internal Mammary Lymph Nodes

Internal mammary lymph nodes (IMLNs) account for approximately 10%-40% of the lymphatic drainage of the breast. Internal mammary lymph nodes measuring up to 10 mm are commonly seen on high-risk screening breast MRI examinations in patients without breast cancer and are considered benign if no other suspicious findings are present. Benign IMLNs demonstrate a fatty hilum, lobular or oval shape, and circumscribed margins without evidence of central necrosis, cortical thickening, or loss of fatty hilum. In patients with breast cancer, IMLN involvement can alter clinical stage and treatment planning. The incidence of IMLN metastases detected on US, CT, MRI, and PET-CT ranges from 10%-16%, with MRI and PET-CT demonstrating the highest sensitivities. Although there are no well-defined imaging criteria in the eighth edition of the American Joint Committee on Cancer Staging Manual for Breast Cancer, a long-axis measurement of ≥ 5 mm is suggested as a guideline to differentiate benign versus malignant IMLNs in patients with newly diagnosed breast cancer. Abnormal morphology such as loss of fatty hilum, irregular shape, and rounded appearance (which can be quantified by a short-axis/long-axis length ratio greater than 0.5) also raises suspicion for IMLN metastases. MRI and PET-CT have good sensitivity and specificity for the detection of IMLN metastases, but fluorodeoxyglucose avidity can be seen in both benign conditions and metastatic disease. US is helpful for staging, and US-guided fine-needle aspiration can be performed in cases of suspected IMLN metastasis. Management of suspicious IMLNs identified on imaging is typically with chemotherapy and radiation, as surgical excision does not provide survival benefit and is performed only in rare cases.

Internal mammary and medial supraclavicular lymph node chain irradiation in stage I-III breast cancer (EORTC 22922/10925): 15-year results of a randomised, phase 3 trial

BACKGROUND

10-year results from several studies showed improved disease-free survival and distant metastasis-free survival, reduced breast cancer-related mortality, and variable effects on overall survival with the addition of partial or comprehensive regional lymph node irradiation after surgery in patients with breast cancer. We present the scheduled 15-year analysis of the European Organisation for Research and Treatment of Cancer (EORTC) 22922/10925 trial, which aims to investigate the impact on overall survival of elective internal mammary and medial supraclavicular (IM-MS) irradiation.

METHODS

EORTC 22922/10925, a randomised, phase 3 trial done across 46 radiation oncology departments from 13 countries, included women up to 75 years of age with unilateral, histologically confirmed, stage I-III breast adenocarcinoma with involved axillary nodes or a central or medially located primary tumour. Surgery consisted of mastectomy or breast-conserving surgery and axillary staging. Patients were randomly assigned (1:1) centrally using minimisation to receive IM-MS irradiation at 50 Gy in 25 fractions (IM-MS irradiation group) or no IM-MS irradiation (control group). Stratification was done for institution, menopausal status, site of the primary tumour within the breast, type of breast and axillary surgery, and pathological T and N stage. Patients and investigators were not masked to treatment allocation. The primary endpoint was overall survival analysed according to the intention-to-treat principle. Secondary endpoints were disease-free survival, distant metastasis-free survival, breast cancer mortality, any breast cancer recurrence, and cause of death. Follow-up is ongoing for 20 years after randomisation. This study is registered with ClinicalTrials.gov, NCT00002851.

FINDINGS

Between Aug 5, 1996, and Jan 13, 2004, we enrolled 4004 patients, of whom 2002 were randomly assigned to the IM-MS irradiation group and 2002 to the no IM-MS irradiation group. At a median follow-up of 15·7 years (IQR 14·0-17·6), 554 (27·7%) patients in the IM-MS irradiation group and 569 (28·4%) patients in the control group had died. Overall survival was 73·1% (95% CI 71·0-75·2) in the IM-MS irradiation group and 70·9% (68·6-72·9) in the control group (HR 0·95 [95% CI 0·84-1·06], p=0·36). Any breast cancer recurrence (24·5% [95% CI 22·5-26·6] vs 27·1% [25·1-29·2]; HR 0·87 [95% CI 0·77-0·98], p=0·024) and breast cancer mortality (16·0% [14·3-17·7] vs 19·8% [18·0-21·7]; 0·81 [0·70-0·94], p=0·0055) were lower in the IM-MS irradiation group than in the control group. No significant differences in the IM-MS irradiation group versus the control group were seen for disease-free survival (60·8% [95% CI 58·4-63·2] vs 59·9% [57·5-62·2]; HR 0·93 [95% CI 0·84-1·03], p=0·18), or distant metastasis-free survival (70·0% [67·7-72·2] vs 68·2% [65·9-70·3]; 0·93 [0·83-1·04], p=0·18). Causes of death between groups were similar.

INTERPRETATION

The 15-year results show a significant reduction of breast cancer mortality and any breast cancer recurrence by IM-MS irradiation in stage I-III breast cancer. However, this is not converted to improved overall survival.

FUNDING

US National Cancer Institute, Ligue Nationale contre le Cancer, and KWF Kankerbestrijding.

Dopamine D1 Receptor in Cancer

Simple Summary

Circulating hormones and their specific receptors play a significant role in the development and progression of various cancers. This review aimed to summarize current knowledge about the dopamine D1 receptor’s biological role in different cancers, including breast cancer, central nervous system tumors, lymphoproliferative disorders, and other neoplasms. Treatment with dopamine D1 receptor agonists was proven to exert a major anti-cancer effect in many preclinical models. We highlight this receptor’s potential as a target for the adjunct therapy of tumors and discuss possibilities and necessities for further research in this area.

Abstract

Dopamine is a biologically active compound belonging to catecholamines. It plays its roles in the human body, acting both as a circulating hormone and neurotransmitter. It acts through G-protein-coupled receptors divided into two subgroups: D1-like receptors (D1R and D5R) and D2-like receptors (D2R, D3R, D4R). Physiologically, dopamine receptors are involved in central nervous system functions: motivation or cognition, and peripheral actions such as blood pressure and immune response modulation. Increasing evidence indicates that the dopamine D1 receptor may play a significant role in developing different human neoplasms. This receptor’s value was presented in the context of regulating various signaling pathways important in tumor development, including neoplastic cell proliferation, apoptosis, autophagy, migration, invasiveness, or the enrichment of cancer stem cells population. Recent studies proved that its activation by selective or non-selective agonists is associated with significant tumor growth suppression, metastases prevention, and tumor microvasculature maturation. It may also exert a synergistic anti-cancer effect when combined with tyrosine kinase inhibitors or temozolomide. This review provides a comprehensive insight into the heterogeneity of dopamine D1 receptor molecular roles and signaling pathways in human neoplasm development and discusses possible perspectives of its therapeutic targeting as an adjunct anti-cancer strategy of treatment. We highlight the priorities for further directions in this research area.

Quality of Regional Nodal Irradiation Plans in Breast Cancer Patients Across a Large Network-Can We Translate Results From Randomized Trials Into the Clinic?

PURPOSE

Regional nodal irradiation (RNI) improved disease-free survival by 3% to 5% in 2 large randomized trials, but this small absolute advantage relies on accurate contouring and dose delivery. We audited our network to determine compliance on regional nodal coverage, contouring, and dosimetric parameters with respect to accepted guidelines.

METHODS AND MATERIALS

In our network, we have established a clinical pathway for patients with node-positive breast cancer that guides indications for RNI and dosimetric goals. We reviewed records of 183 patients with nodal macrometastases after upfront surgery or involved nodes of any size after neoadjuvant chemotherapy. Radiation treatment plans were examined to determine lymph node volumes treated, whether nodes were contoured, quality of nodal contours, and whether target coverage and normal organ dosimetric constraints were met when RNI was delivered.

RESULTS

Despite the presence of macrometastases on sentinel lymph node biopsy, no lymph nodes were treated in 2.2% (4 of 183). Of 179 patients who received nodal irradiation, 18 received radiation to axillary levels 1 and 2 only, and 161 patients received RNI. Overall, regional nodes were not treated despite strong indications in 7.6% (14 of 183). Treated nodes were not contoured for 2.2% (4 of 179), and lymph node contours were unacceptable in 15.4% (27 of 175). Of patients receiving RNI, 14.9% (24 of 161) did not have adequate nodal target volume coverage, mean heart dose was >4 Gy for 3.1% (5 of 161), and lung V20 Gy was >35% for 8.7% (14 of 161).

CONCLUSIONS

Adherence to indications for regional nodal treatment was high, but nodes were either not contoured or had unacceptable contour quality in 18% of plans, and coverage was inadequate in 15%. Because the small disease-free survival advantage seen in trials may be decreased with these deviations, routine clinical practice requires detailed peer review to fully translate results of clinical trials.

Utilization patterns and temporal trends of internal mammary nodal irradiation at a tertiary cancer center

PURPOSE

The role and uptake of internal mammary nodal irradiation (IMNI) is variable. This study was designed to quantify the rates and determinants of IMNI at a tertiary cancer center.

METHODS

Consecutively treated breast cancer patients receiving adjuvant locoregional radiation therapy (RT) from January 1, 2012 to December 31, 2017 were sorted by IMNI receipt, disease risk and time period of RT delivery (2012-2015 vs 2016-2017). Differences between risk categories and groups were evaluated using χ²/Fisher's and Mann-Whitney test for categorical and continuous variables, respectively. Univariable and multivariable logistic regression analysis was done to determine factors associated with IMNI receipt.

RESULTS

A total of 1566 patients were eligible, with 376 in Group 1 (IMNI), and 1190 in Group 2 (no IMNI). The proportion of patients receiving IMNI increased significantly each year (p < 0.0001), and 83% of patients receiving IMNI had pT1-2/pN1 disease. On univariable analysis, younger age, lymphovascular invasion, medial/central quadrant, higher stage, PR negative, mastectomy, axillary dissection, receipt of chemotherapy and nodal positivity had higher odds of IMNI. On multivariable analysis, younger age (p =  < 0.001), medial/central quadrant (p = 0.0026), PR negative (p = 0.0011), mastectomy (p = 0.0055), increasing nodal positivity (p < 0.0001) and late cohort (p = 0.001) had increased likelihood of IMNI. The use of deep-inspiration breath hold was significantly higher in those receiving IMNI (45% vs 26%, p < 0.0001), and permitted achievement of acceptable mean heart and lung doses.

CONCLUSIONS

There was a significant increase in IMNI utilization after 2015. Younger age, medial/central quadrant, PR-negative and node-positive disease predicted for receipt of IMNI. Modern RT techniques permit the safe delivery of IMNI.

Heart-sparing effect of postmastectomy radiotherapy for breast cancer patients: A dosimetric study of cardiac substructures

We investigated to what extent can the dose-volumes of the coronary artery and the cardiac substructures be reduced by using IMRT technique in left-sided breast cancer patients. We chose 40 pN2M0 patients treated with postmastectomy IMRT. The original treatment plans were retrieved and the (internal mammary nodes) IMNs and cardiac substructure delineations were added. Three sets of dose-volume parameters including the original plans without internal mammary irradiation (IMNI), the plans with IMNI, and the plans with dose constraints to the heart, were derived. In left-sided patients, when IMNI was included, the V30 for right ventricle (RV), left ventricle (LV), pulmonic valve (PV), and left anterior descending artery (LADA) were 56.37% ± 7.9%, 25.3% ± 7.3%, 48.3% ± 6.3%, and 69.7% ± 6.4%, respectively. Of the 4 main coronary arteries, LADA had the highest dose followed by the left main coronary artery (LMCA). LADA had a V40 of 62% ± 9.7% vs 13.5% ± 3.5%, and a V50 of 27.5% ± 4.7% vs 0, with and without IMNI. For the right-sided patients, the V30s for all the heart substructures were 0 with or without IMNI. When we set a dose constraint of V40 < 10% for the LADA in the left-sided patients, the PTV volumes covered by 50 Gy decreased by only 1%. IMNI increased the V30 of the right and left ventricle and significantly increased the V40 and V50 to the LADA of left-sided breast cancer patients. IMRT markedly reduces the dose to the main coronary arteries and the right and left ventricle.

Internal Mammary Sentinel Lymph Node Biopsy in Clinically Axillary Lymph Node-Positive Breast Cancer: Diagnosis and Implications for Patient Management

BACKGROUND

Routine performance of internal mammary sentinel lymph node biopsy (IM-SLNB) remains a subject of debate due to no clinical relevance in breast cancer, because it was performed only in clinically axillary lymph node (ALN)-negative patients. In this study, IM-SLNB was performed in clinically ALN-positive patients, and its impact on nodal staging and therapeutic strategy were subsequently analyzed.

METHODS

Clinically ALN-positive patients who underwent IM-SLNB were enrolled in this prospective study. Statistical analysis was performed using Chi square test, Mann-Whitney U and logistic regression models with a significance level of 0.05.

RESULTS

Among the 352 recruited patients, the internal mammary sentinel lymph node (IMSLN) visualization rate of patients who received initial surgery and neoadjuvant systemic therapy (NST) was 71.9% (123/171) and 33.1% (60/181), respectively. The 183 patients who underwent IM-SLNB successfully had the average time duration of 7 min and the median IMSLN number of 2. There were 87 positive IMSLNs in all the 347 removed IMSLNs, which were mainly concentrated in the second (50.6%) and third (34.5%) intercostal space. The IMSLN metastasis rate was 39.8% (initial surgery) and 13.3% (NST), respectively. All of the 183 IM-SLNB patients received more accurate nodal staging, 57 of whom had stage elevated, which might have prompted modifications to the therapeutic strategy.

CONCLUSIONS

IM-SLNB should be routinely performed in clinically ALN-positive patients, and thus more accurate nodal staging and perfect pathologic complete response definition could be put forward. The identification of IMLN metastases by IM-SLNB might potentially influence therapeutic strategies.

A Randomized Trial Comparing the Efficacy of Methylene Blue Dye Alone Versus Combination of Methylene Blue Dye and Radioactive Sulfur Colloid in Sentinel Lymph Node Biopsy for Early Stage Breast Cancer Patients

Although sentinel lymph node biopsy (SLNB) has become a standard of care for management of axilla in breast cancer patients, the technique of SLNB is still not well defined. Unlike radioactive sulfur colloid which requires nuclear medicine facilities, methylene blue dye is readily available. The purpose of this study is to validate the use of methylene blue dye alone for SLNB in early breast cancer patients. 60 patients of early breast cancer were randomized to receive either methylene blue alone (Group A-30 patients) or a combination of both methylene blue and radioactive colloid (Group B-30 patients) for detection of sentinel lymph nodes. Sentinel lymph node biopsy was done followed by complete axillary dissection in all patients. In both Groups A and B, sentinel node was identified in all 30 patients, giving identification rate of 100%. In group A, sentinel node was the only positive node in 1 patient, with a false-positive rate of 14.2%. The negative predictive value was 91.3%. The sensitivity of the procedure in predicting further axillary disease was 75% with a specificity of 95.45%. The overall accuracy was 90%. In group B, sentinel node was the only positive node in 2 cases, giving a false-positive rate of 28.7%. The negative predictive value was 95.65%. The sensitivity of the procedure in predicting further axillary disease was 83.33% with a specificity of 91.67%. The overall accuracy was 90%. Although the false-negative rate was slightly higher with methylene blue alone than that using combination (8.6%-4.3%), it was statistically insignificant. Similarly the sensitivity (75%-83.33%), specificity (95.45-91.67%), and negative predictive value (91.3%-95.67%) were also comparable between groups A and B, respectively. Negative predictive value and false-negative rates are comparable, whether blue dye is used alone or a combination of blue dye and radioactive colloid is used. Sentinel lymph node biopsy with blue dye alone is reliable and can be put to clinical practice more widely, even if nuclear medicine facilities are not available in resource constrained centers, so as to reduce long-term morbidity of axillary dissection, with similar oncological outcomes.

Nomogram to Predict Internal Mammary Lymph Nodes Metastasis in Patients With Breast Cancer

Background: Numerous studies have showed that internal mammary lymph node (IMLN) metastasis is an important adverse prognostic factor in patients with breast cancer (BC), however, there are no available prediction model for the preoperative diagnosis of IMLN metastasis.

Methods: Data from 102 breast cancer patients treated with IMLN operation were used to establish and calibrate a nomogram for IMLN status based on multivariate logistic regression. Prediction performance of this model was further validated with a second set of 50 patients with BC. Discrimination of the predict model was assessed by the C-index, and calibration assessed by calibration plots. Moreover, we conducted the decision curve analysis (DCA) to evaluate the clinical value of the nomogram. Finally, the survival status of patients in different risk groups based on nomogram were also compared.

Results: The final multivariate regression model included tumor location, lymph vascular invasion (LVI), and pathological axillary lymph node stage (pALN stage). A nomogram was developed as a graphical representation of the model and had good calibration and discrimination in both sets (with C-index of 0.86 and 0.83 for the training and validation set, respectively). Moreover, the DCA showed the clinical usefulness of our constructed nomogram. False negative (FN) in low risk group classified by nomogram (FN-LR-nomogram) did not significantly impact adjuvant treatment decision making, and more importantly, patients with FN-LR-nomogram had recurrence-free survival equivalent to patients with pathologically ture negative in low risk group classified by nomogram (TN-LR-nomogram).

Conclusions: As a non-invasive prediction tool, our nomogram shows favorable predictive accuracy for IMLN metastasis in patients with BC and can serve as a basis to integrate future molecular markers for its clinical application.

Incidence of internal mammary node in locally advanced breast cancer and its correlation with metastatic disease: a retrospective observational study

OBJECTIVE

To determine incidence of internal mammary nodes (IMN) at baseline CT of locally advanced breast cancer (LABC) and ascertain prognostic implication.

METHODS AND MATERIALS

Retrospective review of all LABC patients from 1 January 2012 through 31 December 2014 was performed after approval from institutional review board. CTs of 182 patients enrolled were reviewed by two radiologists independently, and IMNs were documented based on size, location and relation with location of breast primary. 3-year follow-up was analysed and incidence of metastases was calculated as overall incidence, incidence in patients with and without discernible IMN at baseline imaging. Results are presented as numbers and percentages. Differences in metastases of two groups were compared using χ2 test. 95% CI was calculated and p < 0.05 was considered significant.

RESULTS

77 of 182 had identifiable IMN (42.3% incidence). Majority of identifiable nodes were on ipsilateral side of primary (incidence 90.90%) with higher incidence in patients with upper-outer quadrant tumours (55.9%). Majority were seen in second intercostal space (44.4%). 36 (19.7%) developed distant metastases within 3 years of therapy. Of these, 21 (27.3%) had IMN as compared with 15 (14.3 %) without IMN on baseline imaging. Patients with identifiable IMN on baseline CT had significantly higher incidence of distant metastases (p = 0.0321).

CONCLUSION

Significant number LABC patients have identifiable IMN on baseline imaging with patients showing IMN on baseline CT showing significantly higher rate of metastatic disease following therapy.

ADVANCES IN KNOWLEDGE

Many LABC patients have identifiable IMNs on baseline imaging which show higher incidence of subsequent metastatic disease.

Radiotherapy for initial clinically positive internal mammary nodes in breast cancer

Purpose

Internal mammary lymph node (IMN) involvement is associated with poor prognosis in breast cancer. This study investigated the treatment outcomes of initial clinically IMN-positive breast cancer patients who received adjuvant radiotherapy (RT), including IMN irradiation, following primary breast surgery.

Materials and Methods

We retrospectively reviewed data of 95 breast cancer patients with clinically detected IMNs at diagnosis treated with surgery and RT between June 2009 and December 2015. Patients received adjuvant RT to the whole breast/chest wall and regional lymph node (axillary, internal mammary, and supraclavicular) areas. Twelve patients received an additional boost to the IMN area.

Results

The median follow-up was 43.2 months (range, 4.5 to 100.5 months). Among 77 patients who received neoadjuvant chemotherapy, 52 (67.5%) showed IMN normalization and 19 (24.6%) showed a partial response to IMN. There were 3 and 24 cases of IMN failure and any recurrence, respectively. The 5-year IMN failure-free survival, disease-free survival (DFS), and overall survival (OS) were 96%, 70%, and 84%, respectively. IMN failure-free survival was significantly affected by resection margin status (97.7% if negative, 87.5% for close or positive margins; p = 0.009). All three patients with IMN failure had initial IMN size ≥1 cm and did not receive IMN boost irradiation. The median age of the three patients was 31 years, and all had hormone receptor-negative tumors.

Conclusion

RT provides excellent IMN control without the support of IMN surgery. Intensity-modulated radiotherapy, including IMN boost for breast cancer patients, is a safe and effective technique for regional lymph node irradiation.

Radical chest wall resection and modified reconstruction technique for solitary internal mammary lymph node recurrence in breast cancer

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Solitary internal mammary lymph node metastasis in breast cancer patient.

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Radical enbloc surgical resection of part of manubrium, hemi sternum two ribs and internal mammary lymph node.

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Modified chest wall reconstruction technique provides better chest wall stability and cosmoses.

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There is minimal chance of MMS plate excursion or dislodgment which is the most dreadful complication in chest wall reconstruction.

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To date the patient is disease free.

Introduction

Although the incidence of internal mammary lymph node recurrence rate in breast cancer is low but still it is the second most common drainage site after axilla. Patients with solitary internal mammary lymph node (IMLN) recurrence have overall better prognosis. The role of chemo and radiotherapy in internal mammary lymph node involvement with breast cancer is still controversial. Radical surgical resection and reconstruction remains mainstay for good prognosis.

Presentation of case

Here in we present a case of a 32 year old female with breast cancer who had left mastectomy followed by adjuvant chemo radiotherapy treatment for adenocarcinoma of breast in 2008. She presented with upper left parasternal pain in 2009. Computed tomographic scan (CT) of her thorax showed internal mammary lymph node enlargement, likely metastasis. We performed modified surgical reconstruction after enbloc radical resection of part of manubrium; hemi sternum, chest wall and left parasternal IMLN. Patient remained disease free to date.

Discussion

There is no standard treatment after IMLN metastasis. Previous surgical studies reported no survival benefit with ERM, but is there any role of adjuvant locoregional radiotherapy or systemic therapy to prevent relapses in IMLN is a matter of debate.

Conclusion

To the best of our knowledge this is first case ever managed with radical enbloc surgical resection and modified reconstruction of chest wall using such technique. Our reconstruction technique provides better chest wall stability with minimal risk of plate dislodgement or excursion and at the same time provides good cosmoses and better survival.

Impact of Regional Nodal Irradiation for Breast Cancer Patients with Supraclavicular and/or Internal Mammary Lymph Node Involvement: A Multicenter, Retrospective Study (KROG 16-14)

Purpose

The purpose of this study was to evaluate the treatment outcomes of radiotherapy (RT) for breast cancer with ipsilateral supraclavicular (SCL) and/or internal mammary (IMN) lymph node involvement.

Materials and Methods

A total of 353 patients from 11 institutions were included. One hundred and thirty-six patients had SCL involvement, 148 had IMN involvement, and 69 had both. All patients received neoadjuvant systemic therapy followed by breast-conserving surgery or mastectomy, and postoperative RT to whole breast/chest wall. As for regional lymph node irradiation, SCL RT was given to 344 patients, and IMN RT to 236 patients. The median RT dose was 50.4 Gy.

Results

The median follow-up duration was 61 months (range, 7 to 173 months). In-field progression was present in SCL (n=20) and/or IMN (n=7). The 5-year disease-free survival (DFS) and overall survival rates were 57.8% and 75.1%, respectively. On multivariate analysis, both SCL/IMN involvement, number of axillary lymph node ≥ 4, triple-negative subtype, and mastectomy were significant adverse prognosticators for DFS (p=0.022, p=0.001, p=0.001, and p=0.004, respectively). Regarding the impact of regional nodal irradiation, SCL RT dose ≥ 54 Gy was not associated with DFS (5-year rate, 52.9% vs. 50.9%; p=0.696) in SCL-involved patients, and the receipt of IMN RT was not associated with DFS (5-year rate, 56.1% vs. 78.1%; p=0.099) in IMN-involved patients.

Conclusion

Neoadjuvant chemotherapy followed by surgery and postoperative RT achieved an acceptable in-field regional control rate in patients with SCL and/or IMN involvement. However, a higher RT dose to SCL or IMN RT was not associated with the improved DFS in these patients.

Overall Survival of Breast Cancer Patients With Locoregional Failures Involving Internal Mammary Nodes

Purpose

Internal mammary node recurrence after definitive breast cancer treatment is poorly characterized, with limited data to guide clinical management. The aim of this study was to analyze the outcomes of patients with recurrent breast cancer involving internal mammary nodes to understand their natural history and determine prognostic factors associated with improved overall survival.

Methods and Materials

We performed a retrospective analysis of 553 patients with recurrent breast cancer and identified 161 patients with radiographic evidence of locoregional recurrence as a first event. A total of 67 patients (42%) were identified with internal mammary involvement. Median follow-up times were 76 months from date of initial diagnosis and 30 months from date of recurrence.

Results

Of the 67 patients identified with internal mammary node failures, 10 (15%) presented with isolated recurrence, 14 (21%) presented with other sites of locoregional disease, and 43 (64%) presented with concomitant distant metastases. Median overall survival was 2.5 years and significantly associated with extent of disease (P < .0001). On multivariable analysis, concomitant distant metastases, inflammatory breast cancer, and triple negative histologic type were associated with worse overall survival, whereas salvage radiation therapy was associated with improved overall survival. Among the 10 patients with isolated internal mammary node failures, median progression-free survival was 6.0 years and salvage therapy with surgery, radiation, and chemotherapy were associated with the best outcomes.

Conclusions

Patients with isolated internal mammary node recurrences achieved long-term survival with aggressive therapies, and salvage radiation therapy was associated with improved survival.

Antitumor effect of axitinib combined with dopamine and PK-PD modeling in the treatment of human breast cancer xenograft

Rising evidence has shown the development of resistance to vascular endothelial growth factor receptor (VEGFR) inhibitors in the practices of cancer therapy. It is reported that the efficacy of axitinib (AX), a VEGFR inhibitor, is limited in the treatment of breast cancer as a single agent or in combination with other chemotherapeutic drugs due to the probability of rising population of cancer stem-like cells (CSCs) caused by AX. The present study evaluated the effect of dopamine (DA) improving AX's efficacy on MCF-7/ADR breast cancer in vitro and in vivo, and developed a pharmacokinetic-pharmacodynamic (PK-PD) model describing the in vivo experimental data and characterizing the interaction of effect between AX and DA. The results showed that AX up-regulated the expression of breast CSC (BCSC) markers (CD44⁺/CD24^-/low) in vivo, and DA significantly synergized the inhibitory effect on tumor growth by deducting the BCSC frequency. The PK-PD model quantitatively confirmed the synergistic interaction with the parameter estimate of interaction factor ψ 2.43. The dose regimen was optimized as 60 mg/kg AX i.g. b.i.d. combined with 50 mg/kg DA i.p. q3d in the simulation study on the basis of the PK-PD model. The model where DA synergistically enhances the effect of AX in an all-or-none manner provides a possible solution in modeling the agents like DA. Moreover, the outcome of AX and DA combination therapy in MCF-7/ADR breast cancer provided further insight of co-administering DA in the treatment of the possible CSC-causing AX-resisting breast cancer. And this combination therapy has the prospect of clinical translation.

Internal Mammary Chain Sentinel Nodes in Early-Stage Breast Cancer Patients: Toward Selective Removal

BACKGROUND

Removal of internal mammary chain sentinel nodes (IMCSNs) affects prognosis and treatment of breast cancer, and internal mammary chain radiotherapy (IMCRT) can improve survival for selected patients. This study aimed to determine the effect of IMCSN biopsy on recurrence-free survival (RFS) and overall survival (OS) and to identify predictive factors for IMCSN and distant metastasis.

METHODS

Patients with IMCSNs were selected from a prospective database for the period 1999-2007. Lymphoscintigraphy was performed after intratumoral technetium-99 m injection, and all sentinel nodes were removed. Both RFS and OS were calculated for subgroups with tumor-positive, tumor-negative, or non-removed IMCSNs. Predictive factors were identified for tumor-positive IMCSNs and distant metastasis by regression analysis.

RESULTS

For 287 (85%) of 336 patients, IMCSN biopsy was performed, and metastasis was detected in 38 patients (13%). The patients with tumor-positive IMCSNs had poorer OS than the patients with no IMCSN metastasis or non-removed IMCSNs (p = 0.002). These patients also had worse RFS due to distant metastasis (p = 0.002). Axillary metastasis was predictive for tumor-positive IMCSNs (positive predictive value, 38.5%). The predictive factors for distant metastasis were tumor-positive IMCSNs (hazard ratio [HR], 2.5), non-removed IMCSNs (HR, 2.3), tumor diameter greater than 1.5 cm (HR, 3.5), and age older than 65 years (HR, 3.1; reference, < 50 years).

CONCLUSIONS

Patients with IMCSNs have worse survival due to distant metastasis. The clinically relevant predictive factor for distant metastasis is tumor larger than 1.5 cm. According to the authors' current protocol, IMCSN biopsy is performed for patients younger than 70 years who have a tumor larger than 1.5 cm, with the cardiotoxicity of the adjuvant IMCRT weighed against the survival benefit.

Pre- and post-magnetic resonance imaging features of suspicious internal mammary lymph nodes in breast cancer patients receiving neo-adjuvant therapy: Are any imaging features predictive of malignancy?

Internal mammary lymph nodes constitute a major lymphatic chain draining the breast and a route of spread for breast cancer metastases. Both physiologic and metastatic internal mammary lymph nodes enhance on breast magnetic resonance imaging, and the clinical significance of their prevalence, size, and morphology when visualized in a patient with breast cancer remains unknown. We studied the characteristics of internal mammary lymph nodes visualized on breast MRI studies before and after neo-adjuvant therapy in twenty-three patients with newly diagnosed breast cancer. A measured decrease in internal mammary lymph node size on post-neo-adjuvant therapy MRI indicated metastatic involvement. Determining suspicious features of internal mammary nodes on initial diagnostic MRI can aid radiologists in reporting probable IMLN metastases and may alter the course of care for patients with breast cancer. This study concludes that metastatic internal mammary lymph nodes should be considered when more than two ipsilateral internal mammary lymph nodes measuring 6 mm or greater are seen on diagnostic MRI in a patient with newly diagnosed breast cancer.

Implications of Internal Mammary Lymph Node Sampling During Microsurgical Breast Reconstruction

INTRODUCTION

Internal mammary lymph node (IMN) chain assessment for breast cancer is controversial; however, current oncologic data have shed new light on its importance. Metastatic involvement of the IMN chain has implications for staging, prognosis, treatment, and survival. Here, we analyzed our data gathered during sampling of the IMN and the oncologic treatment changes that resulted from our findings.

METHODS

A retrospective chart review was performed on 581 patients who underwent free-flap breast reconstruction performed by the senior author. All dissected IMNs were submitted for pathological examination. Patient demographics, oncologic data, and the results of IMN sampling were reviewed.

RESULTS

581 patients undergoing 981 free flaps were identified. A total of 400 lymph node basins were harvested from 273 patients. Of these, nine had positive IMNs. Two of these nine patients had positive IMNs of the contralateral nonaffected breast. Five patients had positive axillary lymph nodes. Four patients had multifocal tumors, one of which was bilateral. Seven patients had an increase in cancer stage as a result of having positive IMNs. Six patients had a change in treatment: two patients required additional chemotherapy, one received adjuvant radiation therapy, and three necessitated both supplemental chemotherapy and radiation.

CONCLUSIONS

Opportunistic biopsy of the IMN while dissecting the recipient vessels is simple and results in no added morbidity. We recommend that biopsy of the IMN chain be performed whenever internal mammary vessels are dissected for microsurgical anastomosis in breast cancer patients. Positive IMN involvement should encourage thorough oncological workup and treatment reevaluation.

LEVEL OF EVIDENCE IV

Case series.