ACR appropriateness criteria on postmastectomy radiotherapy expert panel on radiation oncology-breast

Comparative Analysis of Dosimetry: IMRT versus 3DCRT in Left-Sided Breast Cancer Patients with Considering Some Organs in Out - of - Field Borders

Purpose

The local management approach for node-positive breast cancer has undergone substantial evolution. Consequently, there exists a pressing need to enhance our treatment strategies by placing greater emphasis on planning and dosimetric factors, given the availability of more conformal techniques and delineation criteria, achieving optimal goals of radiotherapy treatment. The primary aim of this article is to discuss how the extent of regional nodal coverage influences the choice between IMRT and 3D radiation therapy for patients.

Patients and Methods

A total of 15 patients diagnosed with left breast cancer with disease involved lymph nodes were included in this study. Delivering the recommended dose required the use of a linear accelerator (LINAC) with photon beams energy of 6 mega voltage (6MV). Each patient had full breast radiation using two planning procedures: intensity-modulated radiotherapy (IMRT) and three-dimensional radiotherapy (3D conformal). Following the guidelines set forth by the Radiation Therapy Oncology Group (RTOG), the planned treatment coverage was carefully designed to fall between 95% and 107% of the recommended dose. Additionally, Dose Volume Histograms (DVHs) were generated the dose distribution within these anatomical contours.

Results and Conclusion

The DVH parameters were subjected to a comparative analysis, focusing on the doses absorbed by both Organs at Risk (OARs) and the Planning Target Volume (PTV). The findings suggest that low doses in IMRT plan might raise the risk of adverse oncological outcomes or potentially result in an increased incidence of subsequent malignancies. Consequently, the adoption of inverse IMRT remains limited, and the decision to opt for this therapy should be reserved for situations where it is genuinely necessary to uphold a satisfactory quality of life. Additionally, this approach helps in reducing the likelihood of developing thyroid problems and mitigates the risk of injuries to the supraclavicular area and the proximal head of the humerus bone.

Assessment of Postmastectomy Radiation Therapy Receipt by Age and Association With Outcomes in Women With Breast Cancer

PURPOSE

Postmastectomy radiation therapy (PMRT) reduces locoregional recurrence (LRR) and improves overall survival (OS) in patients with breast cancer. Young age has been recognized as a risk factor for LRR. The primary objective of this study was to determine if recommendations for PMRT differed among patients younger than 50 years as compared to women aged 50 years or older.

METHODS

We reviewed medical records of patients with breast cancer who underwent mastectomy with or without PMRT from 2010 through 2018. Univariable and multivariable models were used to estimate the association of age with PMRT.

RESULTS

Of 2471 patients, 839 (34%) were <50 years; 1632 (66%) were ≥50 years. Patients <50 years had a higher percentage of grade 3 tumors, hormone receptor (HR) negative and/or Her-2/neu positive tumors, clinical stage T2/T3 tumors, and nodal involvement. Compared with patients ≥50 years, patients <50 years were more likely to undergo PMRT (OR 1.57; P = .001) and regional node irradiation (RNI) to the internal mammary nodes. Advanced clinical and pathologic stage, invasive tumor histology, the presence of lymphovascular invasion, and treatment with systemic chemotherapy were predictors of PMRT receipt for patients <50 years (P < .05). PMRT was associated with improved OS and recurrence free survival (RFS) among all patients (P < .01).

CONCLUSION

Patients <50 years were more likely to undergo PMRT and to receive RNI to the internal mammary nodes but were also more likely to have other risk factors for recurrence that would warrant a PMRT recommendation. PMRT improved OS and RFS for all patients.

Skin perfusion and oxygen saturation after mastectomy and radiation therapy in breast cancer patients

The pathophysiological mechanism behind complications associated with postmastectomy radiotherapy (PMRT) and subsequent implant-based breast reconstruction are not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion and saturation in the skin after mastectomy and assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate - MN). Skin microvascular perfusion and oxygenation >2 years after PMRT were measured using white light diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) in the irradiated chest wall of 31 women with the contralateral breast as a control. In the non-irradiated breast, the perfusion after application of MN (median 0.84, 25th-75th centile 0.59-1.02 % RBC × mm/s) was higher compared to the irradiated chest wall (median 0.51, 25th-75th centile 0.21-0.68 % RBC × mm/s, p < 0.001). The same phenomenon was noted for saturation (median 91 %, 25th-75th centile 89-94 % compared to 89 % 25th-75th centile 77-93 %, p = 0.001). Eight of the women (26%) had a ≥10 % difference in skin oxygenation between the non-irradiated breast and the irradiated chest wall. These results indicate that late microvascular changes caused by radiotherapy of the chest wall significantly affect skin perfusion and oxygenation.

Nomogram-Based Risk Stratification to Identify Patients with T3N0M0 Breast Cancer with Survival Benefit from Postmastectomy Radiotherapy

BACKGROUND

The survival benefit of postmastectomy radiotherapy (PMRT) for patients with T3N0M0 breast cancer remains controversial. This study aimed to identify patients with a survival benefit from PMRT by developing a novel risk stratification model.

PATIENTS AND METHODS

The study recruited 2062 patients with pT3N0M0 breast cancer from the Surveillance, Epidemiology, and End Results (SEER) database who underwent mastectomy between 2010 and 2019. Overall survival (OS) and breast-cancer-specific survival (BCSS) prognostic nomograms based on multivariate Cox regression were constructed to quantify the survival risk and classify patients into low- and high-risk groups. Subgroup analyses were undertaken to assess the role of PMRT according to age and risk stratification.

RESULTS

In the overall cohort, PMRT was beneficial in improving OS in patients with pT3N0 breast cancer (5-year OS, non-PMRT versus PMRT: 76.6% vs. 84.2%, P < 0.001), while the benefit on BCSS was not significant (P = 0.084). On the basis of the risk stratification nomogram, in the high-risk group, PMRT improved OS in young patients by 10.1%, OS in elderly patients by 12.4%, and BCSS by 10.2% (P < 0.05), but the use of PMRT in the low-risk group did not improve OS and BCSS in all patients (P > 0.05).

CONCLUSIONS

We presented a new method for quantifying risk using the nomogram to identify patients with high risk of pT3N0M0 breast cancer. This study found that older patients in the newly constructed high-risk group benefited from OS and BCSS benefits from PMRT, while for younger high-risk patients, there was only a benefit in terms of OS.

American Radium Society Appropriate Use Criteria Postmastectomy Radiation Therapy: Executive Summary of Clinical Topics

PURPOSE

To conduct an appropriate use criteria expert panel update on clinical topics relevant to current clinical practice regarding postmastectomy radiation therapy (PMRT).

METHODS AND MATERIALS

An analysis of the medical literature from peer-reviewed journals was conducted from May 4, 2010 to May 4, 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to search the PubMed database to retrieve a comprehensive set of relevant articles. A well-established methodology (modified Delphi) was used by the expert panel to rate the appropriate use of procedures.

RESULTS

Evidence for key questions in PMRT regarding benefit in special populations and technical considerations for delivery was examined and described. Risk factors for local-regional recurrence in patients with intermediate-risk disease that indicate benefit of PMRT include molecular subtype, age, clinical stage, and pathologic response to neoadjuvant chemotherapy. Use of hypofractionated radiation in PMRT has been examined in several recent randomized trials and is under investigation for patients with breast reconstruction. The use of bolus varies significantly by practice region and has limited evidence for routine use. Adverse effects occurred with both PMRT preimplant and postimplant exchange in 2-staged breast reconstruction.

CONCLUSIONS

Most patients with even limited nodal involvement will likely benefit from PMRT with significant reduction in local-regional recurrence and potential survival. Patients with initial clinical stage III disease and/or any residual disease after neoadjuvant chemotherapy should be strongly considered for PMRT. Growing evidence supports the use of hypofractionated radiation for PMRT with equivalent efficacy and decreased acute side effects, but additional evidence is needed for special populations. There is limited evidence to support routine use of bolus in all patients. Timing of PMRT regarding completion of 2-staged breast reconstruction requires a discussion of increased risks with radiation postimplant exchange compared with increased risk of failure of reconstruction or surgical complications with radiation preimplant exchange.

Quality of Life in Breast Reconstruction Patients after Irradiation to Tissue Expander: A Propensity-Matched Preliminary Analysis

BACKGROUND

Tissue expanders (TEs) are routinely placed as a first step in breast reconstruction for women who require postmastectomy radiation therapy (PMRT). The final reconstruction can then be performed with implants or conversion to autologous tissues. The purpose of this study was to compare patient-reported outcomes and surgical complications in autologous (ABR) versus implant-based breast reconstruction (IBR) patients following TE-PMRT.

METHODS

The authors performed a propensity score preliminary analysis (1:1 matching, no replacement) in patients undergoing ABR or IBR following TE-PMRT. Matched covariates included age, race/ethnicity, smoking status, body mass index, history of psychiatric diagnosis, and laterality of reconstruction. Outcomes of interest included complications and BREAST-Q scores for Satisfaction with Breasts, Physical Well-Being of the Chest, Sexual Well-Being, and Psychosocial Well-Being domains.

RESULTS

Of 341 patients with TE-PMRT, a total of 106 patients were included in the matched analysis: 53 ABR patients and 53 IBR patients. ABR and IBR did not differ significantly in matched baseline, cancer, and surgical characteristics. ABR patients had higher scores for Satisfaction with Breasts (greater than the four-point minimal clinically important difference) at all postreconstruction time points compared with IBR patients ( P < 0.05). There were no significant postoperative differences in other BREAST-Q domains. The incidence of complications after definitive reconstruction did not differ significantly among cohorts.

CONCLUSIONS

In this matched preliminary analysis, patients who underwent ABR following irradiation to a TE demonstrated superior satisfaction with breast scores compared with IBR patients. Higher powered matched studies are needed to improve shared decision-making for patients who require mastectomy and PMRT as part of their treatment.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Robustness of VMAT to setup errors in postmastectomy radiotherapy of left-sided breast cancer: Impact of bolus thickness

BACKGROUND

Volumetric modulated arc therapy (VMAT) with varied bolus thicknesses has been employed in postmastectomy radiotherapy (PMRT) of breast cancer to improve superficial target coverage. However, impact of bolus thickness on plan robustness remains unclear.

METHODS

The study enrolled ten patients with left-sided breast cancer who received radiotherapy using VMAT with 5 mm and 10 mm bolus (VMAT-5B and VMAT-10B). Inter-fractional setup errors were simulated by introducing a 3 mm shift to isocenter of the original plans in the anterior-posterior, left-right, and inferior-superior directions. The plans (perturbed plans) were recalculated without changing other parameters. Dose volume histograms (DVH) were collected for plan evaluation. Absolute dose differences in DVH endpoints for the clinical target volume (CTV), heart, and left lung between the perturbed plans and the original ones were used for robustness analysis.

RESULTS

VMAT-10B showed better target coverage, while VMAT-5B was superior in organs-at-risk (OARs) sparing. As expected, small setup errors of 3 mm could induce dose fluctuations in CTV and OARs. The differences in CTV were small in VMAT-5B, with a maximum difference of -1.05 Gy for the posterior shifts. For VMAT-10B, isocenter shifts in the posterior and right directions significantly decreased CTV coverage. The differences were -1.69 Gy, -1.48 Gy and -1.99 Gy, -1.69 Gy for ΔD95% and ΔD98%, respectively. Regarding the OARs, only isocenter shifts in the posterior, right, and inferior directions increased dose to the left lung and the heart. Differences in VMAT-10B were milder than those in VMAT-5B. Specifically, mean heart dose were increased by 0.42 Gy (range 0.10 ~ 0.95 Gy) and 0.20 Gy (range -0.11 ~ 0.72 Gy), and mean dose for the left lung were increased by 1.02 Gy (range 0.79 ~ 1.18 Gy) and 0.68 Gy (range 0.47 ~ 0.84 Gy) in VMAT-5B and VMAT-10B, respectively. High-dose volumes in the organs were increased by approximate 0 ~ 2 and 1 ~ 3 percentage points, respectively. Nevertheless, most of the dosimetric parameters in the perturbed plans were still clinically acceptable.

CONCLUSIONS

VMAT-5B appears to be more robust to 3 mm setup errors than VMAT-10B. VMAT-5B also resulted in better OARs sparing with acceptable target coverage and dose homogeneity. Therefore 5 mm bolus is recommended for PMRT of left-sided breast cancer using VMAT.

Association of Radiation Timing with Long-Term Satisfaction and Health-Related Quality of Life in Prosthetic Breast Reconstruction

BACKGROUND

Radiation therapy is increasingly used after breast cancer surgery, which may impact patients' postoperative quality of life. This study assessed differences in long-term patient satisfaction and health-related quality of life after radiation therapy administered at different stages of implant-based breast reconstruction or with no radiation after surgery.

METHODS

In this observational study, long-term outcomes were evaluated for four cohorts of women who completed breast reconstruction and received (1) no radiation, (2) radiation before tissue expander placement, (3) radiation after tissue expander placement, or (4) radiation after permanent implant between 2010 and 2017 at Memorial Sloan Kettering. Satisfaction and health-related quality of life were assessed using the prospectively collected Satisfaction with Breasts and Physical Well-Being of Chest BREAST-Q subscales. Score distributions were examined by radiation exposure status for 3 years after surgery using nonparametric analyses and regression models.

RESULTS

Of 2932 patients who met the inclusion criteria, 25.8 percent received radiation during breast cancer treatment, including before tissue expander placement ( n = 239; 8.2 percent), after tissue expander placement ( n = 290; 9.9 percent), and after implant placement ( n = 228; 7.8 percent). Radiotherapy patients had average scores 7 to 9 points lower at all postoperative time points for Satisfaction with Breasts and Physical Well-Being of Chest subscales ( p < 0.001). Although patient-reported outcomes did not differ by radiation timing, there were higher rates of severe capsular contracture with postimplant radiotherapy ( p < 0.001).

CONCLUSIONS

Radiation therapy significantly affected patient satisfaction and health-related quality of life following implant breast reconstruction through 3 years postoperatively. Patient perception of outcome was unaffected by radiotherapy timing; however, capsular contracture was higher after postimplant radiotherapy, suggesting there may be an advantage to performing radiotherapy before placement of the final reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Postmastectomy Radiotherapy After Neoadjuvant Chemotherapy in cT1-2N+ Breast Cancer Patients: A Single Center Experience and Review of Current Literature

Purpose

Postmastectomy radiotherapy (PMRT) after neoadjuvant chemotherapy (NAC) in breast cancer patients with initial clinical stage cT1-2N+, especially for those who achieved ypT1-2N0, is still controversial. This study was to evaluate the survival prognosis of cT1-2N+ patients after NAC with or without PMRT, and to discuss the selection of patients who may omit PMRT.

Patients and Methods

From January 2005 to December 2017, 3055 female breast cancer patients underwent mastectomy in our medical center, among whom 215 patients of cT1-2N+ stage, receiving NAC with or without PMRT were finally analyzed. The median follow-up duration was 72.6 months. The primary endpoint was disease-free survival (DFS), and secondary endpoint was overall survival (OS). Comparison was conducted between PMRT and non-PMRT subgroups.

Results

Of the 215 eligible patients, 35.8% (77/215) cT1-2N+ patients achieved ypT0-2N0 after NAC while 64.2% (138/215) of the patients remained nodal positive (ypT0-2N+). The 5-year DFS of ypT0-2N0 non-PMRT was 79.5% (95% confidence interval [CI] 63.4-95.6%). No statistically significant difference was observed between the ypT0-2N0 PMRT and non-PMRT subgroups for the 5-year DFS (78.5% vs 79.5%, p = 0.673) and OS (88.8% vs 90.8%, p = 0.721). The 5-years DFS didn't obviously differ between the ypT0-2N0 non-PMRT subgroup and cT1-2N0 subgroup (79.5% vs 93.3%, p = 0.070). By using Cox regression model in multivariate analyses of prognosis in ypT0-2N+ PMRT subgroup, HER2 overexpression and triple-negative breast cancer were significantly poor predictors of DFS and OS, while ypN stage was significant independent predictors of OS.

Conclusion

An effective response to NAC (ypT0-2N0) indicates a sufficiently favorable prognosis, and PMRT might be omitted for cT1-2N+ breast cancer patients with ypT0-2N0 after NAC.

Breast Radiotherapy after Oncoplastic Surgery-A Multidisciplinary Approach

Oncoplastic breast surgery encompasses a range of techniques used to provide equitable oncological outcomes compared with standard breast surgery while, simultaneously, prioritizing aesthetic outcomes. While the outcomes of oncoplastic breast surgery are promising, it can add an extra complexity to the treatment paradigm of breast cancer and impact on decision-making surrounding adjuvant therapies, like chemotherapy and radiotherapy. As such, early discussions at the multidisciplinary team meeting with surgeons, medical oncologists, and radiation oncologists present, should be encouraged to facilitate best patient care.

The Impact of Post-Mastectomy Radiotherapy on Survival Outcomes in Breast Cancer Patients Who Underwent Neoadjuvant Chemotherapy

Simple Summary

The benefits of post-mastectomy radiotherapy (PMRT) may vary depending on patients’ responses to neoadjuvant chemotherapy (NAC), although PMRT is useful for patients who underwent NAC. One can consider omitting PMRT in patients who have achieved pathologic complete response or who have minimal residual disease, with a neoadjuvant response index value of 0.7–1.0.

Abstract

This study aimed to determine whether post-mastectomy radiotherapy (PMRT) is beneficial for the prognosis of patients who achieved pathologic complete response (pCR), or who had minimal residual disease, after undergoing neoadjuvant chemotherapy (NAC). Patients who underwent a total mastectomy between 2006 and 2018, after NAC, were included. Patients who did not receive PMRT were matched using 1:3 propensity score matching (PSM). Kaplan–Meier survival curves were used to compare locoregional recurrence-free survival (LRRFS) and overall survival (OS). A total of 368 patients were included after 1:3 PSM. PMRT improved the LRRFS (p = 0.016) and OS (p = 0.017) rates of patients who underwent NAC. However, PMRT did not affect the prognosis of patients with pCR (LRRFS: p = 0.999; OS: p = 0.453). In addition, PMRT had a limited effect on LRRFS and OS in patients who responded well to NAC, with a neoadjuvant response index (NRI) value of 0.7–1.0 (LRRFS: p = 0.568; OS: p = 0.875). PMRT improved the OS of patients with a large residual tumor burden, such as nodal metastases or pathologic stage II/III. The benefits of PMRT vary depending on the patients’ response to NAC, although PMRT is useful for treating patients who underwent NAC. PMRT can be omitted, not only in patients with pCR, but also in good responders with an NRI value of 0.7–1.0.

The Survival Effect of Chest Wall With or Without Regional Lymphatic Radiotherapy for Breast Cancer Patients With T3~4N0M0

Background

Peripheral lymphatic radiotherapy in patients with pT3N0M0 and pT4N0M0 breast cancer has been a matter of considerable debate among radiation oncologists. This is the first report in a non-Caucasian population.

Patients and Methods

The study included 165 pT3N0M0 and pT4N0M0 patients. Univariate, multivariate, propensity score matching (PSM), and Kaplan-Meier analyses were conducted to evaluate the survival of patients. We also review all the literature about regional lymph nodes radiation in T3-4N0M0 patients and summarize them with tables to compare with the present study.

Results

The median follow-up duration was 58.7 months. Multivariate analyses showed that advance T stage and grade were dependent poor prognostic factors for OS, DMFS, LRFS, and DFS between group A (chest wall radiation) and group B (chest wall and regional lymph nodes radiation). The overall survival (OS), disease-free survival (DFS), local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were not significantly different between group A and group B. The 5-year OS rate was 92.3% vs 89.7% for group A and group B, respectively (P=0.819). The 5-year LRFS rate was 94.9% vs 94.3% for group A and group B, respectively (P=0.852). Fifty-four pairs of patients were selected after propensity score matching (PSM) analysis was conducted. There was also no significant difference between group A and group B in regard to the OS, DFS, LRFS, and DMFS rates after PSM. The patients included in previous studies were all Caucasians, and our study was focused on non-Caucasians. The cases of previous studies were 10 to 20 years ago, but our study has more recent cases. The radiotherapy techniques of previous studies were conventional, and the techniques used in our study were three-dimensional conformal radiotherapy (3DCRT) or intensity modulated radiotherapy (IMRT).

Conclusion

Both our study and previous studies suggested that regional lymph nodes radiation cannot improve the survival rate for breast cancer patients with T3-4N0M0 in non-Caucasian population. Advance T stage and grade were the dependent poor prognostic factors for T3-4N0M0 patients.

Effect of Radiation Therapy on Microsurgical Deep Inferior Epigastric Perforator Flap Breast Reconstructions: A Matched Cohort Analysis of 4577 Cases

INTRODUCTION

Breast reconstruction with autologous tissue is a state-of-the art procedure. Several patient-related factors have been identified with regard to the safety and efficacy of these reconstructions. The presented study investigates the impact of prereconstruction radiation on outcomes of deep inferior epigastric perforator (DIEP) free-flap breast reconstructions using largest database available in Europe.

MATERIALS AND METHODS

Between 2011 and 2019, 3926 female patients underwent 4577 DIEP flap breast reconstructions in 22 different German breast cancer centers. The cases were divided into a no-radiation (NR) and a radiation (R) group, according to radiation status before reconstruction. Groups were compared with regard to surgical complications and free-flap outcome.

RESULTS

Overall, there was no significant difference between the groups regarding the rate of total flap loss [1.9% (NR) vs 2.1% (R), P = 0.743], partial flap loss [0.9% (NR) vs 1.5 (R), P = 0.069], and revision surgery [vascular revision: 4.4% (NR) vs 4.1% (R), P = 0.686; wound revision: 7.6% (NR) vs 9.4% (R), P = 0.122]. However, the patients had a significantly higher risk of developing wound healing disturbances at the recipient site [1.2% (NR) vs 2.1% (R), P = 0.035] and showed significantly longer hospitalization {8 [SD, 8.4 (NR)] vs 9 [SD, 15.4 {R}] days, P = 0.006} after prereconstruction radiation.

CONCLUSIONS

Our findings suggest that DIEP flap reconstruction after radiation therapy is feasible. Women with a history of radiation therapy should, however, be informed in detail about the higher risk for wound healing disturbances at the recipient site.

Impact of GBBS algorithm on post-mastectomy scar boost irradiation of breast using catheter flap

Purpose

Post-mastectomy radiation therapy significantly reduces locoregional recurrence rates, which can be achieved with external beam radiotherapy delivered to chest wall, followed by scar irradiation either by electron or high-dose-rate (HDR) mould brachytherapy. The present study evaluates dosimetric advantage of Acuros^® BV, a TG-186 MBDCA, over TG-43 formalism using ¹⁹²Ir source for HDR brachytherapy in chest wall scar boost using catheter flap.

Material and methods

A total of 25 patients, free of cardiac and pulmonary co-morbidities, who met the inclusion criteria were involved in the study. Catheter flap made of silicon with 20 channels was used to deliver a total dose of 7.5 Gy/3 fx by HDR surface mould brachytherapy to delineated scar volume. Plan was optimized with iterative method to obtain desired results with TG-43 formalism, followed by Acuros^® BV (GBBS algorithm) without altering dwell positions or time. The two algorithm plans were analyzed qualitatively and quantitatively with dose-volume histograms.

Results

The mean D_98% CTV-HDR_evl coverage decreased by 1.16% compared to TG-43, and near-maximum dose decreased by 8.18% (p = 0.000), mean D_max dose to CTV-HDR_evl, and mean D_mean dose was lesser by 6.25% (p = 0.000) and 10.82% (p = 0.000), respectively, compared to TG-43. Heart D_2% showed significant results, whereas D_median (cGy) revealed very significant difference. A 5 mm thick skin contour showed statistically significant results (p = 0.000) for V_150% and V_200%.

Conclusions

The presented data showed how Acuros^® BV, algorithm-based calculation in scar boost irradiation of breast, accounting for a mass density of the medium and scatter condition, considered actual dose prediction in a medium.

Dosimetric assessment of brass mesh bolus and transparent polymer-gel type bolus for commonly used breast treatment delivery techniques

We investigated skin dose enhancements of brass mesh bolus (BMB) and a recently developed transparent polymer-gel bolus (PGB) for clinically relevant breast treatment delivery techniques. The dose enhancement of the breast surface with BMB and PGB were compared to that of tissue-equivalent bolus. Three breast treatment plans were generated on CT scans of an anthropomorphic chest phantom: tangential step-and-shoot 3D conformal (3DCRT) planned using Field-in-Field (FiF), tangential sliding-window 3DCRT using Electronic Compensator (EC), and volumetric modulated arc therapy (VMAT). All plans were created using 6 MV photons and a prescription dose (Rx) of 180 cGy per fraction. Skin doses of all 3 plans were measured with radiochromic films, separately delivered in triplicate. Each plan was delivered to the phantom without bolus, and then with BMB (1 or 2 layers; 3 or 10 mm tissue-equivalent), PGB, and Superflab (3, 5, and 10 mm tissue-equivalent). Doses were determined by reading the radiochromic films with a flatbed scanner, and analyzing the images using a calibration curve for each specific batch. For all bolus types and plans, surface doses averaged over the 3 measurements were between 88.4% and 107.4% of Rx. Without bolus, average measured skin doses were between 51.2% and 64.2% of Rx. Skin doses with BMB and PGB were comparable to that with tissue-equivalent bolus. Over all 3 treatment delivery techniques, using BMB resulted in average skin doses of 92.8% and 102.1% for 1- and 2 layers, respectively, and using PGB results in average skin doses of 94.8%, 98.2%, and 99.7% for 3, 5, and 10-mm tissue-equivalent, respectively. The average measured skin doses with BMB and PGB agreed within ± 3% compared to the tissue-equivalent thickness bolus. We concluded that BMB and PGB are clinically equivalent in skin dose enhancement for breast treatment as the 3, 5, and 10 mm tissue-equivalent bolus.

Long-Term Outcomes of Immediate Autologous Breast Reconstruction for Breast Cancer Patients

BACKGROUND

There is limited information on the oncological outcomes of immediate autologous breast reconstruction in the Asian population. This study aimed to evaluate the oncological outcomes of immediate one-stage autologous breast reconstruction using a free perforator flap for breast cancer patients at a single institution in Japan.

METHODS

We retrospectively reviewed 239 patients who underwent immediate one-stage autologous breast reconstruction using a free perforator flap after skin- or nipple-sparing mastectomy. The whole breast was pathologically analyzed in 5-mm sections. Clinical and pathological data were collected from medical records.

RESULTS

For tumor stage among the 239 patients, 101 (42.3%) had stage 0, 127 (53.1%) had stage I and II, and 11 (4.6%) had stage III. Twenty-three patients (9.6%) had margin involvement in the surgical specimen. Adjuvant chemotherapy was performed in 75 patients (30%), and endocrine therapy was administered in 153 patients (64%). Radiation therapy was performed in 15 patients (6.3%) because of multiple lymph node metastases or margin involvement. With a median follow-up time of 73 mo, local recurrence was found in 3.3%, distant metastases in 2.5%, and contralateral breast cancer in 3.7%. All patients with local recurrence did not receive radiation therapy as adjuvant treatment.

CONCLUSIONS

Among the patients who underwent immediate one-stage autologous reconstruction after breast surgery, 3.3% had local recurrence. For patients with margin involvement, radiation therapy is a promising option.

Postmastectomy radiation therapy in early breast cancer: Utility or futility?

Postmastectomy radiation therapy (PMRT) has been shown to reduce the risk of locoregional recurrence (LRR), in patients with locally advanced breast cancer who are considered of high-risk because of large tumors (>5 cm) or presence of axillary lymph-node involvement, as well as to reduce breast cancer mortality. However, controversy still remains with respect to indication of PMRT in case of early-stages invasive tumors. This review aims to analyze the impact that PMRT has on final results in women with breast tumors in different scenarios that would otherwise be considered as early breast cancer, such as extensive DCIS, tumors without axillary lymph-node involvement or with minimal microscopic nodal-involvement. The existence of risk factors including young age, premenopausal status, and presence of lymphovascular invasion (LVI), high grade or tumor size >2 cm has been associated with an increased risk of LRR in these patients at early-stages and advises to consider PMRT in selected cases.

Intensity-modulated radiation therapy using TomoDirect for postoperative radiation of left-sided breast cancer including lymph node area: comparison with TomoHelical and three-dimensional conformal radiation therapy

Intensity-modulated radiation therapy (IMRT) delivers an excellent dose distribution compared with conventional three-dimensional conformal radiation therapy (3D-CRT) for postoperative radiation including the lymph nodes in breast cancer patients. The TomoTherapy system, developed exclusively for IMRT, has two treatment modes: TomoDirect (TD) with a fixed gantry angle for beam delivery, and TomoHelical (TH) with rotational beam delivery. We compared the characteristics of TD with TH and 3D-CRT plans in the breast cancer patients. Ten consecutive women with left breast cancer received postoperative radiation therapy using TD including the chest wall/residual breast tissue and level II-III axial and supraclavicular lymph node area. Fifty percent of the planning target volume (PTV) was covered with at least 50 Gy in 25 fractions. TD, TH and 3D-CRT plans were created for each patient, with the same dosimetric constraints. TD and TH showed better dose distribution to the PTV than 3D-CRT. TD and 3D-CRT markedly suppressed low-dose spread to the lung compared with TH. Total lung V5 and V10 were significantly lower, while V20 was significantly higher in the TD and 3D-CRT plans. The mean total lung, heart and contralateral breast doses were significantly lower using TD compared with the other plans. Compared with 3D-CRT and TH, TD can provide better target dose distribution with optimal normal-organ sparing for postoperative radiation therapy including the chest wall/residual breast tissue and lymph node area in breast cancer patients. TD is thus a useful treatment modality in these patients.

The Impact of a Postmastectomy Chest Wall Scar Boost on Local Recurrence-free Survival in High-risk Patients

INTRODUCTION

A scar boost following postmastectomy radiation to a total dose of > 50 Gy can be considered in cases of invasive breast cancer with high-risk features including advanced tumor stage, lymphovascular space invasion (LVSI), and positive margins. The purpose of this study was to determine the impact of a scar boost on 5-year local recurrence-free survival (LRFS).

MATERIALS AND METHODS

We retrospectively analyzed 140 patients with invasive breast cancer treated with mastectomy and postmastectomy radiation at a single institution between 2007 and 2016. Patients received 50 to 50.4 Gy to the chest wall and the majority of scar boosts were 9 to 10 Gy. LRFS was examined using the Kaplan-Meier method and univariable Cox regression.

RESULTS

A total of 140 patients met inclusion criteria with a median follow-up time of 48 months. Ninety-four (67.1%) patients did receive a scar boost and 46 (32.9%) patients did not. On subset analysis of patients with LVSI or positive margins, 5-year LRFS was 79.3% in patients treated with scar boost compared with 71.1% in patients without a scar boost (P = .537). In patients with T3 or T4 disease, 5-year LRFS was 80.9% in those who received scar boost and 71.6% in patients who did not (P = .967). The use of a scar boost was not associated with a significant improvement in LRFS on Cox regression (hazard ratio, 0.83; 95% confidence interval, 0.37-1.84; P = .654).

CONCLUSION

Use of a scar boost following postmastectomy radiation decreased the absolute percentages of local recurrences in patients with high-risk features; however, this did not translate into a statistically significant benefit.

Management of the axilla after neo-adjuvant chemotherapy for breast cancer: Sentinel node biopsy and radiotherapy considerations

Preoperative or neo-adjuvant chemotherapy in the management of breast cancer is a treatment approach that has gained in popularity in recent years. However, it is unclear if the treatment paradigms often employed for patients treated with surgery first hold true for those treated with preoperative chemotherapy. The role of sentinel node biopsy and the data supporting its use is different for those with clinically negative and clinically positive nodes prior to chemotherapy. For clinically node-negative patients, sentinel node biopsy after neo-adjuvant chemotherapy may be appropriate. For those node-positive patients whose axillary disease resolves clinically, the false-negative rate of the sentinel node biopsy is high. However, there are measures that can reduce that rate. After surgery, the radiation oncologist is often faced with complicated decisions surrounding the optimal radiotherapy in this setting. Tailoring radiation plans based on chemotherapy response holds promise and is the subject of ongoing clinical trials. In the accompanying article, we review the current literature on both surgery and radiation in axillary management and describe the interplay between these two treatment modalities. This highlights the need for multidisciplinary management in making treatment decisions for patients treated in this manner.

How Histopathologic Tumor Extent and Patterns of Recurrence Data Inform the Development of Radiation Therapy Treatment Volumes in Solid Malignancies

The ability to deliver highly conformal radiation therapy using intensity-modulated radiation therapy and particle therapy provides for new opportunities to improve patient outcomes by reducing treatment-related morbidities following radiation therapy. By reducing the volume of normal tissue exposed to radiation therapy (RT), while also allowing for the opportunity to escalate the dose of RT delivered to the tumor, use of conformal RT delivery should also provide the possibility of expanding the therapeutic index of radiotherapy. However, the ability to safely and confidently deliver conformal RT is largely dependent on our ability to clearly define the clinical target volume for radiation therapy, which requires an in-depth knowledge of histopathologic extent of different tumor types, as well as patterns of recurrence data. In this article, we provide a comprehensive review of the histopathologic and radiographic data that provide the basis for evidence-based guidelines for clinical tumor volume delineation.

Breast Reconstruction and Radiation Therapy: An Update

With the indications for radiation therapy in the treatment of breast cancer continuing to expand, many patients present for reconstruction having previously had radiation or having a high likelihood of requiring radiation following mastectomy. Both situations are challenging for the plastic surgeon, with different variables impacting the surgical outcome. To date, multiple studies have been performed examining prosthetic and autologous reconstruction in this setting. The purpose of this article was to provide a general platform for understanding the literature as it relates to reconstruction and radiation through an examination of recent systematic reviews and relevant recent publications. We examined this with a focus on the timing of the radiation, and within this context, examined the data from the traditional surgical outcomes standpoint as well as from a patient-reported outcomes perspective. The data provided within will aid in patient counseling and the informed consent process.

Indications for Postmastectomy Radiation After Neoadjuvant Chemotherapy in ypN0 and ypN1-3 Axillary Node-Positive Women

INTRODUCTION

Downstaging with neoadjuvant chemotherapy (NAC) might obscure indications for postmastectomy radiation (PMRT). The degree of downstaging that results in local-regional recurrence (LRR) rates low enough to omit PMRT remains controversial. We examined the rate of LRR in women who received NAC who underwent mastectomy without PMRT.

PATIENTS AND METHODS

Between 2004 and 2013, 81 women with stage I to IIIA breast cancer had NAC and mastectomy; 48 patients (59%) were clinical N0 and 33 patients (41%) were clinical N1; median age was 45 years; 33 patients (41%) had hormone receptor-positive (HR⁺)HER2^-, 21 patients (26%) HR⁺HER2⁺, 19 patients (23%) HR^- HER2^-, and 7 patients (9%) HR^-HER2⁺ disease. We explored how LRR rates varied with age, BRCA status, Grade, receptor status, clinical N status, pathologic response, lymphovascular invasion, and mastectomy margins. Median follow-up was 4.9 years.

RESULTS

After NAC, 35 patients (43%) had a pathologic complete response (pCR), 33 patients (41%) were ypN0, and 13 patients (16%) were ypN1-3+. There were 8 LRRs (6 chest wall, 1 axillary, 1 supraclavicular node). The 5-year cumulative incidence of LRR was 8% for all patients, 3% for pCR, 16% for ypN0, 10% for ypN1-3+, 6% for HR⁺HER2^-, 25% for HR⁺HER2⁺, 0% for HR^-HER2^-, and 0% for HR^-HER2⁺. LRR was 31% in the ypN0 and 33% in the ypN1-3+ HR⁺HER2⁺ women, and 12% in the ypN0 and 0% in the ypN1 to ypN3+ HR⁺HER2^- patients.

CONCLUSION

This study is unique. All HER2⁺ patients received trastuzumab and LRR was analyzed according to treatment response, clinicopathologic factors, and receptor status. pCR patients including young women and clinical stage IIIA had low LRR rates. However, ypN0 and ypN1-3+ HR⁺HER2⁺ patients had higher rates of LRR compared with other receptor subgroups and on the basis of limited data should be considered for PMRT.

Role of postmastectomy radiotherapy in early-stage (T1-2N0-1M0) triple-negative breast cancer: a systematic review

Triple-negative breast cancer (TNBC), which represents 15%–20% of all breast cancers, is defined by the absence of estrogen receptor (ER) and progesterone receptor (PR) and overexpression of human epidermal growth factor receptor 2 (HER2). Owing to the absence of specific therapeutic targets and its aggressive biologic characteristics, TNBC patients often experience a high risk of disease progression and poor overall survival. Furthermore, TNBC exhibits an early pattern of recurrence with a peak recurrence risk at 2–3 years after surgery. Currently, chemotherapy continues to be the mainstay in TNBC patients; however, such treatment leaves them associated with a high rate of local and systemic relapses even in early-stage (T1–2N0–1M0). Therefore, in early-stage disease, greater emphasis is placed on locoregional treatments, based on radiation therapy (RT) after surgery, to reduce local and systemic relapses. However, there are no specific treatment guidelines for early-stage (T1–2N0–1M0) TNBC patients. In this review, we discuss the type of surgery received and the relevant adverse clinicopathologic factors and underlying BRCA1 mutation status regarding the influence of tailing postmastectomy radiotherapy (PMRT). In addition, we assess the role of PMRT in early-stage (T1–2N0–1M0) TNBC patients.

Postmastectomy radiation therapy for breast cancer patients with one to three positive lymph nodes: a propensity score matching analysis

AIM

Conducting postmastectomy radiation therapy (PMRT) for breast cancer patients with one to three positive lymph nodes is still controversial.

METHODS

Propensity score matching analysis was applied to balance the clinical baseline characteristics of patients. Cox proportional hazard analysis was used to analyze the survival prognosis factors and perform subgroup analysis.

RESULTS

There was no statistical difference in overall survival and cancer-specific survival rates (all, p > 0.05) between the PMRT and non-PMRT groups. However, for subgroup patients with tumor size ≥5 cm and the number of positive lymph nodes = 3, PMRT showed a significant survival benefit.

CONCLUSION

PMRT can improve overall survival and cancer-specific survival only in breast cancer patients whose tumor size is larger than 5 cm and with three positive lymph nodes.

Outcomes of Post Mastectomy Radiation Therapy in Patients Receiving Axillary Lymph Node Dissection After Positive Sentinel Lymph Node Biopsy

PURPOSE

We sought to determine the rate of postmastectomy radiation therapy (PMRT) among women treated with axillary lymph node dissection (ALND) after positive sentinel lymph node (SLN) biopsy results and to establish the effect of negative ALND results and PMRT on locoregional recurrence (LRR) and overall survival (OS).

METHODS AND MATERIALS

All patients were treated with mastectomy and ALND after positive SLN biopsy results. All patients had clinical N0 or NX disease at the time of mastectomy and received no neoadjuvant therapy. The presence of lymphovascular space invasion, presence of multifocality, number of positive SLNs and non-SLNs, clinical and pathologic stage, extranodal extension, age, and use of PMRT were evaluated for significance regarding the rates of OS and LRR.

RESULTS

A total of 345 patients were analyzed. ALND after positive SLN biopsy results was negative in 235 patients (68.1%), and a total of 112 patients (32.5%) received radiation therapy. On multivariate analysis, only pathologic stage III predicted for lower OS (hazard ratio, 3.32; P<.001). The rate of 10-year freedom from LRR was 87.9% and 95.3% in patients with positive ALND results and patients with negative ALND results, respectively. In patients with negative ALND results with ≥3 positive SLNs, the rate of freedom from LRR was 74.7% compared with 96.7% in those with <3 positive SLNs (P=.009). In patients with negative ALND results, ≥3 positive SLNs predicted for an increase in LRR on multivariate analysis (hazard ratio, 10.10; P=.034).

CONCLUSIONS

A low proportion of cT1-2, N0 patients with positive SLNs who undergo mastectomy receive PMRT after ALND. Even in this low-risk cohort, patients with ≥3 positive SLNs and negative ALND results are at increased risk of LRR and may benefit from PMRT.

Nation-Scale Adoption of Shorter Breast Radiation Therapy Schedules Can Increase Survival in Resource Constrained Economies: Results From a Markov Chain Analysis

PURPOSE

Hypofractionated whole breast irradiation and accelerated partial breast irradiation (APBI) offer women options for shorter courses of breast radiation therapy. The impact of these shorter schedules on the breast cancer populations of emerging economies with limited radiation therapy resources is unknown. We hypothesized that adoption of these schedules would improve throughput in the system and, by allowing more women access to life-saving treatments, improve patient survival within the system.

METHODS AND MATERIALS

We designed a Markov chain model to simulate the different health states that a postlumpectomy or postmastectomy patient could enter over the course of a 20-year follow-up period. Transition rates between health states were adapted from published data on recurrence rates. We used primary data from a tertiary care hospital in Lahore, Pakistan, to populate the model with proportional use of mastectomy versus breast conservation and to estimate the proportion of patients suitable for APBI. Sensitivity analyses on the use of APBI and relative efficacy of APBI were conducted to study the impact on the population.

RESULTS

The shorter schedule resulted in more women alive and more women remaining without evidence of disease (NED) compared with the conventional schedule, with an absolute difference of about 4% and 7% at 15 years, respectively. Among women who had lumpectomies, the chance of remaining alive and with an intact breast was 62% in the hypofractionation model and 54% in the conventional fractionation model.

CONCLUSIONS

Increasing throughput in the system can result in improved survival, improved chances of remaining without evidence of disease, and improved chances of remaining alive with a breast. These findings are significant and suggest that adoption of hypofractionation in emerging economies is not simply a question of efficiency and cost but one of access to care and patient survivorship.

Operation with less adjuvant therapy for elderly breast cancer

BACKGROUND

The standard of care for elderly women with breast cancer remains controversial. The aim of this study was to clarify the management of elderly breast cancer patients who undergo surgery.

MATERIALS AND METHODS

This retrospective single-center cohort study included 2276 breast cancer patients who underwent surgery between 1993 and 2014. The patients were divided into three groups according to age: ≤64 y (young), 65-74 y (older), and ≥75 y (elderly).

RESULTS

The elderly had more advanced stage disease at diagnosis (stage III and IV, 16.2%, 17.5%, and 22.1% for the young, older, and elderly groups, respectively). The elderly were more likely to undergo mastectomy (43.3%, 41.4%, and 50.7%, respectively), omit axillary operation (0.6%, 1.1%, and 9.3%, respectively), and skip radiotherapy after breast-conserving surgery (93.1%, 86.8%, and 29.1%, respectively). Endocrine therapy was widely used in all the groups (94.4%, 93.8%, and 90.1%, respectively), but frequency of chemotherapy was lower in the elderly regardless of hormone receptor (HR) status (40.8%, 25.5%, and 9.3% in HR(+), 87.2%, 75.3%, and 39.5% in HR(-), respectively). Although the locoregional recurrence rate was higher in the elderly (4.2%, 3.4%, and 7.0% at 5 y, respectively; P = 0.028), there were no differences among groups in distant metastasis-free survival or breast cancer-specific survival.

CONCLUSIONS

Although elderly patients had more advanced stages of cancer and received less treatment, there were no differences in survival. Omission of axillary dissection, radiation, and chemotherapy after operation may be an option for breast cancer patients aged ≥75 y.

National Evaluation of the New Commission on Cancer Quality Measure for Postmastectomy Radiation Treatment for Breast Cancer

BACKGROUND

Current guidelines recommend postmastectomy radiotherapy (PMRT) for patients with ≥4 positive lymph nodes and suggest strong consideration of PMRT in those with 1-3 positive nodes. These recommendations were incorporated into a Commission on Cancer quality measure in 2014. However, national adherence with these recommendations is unknown. Our objectives were to describe PMRT use in the United States in patients with stage I to III invasive breast cancer and to examine possible factors associated with the omission of PMRT.

METHODS

From the National Cancer Data Base, 753,536 mastectomies at 1123 hospitals were identified from 1998 to 2011. PMRT use over time was examined using random effects logistic regression analyses, adjusting for patient, tumor, and hospital characteristics. Analyses were stratified by nodal status (≥4 nodes positive, 1-3 nodes positive, node negative).

RESULTS

The proportion of patients receiving PMRT increased from 1998 to 2011 (>4 positive nodes: 56.2 to 66.6 %; 1-3 positive nodes: 28.0 to 39.1 %; node-negative: 8.3 to 10.0 %, p < 0.001 for all). In adjusted analyses, patients with ≥4 positive nodes were more likely to have PMRT omitted if they had smaller tumors. Patients with 1-3 positive nodes were more likely to have PMRT omitted if they had lower grade or smaller tumors. Irrespective of patients' nodal status, PMRT utilization rates decreased as age increased.

CONCLUSIONS

Though PMRT rates increased over time in patients with ≥4 and 1-3 positive nodes, PMRT in patients with ≥4 positive nodes remains underutilized. Feedback to hospitals using the new Commission on Cancer PMRT measure may help to improve adherence rates.

Post-Mastectomy Radiation Therapy for Invasive Lobular Carcinoma: A Comparative Utilization and Outcomes Study

BACKGROUND

To date, there have been no analyses to assess factors that influence post-mastectomy radiation therapy (PMRT) utilization in invasive lobular carcinoma (ILC) or to quantify the benefit of PMRT in ILC as compared with invasive ductal carcinoma (IDC). We compared histology-specific utilization of PMRT by tumor and patient characteristics and estimated the effect of PMRT on overall and breast cancer-specific survival in ILC and IDC patients meeting American College of Radiology (ACR) criteria for PMRT.

PATIENTS AND METHODS

We used the Surveillance, Epidemiology, and End Results database to identify women diagnosed with ILC or IDC from 2004 to 2009 who underwent mastectomy. We assessed utilization of PMRT by T and N stage, analyzed factors associated with PMRT use, and quantified the histology-specific survival benefit of PMRT using log-rank tests and multivariate Cox regression analysis.

RESULTS

We identified 86,098 IDC and 12,703 ILC patients. Within this cohort, 18.7% of IDC patients and 26.1% of ILC met ACR criteria for PMRT. Among patients with a definite indication, PMRT was more commonly employed in ILC than in IDC (59.6% vs. 56.3%; P = .0004). Among patients with a definite indication for PMRT, radiation improved 5-year breast cancer-specific survival from 71.4% to 77.0% for IDC (P < .0001) and from 80.9% to 84.7% for ILC (P = .0003).

CONCLUSIONS

PMRT was used more commonly in ILC than in IDC. PMRT significantly improves 5-year overall survival and breast cancer-specific survival for ILC patients to a degree comparable with that seen in IDC. Moreover, among ILC and IDC patients who meet ACR criteria, PMRT appears to be significantly underutilized.

Postmastectomy radiation therapy after neoadjuvant chemotherapy: review and interpretation of available data

Postmastectomy radiotherapy (PMRT) has been shown to decrease locoregional recurrence and improve overall survival in patients with tumors greater than 5 cm or positive nodes. Because neoadjuvant chemotherapy (NAC) can cause significant downstaging, the indications for PMRT in the setting of NAC remain controversial and thus careful consideration of clinical stage at presentation, pathologic response to NAC, and other clinical characteristics, such as grade and biomarker status is required. The current review synthesizes both prospective and retrospective data to provide evidence for recommending PMRT after NAC for patients presenting with cT3-4 disease, cN2-3 disease, and residual nodal disease, as well as rationale for omitting PMRT in patients with cT1-2N0-1 disease who achieve a pathologic complete response. Other scenarios, including nodal complete response in the presence of other risk factors, are also explored. The topics of pre-NAC clinical staging and pathologic axillary nodal staging are reviewed, and radiation portal design is briefly discussed.

The Role of Postmastectomy Radiation Therapy in Patients With Breast Cancer Responding to Neoadjuvant Chemotherapy

When surgery is the first line of breast cancer treatment, numerous randomized clinical trials and meta-analyses have demonstrated that postmastectomy radiation therapy (PMRT) improves locoregional control and survival for many women with axillary lymph node-positive disease. In contrast, there are no randomized data regarding the use of PMRT in women who receive neoadjuvant chemotherapy (NAC) first followed by mastectomy. This has led to controversy regarding which patient with breast cancer will benefit from PMRT after NAC, particularly in women with clinically node-positive axillary disease that responds well and is down staged to pathologically negative disease at surgery (ypN0). We review the current evidence on this topic, which forms the underlying basis for the ongoing phase III clinical trial-National Surgical Adjuvant Breast and Bowel Project (NSABP) B51/RTOG 1304-that is examining the role of regional nodal irradiation in patients with clinical N1 disease that responds to NAC and becomes ypN0 at surgery.

Locoregional Recurrence Risk in Breast Cancer Patients with Estrogen Receptor Positive Tumors and Residual Nodal Disease following Neoadjuvant Chemotherapy and Mastectomy without Radiation Therapy

Among breast cancer patients treated with neoadjuvant chemotherapy (NAC) and mastectomy, locoregional recurrence (LRR) rates are unclear in women with ER+ tumors treated with adjuvant endocrine therapy without postmastectomy radiation (PMRT). To determine if PMRT is needed in these patients, we compared LRR rates of patients with ER+ tumors (treated with adjuvant endocrine therapy) with women who have non-ER+ tumors. 85 consecutive breast cancer patients (87 breast tumors) treated with NAC and mastectomy without PMRT were reviewed. Patients were divided by residual nodal disease (ypN) status (ypN+ versus ypN0) and then stratified by receptor subtype. Among ypN+ patients (n = 35), five-year LRR risk in patients with ER+, Her2+, and triple negative tumors was 5%, 33%, and 37%, respectively (p = 0.02). Among ypN+/ER+ patients, lymphovascular invasion and grade three disease increased the five-year LRR risk to 13% and 11%, respectively. Among ypN0 patients (n = 52), five-year LRR risk in patients with ER+, Her2+, and triple negative tumors was 7%, 22%, and 6%, respectively (p = 0.71). In women with ER+ tumors and residual nodal disease, endocrine therapy may be sufficient adjuvant treatment, except in patients with lymphovascular invasion or grade three tumors where PMRT may still be indicated.

Postmastectomy radiotherapy improves disease-free survival of high risk of locoregional recurrence breast cancer patients with T1-2 and 1 to 3 positive nodes

Objectives

The indications for post-mastectomy radiotherapy (PMRT) with T1-2 breast cancer and 1-3 positive axillary lymph nodes is still controversial. The purpose of this study was to investigate the role of PMRT in T1-2 breast cancer with 1-3 positive axillary lymph node.

Methods

We retrospectively reviewed the file records of 79 patients receiving PMRT and not receiving PMRT (618 patients).

Results

The median follow-up was 65 months. Multivariate analysis showed that PMRT was an independent prognostic factor of locoregional recurrence-free survival (LRFS) (P = 0.010). Subgroup analysis of patients who did not undergo PMRT showed that pT stage, number of positive axillary lymph nodes, and molecular subtype were independent prognostic factors of LRFS. PMRT improved LRFS in the entire group (P = 0.005), but did not affect distant metastasis-free survival (DMFS) (P = 0.494), disease-free survival (DFS) (P = 0.215), and overall survival (OS) (P = 0.645). For patients without PMRT, the 5-year LRFS of low-risk patients (0–1 risk factor for locoregional recurrence) of 94.5% was significantly higher than that of high-risk patients (2-3 risk factors for locoregional recurrence) (80.9%, P < 0.001). PMRT improved LRFS (P = 0.001) and DFS (P = 0.027) in high-risk patients, but did not improve LRFS, DMFS, DFS, and OS in low-risk patients.

Conclusions

PMRT is beneficial in patients with high risk of locoregional recurrence breast cancer patients with T1-2 and 1 to 3 positive nodes.