Accelerated partial breast irradiation with external beam three-dimensional conformal radiotherapy

Tumor Bed Boost Radiotherapy in the Conservative Treatment of Breast Cancer: A Review of Intra-Operative Techniques and Outcomes

Conservative surgery is the preferred treatment in the management of breast cancer followed by adjuvant whole-breast irradiation. Since the tumor bed is the main site of relapse, boost doses are conveniently administered according to risk factors for local relapse to increase the efficacy of the treatment. The benefit of a radiation boost is well established and it can be performed by several techniques like brachytherapy, external radiation or intraoperative radiotherapy. Greater precision in localizing the tumor cavity, immediacy and increased biological response are the main advantages of intraoperative boost irradiation. This modality of treatment can be performed by means of mobile electron accelerators or low-photon X-ray devices. There is a lot of research and some published series analyzing the results of the use of an intraoperative boost as an adjuvant treatment, after neoadjuvant systemic therapy and in combination with some reconstructive surgeries. This review discusses advantages of intraoperative radiotherapy and presents the main results of a boost in terms of local control, survival, tolerance and cosmesis.

Pain prevalence and characteristics in survivors of solid cancers: a systematic review and meta-analysis

PURPOSE

The latest systematic review on the prevalence of pain in cancer survivors was published 5 years ago. The current review aims to provide an extended overview on the prevalence of pain, pain mechanisms, pain characteristics, and assessment methods in cancer survivors.

METHODS

A systematic research was conducted on 17th of April 2020 using MEDLINE, Embase, Scopus, Web of Science, and Cochrane looking at studies from 2014 to 2020. Studies had to report pain prevalence rates in cancer survivors with a solid tumor who finished curative treatment at least 3 months ago. Methodological quality was assessed by two independent reviewers using the Joanna Briggs Institute quality appraisal tool. Characteristics of the included studies, participants and reported pain prevalence rates were extracted. The reported prevalence rates of the individual studies were pooled within a meta-analysis. Meta-regressions were performed to identify possible determinants of the pooled pain prevalence.

RESULTS

After deduplication, 7300 articles were screened, after which 38 were included in the meta-analysis. Risk of bias was rated low in 26 articles and moderate in 12 articles. The pooled pain prevalence was 47% (95%CI 39-55), with a heterogeneity of 98.99%.

CONCLUSION

This meta-analysis suggests that nearly half of cancer survivors report pain after completing curative treatment at least 3 months ago. However, substantial unexplained heterogeneity warrants cautious interpretation of these results. Meta-regression using cancer type, treatment location, pain measurement, and follow-up time as a covariate could not explain influencing factors explaining the high heterogeneity.

Pain Prevalence During Cancer Treatment: A Systematic Review and Meta-Analysis

CONTEXT

Pain is one of the most complex and prevalent symptoms in the cancer population. Despite the protective role of acute cancer-related pain, it is also an important predictor for the likelihood of developing chronic pain after cancer treatment.

OBJECTIVES

Since the last systematic review on pain prevalence rates during cancer treatment dates already from 2016, the aim of the present systematic review was to provide an overview of pain prevalence rates during cancer treatment since this previous review.

METHODS

A systematic search of the literature, including studies between 2014 and 2020, was conducted using the databases Pubmed, Embase, Scopus, Web of Science and Cochrane. Studies reporting pain prevalence rates during or within three months after curative cancer treatment was included. Title/abstract and full-text was screened double-blinded, followed by independent evaluation of the risk of bias. All prevalence rates were pooled within meta-analyses and a meta-regression was performed to clarify the amount of heterogeneity.

RESULTS

Of the 9052 studies, 12 studies were included in the meta-analysis of which 10 included breast cancer and two lung cancer patients. The pooled pain prevalence rate was 40% (95%CI 0.29-0.51), with a heterogeneity of 96%. Out of the meta-regression, only the covariate "method of pain measurement" significantly clarified the heterogeneity (P < 0.05), resulting in a residual heterogeneity of 94.88%.

CONCLUSION

Five years after the last systematic review published on this topic, pain is still very prevalent during cancer treatment. However, the pain prevalence rates were also very heterogeneous. These two findings emphasize the need for further research on the development of adequate pain assessment and pain management approaches during cancer treatment.

Delivery of Adjuvant Radiation in 5 Days or Less After Lumpectomy for Breast Cancer: A Systematic Review

BACKGROUND

Recent data have been published supporting the application of ultra-short radiation therapy (RT) regimens for women with early stage breast cancer following breast conserving surgery (BCS). What has remained controversial is whether and how to apply accelerated whole breast irradiation (AWBI) or accelerated partial breast irradiation (APBI) approaches in these patients, as well as the consideration of intraoperative RT (IORT) for this population.

METHODS

We performed a systematic review of the literature searching for randomized and prospective data published evaluating ultra-short RT delivered in 5-days or less with APBI, AWBI, or IORT.

RESULTS

We identified two randomized studies applying AWBI (n=5,011 patients) with 5 to 10 year follow up, which supported the use of ultra-short course AWBI (5 fractions in one week) as compared to hypofractionated WBI. We identified six randomized trials evaluating APBI (as compared to WBI) in 5 days or less (n= 8,415) with numerous (n=55) prospective studies as well, with the data supporting short course APBI as compared to WBI. Finally, we identified two randomized trials evaluating IORT; however, both trials demonstrated elevated rates of recurrence with IORT as compared to WBI.

CONCLUSIONS

The current body of data available for ultra-short adjuvant RT regimens delivered in 5-days or less after BCS overwhelming support their utilization. While data for both exists, APBI regimens have, by far, greater numbers of patients and longer follow-up as compared to AWBI. Also, given increased rates of recurrence seen with IORT with long-term follow-up, this should not be considered a standard approach at this time.

Intraoperative irradiation in breast cancer: preliminary results in 80 patients as partial breast irradiation or anticipated boost prior to hypo-fractionated whole breast irradiation

Purpose

To present the first results of intraoperative irradiation (IORT) in breast cancer with a low-energy photon system used as partial breast irradiation (PBI) or as an anticipated boost before whole breast hypo-fractionated irradiation (IORT + WBI), concerning tolerance, side effects, quality of life, and patient-reported outcomes.

Materials and methods

Eighty patients treated with an Intrabeam^® system of 50 kV X-rays received a 20 Gy dose intraoperatively were included. Moderate daily hypofractionation of 2.7 Gy in 15 fractions up to 40.5 Gy was administered if high-risk factors were present. Acute post-operative toxicity, surgery complications, chronic toxicity, patient-reported cosmesis and Breast-Q questionnaire were performed at follow-up visits.

Results

Thirty-one patients were treated as PBI and the remaining 49 as IORT + WBI. Only the IORT + WBI group presented acute toxicity, mainly mild acute dermatitis (11 patients) and one subacute mastitis. A total of 20 patients presented fibrosis (18 patients grade I, 2 patients grade II), 15 (30.5%) patients in the IORT + WBI group and 3 (9.6%) patients in the group of PBI. The cosmesis evaluation in 73 patients resulted poor, fair, good or excellent in 2, 7, 38 and 26 patients, respectively. In PBI group Breast-Q scored higher, especially in terms of their psychosocial well-being (78 vs 65) and satisfaction with radiation-induced toxicity (77 vs 72, respectively) compared to IORT + WBI group.

Conclusion

IORT is a well-tolerated procedure with low toxicity, good cosmesis and favorable patient-reported outcomes mainly when administered as PBI.

Long-Term Outcomes of Once-Daily Accelerated Partial-Breast Irradiation With Tomotherapy: Results of a Phase 2 Trial

PURPOSE

We report long-term outcomes of phase 2 trial on patients with invasive breast cancer treated with accelerated partial-breast irradiation (APBI) using tomotherapy after breast conservative surgery.

METHODS AND MATERIALS

From December 2010 to December 2018, we treated 338 women with APBI-tomotherapy: 38.5 Gy in 10 once-daily fractions. Patients selected were age ≥50 years old, with ≤3 cm in size unifocal tumor and at least 2 mm of clear margins. Disease outcomes were analyzed by clinicopathologic characteristics, molecular phenotypes, and American Society for Radiation Oncology (ASTRO) 2017 updated consensus groupings.

RESULTS

The median age was 65 years (range, 50-86). The invasive ductal (87.5%) and the luminal A-like molecular phenotype (70%) were the most common tumors. Overall 242 patients (71.6%) were considered "suitable" for enrollment in APBI according to the eligibility criteria of the ASTRO-2017 consensus statement. With a median follow-up of 76 months (range, 17-113), 2 patients (0.6%) had an invasive ipsilateral breast tumor recurrence (IBTR), and 2 patients (0.6%) had an axillary ipsilateral failure. The rate of local control in terms of free of IBTR was 99.4% and locoregional control (no recurrence in ipsilateral breast as well as in regional nodes) was 98.8%. Progression-free survival was 98.4% and 92% at 5 and 10 years, respectively. Acute and late skin toxicity, graded according to the Common Terminology Criteria for Adverse Events, were 7.7% (G1) and 0.6% (G2) and 4.4% (G1) and 1.1% (G2), respectively. There were no grade 3/4 toxicities, however. Very few patients (2%) or physicians (2%) assessed cosmetic outcome as fair or poor at the 2-year follow-up.

CONCLUSIONS

This phase 2 trial on APBI-tomotherapy shows excellent long-term results. Once-daily fractionation schedule was well tolerated with a low rate of adverse events and worse cosmetic outcome. In this series, even among those deemed cautionary or unsuitable for APBI by ASTRO criteria, we demonstrated a low rate of IBTR.

Breast-Conserving Surgery Followed by Partial or Whole Breast Irradiation: Twenty-Year Results of a Phase 3 Clinical Study

PURPOSE

To report the 20-year results of a phase 3 clinical trial comparing the survival and cosmetic results of breast-conserving surgery followed by partial breast irradiation (PBI) or whole breast irradiation (WBI).

METHODS AND MATERIALS

Between 1998 and 2004, 258 selected patients with low-risk invasive breast carcinoma (pT1 pN0-1mi, grade 1-2, nonlobular breast cancer) resected with negative margins were randomized after breast-conserving surgery to receive PBI (n = 128) or 50 Gy WBI (n = 130). Partial breast irradiation was given either by multicatheter high-dose-rate (HDR) brachytherapy (BT; n = 88) with 7 × 5.2 Gy twice daily or 50 Gy external beam irradiation with electron beams (n = 40).

RESULTS

Median follow-up time was 17 years. The 20-year actuarial rates of ipsilateral breast tumor recurrences were 9.6% versus 7.9% (P = .59) in the PBI and WBI arms, respectively. There was no significant difference in the 20-year probability of disease-free (79.7% vs 78.3%), cancer-specific (92.6% vs 88.1%), and overall survival (59.5% vs 59.7%). Significantly more patients had excellent or good cosmetic result in the PBI and WBI groups (79.2% vs 59.5%; P = .0007).

CONCLUSIONS

The 20-year updated results of our phase 3 clinical trial add further scientific evidence that PBI either with multicatheter HDR BT or electron beams for low-risk invasive breast carcinomas yield long-term local tumor control and survival comparable to those achieved with standard WBI. Interstitial HDR BT improved cosmetic results compared with WBI.

Accelerated partial breast irradiation with 3-dimensional conformal and image-guided intensity-modulated radiotherapy following breast conserving surgery - 7-Year results of a phase II trial

Purpose

To present the 7-year results of accelerated partial breast irradiation (APBI) using three-dimensional conformal (3D-CRT) and image-guided intensity-modulated radiotherapy (IG-IMRT) following breast-conserving surgery (BCS).

Patients and methods

Between 2006 and 2014, 104 patients were treated with APBI given by means of 3D-CRT using 3–5 non-coplanar, isocentric wedged fields, or IG-IMRT using kV-CBCT. The total dose of APBI was 36.9 Gy (9 × 4.1 Gy) using twice-a-day fractionation. Survival results, side effects and cosmetic results were assessed.

Results

At a median follow-up of 90 months three (2.9%) local recurrences, one (0.9%) regional recurrence and two (1.9%) distant metastases were observed. The 7-year local (LRFS), recurrence free survival was 98.9%. The 7-year disease-free (DFS), metastases free (MFS) and overall survival (OS) was 94.8%, 97.9% and 94.8%, respectively. Late side effects included G1 skin toxicity in 15 (14.4%), G1, G2, and G3 fibrosis in 26 (25%), 3 (2.9%) and 1 (0.9%) patients respectively. Asymptomatic (G1) fat necrosis occurred in 10 (9.6%) patients. No ≥ G2 or higher late side effects occurred with IMRT. The rate of excellent/good and fair/poor cosmetic results was 93.2% and 6.8%, respectively.

Conclusion

7-year results of APBI with 3D-CRT and IG-IMRT are encouraging. Toxicity profile and local tumor control are comparable to other series using multicatheter interstitial brachytherapy. Therefore, these external beam APBI techniques are valid alternatives to whole breast irradiation and brachytherapy based APBI.

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Phase II APBI trial using 3D-CRT or IG-IMRT.

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Twice-a-day fractionation, with a total dose of 36.9 Gy (9 × 4.1Gy).

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No Grade 2 or worst late side effects with IG-IMRT at median follow up of 90 months.

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These APBI techniques are valid alternatives to WBI or brachytherapy based APBI.

Implementation of Stereotactic Accelerated Partial Breast Irradiation Using Cyber-Knife - Technical Considerations and Early Experiences of a Phase II Clinical Study

To report the implementation, dosimetric results of and early experiences with stereotactic accelerated partial breast irradiation (SAPBI) following breast conserving surgery (BCS) for postmenopausal low-risk St I-II invasive breast cancer (IBC) patients. Between November 2018 and August 2019, 27 patients were registered in our phase II prospective study. SAPBI was performed with Cyber-Knife (CK) M6 machine, in 4 daily fractions of 6.25 Gy to a total dose of 25 Gy. Respiratory movements were followed with implanted gold markers and Synchrony system. Corrections for patient displacement and respiratory movement during treatment were performed with the robotic arm. Early side effects, cosmetic results, and dosimetric parameters were assessed. The average volume of the surgical cavity, clinical target volume (CTV), and planning target volume (PTV_EVAL) were 8.1 cm³ (range: 1.75–27.3 cm³), 55.3 cm³ (range: 26.2–103.5 cm³), and 75.7 cm³ (range: 40–135.4 cm³), respectively. The mean value of the PTV_eval/whole breast volume ratio was 0.09 (range: 0.04–0.19). No grade 2 or worst acute side-effect was detected. Grade 1 (G1) erythema occurred in 6 (22.2%) patients, while G1 oedema was reported by 3 (11.1%) cases. G1 pain was observed in 1 (3.4%) patient. Cosmetic result were excellent in 17 (62.9%) and good in 10 (37.1%) patients. SAPBI with CK is a suitable and practicable technique for the delivery of APBI after BCS for low-risk, St. I-II. IBC. Our early findings are encouraging, CK-SAPBI performed with four daily fractions is convenient and perfectly tolerated by the patients.

Six-Year Results From a Phase I/II Trial for Hypofractionated Accelerated Partial Breast Irradiation Using a 2-Day Dose Schedule

BACKGROUND

To report 6-year outcomes from a phase I/II trial using balloon-based brachytherapy to deliver APBI in 2 days.

METHODS

A total of 45 patients with early-stage breast cancer received adjuvant APBI in 2 days with high-dose rate (HDR) brachytherapy totaling 2800 cGy in 4 fractions (700 cGy BID) using a balloon-based applicator as part of a prospective phase I/II clinical trial. All patients had negative margins and skin spacing ≥8 mm. We evaluated toxicities (CTCAE v3) as well as ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), distant metastasis, disease-free survival, cause-specific survival, and overall survival.

RESULTS

Median age and tumor size were 66 years old (48 to 83) and 0.8 cm (0.2 to 2.3 cm), respectively. Four percent of patients were N1 (n=2) and 73% were estrogen receptor (ER) positive (n=32). Median follow-up was 6.2 years (2.4 to 8.0 y). Nearly all toxicities at 6 years were grade 1 to 2 except 1 instance of grade 3 telangiectasia (2%). Eleven percent (n=5) of patients had chronic asymptomatic fat necrosis whereas asymptomatic seromas were noted on mammogram in 13% of cases (n=6). Cosmesis at last follow-up was good or excellent in 91% of cases (n=40) and fair in 9% (n=4). Two of the previously reported rib fractures healed with conservative measures. There were no IBTR or RNF (6 y IBTR/RNF rate 0%); however, 2 patients experienced distant metastasis (4% at 6 y). The 6-year actuarial disease-free survival, cause-specific survival, and overall survival were 96%, 100%, and 93%, respectively.

CONCLUSIONS

Hypofractionated 2-day APBI using brachytherapy resulted in excellent clinical outcomes with acceptable chronic toxicities.

Measurement of dose exposure of image guidance in external beam accelerated partial breast irradiation: Evaluation of different techniques and linear accelerators

INTRODUCTION

Verifying the patient position is always an essential part of the treatment process, especially in hypofractionated treatments such as accelerated partial breast irradiation (APBI). The purpose of the study was to compare five image guidance techniques with respect to imaging dose and image quality.

METHODS AND MATERIALS

We chose five types of imaging methods applicable for APBI and measured their dose exposure on four different accelerators (Synergy, TrueBeam, Artiste and CyberKnife). Absorbed dose was measured with ionization chamber in thorax phantom. Besides dose exposure image quality was also compared.

RESULTS

The lowest dose exposure was measured with kV-kV planar imaging followed by kV-CBCT, MV-MV pair and MV-CBCT in ascending order. Average phantom dose with kV-kV image pair on CyberKnife was 0.01 cGy as the lowest and with MV-CBCT on Artiste was 7.11 cGy as the highest. Average dose exposures of MV-MV images with TrueBeam, Synergy and Artiste were 1.18 cGy, 2.13 cGy and 1.61 cGy, respectively, with similar image quality. For the same machines the doses of kV-CT imaging were comparable: 0.65 cGy, 0.65 cGy and 0.52 cGy, with some differences in image quality. MV-CBCT technique resulted in the highest dose and poorest image quality.

CONCLUSIONS

In APBI the position of the patient and tumour bed can be verified with many tools. When fiducials are available, often 2D imaging is enough to achieve appropriate positioning and the kV-kV method is recommended. Imaging with 2.5MV can also be a good solution instead of 6MV. Without fiducials 3D images should be acquired and the recommended method is the kV-CBCT.

A comparative study based on deformable image registration of the target volumes for external-beam partial breast irradiation defined using preoperative prone magnetic resonance imaging and postoperative prone computed tomography imaging

Background

To explore the differences and correlations between the target volumes defined using preoperative prone diagnostic magnetic resonance imaging (MRI) and postoperative prone computed tomography (CT) simulation imaging based on deformable image registration (DIR) for external-beam partial breast irradiation (EB-PBI) after breast-conserving surgery (BCS).

Methods

Eighteen breast cancer patients suitable for EB-PBI were enrolled. Preoperative prone diagnostic MRI and postoperative prone CT scan sets for all the patients were acquired during free breathing. Target volumes and ipsilateral breast were all contoured by the same radiation oncologist. The gross tumor volume (GTV) delineated on the preoperative MRI images was denoted as the GTV_preMR and the tumor bed (TB) delineated on the postoperative prone CT images was denoted as the GTV_postCT. The MIM software system was used to deformably register the MRI and CT images.

Results

When based on the coincidence of the compared target centers, there were statistically significant increases in the conformity index (CI) and degree of inclusion (DI) values for GTV_postCT-GTV_preMR, GTV_postCT-CTV_{preMR + 10}, CTV_{postCT + 10}-GTV_preMR, and CTV_{postCT + 10}-CTV_{preMR + 10} when compared with those based on the DIR of the thorax (Z = − 3.724, − 3.724, − 2.591, − 3.593, all P < 0.05; Z = -3.724, − 3.724, − 3.201, − 3.724, all P < 0.05, respectively).

Conclusions

Although based on DIR, there was relatively poor spatial overlap between the preoperative prone diagnostic MRI images and the postoperative prone CT simulation images for either the whole breast or the target volumes. Therefore, it is unreasonable to use preoperative prone diagnostic MRI images to guide postoperative target delineation for EB-PBI.

External beam accelerated partial breast irradiation: dosimetric assessment of conformal and three different intensity modulated techniques

Background The aim of the study was to evaluate and compare four different external beam radiotherapy techniques of accelerated partial breast irradiation (APBI) considering target coverage, dose to organs at risk and overall plan quality. The investigated techniques were three dimensional conformal radiotherapy (3D-CRT), "step and shoot" (SS) and "sliding window" (SW) intensity-modulated radiotherapy (IMRT), intensity-modulated arc therapy (RA). Patients and methods CT scans of 40 APBI patients were selected for the study. The planning objectives were set up according to the international recommendations. Homogeneity, conformity and plan quality indices were calculated from volumetric and dosimetric parameters of target volumes and organs at risk. The total monitor units and feasibility were also investigated. Results There were no significant differences in the coverage of the target volume between the techniques. The homogeneity indices of 3D-CRT, SS, SW and RA plans were 0.068, 0.074, 0.058 and 0.081, respectively. The conformation numbers were 0.60, 0.80, 0.82 and 0.89, respectively. The V50% values of the ipsilateral breast for 3D-CRT, SS, SW and RA were 47.5%, 40.2%, 39.9% and 31.6%, respectively. The average V10% and V40% values of ipsilateral lung were 13.1%, 28.1%, 28%, 36% and 2.6%, 1.9%, 1.9%, 3%, respectively. The 3D-CRT technique provided the best heart protection, especially in the low dose region. All contralateral organs received low doses. The SW technique achieved the best plan quality index (PQI). Conclusions Good target volume coverage and tolerable dose to the organs at risk are achievable with all four techniques. Taking into account all aspects, we recommend the SW IMRT technique for APBI.

Assessment of the implant geometry in fractionated interstitial HDR breast brachytherapy using an electromagnetic tracking system

PURPOSE

During the partial-breast treatment course by interstitial brachytherapy, electromagnetic tracking (EMT) was applied to measure the implant geometry. Implant-geometry variation, choice of reference data, and three registration methods were assessed.

METHODS AND MATERIALS

The implant geometry was measured in 28 patients after catheter implantation (EMT_bed), during CT imaging (EMT_CT), and in each of up to n = 9 treatment fractions (EMT_{F(k), k = 1, 2,… n}). EMT_F(k) were registered to the planned implant reconstruction (CT_plan) by using all dwell positions (DPs), the button centers, or three fiducial sensors on the patient's skin. Variation in implant geometry obtained from EMT_F(k) was assessed for EMT_bed, EMT_CT, and CT_plan.

RESULTS

EMT was used to measure 3932 catheters. A duration of 6.5 ± 1.7 min was needed for each implant measurement (mean, 17 catheters) plus setup of the EMT system. Data registration based on the DP deviated significantly lower than registration on button centers or fiducial sensors. Within a registration group, there was a <0.5-mm difference in the choice of reference data. Using CT_plan as reference for registration, the mean residual distance of DPs on EMT-derived DPs was found at 2.1 ± 1.6 mm (EMT_bed), 1.3 ± 0.9 mm (EMT_CT), and 2.5 ± 1.5 mm (EMT_F(k)).

CONCLUSIONS

EMT can assess the implant geometry in high-dose-rate interstitial brachytherapy breast treatments. EMT_bed, EMT_CT, and CT_plan data can serve as reference for assessment of implant changes.

Late side-effects and cosmetic results of accelerated partial breast irradiation with interstitial brachytherapy versus whole-breast irradiation after breast-conserving surgery for low-risk invasive and in-situ carcinoma of the female breast: 5-year results of a randomised, controlled, phase 3 trial

BACKGROUND

We previously confirmed the non-inferiority of accelerated partial breast irradiation (APBI) with interstitial brachytherapy in terms of local control and overall survival compared with whole-breast irradiation for patients with early-stage breast cancer who underwent breast-conserving surgery in a phase 3 randomised trial. Here, we present the 5-year late side-effects and cosmetic results of the trial.

METHODS

We did this randomised, controlled, phase 3 trial at 16 centres in seven European countries. Women aged 40 years or older with stage 0-IIA breast cancer who underwent breast-conserving surgery with microscopically clear resection margins of at least 2 mm were randomly assigned 1:1, via an online interface, to receive either whole-breast irradiation of 50 Gy with a tumour-bed boost of 10 Gy or APBI with interstitial brachytherapy. Randomisation was stratified by study centre, menopausal status, and tumour type (invasive carcinoma vs ductal carcinoma in situ), with a block size of ten, according to an automated dynamic algorithm. Patients and investigators were not masked to treatment allocation. The primary endpoint of our initial analysis was ipsilateral local recurrence; here, we report the secondary endpoints of late side-effects and cosmesis. We analysed physician-scored late toxicities and patient-scored and physician-scored cosmetic results from the date of breast-conserving surgery to the date of onset of event. Analysis was done according to treatment received (as-treated population). This trial is registered with ClinicalTrials.gov, number NCT00402519.

FINDINGS

Between April 20, 2004, and July 30, 2009, we randomly assigned 1328 women to receive either whole-breast irradiation (n=673) or APBI with interstitial brachytherapy (n=655); 1184 patients comprised the as-treated population (551 in the whole-breast irradiation group and 633 in the APBI group). At a median follow-up of 6·6 years (IQR 5·8-7·6), no patients had any grade 4 toxities, and three (<1%) of 484 patients in the APBI group and seven (2%) of 393 in the whole-breast irradiation group had grade 3 late skin toxicity (p=0·16). No patients in the APBI group and two (<1%) in the whole-breast irradiation group developed grade 3 late subcutaneous tissue toxicity (p=0·10). The cumulative incidence of any late side-effect of grade 2 or worse at 5 years was 27·0% (95% CI 23·0-30·9) in the whole-breast irradiation group versus 23·3% (19·9-26·8) in the APBI group (p=0·12). The cumulative incidence of grade 2-3 late skin toxicity at 5 years was 10·7% (95% CI 8·0-13·4) in the whole-breast irradiation group versus 6·9% (4·8-9·0) in the APBI group (difference -3·8%, 95% CI -7·2 to 0·4; p=0·020). The cumulative risk of grade 2-3 late subcutaneous tissue side-effects at 5 years was 9·7% (95% CI 7·1-12·3) in the whole-breast irradiation group versus 12·0% (9·4-14·7) in the APBI group (difference 2·4%; 95% CI -1·4 to 6·1; p=0·28). The cumulative incidence of grade 2-3 breast pain was 11·9% (95% CI 9·0-14·7) after whole-breast irradiation versus 8·4% (6·1-10·6) after APBI (difference -3·5%; 95% CI -7·1 to 0·1; p=0·074). At 5 years' follow-up, according to the patients' view, 413 (91%) of 454 patients had excellent to good cosmetic results in the whole-breast irradiation group versus 498 (92%) of 541 patients in the APBI group (p=0·62); when judged by the physicians, 408 (90%) of 454 patients and 503 (93%) of 542 patients, respectively, had excellent to good cosmetic results (p=0·12). No treatment-related deaths occurred, but six (15%) of 41 patients (three in each group) died from breast cancer, and 35 (85%) deaths (21 in the whole-breast irradiation group and 14 in the APBI group) were unrelated.

INTERPRETATION

5-year toxicity profiles and cosmetic results were similar in patients treated with breast-conserving surgery followed by either APBI with interstitial brachytherapy or conventional whole-breast irradiation, with significantly fewer grade 2-3 late skin side-effects after APBI with interstitial brachytherapy. These findings provide further clinical evidence for the routine use of interstitial multicatheter brachytherapy-based APBI in the treatment of patients with low-risk breast cancer who opt for breast conservation.

FUNDING

German Cancer Aid.

Cosmetic changes following surgery and accelerated partial breast irradiation using HDR interstitial brachytherapy : Evaluation by a multidisciplinary/multigender committee

BACKGROUND

Patients with early-stage breast cancer can benefit from adjuvant accelerated partial breast irradiation (APBI) following breast-conserving surgery (BCS). This work reports on cosmetic results following APBI using multicatheter high-dose-rate interstitial brachytherapy (HDR-IBT).

PATIENTS AND METHODS

Between 2006 and 2014, 114 patients received adjuvant APBI using multicatheter HDR-IBT. For each patient, two photographs were analyzed: the first was taken after surgery (baseline image) and the second at the last follow-up visit. Cosmesis was assessed by a multigender multidisciplinary team using the Harvard Breast Cosmesis Scale. Dose-volume histogram (DVH) parameters and the observed cosmetic results were investigated for potential correlations.

RESULTS

The median follow-up period was 3.5 years (range 0.6-8.5 years). The final cosmetic scores were 30% excellent, 52% good, 14.5% fair, and 3.5% poor. Comparing the baseline and follow-up photographs, 59.6% of patients had the same score, 36% had a better final score, and 4.4% had a worse final score. Only lower target dose nonuniformity ratio (DNR) values (0.3 vs. 0.26; p = 0.009) were significantly associated with improved cosmetic outcome vs. same/worse cosmesis.

CONCLUSION

APBI using multicatheter HDR-IBT adjuvant to BCS results in favorable final cosmesis. Deterioration in breast cosmesis occurs in less than 5% of patients. The final breast cosmetic outcome in patients treated with BCS and APBI using multicatheter HDR-IBT is influenced primarily by the cosmetic result of the surgery. A lower DNR value is significantly associated with a better cosmetic outcome.

Implementation of image-guided intensity-modulated accelerated partial breast irradiation : Three-year results of a phase II clinical study

PURPOSE

To report 3‑year results of accelerated partial breast irradiation (APBI) using image-guided intensity-modulated radiotherapy (IG-IMRT) following breast conserving surgery (BCS) for low-risk early invasive breast cancer.

PATIENTS AND METHODS

Between July 2011 and March 2014, 60 patients with low-risk early invasive breast cancer underwent BCS and were enrolled in this phase II prospective study. The total dose was 36.9 Gy (9 fractions of 4.1 Gy, two fractions/day). Patient setup errors were detected in LAT, LONG and VERT directions. Local tumour control, survival results, early and late side effects and cosmetic outcome were assessed.

RESULTS

At a median follow-up of 39 months, all patients were alive and neither locoregional nor distant failure occurred. One contralateral breast cancer and two new primary malignancies outside the breast were observed. No grade (G) 3-4 acute toxicity was detected. G1 and G2 erythema occurred in 21 (35%) and 2 (3.3%) patients, respectively; while G1 oedema was observed in 23 (38.8%) cases. G1 and G2 pain was reported by 6 (10%) and 2 (3.3%) patients, respectively. Among the late radiation side effects, G1 pigmentation or telangiectasia, G1 fibrosis and G1 asymptomatic fat necrosis occurred in 10 (16.7%), 7 (11.7%) and 3 (5%) patients, respectively. No ≥ G2 late toxicity was detected. Cosmetic outcome was excellent in 43 (71.7%) and good in 17 (28.3%) patients.

CONCLUSION

IG-IMRT is a reproducible and feasible technique for delivery of external beam APBI following BCS for treatment of low-risk, early-stage invasive breast carcinoma. In order to avoid toxicity, image guidance performed before each radiation fraction is necessary to minimize the PTV. Three-year results are promising, early and late radiation side-effects are minimal, and cosmetic results are excellent to good.

The Influence of Treatment Position (Prone vs. Supine) on Clip Displacement, Seroma, Tumor Bed and Partial Breast Target Volumes: Comparative Study

To analyse the displacement of surgical clips in prone (Pr) position and assess the consequences on target volumes and integral dose of partial breast irradiation (PBI). 30 post-lumpectomy breast cancer patients underwent CT imaging in supine (Su) and Pr. Clip displacements were measured by the distances from the clips to a common fix bony reference point. On each dataset, the tumour bed (TB = clips ± seroma), clinical target volume (CTV = TB + 1.5 cm) and planning target volumes (PTV = CTV + 1 cm) for PBI were determined and the volume pairs were compared. Furthermore estimation of integral dose ratio (IDR) within the breast from tangential treatment was performed as the ratio of the irradiated breast volume and the volume encompassing all clips. Clips close to the chest wall (CW) in Su showed significantly less displacement in Pr. The mean volumes of seroma, CTV and PTV were significantly higher in Pr than in Su. The PTV volume difference (Pr-Su) was significantly higher in patients with presence of seroma, deep clips and TB location in the superior-internal-quadrant (SIQ) and at the junction of superior quadrants (jSQ). In a multivariate analysis two factors remained significant: seroma and TB localization in SIQ-jSQ. The IDR was significantly larger in Su than in Pr (7.6 vs. 4.1 p < 0.01). Clip displacements varied considerably with respect to their relative position to the CW. In selected patients Pr position potentially leads to a significant increase in target volumes of PBI. Tangential beam arrangement for PBI should be avoided, not only in Su but in Pr as well in case of clip-based target volume definition.

Preoperative Single-Fraction Partial Breast Radiation Therapy: A Novel Phase 1, Dose-Escalation Protocol With Radiation Response Biomarkers

PURPOSE

Women with biologically favorable early-stage breast cancer are increasingly treated with accelerated partial breast radiation (PBI). However, treatment-related morbidities have been linked to the large postoperative treatment volumes required for external beam PBI. Relative to external beam delivery, alternative PBI techniques require equipment that is not universally available. To address these issues, we designed a phase 1 trial utilizing widely available technology to 1) evaluate the safety of a single radiation treatment delivered preoperatively to the small-volume, intact breast tumor and 2) identify imaging and genomic markers of radiation response.

METHODS AND MATERIALS

Women aged ≥55 years with clinically node-negative, estrogen receptor-positive, and/or progesterone receptor-positive HER2-, T1 invasive carcinomas, or low- to intermediate-grade in situ disease ≤2 cm were enrolled (n=32). Intensity modulated radiation therapy was used to deliver 15 Gy (n=8), 18 Gy (n=8), or 21 Gy (n=16) to the tumor with a 1.5-cm margin. Lumpectomy was performed within 10 days. Paired pre- and postradiation magnetic resonance images and patient tumor samples were analyzed.

RESULTS

No dose-limiting toxicity was observed. At a median follow-up of 23 months, there have been no recurrences. Physician-rated cosmetic outcomes were good/excellent, and chronic toxicities were grade 1 to 2 (fibrosis, hyperpigmentation) in patients receiving preoperative radiation only. Evidence of dose-dependent changes in vascular permeability, cell density, and expression of genes regulating immunity and cell death were seen in response to radiation.

CONCLUSIONS

Preoperative single-dose radiation therapy to intact breast tumors is well tolerated. Radiation response is marked by early indicators of cell death in this biologically favorable patient cohort. This study represents a first step toward a novel partial breast radiation approach. Preoperative radiation should be tested in future clinical trials because it has the potential to challenge the current treatment paradigm and provide a path forward to identify radiation response biomarkers.