Partial Breast Irradiation Techniques Research Articles

Abstract ED05-02: When less is more: Patient-friendly radiation courses with WBI and PBI

Abstract Over the past few decades, remarkable progress has been made in understanding the biology and pathology of breast cancer. A personalized conservative approach has been currently adopted addressing the patient's individual risk of relapse. After postoperative whole breast irradiation for early-stage breast cancer, a rate of recurrences outside the initial tumour bed lower than 4% at 5 years was observed. Thus, the highest benefits of breast irradiation seem to result from the dose delivered to the tissue neighbouring the tumour bed. Nonetheless, reducing treatment morbidity while maintaining radiation therapy's ability to decrease local recurrences is an important challenge in treating patients with radiation therapy. In this regard, strategies such as partial-breast irradiation and whole breast hypofractionation have been developed to reduce toxicity without compromising oncologic outcomes. According to the national and international published guidelines, clinical oncologists can refer to specific dose/fractionation schedules and eligible criteria. However, there are still some areas of open questions. Breast cancer represents a multidisciplinary paradigm; it should be considered a heterogeneous disease where a "one-treatment-fits-all" approach cannot be considered an appropriate option. A wide overview on the main partial and whole breast irradiation advantages, risks, timings, techniques, and available recommendations is presented, providing practical findings to support clinical decision-making, exploring future perspectives, towards a balance for optimisation of breast cancer. Citation Format: I. Meattini. When less is more: Patient-friendly radiation courses with WBI and PBI [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr ED05-02.

Brachytherapy in Breast Cancer Treatment: Physical and Biological Aspects

This scientific paper focuses on the treatment of breast cancer, one of the most common cancers among women. Despite increased awareness and the popularity of screening tests, statistics indicate a significant rise in incidence. The paper presents breast-conserving treatment methods, including brachytherapy, as a modern technique with promising outcomes. It describes the physical properties of ionizing radiation used in brachytherapy, discussing the photoelectric effect, Compton effect, and the phenomenon of pair production.
 The paper then delves into the biological effects of ionizing radiation, emphasizing the dependence on the cell cycle phase. It highlights lethal, sublethal, and potentially lethal cellular damage, categorizing the effects of radiation interaction into early and late responses.
 The discussion transitions to the application of brachytherapy in breast cancer treatment, focusing on various techniques such as LDR, PDR, and HDR. The paper provides a detailed description of brachytherapy's use in breast-conserving treatment, considering contraindications, treatment planning, and Accelerated Partial Breast Irradiation (APBI) techniques.
 The radioisotopes used in brachytherapy are also presented, with special attention to Iridium-192. The physical and practical aspects related to this isotope are discussed, along with other commonly used radioisotopes such as Cesium-137, Cobalt-60, and Strontium-90.
 The paper concludes with a summary, emphasizing the significance of brachytherapy in breast cancer treatment and outlining its prospects for development. The authors highlight precision and shortened therapy duration.

Experience with intraoperative radiation therapy in an urban cancer center

Background/objectiveIntra-operative radiation therapy (IORT) is a newer partial breast irradiation technique that has been well studied in 2 large randomized trials, the TARGIT-A and ELIOT trials. We initiated our IORT program in 2018 in the context of a registry trial, and aim to report our early results thus far.MethodsWe instituted an IORT practice using Intrabeam® low energy 50kVp x-rays for selected breast cancer cases in 2018. Patients were enrolled on our institutional registry protocol which allowed for IORT in ER + patients with grade 1–2 DCIS ≤ 2.5 cm or invasive disease ≤ 3.5 cm in patients of at least 45 years of age.ResultsBetween January 2018 and December 2021, 181 patients with clinical stage 0-IIA ER + breast cancer were evaluated. One hundred sixty-seven patients ultimately received IORT to 172 sites. The majority of patients received IORT at the time of initial diagnosis and surgery (160/167; 95.8%). Re-excision post IORT occurred in 16/167 patients (9.6%) due to positive margins. Adjuvant RT to the whole breast +/- LN was ultimately given to 23/167 (13.8%) patients mainly due to positive sentinel LN found on final pathology (12/23; 52%); other reasons were close margins for DCIS (3/23; 13%), tumor size (3/23; 4.3%), and multifactorial (5/23; 17.4%). Five patients (3%) had post-operative complications of wound dehiscence. There were 3 local recurrences (1.6%) at a median follow-up of 27.9 months (range: 0.7– 54.8 months).ConclusionsIORT has been proven to be a safe and patient-centered form of local adjuvant RT for our population, in whom compliance with a longer course of external beam radiation can be an issue. Long term efficacy remains to be evaluated through continued follow up. In the era of COVID-19 and beyond, IORT has been an increasingly attractive option, as it greatly minimizes toxicities and patient visits to the clinic.Trial registrationAll patients were prospectively enrolled on an institutional review board-approved registry trial (IRB number: 2018–9409).

Special issue. De-escalation of loco-regional treatment in breast cancer: Time to find the balance? Partial breast irradiation.

Breast cancer is the most common cancer in women worldwide. Over the past few decades, remarkable progress has been made in understanding the biology and pathology of breast cancer. A personalized conservative approach has been currently adopted addressing the patient's individual risk of relapse. After postoperative whole breast irradiation for early-stage breast cancer, a rate of recurrences outside the initial tumour bed lower than 4% was observed. Thus, the highest benefits of breast irradiation seem to result from the dose delivered to the tissue neighbouring the tumour bed. Nonetheless, reducing treatment morbidity while maintaining radiation therapy's ability to decrease local recurrences is an important challenge in treating patients with radiation therapy. In this regard, strategies such as partial-breast irradiation have been developed to reduce toxicity without compromising oncologic outcomes. According to the national and international published guidelines, clinical oncologists can refer to specific dose/fractionation schedules and eligible criteria. However, there are still some areas of open questions. Breast cancer represents a multidisciplinary paradigm; it should be considered a heterogeneous disease where a "one-treatment-fits-all" approach cannot be considered an appropriate option. This is a wide overview on the main partial breast irradiation advantages, risks, timings, techniques, and available recommendations. We aim to provide practical findings to support clinical decision-making, exploring future perspectives, towards a balance for optimisation of breast cancer.

Physicians' Opinion on Intraoperative Radiotherapy as a Therapeutic De-Escalation Option in Older Women with Early Breast Cancer.

Intraoperative radiotherapy (IORT) is a therapeutic de-escalation option in older women with low-risk early breast cancer (EBC). A qualitative study was implemented to describe EBC physicians' points of view on IORT as a de-escalation option. Recorded face-to-face and telephone semi-structured interviews were conducted among diverse physicians from seven French comprehensive cancer centers. Interview transcripts were grouped as corpus to construct a typology. Thematic analysis was performed. Positions toward IORT were contrasted between the 16 participating physicians. Five fully supported IORT as a de-escalation option, four were not in favor, and seven had a more reserved or neutral opinion. Points of divergence concerned treatment efficacy, treatment duration, side effects and sequelae, psychological impact, compliance with adjuvant endocrine therapy, logistical constraints, financial cost, and availability of other techniques of partial breast irradiation. Physicians in favor of IORT emphasized direct benefits for the patient, and those against pointed the lack of specific guidelines, risk of lost opportunity in older women with long life expectancy, and challenges of shared decision making. Despite national policies to preserve cancer patients' quality of life and increase their participation in medical decision making, therapeutic de-escalation using IORT is not consensual among physicians. Further efforts are needed to promote patient-centered care.

A Meta-Analysis of Trials of Partial Breast Irradiation

Partial breast irradiation (PBI) is the delivery of radiation therapy (RT) limited to the tumor bed after breast conserving surgery. The results of recent trials of PBI compared with whole breast irradiation (WBI) have suggested conflicting results with respect to local control and toxicity. The purpose of this meta-analysis was to assess effectiveness of PBI and to compare the different techniques. A meta-analysis of aggregate data from published randomized trials was performed to examine the effectiveness of PBI compared with WBI in patients with invasive breast cancer and ductal carcinoma in situ. Relevant data were extracted. The primary outcome was any ipsilateral breast event (invasive or noninvasive). Secondary outcomes included acute and late toxicity. The results of randomized trials were pooled using a fixed effects model and the inverse variance method. Fifteen trials involving 16,474 patients were identified. The majority of enrolled patients were >60 years of age and had T1N0 grade 1 to 2 disease treated with hormone therapy. The percent of ipsilateral breast events was higher in patients treated with PBI compared with WBI (5.0% vs 2.8%; risk ratio [RR], 1.72; 95% confidence interval [CI], 1.47-2.02). Heterogeneity (P=.0002) was observed between the 4 PBI techniques: external beam RT without computed tomography (CT) planning (RR, 2.06; 95% CI, 1.36-3.12); brachytherapy (RR, 1.21; 95% CI, 0.65-2.25); intraoperative RT (RR, 2.79; 95% CI, 2.08-3.73); and external beam RT with CT planning (RR, 1.25; 95% CI, 0.99-1.58). When external beam RT without CT planning and intraoperative RT trials were excluded, the percent of ipsilateral breast events was 3.3% versus 2.6%, respectively (RR, 1.25; 95% CI, 1.00-1.55; P=.05), and no heterogeneity was observed (P=.92). Overall, acute toxicity was less with PBI, and the effect on late toxicity varied by technique. Overall, WBI was more effective than PBI, but the effectiveness of PBI was technique related. PBI was less effective when given by external beam RT without CT planning or intraoperative therapy. Although PBI given by multicatheter brachytherapy or external beam RT with CT planning tended to be statistically less effective than WBI, the absolute difference between groups for ipsilateral breast events was very small (<1%), supporting these approaches for women considering PBI.

Partial breast irradiation: An updated consensus statement from the American brachytherapy society

PurposeIn recent years, results with mature follow-up have been reported for several Phase III trials randomizing women to receive whole breast irradiation (WBI) versus varying modalities of partial breast irradiation (PBI). It is important to recognize that these methods vary in terms of volume of breast tissue treated, dose per fraction, and duration of therapy. As such, clinical and technical guidelines may vary among the various PBI techniques. MethodsMembers of the American Brachytherapy Society with expertise in PBI performed an extensive literature review focusing on the highest quality data available for the numerous PBI options offered in the modern era. Data were evaluated for strength of evidence and published outcomes were assessed. ResultsThe majority of women enrolled on randomized trials of WBI versus PBI have been age >45 years with tumor size <3 cm, negative margins, and negative lymph nodes. The panel also concluded that PBI can be offered to selected women with estrogen receptor negative and/or Her2 amplified breast cancer, as well as ductal carcinoma in situ, and should generally be avoided in women with extensive lymphovascular space invasion. ConclusionsThis updated guideline summarizes published clinical trials of PBI methods. The panel also highlights the role of PBI for women facing special circumstances, such as history of cosmetic breast augmentation or prior breast irradiation, and discusses promising novel modalities that are currently under study, such as ultrashort and preoperative PBI. Updated consensus guidelines are also provided to inform patient selection for PBI and to characterize the strength of evidence to support varying PBI modalities.

Accelerated Partial Breast Irradiation Using External Beam or Intraoperative Electron Radiation Therapy: 5-Year Oncological Outcomes of a Prospective Cohort Study

To evaluate the ipsilateral breast tumor recurrence (IBTR) after 2 accelerated partial breast irradiation (APBI) techniques (intraoperative electron radiation therapy [IOERT] and external beam APBI [EB-APBI]) in patients with early-stage breast cancer. Between 2011 and 2016, women ≥60 years of age with breast carcinoma or Ductal Carcinoma In Situ (DCIS) of ≤30 mm and cN0 undergoing breast-conserving therapy were included in a 2-armed prospective multicenter cohort study. IOERT (1×23.3 Gy prescribed at the 100% isodose line) was applied in 1 hospital and EB-APBI (10×3.85 Gy daily) in 2 other hospitals. The primary endpoint was IBTR (all recurrences in the ipsilateral breast irrespective of localization) at 5 years after lumpectomy. A competing risk model was used to estimate the cumulative incidences of IBTR, which were compared using Fine and Gray's test. Secondary endpoints were locoregional recurrence rate, distant recurrence, disease-specific survival and overall survival. Univariate Cox regression models wereestimated to identify risk factors for IBTR. Analyses were performed of the intention to treat (ITT) population (IOERT n=305; EB-APBI n=295), and sensitivity analyses were done of the per-protocol population (IOERT n=270; EB-APBI n=207). The median follow-up was 5.2 years (IOERT) and 5 years (EB-APBI). Cumulative incidence of IBTR in the ITT population at 5 years after lumpectomy was 10.6% (95% confidence interval, 7.0%-14.2%) after IOERT and 3.7% (95% confidence interval, 1.2%-5.9%) after EB-APBI (P=.002). The locoregional recurrence rate was significantly higher after IOERT than EB-APBI (12.1% vs 4.5%, P=.001). There were no differences between groups in other endpoints. Sensitivity analysis showed similar results. For both groups, no significant risk factors for IBTR were identified in the ITT population. In the per-protocol population, surgical margin status of the DCIS was the only significant risk factor for developing IBTR in both treatment groups. Ipsilateral breast tumor recurrences and locoregional recurrence rates were unexpectedly high in patients treated with IOERT, and acceptable in patients treated with EB-APBI.

Cardiac dosage comparison among whole breast irradiation and partial breast irradiation techniques

Cardiac dosage comparison among whole breast irradiation and partial breast irradiation techniques

Comparing Local and Systemic Control between Partial- and Whole-Breast Radiotherapy in Low-Risk Breast Cancer-A Meta-Analysis of Randomized Trials.

Simple SummaryThis meta-analysis compares the treatment results of partial-breast radiotherapy to those of whole-breast radiotherapy after breast conserving surgery in early-stage breast cancer. The results show that the tumor is slightly more likely to recur in the operated breast after partial radiotherapy compared to radiation therapy to the whole breast. These additional recurrences are located away from the original tumor bed. The technique by which partial-breast radiotherapy is applied also appears to affect the likeliness of tumor regrowth. Intraoperative radiation, given during the removal of the tumor, might lead to more relapses compared to other techniques. Partial-breast treatment also led to more lymph node recurrences in a very small number of patients. However, rates of distant relapses were not increased. We were unable to identify a specific subgroup that was most suitable for partial-breast irradiation. The differences between treatment of partial- and whole-breast radiotherapy are small when the patient groups and the radiation technique are appropriately selected.Purpose/Objective: The standard treatment for localized low-risk breast cancer is breast-conserving surgery, followed by adjuvant radiotherapy and appropriate systemic therapy. As the majority of local recurrences occur at the site of the primary tumor, numerous trials have investigated partial-breast irradiation (PBI) instead of whole-breast treatment (WBI) using a multitude of irradiation techniques and fractionation regimens. This meta-analysis addresses the impact on disease-specific endpoints, such as local and regional control, as well as disease-free survival of PBI compared to that of WBI in published randomized trials. Material and Methods: We conducted a systematic literature review and searched for randomized trials comparing WBI and PBI in early-stage breast cancer with publication dates after 2009. The meta-analysis was based on the published event rates and the effect sizes for available oncological endpoints of at least two trials reporting on them. We evaluated in-breast tumor recurrences (IBTR), local recurrences at the primary site and elsewhere in the ipsilateral breast, regional recurrences (RR), distant metastasis-free interval (DMFI), disease-free survival (DFS), contralateral breast cancer (CBC), and second primary cancer (SPC). Furthermore, we aimed to assess the impact of different PBI techniques and subgroups on IBTR. We performed all statistical analyses using the inverse variance heterogeneity model to pool effect sizes. Results: For the intended meta-analysis, we identified 13 trials (overall 15,561 patients) randomizing between PBI and WBI. IBTR was significantly higher after PBI (OR = 1.66; CI-95%: 1.07–2.58; p = 0.024) with an absolute difference of 1.35%. We detected significant heterogeneity in the analysis of the PBI technique with intraoperative radiotherapy resulting in higher local relapse rates (OR = 3.67; CI-95%: 2.28–5.90; p < 0.001). Other PBI techniques did not show differences to WBI in IBTR. Both strategies were equally effective at the primary tumor site, but PBI resulted in statistically more IBTRs elsewhere in the ipsilateral breast. IBTRs after WBI were more likely to be located at the primary tumor bed, whereas they appeared equally distributed within the breast after PBI. RR was also more frequent after PBI (OR = 1.75; CI-95%: 1.07–2.88; p < 0.001), yet we did not detect any differences in DMFI (OR = 1.08; CI-95%: 0.89–1.30; p = 0.475). DFS was significantly longer in patients treated with WBI (OR = 1.14; CI-95%: 1.02–1.27; p = 0.003). CBC and SPC were not different in the test groups (OR = 0.81; CI-95%: 0.65–1.01; p = 0.067 and OR = 1.09; CI-95%: 0.85–1.40; p = 0.481, respectively). Conclusion: Limiting the target volume to partial-breast radiotherapy appears to be appropriate when selecting patients with a low risk for local and regional recurrences and using a suitable technique.

Outcomes After Accelerated Partial Breast Irradiation in Women With Triple Negative Subtype and Other "High Risk" Variables Categorized as Cautionary in The ASTRO Guidelines.

PurposeTo report a primary objective clinical outcome of ipsilateral breast recurrence following accelerated partial breast irradiation (APBI) in women with triple negative and other high risk breast cancer (as described in 2017 ASTRO guidelines) (i.e., age 40–49, size 2.1–3.0 cm, estrogen receptor negative and invasive lobular breast cancer). Secondary objectives of axillary and regional failure as well as overall survival are also reported.Methods and MaterialPatients from two clinical trials (NCT01185145, NCT01185132) were treated with 38.5 Gy IMRT or 3D-CRT APBI w/3.85 Gy fraction/BID fractionation for 10 fractions. Triple negative and other high risk patients (n=269) were compared to a total of 478 low risk patients which ASTRO defined as “suitable” for APBI. High risk patients, for the purpose of this study, were defined as those who possess one or more high risk criteria: triple negative (n=30), tumor size >2 cm <3 cm (n=50), HER 2+ (n=54), age range 40–50 years (n=120), ER- (n=43), and ILC histology (n=52).ResultsMedian follow up was 4.0 years for all patients. No significant difference was found for this high-risk cohort at 5 years for ipsilateral breast, or regional recurrences. Axillary recurrence was significantly adversely impacted by triple negative and ER- statuses (p=0.01, p=0.04). There were significant correlations between triple negative type and axillary recurrence on multivariate analysis (p=0.03). Overall survival for all patients was unaffected by any of the high-risk categories.ConclusionThe data from this study suggests that women possessing high risk features are at no more meaningful risk for recurrence than other patients considered to be acceptable for APBI treatment. However, the finding of axillary recurrence in patients with triple negative breast cancer does warrant a degree of caution in proceeding with accelerated partial breast irradiation technique in this patient group.

Outcomes with Partial Breast Irradiation vs. Whole Breast Irradiation: a Meta-Analysis.

Several randomized trials have been performed comparing partial breast irradiation (PBI) and whole breast irradiation (WBI) though controversy remains, including regarding differences by PBI technique. We performed a meta-analysis to compare results between WBI versus PBI and between PBI techniques. A systematic review was performed to identify modern randomized studies listed in MEDLINE from 2005 to 2020. PBI trials were divided into external beam radiation and brachytherapy techniques, with intraoperative radiation excluded. A Bayesian logistic regression model evaluated the risk of ipsilateral breast tumor recurrence (IBTR) and acute and chronic toxicities. The primary outcome was IBTR at 5years with WBI compared with PBI. A total of 9758 patients from 7 studies were included (4840-WBI, 4918-PBI). At 5years, no statistically significant difference in the rate of IBTR was noted between PBI (1.8%, 95% HPD 0.68-3.2%) and WBI (1.7%, 95% HPD 0.92-2.4%). By PBI technique, the 5-year rate of IBTR rate for external beam was 1.7% and 2.2% for brachytherapy. Rates of grade 2 + acute toxicity were 7.1% with PBI versus 47.5% with WBI. For late toxicities, grade 2/3 rates were 0%/0% with PBI compared with 1.0%/0% with WBI. IBTR rates were similar between PBI and WBI with no significant differences noted by PBI technique; PBI had reduced acute toxicities compared to WBI. Because studies did not provide toxicity data in a consistent fashion, definitive conclusions cannot be made with additional data from randomized trials needed to compare toxicity profiles between PBI techniques.

Outcomes and Toxicities with Partial Breast Irradiation vs. Whole Breast Irradiation: A Meta-Analysis

Whole breast irradiation (WBI) has traditionally been considered the primary adjuvant radiation therapy technique after breast conserving surgery. However, over the past two decades, partial breast irradiation (PBI) has emerged as an alternative to WBI, offering the potential for shorter courses of radiation and improved toxicity profiles. Several randomized trials using different PBI techniques have recently been published. We therefore performed a meta-analysis to compare outcomes between WBI and PBI as well as compare outcomes with various PBI techniques. For this analysis, seven randomized trials were included (National Institute of Oncology, GEC-ESTRO, University of Florence, Barcelona, RAPID, IMPORT-LOW, and NSABP B39). Older trials evaluating PBI were excluded as they were performed prior to the 3-dimensional treatment era and were not consistent with modern PBI techniques. Randomized trials evaluating intraoperative radiation therapy were excluded due to differences in technique as compared to traditional PBI techniques. PBI trials were divided into external beam (3D-CRT/IMRT; University of Florence, Barcelona, RAPID, IMPORT-LOW, and NSABP B39) and brachytherapy (National Institute of Oncology, GEC-ESTRO). As the majority of patients in NSABP B39 were treated with 3D-CRT (73%, n = 1536), this was considered an external beam PBI trial in this analysis. Outcomes evaluated included ipsilateral breast tumor recurrence (IBTR) at 5 years as well as acute (RAPID, University of Florence and Barcelona trials) and late toxicities (RAPID, University of Florence, Barcelona; GEC-ESTRO, IMPORT LOW trials provided Grade 2+ toxicities). A Bayesian logistic regression model evaluated the risk of above outcomes for evidence of deviation by WBI and PBI techniques. Statistical estimation reports risk of rate by posterior median and 95% highest posterior density (HPD) interval. A total of 9,758 patients were included with 4,840 receiving WBI and 4,918 PBI. At 5 years, no difference in IBTR was noted between PBI (1.8%, 95% CI 0.68%-3.2%) and WBI (1.7%, 95% CI 0.92%-2.4%). By PBI technique, the 5-year IBTR rate for 3DCRT/IMRT was 1.7%, and 2.2% for brachytherapy. With respect to acute toxicities, grade 2/3 rates were 7.1%/0% with PBI as compared to 40.0%/3.6% with WBI. For late toxicities, grade 2/3 rates were 0%/0% with PBI as compared to 1.0%/0% with WBI and for grade 2+ were 1.2% with PBI versus 3.6% with WBI. IBTR rates were similar between PBI and WBI with no differences noted by PBI technique. Acute and late toxicities were lower with PBI as compared to WBI. Additional data from randomized trials is needed to compare toxicity profiles between various PBI techniques.

Does Intraoperative Radiation Therapy Result in Improved Overall Survival in Early-Stage Breast Cancer? An Analysis of the National Cancer Database

The TARGIT-A trial of kilovoltage intraoperative radiation therapy (IORT) vs. external beam radiation therapy (EBRT) demonstrated a significant reduction in non-breast cancer mortality (nBCM) with a trend towards improved overall survival (OS) in women that received IORT. The trend towards improved OS was attributed to an increase in cardiac mortality in EBRT patients. We set to determine whether EBRT results in inferior OS compared to IORT in women with low-risk, early-stage breast cancer (BC) in a United States database with a hypothesis that the two approaches should result in equivalent OS. We used the National Cancer Database (NCDB) to identify women with low-risk BC treated with lumpectomy and either IORT or EBRT from 2004-2016. Low-risk BC included: age≥50 years, stage 0-I (ductal histology), lymph node-negative, ER+. Patients were categorized into 1 of 2 groups: IORT (20 Gy/1 fraction and no further EBRT) or EBRT (4256-6000 cGy to the breast [no regional lymph node irradiation]). The primary endpoint was OS. We compared OS between the IORT and EBRT patients using the Kaplan-Meier method and Cox-regression multivariate analysis (p<.05 considered significant). We used propensity-score matching (PSM) as an independent test of the Cox regression analysis. We identified 81,889 women that met the inclusion criteria (1,321 IORT; 80,568 EBRT). Compared to EBRT patients, IORT patients were older (mean age = 68.3 years vs. 64.8 years, p<.0001), had a similar proportion of patients with no comorbidities (83.1% vs. 84.7%, p = .13), and were less likely to have DCIS (11.3% vs. 27.5%, p<.0001), grade 3 tumors (9.9% vs. 16.8%, p<.0001), or PR- disease (9.3% vs. 14.7%, p<.0001). IORT patients were more often treated at academic medical centers (53.8% vs. 31.4%, p<.0001). Median follow-up was 44.9 months (IQR 23.7 months-75.9 months). The 4-year OS for IORT vs. EBRT was 94.9% vs. 95.7% (HR = 1.24, 95% CI 0.93-1.64, p = .15). Only tumor laterality and receipt of lymph node surgery were not associated with OS on univariate analysis. After adjustment for all other potential confounders (age, comorbidity, race, facility type, insurance status, income level, education level, stage, tumor size, grade, PR status, hormone therapy receipt, and chemotherapy receipt) the HR for OS from IORT vs. EBRT was 0.90 (95% CI 0.67-1.21, p = .48). The PSM cohort included 1320 of a possible 1321 matched pairs. The 4-year OS for IORT vs. EBRT was 94.9% vs. 95.9% with a HR = 1.13 (0.79-1.63, p = 0.51). In summary, we found that there was no significant trend towards improved OS between patients with low-risk BC treated with IORT vs. EBRT. We included only the lowest risk BC patients, including those with DCIS, to allow for the detection a potentially small harmful effect of EBRT. Further study is warranted to determine if IORT or other partial breast irradiation techniques result in reduced nBCM, especially in an era of more precise, conformal EBRT delivery techniques.

Individualized Partial-Breast Irradiation Technique after Breast-Conserving Surgery for Small-Breasted Women

Individualized Partial-Breast Irradiation Technique after Breast-Conserving Surgery for Small-Breasted Women

Apples and oranges: comparing partial breast irradiation techniques.

Apples and oranges: comparing partial breast irradiation techniques.

Predicting adherence of dose–volume constraints for personalized partial-breast irradiation technique

PurposeMulticatheter interstitial brachytherapy (MIB) and external-beam (EB) radiotherapy are established partial-breast irradiation (PBI) techniques. Although EB-PBI is widely available, it requires extra irradiated margins for target uncertainties. We examined the impact of EB-PBI on dose–volume constraints as compared to MIB-PBI. Methods and MaterialsAmong 653 patients receiving MIB-PBI between October 2008 and April 2020, consequent 159 patients after September 2018 were examined. Clinical target volume (CTV) included the lumpectomy cavity plus 1.0 cm. Planning target volume (PTV) for EB-PBI was defined as CTV with 1.0-cm expansion. Because the ratio of PTV to breast volume (RPB) was related to cosmesis, <25% of RPB was defined as suitable for the ipsilateral breast constraints. Preoperative breast size was classified as very small (<350 cm3), small (350–699 cm3), and medium or large (≥700 cm3). According to each category, the dose–volume constraints of the organs at risk were compared between the two PBI techniques. ResultsPatients including 84 very small, 59 small, and 16 moderate to large breasts were examined. Although RPB was suitable in all patients receiving MIB-PBI, it was achieved in 74 patients (46.5%) receiving EB-PBI (p < 0.0001). The suitable RPB in patients with very small, small, and moderate to large breast was 32.1%, 55.9%, and 100%, respectively (p < 0.0001). Normal-tissue constraints for the other organs could be satisfied in patients with moderate to large breasts. ConclusionAlthough EB-PBI may be an appropriate option for patients with moderate to large breasts, MIB-PBI could still be a crucial technique, especially for patients with small breasts.

Partial-breast irradiation versus whole-breast radiotherapy for early breast cancer: A systematic review and update meta-analysis

PurposeThe purpose of this study was to compare the treatment outcomes of partial-breast irradiation (PBI) versus whole-breast radiotherapy (WBRT) in early breast cancer. Methods and MaterialsEligible randomized clinical trials were identified on Medline, Embase, the Cochrane Library, and the proceedings of annual meetings through December 2019. A meta-analysis for local recurrence (LR), overall mortality (OM), and non-breast cancer mortality (NBCM) was conducted. When possible, the outcomes were calculated for 5, 7, and 10 years of followup. A subgroup analysis by PBI technique (brachytherapy [BT], external beam radiotherapy [EBRT], intraoperative radiotherapy [IORT], and mixed) was performed. A p value < 0.05 was considered significant. ResultsEleven randomized clinical trials with a total of 14,436 patients (7186 PBI vs. 7250 WBRT) were included in the meta-analysis. The odds ratio (OR) for LR in 5 y was 1.46 (95% CI 1.15–2, p = 0.024) for PBI. In the subgroup analysis, no significant difference for LR was observed between PBI and WBRT using BT (p = 0.51), EBRT (p = 0.25), or mixed techniques (p = 0.89). The only subgroup with statistical difference was IORT 3.1 (95% CI 1.2–7.6, p = 0.014). No significant difference in LR was observed with 7 and 10 years among the groups. The OM had no difference at 5, 7, and 10 years of followup for any subgroup. A nonsignificant difference was observed comparing PBI with WBRT for NBCM OR = 1.24 (95% CI 0.98–1.57, p = 0.07). The rates of cardiac death, contralateral breast cancer, and development of second tumor were not significant. ConclusionsThe LR with PBI is low and similar to WBRT in selected early breast cancer with a longer followup. The subgroup analysis detected a significant difference for LR associated with IORT and no significant difference for BT and EBRT. Our results confirm a nonsignificant difference for OM and NBCM between PBI and WBRT.

Analysis of breast cosmetic effects 3years after breast-conserving surgery and intraoperative radiotherapy with and without adjuvant whole breast irradiation.

Intraoperative radiotherapy (IORT) based on low-kV photons may be an option for early breast cancer patients. Following Targit trial results some of those patients should undergo whole breast irradiation (WBRT) additionally. Since April 2010, IORT has been applied to early breast cancer patients. One hundred and fifty patients were prospectively followed up and examined to evaluate the side effects (pain, fibrosis, breast edema, telangiectasias). We present the results 3years post-treatment. WBRT was given to 82 (54.7%) patients. Tumor cavity fibrosis grade II and more was observed in 18 (12%) patients, as grade III only in 2 (1.33%) patients. Breast tissue fibrosis outside tumor cavity grade II was observed only in 2 (1.33%) patients. Breast edema was present in 10 (6.66%) patients. WBRT administration led to increased frequency of higher grade tumor cavity fibrosis (P<.0001), breast fibrosis (P<.0001), breast edema (P=.003), and occurrence of telangiectasias (P=.03), with no influence on pain reported by patients. In case of WBRT, tumor location (P=.026) and size of the irradiated breast (P=.015) were independent risk factors for higher degree of breast fibrosis, as seroma evacuation 6months post-WBRT (P=.036) was the only independent risk factor for higher level of tumor cavity fibrosis in multiple regression. The cosmetic result after IORT is good and comparable to other accelerated partial breast irradiation techniques. Administration of WBRT post-IORT in breast cancer patients increases the level of fibrotic changes, breast edema and telangiectasias 3years post-treatment, but with no influence on pain.

Adjuvant radiotherapy for low-risk early breast cancer in elderly women: evidence from randomized trials.

Breast cancer is the most common cancer pathology in women in the Western world. The median age at diagnosis is 60 years and in the coming decades it is estimated that the number of elderly women affected reaches an important percentage. This aging of the cancer population, associated with its inherent comorbidities and aggravated by the lack of consensus about the most appropriate treatment, make it difficult to administer an effective postoperative treatment in elderly women with a low-risk profile. An exhaustive geriatric evaluation is a sine qua non condition to opt for a specific type of treatment. To date, several options are available such as endocrine therapy (ET) alone, moderate/high hypofractionation and various accelerated partial breast irradiation (APBI) techniques. In this article, we provide information about each of them.