Outcomes with intraoperative radiation therapy for early‐stage breast cancer

Intraoperative Radiation Therapy for Early-Stage Breast Cancer: Updated Outcomes from a Single-Institution Experience

BACKGROUND

Increasingly, data have supported the use of partial-breast irradiation (PBI) for low-risk patients after breast-conserving surgery, with techniques allowing for completion of treatment in 1-3 weeks. Intraoperative radiation therapy (IORT) is an alternative to PBI. Our institution had used low-energy photon IORT (TARGIT) for more than a decade. The initial results demonstrated a 2% local recurrence rate with a short follow-up period of 2 years. This report presents updated outcomes during with 5-year follow-up.

METHODS

A review of an institutional review board (IRB)-approved institutional registry was performed. The review identified 215 patients with early-stage breast cancer (stages 0-IIA) who received IORT. At the time of surgery, IORT was delivered with 20 Gy in a single fraction, with 5.1% (n = 11) of patients receiving additional whole-breast irradiation (WBI).

RESULTS

The mean age at diagnosis was 71 years (range, 49-98 years), and the median follow-up was 5.7 years (interquartile range [IQR], 4.2-7.0 years). Of the 215 patients, 2.8% (n = 6) had ductal carcinoma in situ (DCIS), 90.7% (n = 195) had T1 disease, and 6.5% (n = 14) had T2 disease. Endocrine therapy was prescribed for 79% and chemotherapy for 1.4% of the patients. The 5-year rates were 5.3% for local recurrence, 6.4% for locoregional recurrence, and 2.7% for distant metastases. At 5 years, 93% of the patients were alive.

CONCLUSIONS

The 5-year outcomes with TARGIT IORT demonstrated high rates of local recurrence, exceeding those seen with alternative modern approaches. The local recurrence outcomes with IORT are more consistent with studies omitting radiation following breast-conserving surgery, using endocrine therapy alone. Consistent with current guidelines and previous data, TARGIT IORT should not be used as monotherapy outside prospective clinical trials.

Clinical Outcomes of Breast-Conserving Surgery with Synchronous 50-kV X-ray Intraoperative Partial Breast Irradiation in Patients Aged 64 Years or Older with Low-Risk Breast Cancer

Background

Breast-conserving surgery with synchronous 50-kV X-ray intraoperative radiation therapy (TARGIT-IORT) is a convenient form of partial breast irradiation; however, the existing literature supports a wide range of local control rates.

Objectives

We investigated the treatment effectiveness and toxic effects of TARGIT-IORT in a patient cohort aged 64 years or older with low-risk breast cancer.

Design

Retrospective analysis.

Methods

Patients who received breast-conserving surgery with synchronous TARGIT-IORT at a single institution from 2016 to 2019 were reviewed. Additional whole breast irradiation was recommended at the discretion of the treating radiation oncologist. Baseline patient demographics and treatment details were recorded. Acute and chronic toxicities, measured using the Common Terminology Criteria for Adverse Events version 3.0 or 4.0 and breast cosmetic outcomes, using the Harvard Cosmesis score, were recorded. Locoregional recurrence, distant metastasis, and overall survival were recorded, and 5-year rates were estimated using the Kaplan-Meier method.

Results

61 patients were included with a median follow-up of 3.5 years and median age of 72 years. Eight (13%) patients received additional whole breast irradiation, and fifty-four (89%) received adjuvant hormone therapy. There were no local, regional, or distance recurrences. One patient died of complications from COVID-19 infection. Grade 2 + acute and chronic toxicities were observed in 6 (12%) and 7 (14%) patients, respectively. One patient experienced a grade 3 acute toxicity. Cosmetic outcome was "excellent" or "good" in 45 (92%) patients.

Conclusions

Breast TARGIT-IORT was well tolerated and conferred excellent disease control in this cohort of patients with low-risk breast cancer. While continued follow-up is required, TARGIT-IORT may be an appropriate treatment option for this population.

Five Fraction Accelerated Partial Breast Irradiation Versus Intraoperative Radiation Therapy for Early-Stage Breast Cancer

PURPOSE/OBJECTIVE(S)

Accelerated partial breast irradiation (PBI) delivered in 5 fractions with intensity modulated radiation therapy (IMRT) has been shown to have comparable clinical outcomes to whole breast irradiation with reduced toxicity profiles. In contrast, intraoperative radiation therapy (IORT) offers patients the potential to complete adjuvant radiation therapy in a single treatment. While early data were promising, concerns exist regarding long-term rates of local recurrence after IORT. We present a comparison of 5 fraction PBI versus IORT.

MATERIALS/METHODS

We performed a retrospective review of 473 patients with early-stage breast cancer treated at a single institution from 2011 to 2021 with 258 receiving PBI and 215 receiving IORT. PBI patients received 30 Gy in 5 fractions delivered with IMRT. IORT patients received 20 Gy in 1 fraction prescribed to the applicator surface at surgery using the low-energy TARGIT technique.

RESULTS

Mean age was 71 years old (IQR:67-74) for IORT patients and 67 years old (IQR:62-72) for PBI patients. Median follow up was 5.7 years (IQR:4.2-7.0) for IORT patients and 2.4 years (IQR:1.8-3.3) for PBI patients (P < .001). Recurrence at any time (locoregional and distant) was seen in 7.9% (n = 17) of patients receiving IORT as compared to 0.8% (n = 2) of patients receiving PBI. IORT was associated with reduced rates of locoregional relapse free survival at 5 years (93.6% vs. 99.4%, P = .05) with no difference in overall survival(92.8% vs. 95.1%, P = .99).

CONCLUSION

Low-energy TARGIT IORT was associated with higher rates of locoregional recurrence compared to PBI. These outcomes, consistent with other series and current guidelines, suggest a limited role for low-energy IORT as monotherapy.

RING induces cell cycle arrest and apoptosis in human breast cancer cells by regulating the HSF1/MT2A axis

It was reported that lowly expressed RING1 indicates poor prognosis in breast cancer (BC) patients, while the mechanism by which RING1 is involved in BC progression is not fully understood. Here, we found that RING1 was lowly expressed in BC tissues and cells than in normal mammary tissues and epithelial cells. Overexpression of RING1 suppressed the cell proliferative and colony formation abilities, and facilitated cell cycle arrest and cell apoptosis in BC cells (T47D and MCF-7 cells). Mechanistically, as an ubiquitin ligase, RING1 bound to HSF1 and induced its proteasome-dependent degradation. HSF1 could bind to the promoter region of MT2A to promote the transcriptional level of MT2A. While RING1 overexpression hindered the transcriptional activation of MT2A induced by HSF1. Moreover, ectopic expression of MT2A reversed the inhibitory effect of RING1 on cell proliferation and clonogenesis, and antagonized the promotion effect of RING1 on cell cycle arrest and apoptosis in BC cells. Additionally, T47D cells infected with or without lentivirus-mediated RING1 overexpression vector (LV-RING1) were injected subcutaneously into the right back of nude mice to evaluate tumorigenicity. And overexpression of RING1 impeded the growth of BC xenografts in mice. In conclusion, RING1 suppressed the transcriptional activation of MT2A induced by HSF1 by facilitating the ubiquitination degradation of HSF1, resulting in cell cycle arrest and apoptosis in BC cells.

Real World and Public Health Perspectives of Intraoperative Radiotherapy in Early-Stage Breast Cancer: A Multidisciplinary Analysis Beyond the Statistical Facts

Breast conservation therapy (BCT) (usually a lumpectomy plus radiotherapy (RT)) has become a standard alternative to radical mastectomy in early-stage breast cancers with equal, if not higher, survival rates. The established standard of the RT component of the BCT had been about six weeks of Monday through Friday external beam RT to the whole breast (WBRT). Recent clinical trials have shown that partial breast radiation therapy (PBRT) to the region surrounding the lumpectomy cavity with shorter courses can result in equal local control, survival, and slightly improved cosmetic outcomes. Intraoperative RT (IORT) wherein RT is administered at the time of operation for BCT to the lumpectomy cavity as a single-fraction RT is also considered PBRT. The advantage of IORT is that weeks of RT are avoided. However, the role of IORT as part of BCT has been controversial. The extreme views go from "I will not recommend to anyone" to "I can recommend to all early-stage favorable patients." These divergent views are due to difficulty in interpreting the clinical trial results. There are two modalities of delivering IORT, namely, the use of low-energy 50 kV beams or electron beams. There are several retrospective, prospective, and two randomized clinical trials comparing IORT versus WBRT. Yet, the opinions are divided. In this paper, we try to bring clarity and consensus from a highly broad-based multidisciplinary team approach. The multidisciplinary team included breast surgeons, radiation oncologists, medical physicists, biostatisticians, public health experts, nurse practitioners, and medical oncologists. We show that there is a need to more carefully interpret and differentiate the data based on electron versus low-dose X-ray modalities; the randomized study results have to be extremely carefully dissected from biostatistical points of view; the importance of the involvement of patients and families in the decision making in a very transparent and informed manner needs to be emphasized; and the compromise some women may be willing to accept between 2-4% potential increase in local recurrence (as interpreted by some of the investigators in IORT randomized studies) versus mastectomy. We conclude that, ultimately, the choice should be that of women with detailed facts of the pros and cons of all options being presented to them from the angle of patient/family-focused care. Although the guidelines of various professional societies can be helpful, they are only guidelines. The participation of women in IORT clinical trials is still needed, and as genome-based and omics-based fine-tuning of prognostic fingerprints evolve, the current guidelines need to be revisited. Finally, the use of IORT can help rural, socioeconomically, and infrastructure-deprived populations and geographic regions as the convenience of single-fraction RT and the possibility of breast preservation are likely to encourage more women to choose BCT than mastectomy. This option can also likely lead to more women choosing to get screened for breast cancer, thus enabling the diagnosis of breast cancer at an earlier stage and improving the survival outcomes.

Comparison of Clinical Outcomes Between Low- and High-Risk Groups of Early Breast Cancer Patients Treated with Intraoperative Radiotherapy in Addition to External Beam Radiation: A Multi-Centre Prospective Study

BACKGROUND

There is a paucity of data on the use of intraoperative radiotherapy (IORT) with low-energy X-rays in Malaysian women with early breast cancer. The aim of this study is to evaluate the clinical, cosmetic, and patient-reported outcomes in low- and high-risk early breast cancer patients treated with breast conserving surgery (BCS) and IORT.

METHODOLOGY

Patients suitable for BCS who were treated with IORT between January 2016 and June 2019 from three centres were analysed. They were divided into low-risk and high-risk groups based on the risk of recurrence according to the TARGeted Intraoperative radioTherapy (TARGIT) A and B study criteria. Outcomes of interest included local recurrence, wound complications, and radiation toxicity, with a subset analysed for cosmetic and patient-reported outcomes.

RESULTS

Within a median follow-up of 31 months, there were 104 and 211 patients in the low- and high-risk groups, respectively. No significant difference was observed in local recurrence rates (low-risk, 1.0% vs. high-risk, 1.4%; p = 1.000). Both cohorts exhibited low frequencies of severe wound complications ranging between 1.4 and 1.9%. No major radiation toxicities were reported in either group. In the subgroup analysis, low-risk patients had significantly better mean scores in the subscales of inframammary fold and scar. Based on the BREAST-Q patient-reported outcomes questionnaire, seven out of nine parameters were scored similarly between both groups with no significant difference.

CONCLUSION

This study showed that the use of IORT in both low- and high-risk early breast cancers is efficacious and safe with low recurrence rates and an acceptable toxicity profile.

The prevention and treatment of breast cancer- related lymphedema: A review

Background

Breast cancer- related lymphedema (BCRL) affects about 3 to 5 million patients worldwide, with about 20,000 per year in the United States. As breast cancer mortality is declining due to improved diagnostics and treatments, the long-term effects of treatment for BCRL need to be addressed.

Methods

The American Society of Breast Surgeons Lymphatic Surgery Working Group conducted a large review of the literature in order to develop guidelines on BCRL prevention and treatment. This was a comprehensive but not systematic review of the literature. This was inclusive of recent randomized controlled trials, meta-analyses, and reviews evaluating the prevention and treatment of BCRL. There were 25 randomized clinical trials, 13 systemic reviews and meta-analyses, and 87 observational studies included.

Results

The findings of our review are detailed in the paper, with each guideline being analyzed with the most recent data that the group found evidence of to suggest these recommendations.

Conclusions

Prevention and treatment of BCRL involve a multidisciplinary team. Early detection, before clinically apparent, is crucial to prevent irreversible lymphedema. Awareness of risk factors and appropriate practice adjustments to reduce the risk aids are crucial to decrease the progression of lymphedema. The treatment can be costly, time- consuming, and not always effective, and therefore, the overall goal should be prevention.

Advances in Aptamers-Based Applications in Breast Cancer: Drug Delivery, Therapeutics, and Diagnostics

Aptamers are synthetic single-stranded oligonucleotides (such as RNA and DNA) evolved in vitro using Systematic Evolution of Ligands through Exponential enrichment (SELEX) techniques. Aptamers are evolved to have high affinity and specificity to targets; hence, they have a great potential for use in therapeutics as delivery agents and/or in treatment strategies. Aptamers can be chemically synthesized and modified in a cost-effective manner and are easy to hybridize to a variety of nano-particles and other agents which has paved a way for targeted therapy and diagnostics applications such as in breast tumors. In this review, we systematically explain different aptamer adoption approaches to therapeutic or diagnostic uses when addressing breast tumors. We summarize the current therapeutic techniques to address breast tumors including aptamer-base approaches. We discuss the next aptamer-based therapeutic and diagnostic approaches targeting breast tumors. Finally, we provide a perspective on the future of aptamer-based sensors for breast therapeutics and diagnostics. In this section, the therapeutic applications of aptamers will be discussed for the targeting therapy of breast cancer.

Global adoption of single-shot targeted intraoperative radiotherapy (TARGIT-IORT) for breast cancer—better for patients, better for healthcare systems

Micro abstract

Targeted intraoperative radiotherapy (TARGIT-IORT) is delivered immediately after lumpectomy for breast cancer. We estimated its impact. At least 44,752 patients with breast cancer were treated with TARGIT-IORT in 260 centres in 35 countries, saving &gt;20 million miles of travel and preventing ~2,000 non–breast cancer deaths. The TARGIT-IORT website (https://targit.org.uk/travel) provides maps and tools to find the nearest centre offering TARGIT-IORT and travel savings.

Background

Targeted intraoperative radiotherapy (TARGIT-IORT) delivers radiotherapy targeted to the fresh tumour bed exposed immediately after lumpectomy for breast cancer. TARGIT-A trial found TARGIT-IORT to be as effective as whole-breast radiotherapy, with significantly fewer deaths from non–breast cancer causes. This paper documents its worldwide impact and provides interactive tools for clinicians and patients.

Method

Centres using TARGIT-IORT provided the date of the first case and the total number of patients. We plotted these data on a customised Google Map. An interactive web-based tool provided directions to the closest centre. Using the data from the TARGIT-A trial, we estimated the total savings in travel miles, carbon footprint, and the number of non–breast cancer deaths that might be prevented.

Results

Data from 242 (93%) of the 260 centres treating patients from 35 countries were available. From the first patient treated in 1998 to early 2020, at least 44,752 women with breast cancer have been treated with TARGIT-IORT. The TARGIT-IORT website (https://targit.org.uk/travel) displays the Google Map of centres with number of cases and an interactive tool for patients to find the nearest centre offering TARGIT-IORT and their travel savings. Scaling up to the already treated patients, &gt;20 million miles of travel would have been saved and about 2,000 deaths prevented.

Conclusion

One can ascertain the number of patients treated with a novel treatment. These data show how widely TARGIT-IORT has now been adopted and gives an indication of its beneficial worldwide impact on a large number of women with breast cancer.

Targeted Intraoperative Radiotherapy (TARGIT-IORT) for Early-Stage Invasive Breast Cancer: A Single Institution Experience

Purpose/Objective

We present our single-institution experience in the management of invasive breast cancer with targeted intraoperative radiotherapy (TARGIT-IORT), focusing on patient suitability for IORT determined by the American Society for Radiation Oncology (ASTRO) Accelerated Partial Breast Irradiation (APBI) consensus guidelines.

Materials/Methods

We identified 237 patients treated for biopsy-proven early-stage invasive breast cancer using low energy x-ray TARGIT-IORT at the time of lumpectomy between September 2013 and April 2020 who were prospectively enrolled in an institutional review board (IRB) approved database. We retrospectively reviewed preoperative and postoperative clinicopathologic factors to determine each patient’s ASTRO APBI suitability (suitable, cautionary or unsuitable) according to the 2017 consensus guidelines (CG). Change in suitability group was determined based on final pathology. Kaplan-Meier methods were used to estimate the survival probability and recurrence probability across time.

Results

237 patients were included in this analysis, based on preoperative clinicopathologic characteristics, 191 (80.6%) patients were suitable, 46 (19.4%) were cautionary and none were deemed unsuitable. Suitability classification changed in 95 (40%) patients based on final pathology from lumpectomy. Increasing preoperative lesion size or a body mass index (BMI) ≥ 30 kg/m² were significant predictors for suitability group change. Forty-one (17.3%) patients received additional adjuvant whole breast radiotherapy after TARGIT-IORT. At a median follow up of 38.2 months (range 0.4 – 74.5), five (2.1%) patients had ipsilateral breast tumor recurrences (IBTR), including two (0.8%) true local recurrences defined as a recurrence in the same quadrant as the initial lumpectomy bed with the same histology as the initial tumor. IBTR occurred in 1/103 (0.09%) patient in the post-op suitable group, 4/98 (4.08%) patients in the post-op cautionary group, and no patients in the post-op unsuitable group. At 3-years, the overall survival rate was 98.4% and the local recurrence free survival rate was 97.1%.

Conclusion

There is a low rate of IBTR after TARGIT-IORT when used in appropriately selected patients. Change in suitability classification pre to postoperatively is common, highlighting a need for further investigation to optimize preoperative patient risk stratification in this setting. Patients who become cautionary or unsuitable based on final pathology should be considered for additional adjuvant therapy.

Prevention of Breast Cancer-Related Lymphedema

Tremendous progress has been made over the past several decades in the treatment of breast cancer. Mortality and recurrence rates continue to decline. Our ability to tailor patient- and tumor-specific treatments has rapidly advanced. The vast majority of our patients can safely have breast conservation. Unfortunately, for many patients, survivorship is burdened by ongoing quality-of-life issues. Most breast cancer patients are asymptomatic at presentation, and the onus is on us to preserve this. Surgery, radiation, and systemic therapy can result in long-term toxicities that can be amplified with multimodality approaches. We must strive to apply minimally effective therapies rather than a maximally tolerated approach. Breast cancer-related lymphedema (BCRL) is a particularly dreaded chronic complication. This review strives to give the reader a better understanding of BCRL and shed light on wisely choosing an integration of treatment modalities that minimizes BCRL risk. Key literature on emerging concepts is highlighted.

A prospective single-institution study of intraoperative radiotherapy (IORT) for early-stage breast cancer

Intraoperative radiation therapy (IORT) is an option for breast-conserving therapy in early-stage breast cancer. IORT is given in one fraction at the time of surgery and eliminates the need for adjuvant external beam radiation therapy. However, previous trials indicate increased local failure rates compared with whole-breast irradiation, which engenders controversy around the appropriate use of IORT. We conducted a prospective study of patients diagnosed with early-stage breast cancer (T1-T2, N0-N1) at the University of Oklahoma Health Sciences Center (OUHSC) between 2013 and 2017 and treated with lumpectomy followed by intraoperative radiation therapy (IORT). Data collected included stage of disease, tumor location, histology, tumor markers, lymph node status, surgical margin size, recurrence, cosmetic outcomes, and length of follow-up. In-breast tumor recurrence rate (IBTR) in the 77 evaluable patients was 3.9% (3 patients). Margins were close (1 mm or less) in all three recurrent patients, and two were initially diagnosed with DCIS. Recurrence rates in our patients were comparable to prior reports. All recurrences were in patients with close margins indicating that this may represent a predictive feature for exclusion from IORT; additional studies are essential to determine the recurrence rates among patients treated with IORT and to identify potential predictors of IORT eligibility.

TARGIT-R (Retrospective): 5-Year Follow-Up Evaluation of Intraoperative Radiation Therapy (IORT) for Breast Cancer Performed in North America

BACKGROUND

Intraoperative radiation therapy (IORT) has been investigated for patients with low-risk, early-stage breast cancer. The The North American experience was evaluated by TARGIT-R (retrospective) to provide outcomes for patients treated in "real-world" clinical practice with breast IORT. This analysis presents a 5-year follow-up assessment.

METHODS

TARGIT-R is a multi-institutional retrospective registry of patients who underwent lumpectomy and IORT between the years 2007 and 2013. The primary outcome of the evaluation was ipsilateral breast tumor recurrence (IBTR).

RESULTS

The evaluation included 667 patients with a median follow-up period of 5.1 years. Primary IORT (IORT at the time of lumpectomy) was performed for 72%, delayed IORT (after lumpectomy) for 3%, intended boost for 8%, and unintended boost (primary IORT followed by whole-breast radiation) for 17% of the patients. At 5 years, IBTR was 6.6% for all the patients, with 8% for the primary IORT cohort and 1.7% for the unintended-boost cohort. No recurrences were identified in the delayed IORT or intended-boost cohorts. Noncompliance with endocrine therapy (ET) was associated with higher IBTR risk (hazard ratio [HR], 3.67). Patients treated with primary IORT who were complaint with ET had a 5-year IBTR rate of 3.9%.

CONCLUSION

The local recurrence rates in this series differ slightly from recent results of randomized IORT trials and are notably higher than in previous published studies using whole-breast radiotherapy for similar patients with early-stage breast cancer. Understanding differences in this retrospective series and the prospective trials will be critical to optimizing patient selection and outcomes going forward.

Toxicity and cosmetic outcomes after treatment with a novel form of breast IORT

PURPOSE

Intraoperative radiation therapy (IORT), a form of accelerated partial breast irradiation (APBI), is an appealing alternative to postoperative whole breast irradiation for early-stage breast cancer. The purpose of this study was to examine the toxicity and cosmetic outcomes of patients treated with a novel form of breast IORT (precision breast IORT; PB-IORT), that delivers a targeted, higher dose of radiation than conventional IORT.

METHODS AND MATERIALS

The first 204 patients treated with PB-IORT in a Phase II clinical trial (NCT02400658) with 12 months of followup were included. Trial inclusion criteria were age ≥45 years, invasive or in situ breast cancer, tumor size ≤3 cm, and node negative. Toxicity and cosmetic scoring were performed at 6 and 12 months.

RESULTS

98 patients (48%; 95% CI, 41-55%) experienced toxicity. Seven Grade 3 toxicities occurred (3.4%; 95% CI, 1.4-6.9%). Most patients (95%) had excellent or good cosmetic outcomes (95% CI, 91-98%) at 12 months. Most patients (94%) had little or no pigmentation change (95% CI, 90-97%), 88% little to no size change (95% CI, 82-92%), and 87% experienced minimal shape change (95% CI, 82-92%).

CONCLUSIONS

Overall, Grade 3+ toxicity was rare and cosmetic outcomes were excellent. Severe toxicity with PB-IORT is similar to that reported in the TARGIT trial (3.3% rate of major toxicity) but lower than APBI (NSABP-39, 10.1% Grade 3/4 toxicities). We propose that the toxicity of PB-IORT compared with TARGIT and NSABP-39 is related to the radiation dose and delivery schedule. PB-IORT offers low-toxicity and good cosmetic outcomes when compared with other forms of APBI.