Prognosis comparison between intraoperative radiotherapy and whole-breast external beam radiotherapy for T1–2 stage breast cancer without lymph node metastasis treated with breast-conserving surgery: A case–control study after propensity score matching

Background

External beam radiotherapy (EBRT), an adjuvant to breast-conserving surgery (BCS), requires a long treatment period, is costly, and is associated with numerous complications. Large sample studies with long follow-up periods are lacking regarding whether intraoperative radiotherapy (IORT), an emerging radiotherapy modality, can replace EBRT for patients with T1–2 early stage breast cancer without lymph node metastasis treated with BCS.

Methods

We identified 270,842 patients with T1-2N0M0 breast cancer from 2000 to 2018 in the Surveillance, Epidemiology, and End Results (SEER) database. A total of 10,992 patients were matched by propensity score matching (PSM). According to the radiotherapy method, the patients were divided into the IORT and EBRT groups. Overall survival (OS) and breast cancer-specific survival (BCSS) rates were analyzed and compared between the IORT and EBRT groups by Kaplan–Meier analysis. Bilateral P < 0.05 was considered to indicate significance.

Results

After PSM, the survival analysis showed no significant differences in OS or BCSS rates between the IORT and EBRT groups. In the subgroup analysis, the IORT population diagnosed from 2010 to 2013 (HRs = 0.675, 95% CI 0.467–0.976, P = 0.037) or with T2 stage (HRs = 0.449, 95% CI 0.261–0.772, P = 0.004) had better OS rates, but in the overall population, the OS and BCSS rates were better in patients with T1 stage than in patients with T2 stage (P < 0.0001), and the proportion of chemotherapy was significantly higher in T2 stage than in T1 stage. Patients who had EBRT with unknown estrogen receptor had better OS rates (HRs = 3.392, 95% CI 1.368–8.407, P = 0.008). In addition, the IORT group had better BCSS rates for married (HRs = 0.403, 95% CI 0.184–0.881, P = 0.023), grade III (HRs = 0.405, 95% CI 0.173–0.952, P = 0.038), and chemotherapy-receiving (HRs = 0.327, 95% CI 0.116–0.917, P = 0.034) patients with breast cancer compared to the EBRT group.

Conclusion

Intraoperative radiotherapy results of non-inferior OS and BCSS rates, compared to those of EBRT, in patients with early stage breast cancer without lymph node metastasis treated with BCS, and IORT may provide substantial benefits to patients as an effective alternative to standard treatment. This finding provides new insights into radiotherapy strategies for early stage breast cancer.

Breast intraoperative radiotherapy: a review of available modalities, dedicated machines and treatment procedure

Background

Breast intraoperative radiotherapy (IORT) is a partial irradiation technique that delivers a single fraction of radiation dose to the tumour bed during surgery. The use of this technique is increasing (especially in the Middle East), and therefore, it is essential to have a comprehensive approach to this treatment modality. The aim of this study is to conduct a literature review on available IORT modalities during breast irradiation as well as dedicated IORT machines and associated treatment procedures. The main IORT trials and corresponding clinical outcomes are also studied.

Materials and Methods

A computerised search was performed through MEDLINE, PubMed, PubMed Central, ISI web of knowledge and reference list of related articles.

Results

IORT is now feasible through using two main modalities, including low-kilovolt IORT and intraoperative electron radiotherapy (IOERT). The dedicated machines employed and treatment procedure for mentioned modalities are quite different. The outcomes of implemented clinical trials showed that IORT is not inferior to external beam radiotherapy (EBRT) in specifically selected and well-informed patients and can be considered as an alternative to EBRT.

Conclusion

Although the clinical outcomes of introduced IORT methods are comparable, but based on the review results, it could be said that IOERT is the most effective technical method, in view of the treatment time and dose uniformity concepts. The popularity of IORT is mainly due to the distinguished obtained results during breast cancer treatment. Despite the presence of some technical challenges, it is expected that the IORT technique will become more widespread in the immediate future.

Tumor Resection Margin Definitions in Breast-Conserving Surgery: Systematic Review and Meta-analysis of the Current Literature

Worldwide, various guidelines recommend what constitutes an adequate margin of excision for invasive breast cancer or for ductal carcinoma-in-situ (DCIS). We evaluated the use of different tumor resection margin guidelines and investigated their impact on positive margin rates (PMR) and reoperation rates (RR). Thirteen guidelines reporting on the extent of a positive margin were reviewed along with 31 studies, published between 2011 and 2016, reporting on a well-defined PMR. Studies were categorized according to the margin definition. Pooled PMR and RR were determined with random-effect models. For invasive breast cancer, most guidelines recommend a positive margin of tumor on ink. However, definitions of reported positive margins in the clinic vary from more than focally positive to the presence of tumor cells within 3 to 5 mm from the resection surface. Within the studies analyzed (59,979 patients), pooled PMRs for invasive breast cancer ranged from 9% to 36% and pooled RRs from 77% to 99%. For DCIS, guidelines vary between no DCIS on the resection surface to DCIS cells found within a distance of 2 mm from the resection edge. Pooled PMRs for DCIS varied from 4% to 23% (840 patients). Given the differences in tumor margin definition between countries worldwide, quality control data expressed as PMR or RR should be interpreted with caution. Furthermore, the overall definition for positive resection margins for both invasive disease and DCIS seems to have become more liberal.

Intraoperative boost radiation effects on early wound complications in breast cancer patients undergoing breast-conserving surgery

Background/aim: Intraoperative radiation therapy (IORT) may pose a risk for wound complications. All technical aspects of IORT regarding early wound complications were evaluated. Materials and methods: Ninety-three consecutive patients operated on with the same surgical technique and given (study group) or not given (control group) IORT were included. Wound complications were evaluated in two groups. Results: Forty-three patients were treated with boost dose IORT and 50 patients were treated with breast-conserving surgery without IORT. When both groups were compared in terms of early postoperative complications, there were 11 (25.5%) patients with seroma in the IORT group and 3 patients (6%) in the control group (P = 0.04). While 9 (21%) patients were seen to have surgical site infection (SSI) in the IORT group, there was 1 (2%) SSI in the control group (P = 0.005). There were 15 (35%) patients with delayed wound healing in the IORT group and 4 patients (8%) in the control group (P = 0.006). Conclusion: IORT could have a negative effect on seroma formation, SSI, and delayed healing. It should be kept in mind, however, that in centers with IORT implementation, the complication rate could also increase. Necessary measures for better sterilization in the operating room should be taken, while patient wound healing should be monitored closely.

Intraoperative Radiation Therapy: A Promising Treatment Modality in Head and Neck Cancer

Every year, almost 62,000 are diagnosed with a head and neck cancer (HNC) and 13,000 will succumb to their disease. In the primary setting, intraoperative radiation therapy (IORT) can be used as a boost in select patients in order to optimize local control. Addition of external beam radiation to limited volumes results in improved disease control over surgery and IORT alone. In the recurrent setting, IORT can improve outcomes from salvage surgery especially in patients previously treated with external beam radiation. The use of IORT remains limited to select institutions with various modalities being currently employed including orthovoltage, electrons, and high-dose rate brachytherapy. Practically, execution of IORT requires a coordinated effort and careful planning by a multidisciplinary team involving the head and neck surgeon, radiation oncologist, and physicist. The current review summarizes common uses, outcomes, toxicities, and technical aspects of IORT in HNC patients.

Factors predictive of failure to complete planned intraoperative breast radiation using the intrabeam® system

PURPOSE

Intraoperative radiation therapy (IORT) is a form of breast irradiation that is delivered in a single session at the time of partial mastectomy. In up to 10% of patients, planned IORT is not completed; this leads to wasted resources and decreased patient satisfaction. Our objective was to evaluate factors associated with failure to complete planned IORT.

METHODS AND MATERIALS

An IRB-approved review of planned IORT cases from 2011 to 2015 was conducted. Eligibility criteria included: age ≥60, invasive ductal or mammary carcinoma, tumor <3.0 cm, ER positive, and clinically node negative. Discontinuation of planned IORT was at the discretion of the breast surgical and radiation oncologists.

RESULTS

Twenty-one (15%) of one hundred and forty-five planned IORT cases were not completed. Reasons for failure to complete IORT included inadequate applicator to skin distance (n = 15, 71%), altered wire localization findings the day of surgery (n = 4, 19%), equipment failure (n = 1, 5%), and hemodynamic instability (n = 1, 5%). Significant surgeon variability was associated with failure to complete planned IORT (P < 0.001).

CONCLUSIONS

Insufficient skin-to-applicator spacing is the most common reason for failure to complete IORT. In this series, higher volume surgeons completed a greater proportion of IORT cases, suggesting a learning curve to patient selection or intraoperative technique. J. Surg. Oncol. 2016;114:930-932. © 2016 Wiley Periodicals, Inc.

The INTRABEAM® Photon Radiotherapy System for the adjuvant treatment of early breast cancer: a systematic review and economic evaluation

BACKGROUND

Initial treatment for early breast cancer is usually either breast-conserving surgery (BCS) or mastectomy. After BCS, whole-breast external beam radiotherapy (WB-EBRT) is the standard of care. A potential alternative to post-operative WB-EBRT is intraoperative radiation therapy delivered by the INTRABEAM(®) Photon Radiotherapy System (Carl Zeiss, Oberkochen, Germany) to the tissue adjacent to the resection cavity at the time of surgery.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of INTRABEAM for the adjuvant treatment of early breast cancer during surgical removal of the tumour.

DATA SOURCES

Electronic bibliographic databases, including MEDLINE, EMBASE and The Cochrane Library, were searched from inception to March 2014 for English-language articles. Bibliographies of articles, systematic reviews, clinical guidelines and the manufacturer's submission were also searched. The advisory group was contacted to identify additional evidence.

METHODS

Systematic reviews of clinical effectiveness, health-related quality of life and cost-effectiveness were conducted. Two reviewers independently screened titles and abstracts for eligibility. Inclusion criteria were applied to full texts of retrieved papers by one reviewer and checked by a second reviewer. Data extraction and quality assessment were undertaken by one reviewer and checked by a second reviewer, and differences in opinion were resolved through discussion at each stage. Clinical effectiveness studies were included if they were carried out in patients with early operable breast cancer. The intervention was the INTRABEAM system, which was compared with WB-EBRT, and study designs were randomised controlled trials (RCTs). Controlled clinical trials could be considered if data from available RCTs were incomplete (e.g. absence of data on outcomes of interest). A cost-utility decision-analytic model was developed to estimate the costs, benefits and cost-effectiveness of INTRABEAM compared with WB-EBRT for early operable breast cancer.

RESULTS

One non-inferiority RCT, TARGeted Intraoperative radioTherapy Alone (TARGIT-A), met the inclusion criteria for the review. The review found that local recurrence was slightly higher following INTRABEAM than WB-EBRT, but the difference did not exceed the 2.5% non-inferiority margin providing INTRABEAM was given at the same time as BCS. Overall survival was similar with both treatments. Statistically significant differences in complications were found for the occurrence of wound seroma requiring more than three aspirations (more frequent in the INTRABEAM group) and for a Radiation Therapy Oncology Group toxicity score of grade 3 or 4 (less frequent in the INTRABEAM group). Cost-effectiveness base-case analysis indicates that INTRABEAM is less expensive but also less effective than WB-EBRT because it is associated with lower total costs but fewer total quality-adjusted life-years gained. However, sensitivity analyses identified four model parameters that can cause a switch in the treatment option that is considered cost-effective.

LIMITATIONS

The base-case result from the model is subject to uncertainty because the disease progression parameters are largely drawn from the single available RCT. The RCT median follow-up of 2 years 5 months may be inadequate, particularly as the number of participants with local recurrence is low. The model is particularly sensitive to this parameter.

CONCLUSIONS AND IMPLICATIONS

A significant investment in INTRABEAM equipment and staff training (clinical and non-clinical) would be required to make this technology available across the NHS. Longer-term follow-up data from the TARGIT-A trial and analysis of registry data are required as results are currently based on a small number of events and economic modelling results are uncertain.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013006720.

FUNDING

The National Institute for Health Research Health Technology Assessment programme. Note that the economic model associated with this document is protected by intellectual property rights, which are owned by the University of Southampton. Anyone wishing to modify, adapt, translate, reverse engineer, decompile, dismantle or create derivative work based on the economic model must first seek the agreement of the property owners.

TARGIT-R (Retrospective): North American Experience with Intraoperative Radiation Using Low-Kilovoltage X-Rays for Breast Cancer

BACKGROUND

Single-dose intraoperative radiotherapy (IORT) is an emerging treatment for women with early stage breast cancer. The objective of this study was to define the frequency of IORT use, patient selection, and outcomes of patients treated in North America.

METHODS

A multi-institutional retrospective registry was created, and 19 institutions using low-kilovoltage IORT for the treatment of breast cancer entered data on patients treated at their institution before July 31, 2013. Patient selection, IORT treatment details, complications, and recurrences were analyzed.

RESULTS

From 2007 to July 31, 2013, a total of 935 women were identified and treated with lumpectomy and IORT. A total of 822 patients had at least 6 months' follow-up documented and were included in the analysis. The number of IORT cases performed increased significantly over time (p < 0.001). The median patient age was 66.8 years. Most patients had disease that was <2 cm in size (90 %) and was estrogen positive (91 %); most patients had invasive ductal cancer (68 %). Of those who had a sentinel lymph node procedure performed, 89 % had negative sentinel lymph nodes. The types of IORT performed were primary IORT in 79 %, secondary IORT in 7 %, or planned boost in 14 %. Complications were low. At a median follow-up of 23.3 months, crude in-breast recurrence was 2.3 % for all patients treated.

CONCLUSIONS

IORT use for the treatment of breast cancer is significantly increasing in North America, and physicians are selecting low-risk patients for this treatment option. Low complication and local recurrence rates support IORT as a treatment option for selected women with early stage breast cancer.

A novel approach of INTRABEAM intraoperative radiotherapy for nipple-sparing mastectomy with breast reconstruction

BACKGROUND

Despite the advancement and increasing use of breast-conserving surgery, mastectomies, including nipple-sparing mastectomy (NSM), are still carried out in a portion of breast cancer patients. However, the role of NSM is still controversial, mainly because of concern about the oncologic safety of the nipple-areola complex (NAC). INTRABEAM (Carl Zeiss, Oberkochen, Germany) is the most widely used mobile intraoperative radiotherapy (IORT) device to date. This pilot study aims to broaden the application of the INTRABEAM system for breast cancer, investigating the feasibility of INTRABEAM IORT in NSM with breast reconstruction.

PATIENTS AND METHODS

From December 2012 to June 2013, 7 female patients with breast cancer were enrolled in the study. NSM with or without axillary dissection was performed first. After confirming negative retroareolar frozen section results and no poor local bleeding in the NAC, INTRABEAM IORT was carried out with a single dose of 16 Gy, followed by breast reconstruction. The complications and short-term outcomes were assessed.

RESULTS

The median radiation time was 13 minutes 14 seconds in the 7 cases. One patient complained of mild pain in the radiation field on the skin in the first 2 weeks. All 7 patients were followed for a median of 7 months. No acute radiation injury with symptoms (heart, lung, or hematologic system), NAC necrosis, local recurrence, or metastasis was observed. Although every patient had reduction in NAC sensitivity, the contours of the breasts (including the NAC) were satisfactory.

CONCLUSIONS

INTRABEAM IORT may be a feasible and convenient approach for NSM with breast reconstruction in patients with breast cancer.

Comparison of mammographic findings after intraoperative radiotherapy or external beam whole breast radiotherapy

BACKGROUND

The TARGIT (TARGeted Intraoperative Radiotherapy) trial was designed to compare local recurrence and complication rates in breast cancer patients, prospectively randomised to either EBRT (external beam whole breast radiotherapy) or a single dose of IORT (intraoperative radiotherapy). The aim of our study was to compare follow-up mammographic findings, ultrasound and biopsy rates in each group.

METHODS

Follow-up imaging and breast biopsies of women from one centre participating in the TARGIT-A trial were independently reviewed by two radiologists blinded to the radiotherapy treatment received.

RESULTS

The cohort consisted of 141 patients (EBRT n = 80/IORT n = 61). There was no significant difference in the patient or disease characteristics of the two groups. The number of follow-up mammograms and length of follow-up was similar (EBRT/IORT n = 2.0/2.4; 4.3yr/5.1yr; p = 0.386 χ(2) test). There were no significant differences in mammographic scar or calcification appearances of the post-operative site. Generalised increase in breast density and skin thickening were more common in the EBRT compared to the IORT group (p = 0.002; p = 0.030, χ(2) test respectively). A trend towards additional ultrasound at follow-up was observed in the IORT group (15 of 61 [24.6%] versus 11 of 80 [13.8%]), however this was not statistically significant (p = 0.100 χ(2) test). No disease recurrence was demonstrated on any of the breast biopsies taken. Only one biopsy was reported as fat necrosis in the IORT group.

CONCLUSIONS

Mammographic changes were more common following EBRT, although more additional follow-up ultrasounds were performed in the IORT group. IORT is not detrimental to subsequent radiological follow up.

Present status and future directions of intraoperative radiotherapy

In this Review, we summarise recent published work on the use of intraoperative radiotherapy to treat common tumour sites in the primary or recurrent setting. Techniques, radiobiology, and the physics of intraoperative radiotherapy are also explored. Disease sites discussed in this Review include head and neck cancer, breast cancer, sarcoma, gastrointestinal cancer, genitourinary cancer, gynaecological cancer, thoracic cancer, and palliative applications.

High resolution MRI for non-invasive mouse lymph node mapping

Mouse models are fundamental to the study and design of new techniques for the cancer diagnosis and treatment. The lymphatic system plays an active role in oncogenesis and metastatic disease progression. However, the in vivo identification of LNs in mice is challenging with conventional imaging modalities since the LN diameter in normal mice is 1-2 mm. Standard dissection techniques are challenging and can only provide endpoint data. Here, we describe high resolution MRI (HR-MRI) approaches for the non-invasive detection of mouse LNs in vivo. We compare in vivo non-invasive HR-MRI methods (without exogenous contrast injections) to the ex vivo dye injection methods for the identification of commonly studied LNs in both normal mice and a mouse model of pancreatic ductal adenocarcinoma (PDAC). We demonstrated the potential to use HR-MRI techniques as a non-invasive imaging assay for visualizing mouse LNs in vivo.