Internal mammary lymph nodes radiotherapy of breast cancer in the era of individualized medicine

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.

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.

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.

Comparison of 3D-Conformal Planning Using Partially Wide Tangents and Direct Photon/electron Portals for Breast Radiotherapy with Internal Mammary Nodes Inclusion: A Dosimetric Analysis

Background: Internal mammary lymph nodes (IMNs) are a potential site of metastasis for breast cancer. Targeting IMNs as part of a comprehensive regional nodal irradiation comes at the cost of higher unwanted doses to critical nearby organs at risk. Thus, the efficacy and safety of different radiotherapy techniques for the coverage of this area remain elusive. Objectives: We present a dosimetric comparison between partially wide tangents (PWT) and direct photon/electron (P/E) portals in terms of target volume coverage and normal tissue sparing. Methods: Patients with left-sided breast cancer, who were referred to our clinic for post-lumpectomy or post-mastectomy radiotherapy, underwent computed tomography (CT) simulation. The left breast and IMNs, heart, lung, right breast, and esophagus were contoured. Dosimetric comparisons were based on dose-volume histograms (DVHs) generated for all of the aforementioned organs. A subgroup analysis was also performed based on patients’ type of surgical treatment. Results: A total of 30 patients (10 with breast conserving surgery and 20 with modified radical mastectomy) were included. The P/E plan provided a higher coverage of the left breast (P-value of CTV V105%: < 0.001) and IMNs with a P-value of 0.087 regarding the mean dose received by IMNs, and also less volume of the heart (P-value of Heart V30Gy: 0.021), and lungs (P-value of Lung V20Gy: 0.003) were irradiated. However, these advantages came at the cost of a higher dose to the esophagus and right breast and more hotspots compared to the PWT technique. Conclusions: The P/E technique had advantages regarding target volume coverage and toxicity regardless of the type of surgery. Based on the results of this study, overall, the P/E portal is superior to the PWT for radiotherapy of breast cancer with internal mammary node inclusion. However, the appropriate treatment plan should be decided on a case-by-case basis.

99mTc-rituximab tracer injection for guiding internal mammary sentinel lymph nodes biopsy in primary breast cancer: A prospective observational study

Objective

To explore the use of ^99mTc-rituximab tracer injection for internal mammary sentinel lymph node (IM-SLN) detection in patients with primary breast cancer.

Methods

This prospective observational study enrolled female patients with primary breast cancer between September 2017 and June 2022 at Fujian Provincial Hospital. The participants were divided into the peritumoral group (two subcutaneous injection points on the surface of the tumor), two-site group (injections into the glands at 6 and 12 o'clock around the areola area), and four-site group (injections into the gland at 3, 6, 9, and 12 o'clock around the areola area). The outcomes were the detection rates of the IM-SLNs and axillary sentinel lymph nodes (A-SLNs).

Results

Finally, 133 patients were enrolled, including 53 in the peritumoral group, 60 in the two-site group, and 20 in the four-site group. The detection rate of the IM-SLNs in the peritumoral group (9.4% [5/53]) was significantly lower than in the two-site (61.7% [37/60], P<0.001) and four-site (50.0% [10/20], P<0.001) groups. The detection rates of A-SLNs among the three groups were comparable (P=0.436).

Conclusion

The two-site or four-site intra-gland injection of ^99mTc-rituximab tracer might achieve a higher detection rate of IM-SLNs and a comparable detection rate of A-SLNs compared with the peritumoral method. The location of the primary focus has no impact on the detection rate of the IM-SLNs.

Internal mammary lymph node metastasis in breast cancer patients based on anatomical imaging and functional imaging

Internal mammary lymph node (IMLN) metastasis forms part of the clinical node classification for primary breast cancer, which influences the treatment strategy. However, because of the IMLNs' complicated anatomical structures and relationships with adjacent structures, IMLN biopsy or resection is associated with a limited improvement in prognosis and a high complication rate. The positivity rate also varies broadly according to imaging modality, and there is a low rate of agreement between the imaging and pathological diagnoses, which creates imprecision in the preoperative staging. The IMLN positivity rate also varies remarkably, and there are no clear, accurate, and non-invasive modalities for diagnosing the pre-mastectomy IMLN status. Nevertheless, medical imaging modalities continue to evolve, with functional imaging and image-guided thoracoscopic biopsy of sentinel IMLNs being well established. Thus, personalized decision-making and treatment selection should be based on the modality-specific differences in the diagnosis of IMLN metastasis/recurrence and the patient's specific risk factors.

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.

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.

Advances in molecular mechanisms of drugs affecting abnormal glycosylation and metastasis of breast cancer

Breast cancer remains the leading cause of cancer-related death among women worldwide, and its incidence is also increasing. High recurrence rate and metastasis rate are the key causes of poor prognosis and death. It is suggested that abnormal glycosylation plays an important role in the growth, invasion, metastasis and resistance to therapy of breast cancer cells. Meanwhile, it can be used as the biomarkers for the early detection and prognosis of breast cancer and the potential attractive targets for drug treatment. However, only a few attentions have been paid to the molecular mechanism of abnormal glycosylation in the epithelial-mesenchymal transition (EMT) of breast cancer cells and the related intervention of drugs. This manuscript thus investigated the relationship between abnormal glycosylation, the EMT, and breast cancer metastasis. Then, the process of abnormal glycosylation, the classification and their molecular regulatory mechanisms of breast cancer were analyzed in detail. Last, potential drugs are introduced in different categories, which are expected to reverse or intervene the abnormal glycosylation of breast cancer. This review is conducive to an in-depth understanding of the metastasis and drug resistance of breast cancer cells, which will provide new ideas for the clinical regulation of glycosylation and related drug treatments in breast cancer.

Optimal radiotherapy for patients with internal mammary lymph node metastasis from breast cancer

Background

This study aimed to determine the optimal radiotherapy (RT) regimen for patients with clinical metastasis to the internal mammary lymph node (cIMN+) from breast cancer.

Methods

We retrospectively reviewed the medical records of 84 patients with cIMN+ breast cancer treated with curative surgery, taxane-based chemotherapy, and postoperative RT between January 2009 and December 2014. Postoperative RT was administered to the whole breast or chest wall using 50 Gy in 2 Gy fractions. Boost RT to the internal mammary lymph node (IMN) was administered at the physician’s discretion. We categorized patients into two groups according to the IMN dose as follows: low-dose IMN RT (50.0–63.5 Gy) and high-dose IMN RT (63.6–70.4 Gy).

Results

After a median follow-up of 58 months (range, 12–111 months), IMN recurrence was observed in 2 patients (2.4%), and all IMN recurrences developed simultaneously with distant metastases. The 5-year locoregional recurrence-free survival, disease-free survival (DFS), and overall survival rates were 89.1, 72.0, and 81.2%, respectively. The triple-negative subtype, IMN size ≥1.0 cm, old age, and low-dose IMN were significantly associated with poor DFS. Among the patients with IMN size ≥1.0 cm, the 5-year DFS was significantly higher in those treated with high-dose IMN RT than in those treated with low-dose IMN RT (69.3% vs. 33.3%, p = 0.019).

Conclusions

IMN RT without IMN dissection resulted in favorable outcomes in cIMN+ breast cancer. For patients with a large IMN, a higher IMN radiation dose might be needed for disease control.

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.

[Prophylactic nodal radiotherapy for breast cancer]

Adjuvant radiotherapy is a key treatment in early-stage breast cancer. The meta-analysis by the Early Breast Cancer Trialist's Collaborative Group (EBCTCG) has demonstrated a decreased risk of locoregional relapse and death after whole-breast radiotherapy. Prophylactic lymph nodes irradiation in breast cancer has also proven to be beneficial in several therapeutic trials. At a time when three-dimensional conformal radiotherapy has become the standard procedure and with the development of intensity-modulated radiation therapy, defining nodal volumes is essential and practices should be harmonized to assess and compare the efficiency and toxicity of radiotherapy. Furthermore, the indication of lymph nodes irradiation has to take into account the risk/benefit balance as expanding the irradiated volume can increase radio-induced toxicity. Selection of patients receiving this treatment is essential. The aim of this update is to define nodal volumes, to precise the indications of their irradiation and to present the expected benefits as well as the potential side effects.