Surgical technique of intraoperative radiation therapy with electrons (ELIOT) in breast cancer: A lesson learned by over 1000 procedures

In vivodosimetry in cancer patients undergoing intraoperative radiation therapy

In vivodosimetry (IVD) is an important tool in external beam radiotherapy (EBRT) to detect major errors by assessing differences between expected and delivered dose and to record the received dose by individual patients. Also, in intraoperative radiation therapy (IORT), IVD is highly relevant to register the delivered dose. This is especially relevant in low-risk breast cancer patients since a high dose of IORT is delivered in a single fraction. In contrast to EBRT, online treatment planning based on intraoperative imaging is only under development for IORT. Up to date, two commercial treatment planning systems proposed intraoperative ultrasound or in-room cone-beam CT for real-time IORT planning. This makes IVD even more important because of the possibility for real-time treatment adaptation. Here, we summarize recent developments and applications of IVD methods for IORT in clinical practice, highlighting important contributions and identifying specific challenges such as a treatment planning system for IORT. HDR brachytherapy as a delivery technique was not considered. We add IVD for ultrahigh dose rate (FLASH) radiotherapy that promises to improve the treatment efficacy, when compared to conventional radiotherapy by limiting the rate of toxicity while maintaining similar tumour control probabilities. To date, FLASH IORT is not yet in clinical use.

Radiation dose-event relationship after intraoperative radiotherapy as a boost in patients with breast cancer

Purpose

Intraoperative radiotherapy (IORT) can be used as a boost in combination with external whole breast irradiation. This study reports the clinical and dosimetric factors associated with IORT-related adverse events (AE).

Methods and materials

Between 2014 and 2021, 654 patients underwent IORT. A single fraction of 20 Gy was prescribed to the surface of the tumour cavity using the mobile 50-kV X-ray source. For skin dose measurement, at least four optically stimulated luminescent dosimeter (OSLD) chips were annealed and attached to the skin edge in the superior, inferior, medial, and lateral locations during IORT. Logistic regression analyses were conducted to identify factors associated with IORT-related AE.

Results

With a median follow-up period of 42 months, 7 patients experienced local recurrence, resulting in a 4-year local failure-free survival rate of 97.9%. The median skin dose measured by OSLD was 3.85 Gy (range, 0.67-10.89 Gy), and a skin dose of > 6 Gy was observed in 38 patients (2%). The most common AE was seroma (90 patients, 13.8%). We also found that 25 patients (3.9%) experienced fat necrosis during follow-up, and among them, 8 patients underwent biopsy or excision to exclude local recurrence. IORT-related late skin injury occurred in 14 patients, and a skin dose > 6 Gy was significantly associated with IORT-induced skin injury (odds ratio 4.942, 95% confidence interval 1.294-18.871, p = 0.019).

Conclusions

IORT was safely administered as a boost to various populations of patients with breast cancer. However, several patients may experience severe skin injuries, and for older patients with diabetes, IORT should be performed with caution.

Intraoperative electron radiotherapy in early invasive ductal breast cancer: 6-year median follow-up results of a prospective monocentric registry

Background

Intraoperative electron radiotherapy (IOERT) can be used to treat early breast cancer during the conservative surgery thus enabling shorter overall treatment times and reduced irradiation of organs at risk. We report on our first 996 patients enrolled prospectively in a registry trial.

Methods

At Jules Bordet Institute, from February 2010 onwards, patients underwent partial IOERT of the breast. Women with unifocal invasive ductal carcinoma, aged 40 years or older, with a clinical tumour size ≤ 20 mm and tumour-free sentinel lymph node (on frozen section and immunohistochemical analysis). A 21 Gy dose was prescribed on the 90% isodose line in the tumour bed with the energy of 6 to 12 MeV (Mobetron®-IntraOp Medical).

Results

Thirty-seven ipsilateral tumour relapses occurred. Sixteen of those were in the same breast quadrant. Sixty patients died, and among those, 12 deaths were due to breast cancer. With 71.9 months of median follow-up, the 5-year Kaplan–Meier estimate of local recurrence was 2.7%.

Conclusions

The rate of breast cancer local recurrence after IOERT is low and comparable to published results for IORT and APBI. IOERT is highly operator-dependent, and appropriate applicator sizing according to tumour size is critical. When used in a selected patient population, IOERT achieves a good balance between tumour control and late radiotherapy-mediated toxicity morbidity and mortality thanks to insignificant irradiation of organs at risk.

The POLO (Partially Omitted Lobe) approach to safely treat in-breast recurrence after intraoperative radiotherapy with electrons

OBJECTIVES

The aim of this study is to evaluate feasibility of salvage 4-week hypofractionated whole breast radiotherapy (WBRT) in patients with in-breast recurrence after receiving intraoperative radiotherapy with electrons (IOERT) for primary breast cancer (BC).

METHODS

BC patients who had repeated quadrantectomy underwent modified WBRT with intensity-modulated radiotherapy using Helical Tomotherapy to underdose the IOERT region. This approach, called POLO (Partially Omitted Lobe), excluded the IOERT volume from receiving the full prescription dose.

RESULTS

Nine patients were treated with this approach, receiving 45 Gy in 20 fractions. A simultaneous integrated boost of 2.5 Gy in 20 fractions was delivered in 6/9 patients. Dose constraints and planning objectives were reported. No severe toxicity was reported while local control and overall survival were 100%.

CONCLUSION

The POLO approach is technically feasible and capable to achieve a significant reduction of radiation dose delivered to the previous treated IOERT area.

ADVANCES IN KNOWLEDGE

The study demonstrates the technical and dosimetric feasibility of conservative salvage whole breast radiotherapy, while sparing the area already treated with IORT, in patients with in-breast recurrence.

Implementation of an HDR brachytherapy-based breast IORT program: Initial experiences

PURPOSE

A multidisciplinary team at our institution developed a novel method of intraoperative breast radiation therapy (precision breast intraoperative radiation therapy [PB-IORT]) that uses high-dose-rate brachytherapy with CT on-rails imaging to deliver high-dose, customized radiotherapy to patients with early-stage breast cancer. This report summarizes our program's experience developing and implementing PB-IORT.

METHODS AND MATERIALS

Literature on PB-IORT was reviewed including published articles and abstracts. To evaluate case volume, all patients with a breast cancer diagnosis who underwent breast surgery or breast radiation (2010-2017) at our academic institution were identified. Patients were stratified into pre-IORT and post-IORT eras with initiation of our PB-IORT program in October 2013. Overall trends in surgical and radiation therapy volume in each era were analyzed by linear regression. Travel distance for all surgical patients was calculated using Google Maps (Alphabet Inc.) and then compared between IORT and non-IORT patients.

RESULTS

Data from a PB-IORT Phase 1 trial found that the primary endpoints were met and that PB-IORT is feasible and safe. The direct health system's delivery costs for PB-IORT exceed those of 16-fraction whole-breast irradiation when accounting for consumable supplies (multilumen balloon applicator = $2,750 per patient). There was a significant increase in yearly growth of breast cancer surgical volume with PB-IORT.

CONCLUSIONS

Accrual rates for the ongoing Phase II trial have been quicker than expected in an area where more research is needed. The rapid accrual indicates patient interest and demand for this treatment and that it is very feasible to get more data from randomized trials.

Comparison of Local Recurrence Among Early Breast Cancer Patients Treated With Electron Intraoperative Radiotherapy vs Hypofractionated Photon Radiotherapy an Observational Study

Purpose

To evaluate local recurrence (LR) in women with early breast cancer (BC) who underwent intraoperative radiation therapy with electrons particles (IORT-E) or adjuvant hypofractionated external radiotherapy (HYPOFX).

Materials and methods

We retrospectively analyzed 470 patients with early BC treated at our center from September 2009 to December 2012. 235 women were treated with breast-conserving surgery and immediate IORT-E (21 Gy/1 fraction) while 235 patients underwent wide excision followed by hypofractionated whole-breast irradiation. Radiotherapy modality was chosen according to an individualized decision based on tumor features, stage, technical feasibility, age, and acceptance to be enrolled in the IORT-E group.

Results

After a median follow-up of 6 years, we observed 8 (3.4%) and 1 (0.42%) LR in the IORT-E and in the HYPOFX group (p = 0.02), respectively. The two groups differed in the prevalence of clinical characteristics (p < 0.05): age, tumor size, surgical margins, receptors, ki67, and histology. 4 and 1 woman in the IORT-E and HYPOFX group died of BC, respectively (p = 0.167). OS and DFS hazard ratio [HR] were 2.14 (95% IC, 1.10–4.15) and 2.09 (95% IC, 1.17–3.73), respectively.

Conclusion

Our comparison showed that IORT-E and HYPOFX are two effective radiotherapy modalities after conservative surgery in early BC. However, at 6 years a significant higher rate of LR occurred in patients submitted to IORT-E with respect to HYPOFX. This finding may be correlated to some subsets of patients who, depending on the biological characteristics of the BC, may be less suitable to IORT-E.

Dosimetric feasibility of using tungsten-based functional paper for flexible chest wall protectors in intraoperative electron radiotherapy for breast cancer

Intraoperative electron radiotherapy (IOERT), which is an accelerated partial breast irradiation method, has been used for early-stage breast cancer treatment. In IOERT, a protective disk is inserted behind the target volume to minimize the dose received by normal tissues. However, to use such a disk, the surgical incision must be larger than the field size because the disk is manufactured from stiff and unyielding materials. In this study, the applicability of newly developed tungsten-based functional paper (TFP) was assessed as an alternative to the existing protective disk. The radiation-shielding performance of the TFP was verified through experimental measurements and Monte Carlo simulations. Percentage depth dose curves and lateral dose profiles with and without TFPs were measured and simulated on a dedicated IOERT accelerator. The number of piled-up TFPs was changed from 1 to 40. In the experimental measurements, the relative doses at the exit plane of the TFPs for 9 MeV were 42.7%, 9.2%, 0.2%, and 0.1% with 10, 20, 30, and 40 TFPs, respectively, whereas those for 12 MeV were 63.6%, 27.1%, 8.6%, and 0.2% with 10, 20, 30, and 40 TFPs, respectively. Slight dose enhancements caused by backscatter radiation from the TFPs were observed at the entrance plane of the TFPs at both beam energies. The results of the Monte Carlo simulation indicated the same tendency as the experimental measurements. Based on the experimental and simulated results, the radiation-shielding performances of 30 TFPs for 9 MeV and 40 TFPs for 12 MeV were confirmed to be acceptable and close to those of the existing protective disk. The findings of this study suggest the feasibility of using TFPs as flexible chest wall protectors in IOERT for breast cancer treatment.

Present state and issues in IORT Physics

Literature was reviewed to assess the physical aspects governing the present and emerging technologies used in intraoperative radiation therapy (IORT). Three major technologies were identified: treatment with electrons, treatment with external generators of kV X-rays and electronic brachytherapy. Although also used in IORT, literature on brachytherapy with radioactive sources is not systematically reviewed since an extensive own body of specialized literature and reviews exists in this field. A comparison with radioactive sources is made in the use of balloon catheters for partial breast irradiation where these are applied in almost an identical applicator technique as used with kV X-ray sources. The physical constraints of adaption of the dose distribution to the extended target in breast IORT are compared. Concerning further physical issues, the literature on radiation protection, commissioning, calibration, quality assurance (QA) and in-vivo dosimetry of the three technologies was reviewed. Several issues were found in the calibration and the use of dosimetry detectors and phantoms for low energy X-rays which require further investigation. The uncertainties in the different steps of dose determination were estimated, leading to an estimated total uncertainty of around 10-15% for IORT procedures. The dose inhomogeneity caused by the prescription of electrons at 90% and by the steep dose gradient of kV X-rays causes additional deviations from prescription dose which must be considered in the assessment of dose response in IORT.

Current Trends in the Oncologic and Surgical Managements of Breast Cancer in Women with Implants: Incidence, Diagnosis, and Treatment

Breast augmentation is the most common cosmetic surgery in the United States, and thousands of augmented patients develop breast cancer each year. The possible effects of implants on cancer incidence, diagnosis, and treatment usually generate a disarming confusion. The present paper represents an update of the more recent oncologic and surgical strategies, aiming to support plastic and general surgeons in such challenging aspects. Several aspects of breast cancer management in augmented women are investigated, including (1) risk estimation and cancer characteristics, stage at diagnosis, and prognosis; (2) cancer diagnosis with clinical examination, mammography, ultrasound, and magnetic resonance imaging; (3) cancer treatment including breast conservation, intraoperative radiotherapy, sentinel node biopsy and mastectomy, and reconstruction. A brief resume of recommendations and conclusions is suggested, elucidating correct trends in the oncologic management of augmented patients and refusing well-established misconceptions: (1) breast augmentation does not increase the risk of breast cancer incidence, and it does not influence the prognosis; (2) possible risks exist in cancer detection due to technical difficulties; (3) sentinel lymph node detection is feasible; (4) intraoperative radiotherapy represents a good chance for conserving treatment; (5) immediate reconstruction with submuscular-subfascial implants is the most common procedure after mastectomy, and biological substitutes could support this procedure. Breast clinicians should be alerted because of high expectations of this subgroup of patients, accustomed to emphasize the aesthetic result.

LEVEL OF EVIDENCE V

This journal requires that the authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Intraoperative full-dose of partial breast irradiation with electrons delivered by standard linear accelerators for early breast cancer

Purpose. To assess feasibility, efficacy, toxicity, and cosmetic results of intraoperative radiotherapy (IORT) with electrons delivered by standard linear accelerators (Linacs) during breast conserving surgeries for early infiltrating breast cancer (BC) treatment. Materials and Methods. A total of 152 patients with invasive ductal carcinoma (T ≤ 3.0 cm) at low risk for local relapses were treated. All had unicentric lesions by imaging methods and negative sentinel node. After a wide local excision, 21 Gy were delivered on the parenchyma target volume with electron beams. Local recurrences (LR), survival, toxicity, and cosmetic outcomes were analyzed. Results. The median age was 58.3 years (range 40–85); median follow-up was 50.7 months (range 12–101.5). There were 5 cases with LR, 2 cases with distant metastases, and 2 cases with deaths related to BC. The cumulative incidence rates of LR, distant metastases, and BC death were 3.2%, 1.5%, and 1.5%, respectively. Complications were rare, and the cosmetic results were excellent or good in most of the patients. Conclusions. IORT with electrons delivered by standard Linacs is feasible, efficient, and well tolerated and seems to be beneficial for selected patients with early infiltrating BC.

Intraoperative radiation therapy in early breast cancer using a linear accelerator outside of the operative suite: an "image-guided" approach

PURPOSE

To present local control, complications, and cosmetic outcomes of intraoperative radiation therapy (IORT) for early breast cancer, as well as technical aspects related to the use of a nondedicated linear accelerator.

METHODS AND MATERIALS

This prospective trial began in May of 2004. Eligibility criteria were biopsy-proven breast-infiltrating ductal carcinoma, age >40 years, tumor <3 cm, and cN0. Exclusion criteria were in situ or lobular types, multicentricity, skin invasion, any contraindication for surgery and/or radiation therapy, sentinel lymph node involvement, metastasis, or another malignancy. Patients underwent classic quadrantectomy with intraoperative sentinel lymph node and margins evaluation. If both free, the patient was transferred from operative suite to linear accelerator room, and IORT was delivered (21 Gy). Primary endpoint: local recurrence (LR); secondary endpoints: toxicities and aesthetics. Quality assurance involved using a customized shield for chest wall protection, applying procedures to minimize infection caused by patient transportation, and using portal films to check collimator-shield alignment.

RESULTS

A total of 152 patients were included, with at least 1 year follow-up. Median age (range) was 58.3 (40-85.4) years, and median follow-up time was 50.7 (12-110.5) months. The likelihood of 5-year local recurrence was 3.7%. There were 3 deaths, 2 of which were cancer related. The Kaplan-Meier 5-year actuarial estimates of overall, disease-free, and local recurrence-free survivals were 97.8%, 92.5%, and 96.3%, respectively. The overall incidences of acute and late toxicities were 12.5% and 29.6%, respectively. Excellent, good, fair, and bad cosmetic results were observed in 76.9%, 15.8%, 4.3%, and 2.8% of patients, respectively. Most treatments were performed with a 5-cm collimator, and in 39.8% of the patients the electron-beam energy used was ≥12 MeV. All patients underwent portal film evaluation, and the shielding was repositioned in 39.9% of cases. No infection or anesthesia complications were observed.

CONCLUSIONS

Local control with IORT was adequate, with low complication rates and good cosmetic outcomes. More than one-third of patients benefited from the "image-guidance" approach, and almost 40% benefited from the option of higher electron beam energies.

The evolving role of partial breast irradiation in early-stage breast cancer

Whole breast irradiation (WBI) over 5-7 weeks has long been considered standard adjuvant treatment after breast-conserving surgery. Recently the concept of irradiating the whole breast has been challenged by accelerated partial breast irradiation (APBI), which exclusively targets the lumpectomy site plus margin. We review the evidence supporting APBI from modern clinical trials, the pros and cons of various APBI techniques, and the controversies regarding the applicability of APBI to specific patient groups.

Interoperative radiotherapy of seventy-two cases of early breast cancer patients during breast-conserving surgery

OBJECTIVE

To evaluate interoperative radiotherapy after breast conservative surgery in early breast cancer patients in terms of postoperative complications, cosmetic outcome and recurrence events.

METHODS

From June 2007 to Dec 2011, 143 early breast cancer patients received breast conservative surgery. Seventy-two (study group) received interoperative radiotherapy, compared with 71 patients (control group) given routine radiotherapy. Postoperative complications were evaluated 1 month after surgery; cosmetic outcome was evaluated 1 year postoperatively; recurrence and death events were followed up.

RESULTS

The average wound healing time was 13~22 d in the study group and 9~14 d in the control group. In the study group, 2 patients developed lyponecrosis, 16 patients showed wound edema while no such side effects were found in the control group. No infection or hematomas were found in either group. In the study group (59 cases), overall cosmetic outcome in 53 patients was graded as excellent or good, and in 6 as fair or poor. Meanwhile in the control group (56 cases), 42 patients were graded as excellent or good, and 14 as fair or poor (P=0.032). After a follow-up from 3 to 54 months (median: 32 months), two patients (2.78%) in study group developed local relapses, one of them (1.39%) died, 2 patients (2.78%) developed bone metastases. In control group, one patient (1.41%) developed local relapse, 2 patients (2.82%) developed bone metastases, and no one died.

CONCLUSION

Intraoperative radiotherapy is safe and reliable with good cosmetic outcome.

Radiotherapy issues in elderly breast cancer patients

Breast cancer in the elderly is a rising health care challenge. Under-treatment is common. While the proportion of older patients receiving adjuvant radiotherapy (RT) is rising, the proportion undergoing breast-conserving surgery without irradiation has also risen. The evidence base for loco-regional treatment is limited, reflecting the historical exclusion of older patients from randomised trials. The 2011 Oxford overview shows that the risk of first recurrence is halved in all age groups by adjuvant RT after breast-conserving surgery, although the absolute benefit in older 'low-risk' patients is small. There is level 1 evidence that a breast boost after breast-conserving surgery and whole-breast irradiation reduces local recurrence in older as in younger women, although in the former the absolute reduction is modest. Partial breast irradiation (external beam or intraoperative or postoperative brachytherapy) is potentially an attractive option for older patients, but the evidence base is insufficient to recommend it routinely. Similarly, shortened (hypofractionated) dose fraction schedules may be more convenient for older patients and are supported by level 1 evidence. There remains uncertainty about whether there is a subgroup of older low-risk patients in whom postoperative RT can be omitted after breast-conserving surgery. Biomarkers of 'low risk' are needed to refine the selection of patients for the omission of adjuvant RT. The role of postmastectomy irradiation is well established for 'high-risk' patients but uncertain in the intermediate-risk category of patients with 1-3 involved axillary nodes or node-negative patients with other risk factors where its role is investigational.

Phase I/II study of intraoperative radiotherapy for early breast cancer in Japan

BACKGROUND

Intraoperative radiotherapy (IORT) is under evaluation in breast-conserving surgery. We have begun our study with the first step being a phase I-II study. This study was designed to identify the recommended dose and to test the feasibility of and tolerance to IORT in Japanese patients (UMIN000000918).

METHODS

A phase I study was designed using a scheme of dose escalation from 19 to 20 to 21 Gy. We designed the phase II study to use the recommended dose. The primary endpoint was early toxicity. Secondary endpoints were efficacy for a long period and late toxicity. Inclusion criteria included the following: (1) T < 2.5 cm, (2) age >50 years, (3) surgical margin >1 cm, (4) intraoperative pathologically free margins, and (5) sentinel node negative. Partial resection was performed with at least a 1 cm margin around the tumor. Radiation was delivered directly to the mammary gland with the use of a Mobetron(®). The toxicity was evaluated with the Common Terminology Criteria for Adverse Events (CTCAE) v3.0.

RESULTS

Nine patients were enrolled for the phase I study. All patients tolerated and we therefore recommend 21 Gy. The following 23 patients were enrolled in a phase II study and received 21 Gy. After a median follow-up of 26.0 months, their toxicities within 3 months included deep connective tissue fibrosis (G1 23/26, G2 2/26), hematoma (G1 9/26), infection in the musculoskeletal soft tissue (G1 4/26), and soft tissue necrosis (G2 3/26). There have been no local recurrences.

CONCLUSIONS

The first group of Japanese female patients treated with IORT showed very good tolerability in the phase I/II study.

Application of failure mode and effects analysis to intraoperative radiation therapy using mobile electron linear accelerators

PURPOSE

Failure mode and effects analysis (FMEA) represents a prospective approach for risk assessment. A multidisciplinary working group of the Italian Association for Medical Physics applied FMEA to electron beam intraoperative radiation therapy (IORT) delivered using mobile linear accelerators, aiming at preventing accidental exposures to the patient.

METHODS AND MATERIALS

FMEA was applied to the IORT process, for the stages of the treatment delivery and verification, and consisted of three steps: 1) identification of the involved subprocesses; 2) identification and ranking of the potential failure modes, together with their causes and effects, using the risk probability number (RPN) scoring system, based on the product of three parameters (severity, frequency of occurrence and detectability, each ranging from 1 to 10); 3) identification of additional safety measures to be proposed for process quality and safety improvement. RPN upper threshold for little concern of risk was set at 125.

RESULTS

Twenty-four subprocesses were identified. Ten potential failure modes were found and scored, in terms of RPN, in the range of 42-216. The most critical failure modes consisted of internal shield misalignment, wrong Monitor Unit calculation and incorrect data entry at treatment console. Potential causes of failure included shield displacement, human errors, such as underestimation of CTV extension, mainly because of lack of adequate training and time pressures, failure in the communication between operators, and machine malfunctioning. The main effects of failure were represented by CTV underdose, wrong dose distribution and/or delivery, unintended normal tissue irradiation. As additional safety measures, the utilization of a dedicated staff for IORT, double-checking of MU calculation and data entry and finally implementation of in vivo dosimetry were suggested.

CONCLUSIONS

FMEA appeared as a useful tool for prospective evaluation of patient safety in radiotherapy. The application of this method to IORT lead to identify three safety measures for risk mitigation.

Accelerated partial breast irradiation

Whole breast irradiation (WBI) is the standard after breast conservation surgery. However, WBI in selected patients has been questioned. Accelerated partial breast irradiation (APBI) focuses treatment on the lumpectomy bed. Many modalities of delivering APBI have been developed: multicatheter interstitial brachytherapy, MammoSite balloon catheter, single insertion multicatheter devices, three-dimensional conformal external-beam radiation therapy and intraoperative techniques. Numerous studies of APBI have demonstrated excellent local control and cosmetic outcomes in early-stage breast cancer patients.

Health-related quality of life after breast-conserving surgery and intraoperative radiotherapy for breast cancer using low-kilovoltage X-rays

BACKGROUND

Intraoperative radiotherapy (IORT) is currently being evaluated as a novel approach during breast-conserving surgery (BCS). IORT can be used either as a tumor bed boost followed by external-beam radiotherapy (EBRT) or as a single treatment. In a matched-pair study, we assessed quality of life (QoL) in 69 patients with early breast cancer treated with BCS and/or IORT and/or EBRT.

METHODS

Patients were matched for age and time since BCS. IORT was provided with 50 kV x-rays (Intrabeam) delivering 20 Gy at the applicator surface. EBRT (46 to 50 Gy in 2-Gy fractions in the IORT with EBRT group, and 56 Gy in 2-Gy fractions in the EBRT group) was initiated after completion of wound healing and/or chemotherapy. The mailed questionnaires included the European Organization for the Research and Treatment of Cancer QLQ-C30 and BR23, FACT-F, HADS, Body Image Scale, and Rosenberg Self-Esteem Scale. At 18 to 70 months' follow-up (median 47 months), all patients were disease free.

RESULTS

We found only a few differences between the three groups. There was a trend toward more pain (mean ± standard deviation; 42.8 ± 32.9 vs. 27.5 ± 34.7) and reduced QoL (57.6 ± 20.7 vs. 70.3 ± 23.9) after IORT with EBRT compared with EBRT, respectively. IORT patients reported comparable QoL (70.3 ± 23.0), and less breast symptoms and body image concerns compared to EBRT (8.6 ± 12.3 vs. 19.2 ± 23.8, and 1.7 ± 3.3 vs. 3.4 ± 4.4, respectively). IORT alone resulted in significantly fewer breast symptoms (8.6 ± 12.3; P = 0.012) and less pain (23.9 ± 24.5, P = 0.041) compared with IORT with EBRT (26.1 ± 27.6; 42.8 ± 32.9, respectively).

CONCLUSIONS

Patients with early breast cancer after BCS and IORT with or without EBRT present with comparable QoL like patients receiving EBRT without a boost. IORT patients show the lowest rate of breast symptoms.

Radiobiological comparison of hypofractionated accelerated partial-breast irradiation (APBI) and single-dose intraoperative radiotherapy (IORT) with 50-kV X-rays

BACKGROUND AND PURPOSE

Intraoperative radiotherapy (IORT) of the tumor bed in early breast cancer is presently performed with a single dose of 50-kV X-rays from a miniaturized X-ray machine using spherical applicators. The purpose was to model the biological effect of hypofractionated accelerated partial-breast irradiation (APBI) with ten fractions.

MATERIAL AND METHODS

The relative biologic effectiveness (RBE) was estimated from the linear-quadratic (L-Q) formalism including repair of sublethal damage or assuming a constant RBE = 1.2-1.5. The radial distribution of biological effect was assessed from clinical dose-response curves. In accordance with clinical convention, the dose for APBI was prescribed at 1 cm depth in the tumor bed, whereas for IORT it was prescribed at the applicator surface.

RESULTS

The fraction size was fitted to give the same risk of late normal-tissue reaction (fibrosis) as single-dose IORT with a maximum dose of 20 Gy. The isoeffective fraction size at 1 cm depth varied between 1.01 Gy for RBE estimated from the L-Q model and 1.64 Gy for constant RBE. The applicator size and dose prescription point influenced the radial dose distribution. The "sphere of equivalence" within which the risk for local recurrence is the same for whole-breast radiotherapy was predicted to extend to 11-15 mm distance from the applicator for alpha/beta = 10 Gy and 9-13 mm for alpha/beta = 4 Gy for hypofractionated APBI, representing an increase of the sphere of equivalence by 2.5-6 mm relative to single-dose IORT.

CONCLUSION

An increase of the therapeutic window with hypofractionated APBI relative to single-dose IORT should be feasible.

Intraoperative radiotherapy as a boost during breast-conserving surgery using low-kilovoltage X-rays: the first 5 years of experience with a novel approach

PURPOSE

Intraoperative radiotherapy (IORT) during breast-conserving surgery (BCS) has been recently introduced using different devices. We report the first 5 years of a single-center experience after introduction of a novel approach to deliver IORT as a tumor bed boost during BCS for breast cancer.

METHODS AND MATERIALS

A total of 155 breast cancers in 154 women (median age, 63 years; range, 30-83 years; T1/T2 = 100/55; N0/N+ = 108/47) were treated between February 2002 and December 2007 at the University Medical Center Mannheim, in whom IORT as tumor bed boost was applied using 50-kV X-rays (20 Gy) followed by 46-50 Gy whole-breast external-beam radiotherapy (EBRT). Chemotherapy, if indicated, was given before EBRT. The median interval between BCS plus IORT and EBRT was 40 days. Median follow-up was 34 months (maximum 80 months, 1 patient lost to follow-up). Overall survival and local relapse-free survival were calculated at 5 years using the Kaplan-Meier method. Seventy-nine patients were evaluated at 3-year follow-up for late toxicity according to the Late Effects in Normal Tissues-Subjective, Objective, Management, and Analytic system.

RESULTS

Ten patients died, 2 had in-breast relapse, and 8 developed distant metastases (5-year overall survival = 87.0%; 5-year local relapse-free survival = 98.5%). Grade 3 fibroses of the tumor bed were detected in 5% of the patients after 3 years. Skin toxicity was mild (telangiectases and hyperpigmentations in approximately 6% each).

CONCLUSIONS

Intraoperative radiotherapy as a tumor bed boost during BCS for breast cancer using low-kilovoltage X-rays followed by EBRT yields low recurrence and toxicity rates.

Early initiation of external beam radiotherapy (EBRT) may increase the risk of long-term toxicity in patients undergoing intraoperative radiotherapy (IORT) as a boost for breast cancer

BACKGROUND

Intraoperative radiotherapy (IORT) during breast-conserving surgery is increasingly used. We analyzed the influence of the interval between an IORT boost and external beam radiotherapy (EBRT) on late toxicity.

METHODS

Forty-eight patients received 20 Gy IORT (50 kV X-rays (Intrabeam, Carl Zeiss, Oberkochen, Germany) followed by 46-50 Gy EBRT with a median interval of 36 days (14-197). Late toxicity was assessed with the modified LENT SOMA score after a median of 36 months.

RESULTS

Twelve patients developed a higher grade fibrosis ( degrees II-III), three teleangiectases, one a breast edema grade degrees II, six retractions, four hyperpigmentations and five pain ( degrees II-III). The median interval between IORT and EBRT was significantly shorter in these patients (n=18) compared to the 30 patients without higher grade toxicity (29.5 days vs. 39.5 days, p=0.023, Mann-Whitney U-test).

CONCLUSION

Starting EBRT about 5-6 weeks after IORT appears to be associated with a decreased risk of chronic late toxicity compared with a shorter interval. The impact on local recurrence of prolonged gaps between IORT and EBRT is not known.

Full-dose intra-operative radiotherapy with electrons (ELIOT) during breast-conserving surgery: experience with 1246 cases

Background:

Previous studies showed that after breast-conserving surgery for breast cancer, radiotherapy may be applied to the portion of the breast where the primary tumour was removed (partial breast irradiation (PBI), avoiding the irradiation of the whole breast. We developed a procedure of PBI consisting of a single high dose of radiotherapy of 21 Gy with electrons equivalent to 58–60 Gy in fractionated doses, delivered during the surgical session by a mobile linear accelerator, positioned close to the operating table.

Patients and methods:

From July 1999 to December 2006, 1246 patients with primary carcinoma of less than 2.5-cm maximum diameter, mostly over 48 years, were treated with electron intra-operative radiotherapy (ELIOT) at a single dose of 21 Gy.

Results:

After a follow-up from 0.3 to 94.7 months (median 26), 24 (1.9%) patients showed a local recurrence and 22 developed distant metastases. Sixteen patients died, seven from breast carcinoma and nine from others causes. The five-year crude survival was 96.5%. Six (0.5%) developed severe breast fibrosis, which resolved in 2–3 years. An additional 40 patients suffered for mild fibrosis. Cosmetic results were good.

Conclusions:

Electron intra-operative radiotherapy is a safe method for treating conservatively operated breasts and avoids the long period of post-operative radiotherapy, greatly improving the quality of life and reduces the cost of radiotherapy. ELIOT markedly reduces the radiation to normal surrounding tissues and deep organs. Results on short- and medium-term toxicity are good. Data on local control are encouraging.

Single-Fraction Intraoperative Radiotherapy for Breast Cancer: Early Cosmetic Results

PURPOSE

To evaluate the cosmetic outcome of patients treated with wide local excision and intraoperative radiotherapy for early-stage breast cancer.

METHODS AND MATERIALS

A total of 50 women were treated on a pilot study to evaluate the feasibility of intraoperative radiotherapy at wide local excision. The eligibility criteria included age >60, tumor size </=2.0 cm, clinically negative lymph nodes, and biopsy-established diagnosis. After wide local excision, a custom breast applicator was placed in the excision cavity, and a dose of 20 Gy was prescribed to a depth of 1 cm. After 18 patients were treated, the dose was constrained laterally to 18 Gy. The cosmetic outcome was evaluated by photographs at baseline and at 6 and 12 months postoperatively. Four examiners graded the photographs for symmetry, edema, discoloration, contour, and scarring. The grades were evaluated in relationship to the volume of irradiated tissue, tumor location, and dose at the lateral aspects of the cavity.

RESULTS

The median volume of tissue receiving 100% of the prescription dose was 47 cm(3) (range, 20-97 cm(3)). Patients with </=47 cm(3) of treated tissue had better cosmetic outcomes than did the women who had >47 cm(3) of treated tissue. Women who had received 18 Gy at the lateral aspects of their cavities had better cosmetic outcomes than did women who had received 20 Gy at the lateral aspects. When comparing the 6- and 12-month results, the scores remained stable for 63%, improved for 17%, and worsened for 20%.

CONCLUSION

Intraoperative radiotherapy appears feasible for selected patients. A favorable cosmetic outcome appears to be related to a smaller treatment volume. The cosmetic outcome is acceptable, although additional follow-up is necessary.

Intraoperative radiation therapy

Intraoperative radiation therapy (IORT) is the delivery of irradiation at the time of an operation. This is performed by different techniques including intraoperative electron beam techniques and high-dose rate brachytherapy. IORT is usually given in combination with external-beam radiation therapy with or without chemotherapy and surgical resection. IORT excludes part or all dose-limiting sensitive structures, thereby increasing the effective dose to the tumor bed (and therefore local control) without significantly increasing normal tissue morbidity. Despite best contemporary therapy, high rates of local failure occur in patients with locally advanced or recurrent rectal cancer, retroperitoneal sarcoma, select gynecologic cancers, and other malignancies. The addition of IORT to conventional treatment methods has improved local control as well as survival in many disease sites in both the primary and locally recurrent disease settings. More recently, there has been interest in the use of IORT as a technique of partial breast irradiation for women with early breast cancer. Given newer and lower cost treatment devices, the use of IORT in clinical practice will likely grow, with increasing integration into the treatment of nonconventional malignancies. Optimally, phase III randomized trials will be carried out to prove its efficacy in these disease sites.