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

Hypofractionation for Regional Nodal Irradiation in Breast Cancer: Best of Both the Worlds

Locoregional radiotherapy play an important role in controlling the disease after surgery in patients with breast cancer. Radiotherapy schedules vary from conventional fraction to hypofractionation. The purpose of this review is to get an insight into the data on regional nodal irradiation (RNI) with hypofractionation in patients with breast cancer. This systematic review was constructed in accordance with Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) framework. Electronic databases such as PubMed, Cochrane and EMBASE were searched from January 1, 2023 to March 31, 2023 to identify studies published in English language on hypofractionated RNI in post mastectomy patients. The search was carried out with the National Library of Medicine's Medical Subject Heading (MeSH) terms like "regional nodal irradiation," "hypofractionated" and "hypofractionation in breast cancer" with different Boolean operators (and/or). A manual search of reference lists of included articles was also performed to make sure there were no additional cases unidentified from the primary search. Studies deemed potentially eligible were identified and assessed by same independent reviewers to confirm eligibility. RNI data are mainly from a randomized study from Beijing and pooled data from START trials. There are also data from retrospective and single institutional studies and a few phase II studies with limited number of patients using different dose fractionations and techniques of radiotherapy. Doses used in these trials ranged from 26-47.7 Gy in 5-19 fractions over 1-4 weeks. Grade ≥ 2 pulmonary fibrosis and lymphedema rate ranged from 2%-7.9% and 3%-19.8% respectively. Grade ≥ 2 shoulder dysfunction and brachial plexopathy ranged from 0.2%-28% and 0%-< 1%, respectively. Late effects with a dose range of 26-40 Gy delivered in 5 to 15 fractions over 1-3 weeks were less/similar to conventional fraction. Current data showed lower/similar rates of toxicity with hypofractionated RNI compared with conventional fractionation RNI. Doses of 26 Gy to 40 Gy delivered in 5 to 15 fractions over 1-3 weeks are safe for RNI. With limited data, ultra-hypofractionation 26 Gy/5 fractions/1 week also seems to be safe. However, long-term outcome is awaited and many trials are going on to address its efficacy and safety.

A novel nomogram and survival analysis for different lymph node status in breast cancer based on the SEER database

INTRODUCTION

The axillary lymph node status (ALNS) and internal mammary lymph nodes (IMLN) expression associated with breast cancer are closely linked to prognosis. This study aimed to establish a nomogram to predict survival at 3, 5, and 10 years in patients with various lymph node statuses.

METHODS

We obtained data from patients with breast cancer between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER database). Chi-square analysis was performed to test for differences in the pathological characteristics of the groups, and Kaplan-Meier analysis and the log-rank test were used to plot and compare the correlation between overall survival (OS) and breast cancer specific survival (BCSS). The log-rank test was used for the univariate analysis, and statistically significant characteristics were included in the multivariate and Cox regression analyses. Finally, Independent factor identification was included in constructing the nomogram using R studio 4.2.0; area under curve (AUC) values were calculated, and receiver operating characteristic (ROC) curve, calibration, and decision curve analysis (DCA) curves were plotted for evaluation.

RESULTS

A total of 279,078 patients were enrolled and analysed, demonstrating that the isolated tumour cells (ITC) group had clinicopathological characteristics similar to those of micrometastases (Mic). Multivariate analysis was performed to identify each subgroup's independent risk factors and construct a nomogram. The AUC values were 74.7 (95% CI 73.6-75.8), 72.8 (95% CI 71.9-73.8), and 71.2 (95% CI 70.2-72.2) for 3-, 5-, and 10-year OS, respectively, and 82.2 (95% CI 80.9-83.6), 80.1 (95% CI 79.0-81.2), and 75.5 (95% CI 74.3-76.8) for BCSS in overall breast cancer cases, respectively. AUC values for 3-, 5-, and 10-year OS in the ITC group were 64.8 (95% CI 56.5-73.2), 67.7 (95% CI 62.0-73.4), and 65.4 (95% CI 60.0-70.7), respectively. For those in the Mic group, AUC values for 3-, 5-, and 10-year OS were 72.9 (95% CI 70.7-75.1), 72.4 (95% CI 70.6-74.1), and 71.3 (95% CI 69.6-73.1), respectively, and AUC values for BCSS were 77.8 (95% CI 74.9-80.7), 75.7 (95% CI 73.5-77.9), and 70.3 (95% CI 68.0-72.6), respectively. In the IMLN group, AUC values for 3-, 5-, and 10-year OS were 75.2 (95% CI 71.7-78.7), 73.4 (95% CI 70.0-76.8), and 74.0 (95% CI 69.6-78.5), respectively, and AUC values for BCSS were 76.6 (95% CI 73.0-80.3), 74.1 (95% CI 70.5-77.7), and 74.7 (95% CI 69.8-79.5), respectively. The ROC, calibration, and DCA curves verified that the nomogram had better predictability and benefits.

CONCLUSION

This study is the first to investigate the predictive value of different axillary lymph node statuses and internal mammary lymph node metastases in breast cancer, providing clinicians with additional aid in treatment decisions.

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.

Predictive nomogram using multimodal ultrasonographic features for axillary lymph node metastasis in early‑stage invasive breast cancer

Axillary lymph node (ALN) status is a key prognostic factor in patients with early-stage invasive breast cancer (IBC). The present study aimed to develop and validate a nomogram based on multimodal ultrasonographic (MMUS) features for early prediction of axillary lymph node metastasis (ALNM). A total of 342 patients with early-stage IBC (240 in the training cohort and 102 in the validation cohort) who underwent preoperative conventional ultrasound (US), strain elastography, shear wave elastography and contrast-enhanced US examination were included between August 2021 and March 2022. Pathological ALN status was used as the reference standard. The clinicopathological factors and MMUS features were analyzed with uni- and multivariate logistic regression to construct a clinicopathological and conventional US model and a MMUS-based nomogram. The MMUS nomogram was validated with respect to discrimination, calibration, reclassification and clinical usefulness. US features of tumor size, echogenicity, stiff rim sign, perfusion defect, radial vessel and US Breast Imaging Reporting and Data System category 5 were independent risk predictors for ALNM. MMUS nomogram based on these factors demonstrated an improved calibration and favorable performance [area under the receiver operator characteristic curve (AUC), 0.927 and 0.922 in the training and validation cohorts, respectively] compared with the clinicopathological model (AUC, 0.681 and 0.670, respectively), US-depicted ALN status (AUC, 0.710 and 0.716, respectively) and the conventional US model (AUC, 0.867 and 0.894, respectively). MMUS nomogram improved the reclassification ability of the conventional US model for ALNM prediction (net reclassification improvement, 0.296 and 0.288 in the training and validation cohorts, respectively; both P<0.001). Taken together, the findings of the present study suggested that the MMUS nomogram may be a promising, non-invasive and reliable approach for predicting ALNM.

Definitive Radiation With Nodal Boost for Patients With Locally Advanced Breast Cancer

PURPOSE

The optimal local therapy of patients with nodal disease in supraclavicular (SCV), internal mammary nodes (IMN) and level III axilla is not well studied. We aimed to evaluate the outcomes of patients with breast cancer and advanced nodal disease that received a nodal boost.

METHODS AND MATERIALS

This retrospective study included 79 patients with advanced nodal disease who underwent adjuvant radiation with a nodal boost to the SCV, IMNs, and/or axilla. All patients had radiographic changes after systemic therapy concerning for gross nodal disease. Overall survival, disease-free survival (DFS), and local recurrence-free survival were estimated using the Kaplan-Meier method.

RESULTS

All patients received an initial 50 Gy to the breast/chest wall and regional nodes, of whom 46.8% received an IMN boost, 38.0% axillary (ax)/SCV boost, and 15.2% both IMN and ax/SCV boost (IMN + ax/SCV). Most patients had hormone receptor positive (74.7%) and human epidermal growth factor receptor 2 negative disease (83.5%). In addition, 12.7% of patients had clinical (c) N2 disease, 21.5% cN3A disease, 51.9% cN3B disease, and 5.1% cN3C disease. Most patients received chemotherapy (97.5%). The median nodal boost dose was 10 Gy (range, 10-20 Gy), with 21.6% of IMN, 16.7% of ax/SCV, and 16.7% of IMN + ax/SCV receiving 14 to 20 Gy. With a median follow up of 30 months, the 3-year local recurrence-free survival, DFS, and overall survival rates were 94.5%, 86.3%, and 93.8%, respectively. Crude rates of failure were 13.9% (10.1% distant failure [DF] alone; 3.8% DF + locoregional failure [LRF]). Rates of failure by boost group were 13.3% for ax/SCV (10.0% DF alone; 3.3% DF + LRF), 5.4% for IMN (2.7% DF alone, 2.7% DF + LRF), and 41.7% for IMN + ax/SCV (33.3% DF, 8.3% DF + LRF). There were no LRFs without DFs. The median time to failure was 22.8 months (interquartile range, 18-34 months). Clinical tumor size and IMN + ax/SCV versus IMN or ax/SCV alone was associated with worse DFS (hazard ratio [HR]: 9.78; 95% confidence interval [CI], 2.07-46.2; P = .004 and HR: 9.49; 95% CI, 2.67-33.7; P = .001, respectively). On multivariate analysis, IMN + ax/SCV versus IMN or ax/SCV alone retained significance (HR: 4.80; 95% CI, 1.27-18.13; P = .02).

CONCLUSIONS

In this population of patients with locally advanced breast cancer, the majority of failures were distant with no isolated LRFs. Failures were the highest in the IMN + ax/SCV group (∼40%). Further treatment escalation is necessary for these patients.

Chronological Skin Changes Through Postmastectomy Radiotherapy Based on Radiotherapy Techniques: Using Quantitative Dermatological Measurements

BACKGROUND

There has been few research on how to measure skin status quantitatively throughout the course of radiotherapy (RT). We evaluated the changes in the skin induced by 2 different RT techniques using objective measurements in breast cancer patients.

METHODS

In this prospective study, between August 2015 and March 2019, serial measurements of the dermatological factors during and after postmastectomy radiotherapy (PMRT) were made in 40 breast cancer patients. PMRT was performed using the conventional photon tangential technique (PTT) or patient-tailored bolus technique (PTB). We analyzed these measurements using a mixed effect model and compared the clinically evaluated radiation dermatitis and patient-reported outcomes (PROs).

RESULTS

The trend of changes in melanin and erythema was significantly different between the PTB and PTT groups (p = 0.045 and 0.016, respectively). At the 3-month follow-up erythema intensity and melanin were higher in the PTB group than in PTT group (both p < 0.001). Eight patients (40% in the PTB group) reported grade 2 radiation dermatitis and 1 patient (5% in the PTB group) reported grade 3 radiation dermatitis. No grade 2 or higher radiation dermatitis was found in the PTT group. Ten patients (50%) in the PTB group and 3 patients (15%) in the PTT group reported severe erythema likely due to questionable clinical evaluation, but hyperpigmentation was rarely reported at the follow-up visits.

CONCLUSION

The PTB group showed higher intensity of erythema at the end of RT than the PTT group and the increase in melanin lasted until the 3-month follow-up visits in the PTB group. Moreover, patients subjectively appealed more severe symptoms following PTB in PROs.

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.

Outcome of radiotherapy for clinically overt metastasis to the internal mammary lymph node in patients receiving neoadjuvant chemotherapy and breast cancer surgery

PURPOSE

This study was aimed to assess the outcome of radiotherapy and determine prognostic factors for survival in breast cancer patients with clinically overt metastasis to the internal mammary lymph node (IMN+).

METHODS

We retrospectively reviewed the medical records of 193 patients with IMN + breast cancer who received neoadjuvant chemotherapy (NAC), breast surgery without internal mammary lymph node (IMN) dissection, and postoperative radiotherapy at 9 hospitals between 2009 and 2013. Breast-conserving surgery or mastectomy was performed after taxane-based NAC. Radiotherapy was administered to the whole breast/chest wall and regional nodes. IMN-covering radiotherapy was performed in 92.2% of patients with median dose of 58.4 Gy (range, 44.9-69.1 Gy). The overall survival (OS), disease-free survival (DFS), and IMN failure-free survival (IMNFFS) were analyzed.

RESULTS

After median follow-up of 71 months, 9 patients (4.7%) developed IMN failure and simultaneous distant metastasis. The 5-year DFS, OS, and IMNFFS was 68.6%, 81.8%, and 95.3%, respectively. Non-triple-negative breast cancer, Ki-67 ≤ 10%, pathological complete response (CR) in tumor and axillary node, and radiologic CR of IMN after NAC were significant factors for predicting higher DFS; however, IMN radiation dose was not significant determinants for DFS. The 5-year DFS of patients with IMN-dose ≤ 50.0 Gy and those with >50.0 Gy was 86.7% and 76.7%, respectively (p = 0.41).

CONCLUSIONS

A multimodality strategy including NAC, breast surgery, and IMN-covering radiotherapy was effective for patients with overt IMN + breast cancer. Even without an IMN dissection, most patients were IMN failure-free with an IMN-focusing radiotherapy.

Prognostic significance of the primary tumor site and immune indexes in patients with estrogen receptor-positive, human epidermal growth factor receptor-2-negative breast cancer

BACKGROUND

The ability to predict high risk factors for recurrence after neoadjuvant chemotherapy (NAC) is controversial. The purpose of the present study was to investigate the prognostic significance of tumor location, tumor-infiltrating lymphocyte (TIL) level, and pretreatment lymphocyte-to-monocyte ratio (LMR) in determining the survival of patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor-2 (HER2)-negative breast cancer after treatment with NAC.

METHODS

The clinical data of 285 ER-positive, HER2-negative patients with clinical stage II-III breast cancer were analyzed from January 2009 to January 2015. To explore the prognostic factors for ER-positive, HER2-negative patients, we combined the conventional clinicopathological prognostic factors with tumor location, pretreatment LMR, and TIL. In addition, samples from 79 patients, who did not achieve pathological complete response (pCR) testing after NAC, were selected for hematoxylin-eosin (HE) staining to analyze the effect of TIL on prognosis.

RESULTS

An LMR >5.2 was correlated with better 5-year disease-free survival (DFS) and overall survival (OS; P<0.001 and P<0.001, respectively). Patients with lower-inner/central quadrant tumors had lower 5-year DFS and OS than patients with tumors in the other quadrants (P=0.012 and P=0.048). Patients with a lower TIL level (≤10%) had better 5-year DFS than patients with a higher TIL level (P=0.010). According to the results of the multivariate analyses, tumor location was an independent prognostic factor for 5-year DFS (P=0.021). Pretreatment LMR was associated with both 5-year DFS and OS (P<0.001 and P<0.001, respectively). In the subgroup analysis stratified by TIL level, the TIL level and the initial clinical stage were associated with 5-year DFS (P=0.027 and P<0.001, respectively).

CONCLUSIONS

We explored the prognostic significance of the tumor site, TIL level, and pretreatment LMR level for ER-positive, HER2-negative patients. We concluded that the lower-inner/central quadrant tumors, TIL >10%, and pretreatment LMR level ≤5.2 were correlated with a poor prognosis. More aggressive NAC and/or endocrine therapy with internal mammary node radiotherapy (IMN-RT) should be administered to address the relatively poor prognosis of patients with breast carcinoma presenting the aforementioned adverse factors.