A systematic review of intraoperative radiotherapy in early breast cancer

Efficacy and Tolerance of IMRT Boost Compared to IORT Boost in Early Breast Cancer: A German Monocenter Study

The aim of this retrospective study is to compare the two boost subgroups, IORT or IMRT, in terms of overall survival (OS), progression-free survival (PFS), cosmesis, and acute and late toxicity. It shall be shown whether and which of the boost techniques offers better results with respect to the facial points, since there are already many studies on applying boost to the tumor bed after/during breast conserving surgery, and there are few which compare the different techniques. For this comparison, two subgroups of 76 patients each (n = 152), treated between 2002 and 2015, were enrolled in the study. In one subgroup, the 9 Gy boost was intraoperatively administered after complete removal of the primary tumor, while the other subgroup received the boost of 8.4 Gy percutaneously and simultaneously integrated into the tumor bed after breast conserving surgery. Both subgroups have subsequently undergone whole breast irradiation (WBI) of 50.4/50 Gy in 1.8−2 Gy per fraction. OS and the incidence of late toxicity did not differ between the two subgroups and no risk factor was found regarding PFS. Acute toxicities initially occurred significantly less (p < 0.001) in the IORT subgroup; however, after WBI took place, this difference vanished. Therefore, boost application by means of IORT or IMRT can be considered equivalent.

In vivo dosimetry in low-voltage IORT breast treatments with XR-RV3 radiochromic film

PURPOSE

The objectives of the study were to establish a procedure for in vivo film-based dosimetry for intraoperative radiotherapy (IORT), evaluate the typical doses delivered to organs at risk, and verify the dose prescription.

MATERIALS AND METHODS

In vivo dose measurements were studied using XR-RV3 radiochromic films in 30 patients with breast cancer undergoing IORT using the Axxent® device (Xoft Inc.). The stability of the radiochromic films in the energy ranges used was verified by taking measurements at different depths. The stability of the scanner response was tested, and 5 different calibration curves were constructed for different beam qualities. Six pieces of film were placed in each of the 30 patients. All the pieces were correctly sterilized and checked to ensure that the process did not affect the outcome. All calibration and dose measurements were analyzed using the Radiochromic.com software application.

RESULTS

The doses were measured for 30 patients. The doses in contact with the applicator (prescription zone) were 19.8 ± 0.9 Gy. In the skin areas, the doses were as follows: 1-2 cm from the applicator, 1.86 ± 0.77 Gy; 2-5 cm, 0.73 ± 0.14 Gy; and greater than 5 cm, 0.28 ± 0.17 Gy. The dose delivered to the pectoral muscle (tungsten shielding disc) was 0.51 ± 0.27 Gy.

CONCLUSIONS

The study demonstrated the viability of XR-RV3 films for in vivo dose measurement in the dose and energy ranges applied in a complex procedure, such as breast IORT. The doses in organs at risk were far below the tolerances for cases such as those studied.

Intraoperative Radiotherapy (Iort) for Breast Cancer Using the Intrabeam™ System

Introduction

Intraoperative radiotherapy (IORT) with low-energy X-rays (30–50 KV) is an innovative technique that can be used both for accelerated partial breast irradiation (APBI) and intraoperative boosting in patients affected by breast cancer. Immediately after tumor resection the tumor bed can be treated with low-distance X-rays by a single high dose. Whereas often a geographic miss in covering the boost target occurs with external beam boost radiotherapy (EBRT), the purpose of IORT is to cover the tumor bed safely. This report will focus on the feasibility and technical aspects of the Intrabeam™ device and will summarize our experience with side effects and local control.

Materials and methods

Between February 2002 and June 2003 57 breast cancer patients, all eligible for breast conserving surgery (BCS), were treated at the Mannheim Medical Center with IORT using the mobile X-ray system Intrabeam™. The patient population in this feasibility study was not homogeneous consisting of 49 patients with primary stage I or II breast cancer, seven with local recurrence after previous EBRT and one with a second primary in a previously irradiated breast. The selection criteria for referral for IORT included tumor size, tumor cavity size, margin status and absence of an extensive intraductal component. The previously irradiated patients with local recurrences and 16 others received IORT as single modality. In all other cases IORT was followed by EBRT with a total dose of 46 Gy in 2-Gy fractions. The intraoperatively delivered dose after tumor resection was 20 Gy prescribed to the applicator surface. EBRT was delivered with a standard two-tangential-field technique using linear accelerators with 6- or 18-MV photons. Patients were assessed every three months by their radiation oncologist or surgeon during the first year after treatment and every six months thereafter. Breast ultrasound for follow-up was done every six months and mammographies once yearly. Acute side effects were scored according to the CTC/EORTC score and late side effects according to the Lent-Soma classification.

Results

Twenty-four patients received IORT only; eight patients because they had received previous radiotherapy, 16 because of a very favorable risk profile or their own preference. Thirty-three patients with tumor sizes between 1 and 30 mm and no risk factors were treated by IORT as a boost followed by EBRT. The Intrabeam™ system was used for IORT. The Intrabeam source produces 30–50 KV X-rays and the prescribed dose is delivered in an isotropic dose distribution around spherical applicators. Treatment time ranged between 20 and 48 minutes. No severe acute side effects or complications were observed during the first postoperative days or after 12 months. One local recurrence occurred 10 months after surgery plus IORT followed by EBRT. In two patients distant metastases were diagnosed shortly after BCS.

Discussion

IORT with the Intrabeam system is a feasible method to deliver a single high radiation dose to breast cancer patients. As a preliminary boost it has the advantage of reducing the EBRT course by 1.5 weeks, and as APBI it might be a promising tool for patients with a low risk of recurrence. The treatment is well tolerated and does not cause greater damage than the expected late reaction in normal tissue.

Breast intraoperative electron radiotherapy: Image-based setup verification and in-vivo dosimetry

INTRODUCTION

Single fraction nature of intraoperative radiotherapy highly demands a quality assurance procedure to qualify both beam setup and treatment delivery. The aim of this study is to evaluate the treatment setup during breast intraoperative electron radiotherapy (IOERT) and in-vivo dose delivery verification.

MATERIALS AND METHODS

Twenty-five breast cancer patients were enrolled and setup verification for each case was performed using C-arm imaging. The received dose by surface and distal end of target was measured by EBT2 film. The significance level of difference between obtained dosimetry results and predicted ones was evaluated by the T statistical test.

RESULTS

Acquired C-arm images in two different oblique views revealed any misalignment between the applicator and shielding disk. The mean difference between the measured surface dose and expected one was 1.8% ± 1.2 (p = 0.983) while a great disagreement, 11.1% ± 1.5 (p < 0.001), was observed between the measured distal end dose and expected one. This discrepancy is mainly correlated to the backscattering effect from the shielding disk. Target depth nonuniformities can also contribute to this remarkable difference.

CONCLUSION

Employing the intraoperative imaging for IOERT setup verification can considerably improve the treatment quality. Therefore, it is suggested to implement this imaging procedure as a part of treatment quality assurance. Favorable agreement between the predicted and measured surface doses demonstrates the applicability of EBT2 film for dose delivery verification. The results of in-vivo dosimetry showed that the electron backscattering from employed shielding disk can affect the received dose by the distal end of tumor bed.

Impact of intraoperative radiotherapy on cosmetic outcome and complications after oncoplastic breast surgery

Breast cancer is one of the most common tumors in the population worldwide. Conservative breast surgery (CBS) is one of the preferred surgical options, because both the oncologic and esthetic needs of the patient can be addressed. CBS surgical outcomes tend to be more effective with reduced chances of disease recurrence when radiotherapy (RT) treatment is considered as an adjunct treatment, either applied during surgery (IORT) and/or after (EBRT). The purpose of our study was to compare surgical outcomes between IORT and EBRT after CBS. In the past 5 years, we performed CBS in 489 patients in our clinic. Of these patients, 83 underwent adjunct treatment with IORT and 109 were treated with EBRT in accordance with our university approved clinical protocol. Surgical outcomes, early complication rates, and esthetic results were compared between these two groups of CBS patients, with a mean follow-up time of 17 months. IORT allowed breast irradiation treatment to be performed without effecting overlying skin, thus cosmetic outcomes tended to be favorable. Esthetic postoperative results assessed with the Breast Cancer Conservation Treatment (BCCTcore) software showed that the differences between IORT and EBRT were not statistically significant (including those patients that underwent further oncoplastic techniques after EBRT). The disease recurrence rates between the two groups were not significantly different. IORT is a safe, fast, and feasible technique that provides effective and comparable CBS outcomes for patients with breast cancer.

Efficacy and safety of intraoperative radiotherapy in breast cancer: a systematic review

The objective of this study is to assess the efficacy and safety of intraoperative radiotherapy (IORT) for early breast cancer through a systematic review. Fifteen studies met the inclusion criteria. Most studies assessed the combined treatment with IORT (10-24Gy) and external beam radiotherapy (EBRT) (45-50Gy) on early stage breast cancer (T(0-2)). Local control was over 95% for 1 and 4years of follow-up and the 5-year overall survival was 99%. The TARGIT-A study found a similar survival comparing IORT with standard treatment. The incidence of acute and chronic complications was scarce. IORT is well tolerated by patients and acute and late toxicities are low. There are no differences in survival for IORT treated patients versus standard treatment.

Perspectives and potential applications of nanomedicine in breast and prostate cancer

Nanomedicine is a branch of nanotechnology that includes the development of nanostructures and nanoanalytical systems for various medical applications. Among these applications, utilization of nanotechnology in oncology has captivated the attention of many research endeavors in recent years. The rapid development of nano-oncology raises new possibilities in cancer diagnosis and treatment. It also holds great promise for realization of point-of-care, theranostics, and personalized medicine. In this article, we review advances in nano-oncology, with an emphasis on breast and prostate cancer because these organs are amenable to the translation of nanomedicine from small animals to humans. As new drugs are developed, the incorporation of nanotechnology approaches into medicinal research becomes critical. Diverse aspects of nano-oncology are discussed, including nanocarriers, targeting strategies, nanodevices, as well as nanomedical diagnostics, therapeutics, and safety. The review concludes by identifying some limitations and future perspectives of nano-oncology in breast and prostate cancer management.

Relative biological effectiveness of photon energies used in brachytherapy and intraoperative radiotherapy techniques for two breast cancer cell lines

BACKGROUND

Partial breast irradiation (IORT or brachytherapy) differ from external radiation of whole breast in terms of irradiated volumes, fractionation, radiation energy and dose rate; all factors influencing the treatment outcome in a complex manner. Theoretically obtained RBE values comparing effects of radiation used in IORT and external therapy are published, but experimental studies are required to confirm these data. The aim of this study is to establish such RBE values for two breast cancer cell lines.

MATERIALS AND METHODS

Colony formation of breast cancer cell lines (MCF-7 and T-47D) were studied after photon irradiation with qualities and dose rates used in IORT, brachytherapy and external radiation. RBE values from survival data were used to compare effects.

RESULTS

Increasing the photon energy (dose rate 0.2 Gy/min) from 50 kV (Intrabeam) to 380 keV (¹⁹²Ir source) and 6 MV (linear accelerator) yielded an increase in the cell survival, whereas increasing the dose rate to 6 Gy/min had minor effect. Average RBE values for 50 kV with 6 MV as reference radiation varied from about 1.4 (for doses < 5 Gy) to > 1.9 (for doses < 0.02 Gy) for MCF-7 cells and from about 1.4 to > 3.1 for T-47D cells for the same dose levels. Corresponding RBE values for 380 keV radiation were about 1.4 for MCF-7 cells and 1.3-2.3 for T-47D cells.

CONCLUSION

RBE data for breast cancer cells exposed to radiation used in IORT, brachytherapy or external radiation differ among the cell lines tested. The values are in agreement with published theoretical and experimental work.

Accelerated Partial Breast Irradiation (APBI): A review of available techniques

Breast conservation therapy (BCT) is the procedure of choice for the management of the early stage breast cancer. However, its utilization has not been maximized because of logistics issues associated with the protracted treatment involved with the radiation treatment. Accelerated Partial Breast Irradiation (APBI) is an approach that treats only the lumpectomy bed plus a 1-2 cm margin, rather than the whole breast. Hence because of the small volume of irradiation a higher dose can be delivered in a shorter period of time. There has been growing interest for APBI and various approaches have been developed under phase I-III clinical studies; these include multicatheter interstitial brachytherapy, balloon catheter brachytherapy, conformal external beam radiation therapy and intra-operative radiation therapy (IORT). Balloon-based brachytherapy approaches include Mammosite, Axxent electronic brachytherapy and Contura, Hybrid brachytherapy devices include SAVI and ClearPath. This paper reviews the different techniques, identifying the weaknesses and strength of each approach and proposes a direction for future research and development. It is evident that APBI will play a role in the management of a selected group of early breast cancer. However, the relative role of the different techniques is yet to be clearly identified.

ASERNIP-S: international trend setting

The Australian Safety and Efficacy Register of New Interventional Procedures--Surgical (ASERNIP-S) came into being 10 years ago to provide health technology assessments specifically tailored towards new surgical techniques and technologies. It was and remains the only organisation in the world to focus on this area of research. Most funding has been provided by the Australian Government Department of Health, and assessments have helped inform the introduction of new surgical techniques into Australia. ASERNIP-S is a project of the Royal Australasian College of Surgeons. The ASERNIP-S program employs a diverse range of methods including systematic reviews, technology overviews, assessments of new and emerging surgical technologies identified by horizon scanning, and audit. Support and guidance for the program is provided by Fellows of the Royal Australasian College of Surgeons. ASERNIP-S works closely with consumers to produce health technology assessments and audits, as well as consumer information to keep patients fully informed of research. Since its inception, the ASERNIP-S program has developed a strong international profile through the production of over 60 reports on evidence-based surgery, surgical technologies and audit. The work undertaken by ASERNIP-S has evolved from assessments of the safety and efficacy of procedures to include guidance on policies and surgical training programs. ASERNIP-S needs to secure funding so that it can continue to play an integral role in the improvement of quality of care both in Australia and internationally.

Prototyping a large field size IORT applicator for a mobile linear accelerator

The treatment of large tumors such as sarcomas with intra-operative radiotherapy using a Mobetron is often complicated because of the limited field size of the primary collimator and the available applicators (max Ø100 mm). To circumvent this limitation a prototype rectangular applicator of 80 x 150 mm(2) was designed and built featuring an additional scattering foil located at the top of the applicator. Because of its proven accuracy in modeling linear accelerator components the design was based on the EGSnrc Monte Carlo simulation code BEAMnrc. First, the Mobetron treatment head was simulated both without an applicator and with a standard 100 mm applicator. Next, this model was used to design an applicator foil consisting of a rectangular Al base plate covering the whole beam and a pyramid of four stacked cylindrical slabs of different diameters centered on top of it. This foil was mounted on top of a plain rectangular Al tube. A prototype was built and tested with diode dosimetry in a water tank. Here, the prototype showed clinically acceptable 80 x 150 mm(2) dose distributions for 4 MeV, 6 MeV and 9 MeV, obviating the use of complicated multiple irradiations with abutting field techniques. In addition, the measurements agreed well with the MC simulations, typically within 2%/1 mm.

Bilateral reduction mammaplasty for immediate breast conservation surgery reconstruction and intraoperative radiotherapy: a preliminary report

BACKGROUND

Breast conservation surgery and postoperative radiotherapy are widely accepted as the treatment of choice for patients with early breast cancer. Despite its oncologic benefits, the radiotherapy may cause unpredictable outcomes in soft tissues, especially in patients undergoing breast reconstruction. Described recently, intraoperative irradiation (IORT) has been indicated for selected patients as an alternative to radiotherapy with fewer adverse local effects. Clinical use of reduction mammaplasty (RM) techniques in oncologic breast surgery has been described previously. However, no previous studies have mentioned its application after breast conservation surgery and IORT.

METHODS

The authors used RM to reconstruct a partial breast tissue defect secondary to breast conservation surgery followed by IORT treatment in a 46-year-old patient with an 11-mm invasive ductal carcinoma between the superior internal quadrants of the right breast.

RESULTS

Satisfactory breast volume and shape were achieved, and no immediate or late complications were observed. After 2 postoperative years, no evidence of fat necrosis, tumor recurrence, or tissue volume loss was observed.

CONCLUSION

The initial data indicate that RM in the setting of breast conservation surgery reconstruction and IORT is feasible. With appropriate patient selection, respecting indications and limitations, RM has its place among the various reconstructive techniques. Additional studies with larger clinical series and longer follow-up periods are necessary to analyze the precise IORT effects in patients submitted to immediate breast conservation surgery reconstruction.

Radiation Options for Early Stage Breast Cancer

OBJECTIVE

To explore the current radiation therapy options for early stage breast cancer.

DATA SOURCES

Research literature and review articles.

CONCLUSION

With 20 years of clinical data supporting the efficacy of whole breast radiotherapy after lumpectomy for early stage breast cancer, the attention has shifted to an even more conservative approach, namely partial breast irradiation following lumpectomy. A number of large clinical trials in North America and Europe are currently enrolling patients for the evaluation of several different techniques, including interstitial brachytherapy, the Mammosite device, 3-dimensional conformal external radiation therapy, and intraoperative radiotherapy.

IMPLICATIONS FOR NURSING PRACTICE

Radiation oncology nurses can significantly impact the coordination of services and the education of patients who enroll in these important clinical trials.

The evolution of accelerated, partial breast irradiation as a potential treatment option for women with newly diagnosed breast cancer considering breast conservation

Breast conservation therapy (BCT) is a safe, effective alternative to mastectomy for many women with newly diagnosed breast cancer. This approach involves local excision of the malignancy with tumor-free margins, followed by 5-7 weeks of external beam whole breast (WB) radiotherapy (XRT) to minimize the risk of an in-breast tumor recurrence (IBTR). Though clearly beneficial, the extended course of almost daily postoperative radiotherapy interrupts normal activities and lengthens care. Additional options are now available that shorten the radiotherapy treatment time to 1-5 days (accelerated) and focus an increased dose of radiation on just the breast tissue around the excision cavity (partial breast). Recent trials with accelerated, partial breast irradiation (APBI) have shown promise as a potential replacement to the longer, whole breast treatments for select women with early-stage breast cancer. Current APBI approaches include interstitial brachytherapy, intracavitary (balloon) brachytherapy, and accelerated external beam (3-D conformal) radiotherapy, all of which normally complete treatment over 5 days, while intraoperative radiotherapy (IORT) condenses the entire treatment into a single dose delivered immediately after tumor excision. Each approach has benefits and limitations. This study covers over 2 decades of clinical trials exploring APBI, discusses treatment variables that appear necessary for successful implementation of this new form of radiotherapy, compares and contrasts the various APBI approaches, and summarizes current and planned randomized trials that will shape if and how APBI is introduced into routine clinical care. Some of the more important outcome variables from these trials will be local toxicity, local and regional recurrence, and overall survival. If APBI options are ultimately demonstrated to be as safe and effective as current whole breast radiotherapy approaches, breast conservation may become an even more appealing choice, and the overall impact of treatment may be further reduced for certain women with newly diagnosed breast cancer.

Radioresistance in carcinoma of the breast

Radiotherapy plays an important role in the management of breast cancer. Whilst its role in achieving local control following surgery in patients with early stage cancer is well established, there is still unclear evidence to explain the factors governing radioresistance in patients who develop recurrences both in the breast and axilla. Radiotherapy induces damage to the DNA. Various cell cycle damage check points and DNA damage repair pathways have been demonstrated. Ataxia telangiectasia mutant (ATM) kinase, which is a member of phosphatidylinositol-3 kinase (PI-3K) family appears to play a central role in DNA damage check point pathways. Over-expression of Insulin like growth factor-I receptor (IGF-IR), Human Epidermal Growth factor receptors (HERS), Vascular Endothelial growth factor (VEGF) on the cell surface and increased concentration of Epidermal Growth factor in the extracellular fluid have been associated with radioresistance. Specific genes such as p53, BRCA, Bcl-2 and chromosomal characteristics like telomere lengths have also been identified as playing significant roles in radiation responsiveness of a cell. This article reviews the current data on general principles of radiotherapy, the cellular mechanisms that operate in response to radiation damage and various molecular markers, intranuclear and extranuclear which have been demonstrated to influence radiation sensitivity in breast cancer cells.

The role of magnetic resonance imaging in diagnosis and management of breast cancer

A review of the literature on the current applications of breast magnetic resonance imaging (MRI) indications, their rationale and their place in diagnosis and management of breast cancer was given. Contrast-enhanced breast MRI is developing as a valuable adjunct to mammography and sonography. Its high sensitivity for invasive breast cancer establishes its superiority in evaluation of multifocality/multicentricity, tumor response to neoadjuvant chemotherapy, detection of recurrence, and staging. Emerging applications include spectroscopy, usage of new contrast agents, and MRI-guided interventions, including noninvasive treatment of breast cancer. Its potential benefit in screening high-risk women has yet to be established with prospective studies, particularly with regard to false positive results.

Sophisticated radiotherapy with optimal surgery is the way forward

PURPOSE OF REVIEW

Radiotherapy has been one of the cornerstones of treatment for breast cancer for more than a century and has contributed to conservation of the breast and improved locoregional control after mastectomy. This review assesses the most recent evidence generated by clinical scientists in the field of radiotherapy for breast cancer.

RECENT FINDINGS

Results from mature trials investigating the role of radiotherapy in breast cancer treatment and the publication of meta-analyses of treatment effects have shown that in addition to improvements in local control, a survival benefit is obtained in several disease settings. These include breast-conserving therapy and postmastectomy radiotherapy. Further, improved diagnostic abilities and surgical techniques, together with advances in treatment delivery, will help to increase the therapeutic ratio of radiotherapy.

SUMMARY

There is increasing evidence for long-term benefits of radiotherapy for breast cancer and a reduction in the risks of late side effects in recent decades. This can have a profound impact on clinical practice in the future, leading to a broadening and individualizing of the indications for radiotherapy and improvements in patient survival.