Intraoperative radiotherapy in breast cancer: Alterations to the tumor microenvironment and subsequent biological outcomes (Review)

Intraoperative radiotherapy (IORT) is a precise, single high‑dose irradiation directly targeting the tumor bed during surgery. In comparison with traditional external beam RT, it minimizes damage to other normal tissues, ensures an adequate dose to the tumor bed and results in improved cosmetic outcomes and quality of life. Furthermore, IORT offers a shorter treatment duration, lower economic costs and therapeutic efficacy comparable with traditional RT. However, its relatively higher local recurrence rate limits its further clinical applications. Identifying effective radiosensitizing drugs and rational RT protocols will improve its advantages. Furthermore, IORT may not only damage DNA to directly kill breast tumor cells but also alter the tumor microenvironment (TME) to exert a sustained antitumor effect. Specific doses of IORT may exert anti‑angiogenic effects, and consequently antitumor effects, by impacting post‑radiation peripheral blood levels of vascular endothelial growth factor and delta‑like 4. IORT may also modify the postoperative wound fluid composition to continuously inhibit tumor growth, e.g. by reducing components such as microRNA (miR)‑21, miR‑221, miR‑115, oncostatin M, TNF‑β, IL‑6 and IL‑8, and by elevating levels of components such as miR‑223, to inhibit the ability of postoperative wound fluid to induce proliferation, invasion and migration of residual cancer cells. IORT can also modify cancer cell glucose metabolism to inhibit the proliferation of residual tumor cells. In addition, IORT can induce a bystander effect, eliminating the postoperative wound fluid‑induced epithelial‑mesenchymal transition and tumor stem cell phenotype. Insights gained at the molecular level may provide new directions for identifying novel therapeutic targets and approaches. A more comprehensive understanding of the effects of IORT on the breast cancer (BC) TME may further its clinical application. Hence, the present article reviews the primary effects of IORT on BC and its impact on the TME, aiming to offer fresh research perspectives for relevant professionals.

Comparison of mammography and ultrasound findings in the follow-up of patients with breast cancer treated with segmental mastectomy followed by intraoperative electron radiotherapy versus external whole breast radiotherapy

PURPOSE

This study aims to describe imaging findings in patients treated with intraoperative electron radiotherapy and compare them with those detected in patients treated with external whole breast radiotherapy (WBRT).

METHODS

The study population consisted of 25 patients who received intraoperative radiotherapy [IORT (21 Gy)] as single-dose radiotherapy and a control group of 25 patients who received WBRT at the same institution. Mammography and ultrasound (US) findings were divided into three groups: minor, intermediate, and advanced. On mammography, mass lesions were considered advanced, and asymmetries or architectural distortions were considered intermediate. Oil cysts, linear scars, and the increase in parenchymal density were considered minor findings. On US, irregular non-mass lesions were considered advanced, and circumscribed hypoechoic lesions or planar irregular scars with shadowing were considered intermediate. Oil cysts, fluid collections, or linear scars were considered minor findings.

RESULTS

On mammography, skin thickening (P = 0.001), edema (P < 0.001), increased parenchymal density (P < 0.001), dystrophic calcifications (P = 0.045), and scar/distortion (P = 0.005) were significantly more common in the WBRT group. On US, irregular non-mass lesions, which made interpretation considerably difficult, were significantly more common in the IORT group (P = 0.004). Dominant US findings were fluid collections and postoperative linear or planar scars in the WBRT group. Minor findings were more common in low-density breasts, and major findings (intermediate and advanced) were more common in high-density breasts on both mammographies (P = 0.011) and US (P = 0.027) in the IORT group.

CONCLUSION

Ill-defined non-mass lesions detected on US in the IORT group have not been defined previously. Radiologists should be aware of these lesions because they can be confusing, especially in early follow-up studies. This study has found that minor findings are seen more frequently in low-density breasts, while major findings are more common in high-density breasts in the IORT group. This has not been reported before, and further studies with more cases are needed to verify these results.

Evaluating the induced photon contamination by different breast IOERT shields using Monte Carlo simulation

BACKGROUND AND OBJECTIVE

Avoiding the underlying healthy tissue over-exposure during breast intraoperative electron radiotherapy (IOERT) is owing to the use of some dedicated radioprotection disks during patient irradiation. The originated contaminant photons from some widely used double-layered shielding disks including PMMA+Cu, PTFE+steel, and Al+Pb configurations during the breast IOERT have been evaluated through a Monte Carlo (MC) simulation approach.

METHODS

Produced electron beam with energies of 6, 8, 10, and 12 MeV by a validated MC model of Liac12 dedicated IOERT accelerator was used for disk irradiations. Each of above-mentioned radioprotection disks was simulated inside a water phantom, so that the upper disk surface was positioned at R90 depth of each considered electron energy. Simulations were performed by MCNPX (version 2.6.0) MC code. Then, the energy spectra of the contaminant photons at different disk surfaces (upper, middle, and lower one) and relevant contaminant dose beneath the studied disks were determined and compared.

RESULTS

None of studied shielding disks show significant photon contamination up to 10 MeV electron energy, so that the induced photon dose by the contaminant X-rays was lower than those observed in the disk absence under the same conditions. In return, the induced photon dose at a close distance to the lower disk surface exceeded from calculated values in the disk absence at 12 MeV electron energy. The best performance in contaminant dose reduction at the energy range of 6-10 MeV belonged to the Al+Pb disk, while the PMMA+Cu configuration showed the best performance in this regard at 12 MeV energy.

CONCLUSION

Finally, it can be concluded that all studied shielding disks not only don't produce considerable photon contamination but also absorb the originated X-rays from electron interactions with water at the electron energy range of 6-10 MeV. The only concern is related to 12 MeV energy where the induced photon dose exceeds the dose values in the disk absence. Nevertheless, the administered dose by contaminant photons to underlying healthy tissues remains beneath the tolerance dose level by these organs at the entire range of studied electron energies.

Case Report: Bilateral targeted intraoperative radiotherapy: a safe and effective alternative for synchronous bilateral breast cancer

Background

The incidence of bilateral breast cancer (BBC) ranges from 1.4% to 11.8%. BBC irradiation is a challenge in current clinical practice due to the large target volume that must be irradiated while minimizing the dose to critical organs. Supine or prone breast techniques can be used, with the latter providing better organ sparing; both, however, result in lengthy treatment times. The use of Intra-operative radiotherapy (IORT) in breast cancer patients who choose breast conservation has been highlighted in previous studies, but there is a scarcity of literature analyzing the utility and applicability of IORT in BBC. This case series aims to highlight the applicability of administering bilateral IORT in patients with BBC.

Case reports

Five patients with bilateral early-stage breast cancer (or DCIS) were treated with breast-conserving surgery followed by bilateral IORT. Of the 10 breast cancers, 8 were diagnosed as either DCIS or IDC, while the other 2 were diagnosed as invasive lobular carcinoma and invasive carcinoma, respectively. During surgery, all patients received bilateral IORT. Furthermore, 1 patient received external beam radiation therapy after her final pathology revealed grade 3 DCIS. The IORT procedure was well tolerated by all five patients, and all patients received aromatase inhibitors as adjuvant therapy. Additionally, none of these patients showed evidence of disease after a 36-month median follow-up.

Conclusion

Our findings demonstrate the successful use of IORT for BCS in patients with BBC. Furthermore, none of the patients in our study experienced any complications, suggesting the feasibility of the use of IORT in BBC. Considering the benefits of improved patient compliance and a reduced number of multiple visits, IORT may serve as an excellent patient-centered alternative for BBC. Future studies are recommended to reinforce the applicability of IORT in patients with BBC.

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.

Full-Dose Intraoperative Electron Radiotherapy for Early Breast Cancer: Evidence from a Single Center's Experience

To evaluate the clinical response rate and cosmetic outcome after full-dose intraoperative electron radiotherapy (IOERT) in early breast cancer (BC) treated with conserving surgery. Inclusion criteria were: >60 years old, clinical tumor size ≤2 cm, luminal A carcinoma, patological negative lymph nodes, excluded lobular carcinoma histology. IOERT was delivered with a dose of 21 Gy at 90% isodose. Clinical, cosmetic and/or instrumental follow-up were performed 45 days after IOERT, 6 months after the first check, and every 12 months thereafter. Acute and late toxicities were assessed with the CTCAE v.4.03 and EORTC-RTOG scales, respectively. Cosmetic outcome was evaluated using the Harvard/NSABO/RTOG Breast Cosmesis Grading Scale. Overall, 162 consecutive patients were included in this analysis (median follow-up: 54 months, range: 1-98 months). The overall response rate was 97.5% (CI 95%: 0.93-0.99%). Locoragional relapse occurred in 2.5% of patients. No patient showed distant metastases. No patient showed radiation-related acute complications, with 3.7% showing late G2-3 toxicity. Only 3.7% of patients showed poor cosmetic results. Our data confirmed that IOERT is a feasible and valid therapeutic option in low-risk BC patients treated with lumpectomy. A low local recurrence rate combined with good cosmetic results validates the settings of our operative method in routinely clinical practice.

Case Report: Intraoperative radiotherapy as the new standard of care for breast cancer patients with disabling health conditions or impairments

In selected patients, intraoperative radiotherapy (IORT) offers an alternative to standard external beam radiotherapy (EBRT) while providing equivalent breast cancer control outcomes. After IORT, most patients do not require external beam radiotherapy and thus avoid the need to travel to and from a radiotherapy centre in the weeks after surgery. EBRT is associated with an increased risk of non-breast cancer mortality and poorer cosmetic outcomes while increasing patient travel time, emissions associated with travel and time spent in the hospital. Consequently, EBRT is associated with an overall reduction in quality of life compared to IORT. Patients with other on-going health conditions or clinical impairments are likely to be affected by the daily radiotherapy requirement. Should these patients be consulted during their pre-operative assessment as to options to undergo IORT? This paper describes a case of IORT and follow up in a functionally blind patient. Quality of life effects are elucidated and further support the use of IORT in selected breast cancer patients with health conditions or impairments.

Preoperative Dose-Escalated Intensity-Modulated Radiotherapy (IMRT) and Intraoperative Radiation Therapy (IORT) in Patients with Retroperitoneal Soft-Tissue Sarcoma: Final Results of a Clinical Phase I/II Trial

BACKGROUND

To report the final results of a prospective, one-armed, single-center phase I/II trial (NCT01566123).

METHODS

Between 2007 and 2017, 37 patients with primary or recurrent (N = 6) retroperitoneal sarcomas were enrolled. Treatment included preoperative IMRT of 45-50 Gy with a simultaneous integrated boost of 50-56 Gy, surgery and IORT. The primary endpoint was local control (LC) at 5 years. The most common histology was dedifferentiated liposarcoma (51%), followed by leiomyosarcoma (24%) and well-differentiated liposarcoma (14%). The majority of lesions were high-grade (FNCLCC G1: 30%, G2: 38%, G3: 27%, two missing). Five patients were excluded from LC analysis per protocol.

RESULTS

The minimum follow-up of the survivors was 62 months (median: 109; maximum 162). IORT was performed for 27 patients. Thirty-five patients underwent gross total resection; the pathological resection margin was mostly R+ (80%) and, less often, R0 (20%). We observed 10 local recurrences. The 5-year LC of the whole cohort was 59.6%. Eleven patients received a dose > 50 Gy plus IORT boost; LC was 64.8%; the difference, however, was not significant (p = 0.588). Of 37 patients, 15 were alive and 22 deceased at the time of final analysis. The 5-year OS was 59.5% (68.8% per protocol).

CONCLUSIONS

The primary endpoint of a 5-year LC of 70% was not met. This might be explained by the inclusion of recurrent disease and the high rate of G3 lesions and leiomyosarcoma, which have been shown to profit less from radiotherapy. Stratification by grading and histology should be considered for future studies.

Patient satisfaction after nipple-sparing mastectomy with intraoperative radiotherapy and breast reconstruction for breast cancer

INTRODUCTION

The use of nipple-sparing mastectomy (NSM) combined with breast reconstruction is increasing in breast cancer surgeries despite its controversial safety profile. To reduce the recurrence rate of tumors in the nipple-areola complex (NAC), we used intraoperative radiotherapy (IORT). The purpose of this study was to explore patients' feedback on this novel treatment strategy.

PATIENTS AND METHODS

From January 2014 to May 2018, eligible patients with breast cancer were enrolled in this study and separated into 2 groups. Patients in the NSM group underwent IORT to the NAC flap, and patients in the skin-sparing mastectomy (SSM) group underwent SSM and breast reconstruction. The postoperative satisfaction was collected and assessed using the Breast-Q reconstruction questionnaire and a standardized questionnaire; this was compared between the 2 groups.

RESULTS

There were 46 patients (52 NSMs) in the NSM group and 20 patients (22 SSMs) in the SSM group. The breast-Q scores were higher in the NSM group than the SSM group, with trends for a 'higher satisfaction with breasts' (67.39 ± 20.59 vs. 55.00 ± 19.33; p = 0.026) and 'higher sexual well-being' (61.74 ± 22.24 vs. 49.50 ± 20.12; p = 0.039). All the patients recognized the importance of nipple preservation. Thirty-seven women (80.40%) were satisfied or very satisfied with the appearance and shape of the NAC in the NSM group, while 38/46 women (82.60%) were very unsatisfied or unsatisfied with the sensitivity of the nipples.

CONCLUSIONS

The Breast-Q scores showed great satisfaction with breasts and sexual well-being in the NSM group. However, more effort should be made in improving postoperative NAC sensitivity.

End-To-End Procedure For IORT in Brain Metastases and Film Dosimetry

Purpose

The study is intended to perform an end-to-end test of the entire intraoperative process using cadaver heads. A simulation of tumor removal was performed, followed by irradiation of the bed and measurement of absorbed doses with radiochromic films.

Materials and Methods

Low-energy X-ray intraoperative radiotherapy (IORT) was used for irradiation. A computed tomography study was performed at each site and the absorbed doses calculated by the treatment planning system, as well as absorbed doses with radiochromic films, were studied.

Results

The absorbed doses in the organs at risk (OAR) were evaluated in each case, obtaining maximum doses within the tolerance limits. The absorbed doses in the target were verified and the deviations were <1%.

Conclusions

These tests demonstrated that this comprehensive procedure is a reproducible quality assurance tool which allows continuous assessment of the dosimetric and geometric accuracy of clinical brain IORT treatments. Furthermore, the absorbed doses measured in both target and OAR are optimal for these treatments.

Real World and Public Health Perspectives of Intraoperative Radiotherapy in Early-Stage Breast Cancer: A Multidisciplinary Analysis Beyond the Statistical Facts

Breast conservation therapy (BCT) (usually a lumpectomy plus radiotherapy (RT)) has become a standard alternative to radical mastectomy in early-stage breast cancers with equal, if not higher, survival rates. The established standard of the RT component of the BCT had been about six weeks of Monday through Friday external beam RT to the whole breast (WBRT). Recent clinical trials have shown that partial breast radiation therapy (PBRT) to the region surrounding the lumpectomy cavity with shorter courses can result in equal local control, survival, and slightly improved cosmetic outcomes. Intraoperative RT (IORT) wherein RT is administered at the time of operation for BCT to the lumpectomy cavity as a single-fraction RT is also considered PBRT. The advantage of IORT is that weeks of RT are avoided. However, the role of IORT as part of BCT has been controversial. The extreme views go from "I will not recommend to anyone" to "I can recommend to all early-stage favorable patients." These divergent views are due to difficulty in interpreting the clinical trial results. There are two modalities of delivering IORT, namely, the use of low-energy 50 kV beams or electron beams. There are several retrospective, prospective, and two randomized clinical trials comparing IORT versus WBRT. Yet, the opinions are divided. In this paper, we try to bring clarity and consensus from a highly broad-based multidisciplinary team approach. The multidisciplinary team included breast surgeons, radiation oncologists, medical physicists, biostatisticians, public health experts, nurse practitioners, and medical oncologists. We show that there is a need to more carefully interpret and differentiate the data based on electron versus low-dose X-ray modalities; the randomized study results have to be extremely carefully dissected from biostatistical points of view; the importance of the involvement of patients and families in the decision making in a very transparent and informed manner needs to be emphasized; and the compromise some women may be willing to accept between 2-4% potential increase in local recurrence (as interpreted by some of the investigators in IORT randomized studies) versus mastectomy. We conclude that, ultimately, the choice should be that of women with detailed facts of the pros and cons of all options being presented to them from the angle of patient/family-focused care. Although the guidelines of various professional societies can be helpful, they are only guidelines. The participation of women in IORT clinical trials is still needed, and as genome-based and omics-based fine-tuning of prognostic fingerprints evolve, the current guidelines need to be revisited. Finally, the use of IORT can help rural, socioeconomically, and infrastructure-deprived populations and geographic regions as the convenience of single-fraction RT and the possibility of breast preservation are likely to encourage more women to choose BCT than mastectomy. This option can also likely lead to more women choosing to get screened for breast cancer, thus enabling the diagnosis of breast cancer at an earlier stage and improving the survival outcomes.

Clinical Outcomes of Intraoperative Radiotherapy, Postoperative Radiotherapy, and Definitive Radiotherapy for Non-metastatic Pancreatic Cancer

OBJECTIVE

The aim of this study is to evaluate the utility of adjuvant radiotherapy (intraoperative radiotherapy, IORT; postoperative radiotherapy, PORT), and definitive radiotherapy for non-metastatic pancreatic cancer.

METHODS

Ninety-nine patients were analyzed. Thirty patients underwent IORT with surgery, 31 underwent PORT after surgery, and 38 underwent definitive radiotherapy. Tumor stage [Union for International Cancer Control (UICC) 2009] was as follows: Stage I, 7; IIA, 16; IIB, 31; III, 45. The doses for IORT, PORT, and definitive radio therapy were 20 to 30, 40 to 64.6, and 50.4 to 61.2 Gy, respectively. Associations between clinical parameters including age, gender, tumor site, stage, performance status, surgical margin, and use of chemotherapy and local control (LC) or overall survival (OS) were analyzed.

RESULTS

Follow-up periods for all patients were 1.1-145 months (median, 11). OS rate in the IORT, PORT, and definitive radiotherapy groups was 22%, 16%, and 6%, respectively, at 2 years. The 5-year OS rate was 13%, 3.2%, and 0%, respectively. Local control rate at 2 years was 33%, 35%, and 0%, respectively. No Grade ≥ 3 tox icities were observed. Distant metastasis was less common in the IORT group. Stage and surgical margin were sig nificant factors for OS after IORT. Performance status and chemotherapy were significant factors for OS after PORT and definitive radiotherapy.

CONCLUSIONS

The present study showed the safety of the three treatment modalities, but the outcomes were not satisfactory. More intensive strategies including radiotherapy should be investigated.

Combined CT and serum CA19-9 for stratifying risk for progression in patients with locally advanced pancreatic cancer receiving intraoperative radiotherapy

Background and purpose

The aim of this study was to evaluate the significance of baseline computed tomography (CT) imaging features and carbohydrate antigen 19-9 (CA19-9) in predicting prognosis of locally advanced pancreatic cancer (LAPC) receiving intraoperative radiotherapy (IORT) and to establish a progression risk nomogram that helps to identify the potential beneficiary of IORT.

Methods

A total of 88 LAPC patients with IORT as their initial treatment were enrolled retrospectively. Clinical data and CT imaging features were analyzed. Cox regression analyses were performed to identify the independent risk factors for progression-free survival (PFS) and to establish a nomogram. A risk-score was calculated by the coefficients of the regression model to stratify the risk of progression.

Results

Multivariate analyses revealed that relative enhanced value in portal-venous phase (REV-PVP), peripancreatic fat infiltration, necrosis, and CA19-9 were significantly associated with PFS (all p < 0.05). The nomogram was constructed according to the above variables and showed a good performance in predicting the risk of progression with a concordance index (C-index) of 0.779. Our nomogram stratified patients with LAPC into low- and high-risk groups with distinct differences in progression after IORT (p < 0.001).

Conclusion

The integrated nomogram would help clinicians to identify appropriate patients who might benefit from IORT before treatment and to adapt an individualized treatment strategy.

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.

Accelerated Partial Breast Irradiation with Intraoperative Radiotherapy Is Effective in Luminal Breast Cancer Patients Aged 60 Years and Older

Adjuvant whole breast irradiation (AWBI) improves local control and survival in breast cancer patients after breast-conserving surgery. Between 2010 and 2017, 823 patients ≥ 60 years with ER-positive, Her-2 negative, clinically N0 breast cancer underwent breast-conserving surgery (BCS) at the West Pomeranian Oncology Center. Intraoperative radiotherapy (IORT) with kV photons was applied to 199 (24.2%) patients according to the IORT protocol, and AWBI only was applied to 624 (75.8%). IORT patients in cases with lymph node metastasis, lobular type presence, extensive in situ components, lymphatic vessel invasion, or resection margin < 2 mm, additionally underwent AWBI. Median follow-up was 74 months. There were two (1%) breast relapses in the IORT protocol group and one (0.2%) in the AWBI-only group. In each group, one axillary lymph node relapse was diagnosed (0.5% and 0.2%, respectively). There were two local relapses in the IORT-only group, and they were treated further with BCS and AWBI. Although locoregional relapse-free survival differed between the AWBI-only and IORT protocol groups (98.5% vs. 99.7%, p = 0.048), the local control, distant metastasis-free survival, and breast cancer-specific survival were similar. IORT is a reasonable option to avoid AWBI in ER-positive, Her-2 negative, cN0 women with breast cancer aged ≥ 60 years.

Long-Term Outcomes of an International Cooperative Study of Intraoperative Radiotherapy Upfront Boost With Low Energy X-Rays in Breast Cancer

Purpose

The purpose of this study was to assess the effectivity of upfront kilovoltage intraoperative radiotherapy (IORT) as a boost in high-risk early-stage breast cancer patients from an international pooled cohort.

Materials/Methods

Patients from four centers in three different countries were retrospectively screened. Those with a minimum 1-year follow-up were included. Cumulative local (LR), regional (RR), and distant metastasis rates (DM) were analyzed. Additionally, the estimated overall survival (OS) was assessed. The Cox regression analysis was performed to identify failure predicting factors.

Results

A total of 653 patients from centers in Peru, Spain, and Germany were included. The median follow-up was 55 (12–180) months, and age was 58 (27–86) years. Clinical tumor (T) staging was T1 65.85%, T2 30.17%, and T3 3.98%. Positive margins were found in 7.9% and in-situ component in 20.06%. The median IORT dose was 20 (6–20). The median time from IORT to EBRT was 74.5 (13-364) days. An overall 3.4% (n = 22) of patients developed local recurrence at some point during follow-up. The 12-, 60-, and 120-month cumulative LR were 0.3%, 2.3%, and 7.9%, respectively. After multivariate analysis, only age <50 remained to be a significant prognostic factor for local recurrence (HR 0.19, 95% CI 0.08–0.47; p < 0.05). The 10-year estimated OS was 81.2%.

Conclusion

Upfront boost with IORT yields similar local control outcomes to those EBRT-based reports. Results from prospective trials, regarding toxicity, cosmesis, and effectivity are awaited to confirm these findings.

Benchmarking Safety Indicators of Surgical Treatment of Brain Metastases Combined with Intraoperative Radiotherapy: Results of Prospective Observational Study with Comparative Matched-Pair Analysis

Simple Summary

Patients with brain metastasis (BM) are at advanced stages of metastatic cancer, and surgical resection is often required in order to avoid severe neurologic deficits. After surgery, patients are usually committed to postoperative radiotherapy. In recent years, intraoperative radiotherapy (IORT) has been proposed as an alternative to conventional postsurgical radiation approaches. This possibility has several advantages, e.g., as IORT is administered only once during the surgical procedure, patients do not have to attend several radiotherapy sessions afterward. However, the application of radiation therapy directly into the open brain during surgery might be accompanied by severe perioperative complications and, therefore, might negatively impact the overall benefit. In the present study, we show that patients who underwent surgery for BM combined with IORT do not suffer from elevated levels of perioperative complications compared to patients without IORT. Therefore, IORT constitutes a safe treatment strategy for cancer patients with BM.

Abstract

Intraoperative radiotherapy (IORT) of the operative cavity for surgically treated brain metastasis (BM) has gained increasing prominence with respect to improved local tumor control. However, IORT immediately performed at the time of surgery might be associated with increased levels of perioperative adverse events (PAEs). In the present study, we performed safety metric profiling in patients who had undergone surgery for BM with and without IORT in order to comparatively analyze feasibility of IORT as an adjuvant radiation approach. Between November 2020 and October 2021, 35 patients were surgically treated for BM with IORT at our neuro-oncological center. Perioperative complication profiles were collected in a prospective observational cohort study by means of patient safety indicators (PSIs), hospital-acquired conditions (HACs), and specific cranial-surgery-related complications (CSCs) as high-standard quality metric tools and compared to those of an institutional cohort of 388 patients with BM resection without IORT in a balanced comparative matched-pair analysis. Overall, 4 out of 35 patients (11%) with IORT in the course BM resection suffered from PAEs, accounting for 3 PSIs (9%) and 1 HAC (3%). Balanced matched-pair analysis did not reveal significant differences in the perioperative complication profiles between the cohorts of patients with and without IORT (p = 0.44). Thirty-day mortality rates were 6% for patients with IORT versus 8% for patients without IORT (p = 0.73). The present study demonstrates that IORT constitutes a safe and clinically feasible adjuvant treatment modality in patients undergoing surgical resection of BM.

Comparison of the Oncological Efficacy Between Intraoperative Radiotherapy With Whole-Breast Irradiation for Early Breast Cancer: A Meta-Analysis

Background

Intraoperative radiotherapy (IORT) and whole-breast irradiation (WBI) are both effective radiotherapeutic interventions for early breast cancer patients undergoing breast-conserving surgery; however, an issue on whether which one can entail the better prognosis is still controversial. Our study aimed to investigate the 5-year oncological efficacy of the IORT cohort and the WBI cohort, respectively, and compare the oncological efficacy between the cohorts.

Materials and Methods

We conducted a computerized retrieval to identify English published articles between 2000 and 2021 in the PubMed, the Web of Science, the Cochrane Library, and APA PsycInfo databases. Screening, data extraction, and quality assessment were performed in duplicate.

Results

A total of 38 studies were eligible, with 30,225 analyzed participants. A non-comparative binary meta-analysis was performed to calculate the weighted average 5-year local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS) in the two cohorts, respectively. The LRFS, DMFS, and OS (without restriction on the 5-year outcomes) between the two cohorts were further investigated by a comparative binary meta-analysis. The weighted average 5-year LRFS, DMFS, and OS in the IORT cohort were 96.3, 96.6, and 94.1%, respectively, and in the WBI cohort were 98.0, 94.9, and 94.9%, respectively. Our pooled results indicated that the LRFS in the IORT cohort was significantly lower than that in the WBI cohort (pooled odds ratio [OR] = 2.36; 95% confidential interval [CI], 1.66–3.36). Nevertheless, the comparisons of DMFS (pooled OR = 1.00; 95% CI, 0.76–1.31), and OS (pooled OR = 0.95; 95% CI, 0.79–1.14) between the IORT cohort with the WBI cohort were both not statistically significant.

Conclusions

Despite the drastically high 5-year oncological efficacy in both cohorts, the LRFS in the IORT cohort is significantly poorer than that in the WBI cohort, and DMFS and OS do not differ between cohorts.

Verification of electron beam parameters in an intraoperative linear accelerator using dosimetric and radiobiological response methods

BACKGROUND

The availability of linear accelerators (linac) for research purposes is often limited and therefore alternative radiation sources are needed to conduct radiobiological research. The National Centre for Radiation Research in Poland recently developed an intraoperative mobile linac that enables electron irradiation at energies ranging from 4 to 12 MeV and dose rates of 5 or 10 Gy/min. The present study was conducted to evaluate the electron beam parameters of this intraoperative linac and to verify the set-up to evaluate out-of-field doses in a water phantom, which were determined through dosimetric and biological response measurements.

MATERIALS AND METHODS

The distribution of radiation doses along and across the radiation beam were measured in a water phantom using a semiconductor detector and absolute doses using an ionisation chamber. Two luminal breast cancer cell lines (T-47D and HER2 positive SK-BR-3) were placed in the phantom to study radiation response at doses ranging from 2 to 10 Gy. Cell response was measured by clonogenic assays.

RESULTS AND CONCLUSION

The electron beam properties, including depth doses and profiles, were within expected range for the stated energies. These results confirm the viability of this device and set-up as a source of megavoltage electrons to evaluate the radiobiological response of tumour cells.

Management of a Pelvic Abscess and Abdominal Fistula after Palliative Total Pelvic Exenteration with Intraoperative Radiotherapy in Recurrent Rectal Cancer Without NPWT: A Case Report

ABSTRACT

A 59-year-old man with recurrent rectal cancer and type 2 diabetes mellitus underwent palliative total pelvic exenteration and intraoperative radiotherapy. After surgery, he experienced a pelvic abscess and abdominal-perineal fistula. Profuse exudate contaminated the midline abdominal incision through the abdominal-perineal fistula and delayed healing. Because of a residual tumor and the high cost, negative-pressure wound therapy was not performed. After 76 days of local treatment that involved removing necrotic tissue, controlling inflammation with an antimicrobial silver dressing, absorbing and draining exudate with a hypertonic saline dressing, promoting granulation and preventing infection with a silver alginate dressing, and promoting re-epithelialization with recombinant human epidermal growth factor gel, the abdominal wound and abdominal-perineal fistula healed successfully.

Intraoperative Radiotherapy with Balloon-Based Electronic Brachytherapy System-A Systematic Review and First Bulgarian Experience in Breast Cancer Patients

(1) Background: We aimed to analyze currently available studies with intraoperative radiotherapy (IORT) as a choice of treatment where the Xoft Axxent^® electronic brachytherapy (eBx) system was used as a single-dose irradiation and an exclusive radiotherapy approach at the time of surgery in patients with early breast cancer (EBC). We also compared the results of the systematic review to the Bulgarian experience. (2) Methods and Materials: We performed a systematic review of the studies published before February 2021, which investigate the application of a single-fraction 20 Gy radiation treatment, delivered at the time of lumpectomy in EBC patients with the Xoft Axxent^® eBx System. A systematic search in PubMed, Scopus, and ScienceDirect was performed. The results are reported following the PRISMA guidelines. The criteria on patients’ selection for IORT (the additional need for EBRT), cosmetic outcomes, and recurrence rate from the eligible studies are compared to the treatment results in Bulgarian patients. (3) Results: We searched through 1032 results to find 17 eligible studies. There are no published outcomes from randomized trials. When reported, the cosmetic outcomes in most of the studies are defined as excellent. The observed recurrence rate is low (1–5.8%). Still, the number of patients additionally referred to postoperative external breast radiotherapy (EBRT) is up to 31%. Amongst the 20 patients treated in Bulgaria, the cosmetic outcomes are also evaluated as excellent, five of which (25%) are referred for EBRT. Within median follow-up of 39 months, there was one local and one distal recurrence. (4) Conclusions: Current evidence demonstrates the Xoft Axxent^® eBx system as a safe and feasible technique for IORT delivery in EBC patients. There are no randomized controlled trials conducted at this time point to prove its long-term effectiveness. Better patient selection and a reimbursement strategy have to be proposed to extend the application of this technique in Bulgaria.

Wound Fluid from Breast Cancer Patients Undergoing Intraoperative Radiotherapy Exhibits an Altered Cytokine Profile and Impairs Mesenchymal Stromal Cell Function

Intraoperative radiotherapy (IORT) displays an increasingly used treatment option for early breast cancer. It exhibits non-inferiority concerning the risk of recurrence compared to conventional external irradiation (EBRT) in suitable patients with early breast cancer. Since most relapses occur in direct proximity of the former tumor site, the reduction of the risk of local recurrence effected by radiotherapy might partially be due to an alteration of the irradiated tumor bed's micromilieu. Our aim was to investigate if IORT affects the local micromilieu, especially immune cells with concomitant cytokine profile, and if it has an impact on growth conditions for breast cancer cells as well as mammary mesenchymal stromal cells (MSC), the latter considered as a model of the tumor bed stroma.42 breast cancer patients with breast-conserving surgery were included, of whom 21 received IORT (IORT group) and 21 underwent surgery without IORT (control group). Drainage wound fluid (WF) was collected from both groups 24 h after surgery for flow cytometric analysis of immune cell subset counts and potential apoptosis and for multiplex cytokine analyses (cytokine array and ELISA). It served further as a supplement in cultures of MDA-MB 231 breast cancer cells and mammary MSC for functional analyses, including proliferation, wound healing and migration. Furthermore, the cytokine profile within conditioned media from WF-treated MSC cultures was assessed. Flow cytometric analysis showed no group-related changes of cell count, activation state and apoptosis rates of myeloid, lymphoid leucocytes and regulatory T cells in the WF. Multiplex cytokine analysis of the WF revealed group-related differences in the expression levels of several cytokines, e.g., oncostatin-M, leptin and IL-1β. The application of WF in MDA-MB 231 cultures did not show a group-related difference in proliferation, wound healing and chemotactic migration. However, WF from IORT-treated patients significantly inhibited mammary MSC proliferation, wound healing and migration compared to WF from the control group. The conditioned media collected from WF-treated MSC-cultures also exhibited altered concentrations of VEGF, RANTES and GROα. IORT causes significant changes in the cytokine profile and MSC growth behavior. These changes in the tumor bed could potentially contribute to the beneficial oncological outcome entailed by this technique. The consideration whether this alteration also affects MSC interaction with other stroma components presents a promising gateway for future investigations.

Outcome of hypofractionated breast irradiation and intraoperative electron boost in early breast cancer: A randomized non-inferiority clinical trial

BACKGROUND

Intraoperative electron radiotherapy (IOERT) followed by hypofractionated whole breast irradiation (HWBI) provides the shortest possible time of adjuvant breast irradiation. The efficacy of either method has been described in previous reports; however, to our knowledge, the efficacy of combined therapy has not been reported.

AIM

To compare the toxicity and cosmetic outcome of IOERT as a tumor bed boost followed by HWBI with conventional whole breast irradiation (CWBI) followed by external electron tumor bed boost (EETBB) after breast conserving surgery (BCS) in patients with invasive breast cancer.

METHODS

In 2019, a prospective noninferiority trial (IRCT20180919041070N2) was started. After BCS, early-stage breast cancer patients were treated by IOERT (10 Gy) and HWBI (42.56 Gy in 16 fractions) or CWBI (50 Gy in 25 fraction) and EETBB (10 Gy in 5) in a double-arm design. Acute/late toxicity and cosmetic outcome were evaluated by common toxicity criteria (CTC) after 1-year follow-up (FUP) at the level of p < .05.

RESULTS

Of 60 eligible patients, 30 were allocated to each group. Regarding acute effects after a median FUP of 12 months, CTC-score of grade II-III erythema (p = .001) and desquamation (p = .005) were significantly higher in CWBI+EETBB compared to IOERT+ HWBI. However, there were no significant differences at the end of radiotherapy and after 1 month, 6 months, and 1 year. Cosmetic outcome after radiation was similar in both groups mostly rating as good/excellent after 1-year FUP.

CONCLUSIONS

Boost-IOERT/HWBI regimen has comparable acute and late treatment toxicity profiles compared to the CWBI.

A prospective single-institution study of intraoperative radiotherapy (IORT) for early-stage breast cancer

Intraoperative radiation therapy (IORT) is an option for breast-conserving therapy in early-stage breast cancer. IORT is given in one fraction at the time of surgery and eliminates the need for adjuvant external beam radiation therapy. However, previous trials indicate increased local failure rates compared with whole-breast irradiation, which engenders controversy around the appropriate use of IORT. We conducted a prospective study of patients diagnosed with early-stage breast cancer (T1-T2, N0-N1) at the University of Oklahoma Health Sciences Center (OUHSC) between 2013 and 2017 and treated with lumpectomy followed by intraoperative radiation therapy (IORT). Data collected included stage of disease, tumor location, histology, tumor markers, lymph node status, surgical margin size, recurrence, cosmetic outcomes, and length of follow-up. In-breast tumor recurrence rate (IBTR) in the 77 evaluable patients was 3.9% (3 patients). Margins were close (1 mm or less) in all three recurrent patients, and two were initially diagnosed with DCIS. Recurrence rates in our patients were comparable to prior reports. All recurrences were in patients with close margins indicating that this may represent a predictive feature for exclusion from IORT; additional studies are essential to determine the recurrence rates among patients treated with IORT and to identify potential predictors of IORT eligibility.

Effectiveness of intraoperative radiotherapy vs hypofractionated postmastectomy radiotherapy for early stage breast cancer: A protocol for systematic review and meta-analysis

BACKGROUND

Radiotherapy is one of the essential components of breast cancer treatment. It destroys the remaining cells in the chest area after breast cancer surgery and is useful for reducing the necessity of mastectomies. As a single dose of radiation at the time of breast conserving surgery, intraoperative radiotherapy delivers radiotherapy directly and accurately to the tumor itself or the tumor bed whilst delivering minimal dose to the surrounding normal tissues. Hypofractionated postmastectomy radiotherapy with shorter and more convenient hypofractionated dose schedules might help to treat more patients and reduce cost. We will conduct a comprehensive systematic review and meta-analysis to compare the effectiveness of these 2 therapies in the management of early stage breast cancer.

METHODS

Four English databases (PubMed, Embase, Cochrane Library, and Web of Science) and 3 Chinese databases (China National Knowledge Infrastructure, China Science and Technology Journal Database, and Chinese Biomedical Literature Database) will be searched from inception of databases to December 2020 without language limitation. Two reviewers will independently conduct selection of studies, data extraction and management, and assessment of risk of bias. Any disagreement will be resolved by the third reviewer. Review Manager 5.3 (The Cochrane Collaboration, Software Update, Oxford, UK) will be used for data synthesis. Cochrane risk of bias assessment tool will be used to assess the risk of bias.

RESULTS

This study will provide a systematic synthesis of current published data to compare the effectiveness of intraoperative radiotherapy vs hypofractionated postmastectomy radiotherapy for early stage breast cancer.

CONCLUSIONS

This systematic review and meta-analysis will provide clinical evidence for the effectiveness of intraoperative radiotherapy vs hypofractionated postmastectomy radiotherapy for early stage breast cancer, and inform our understanding of the value of intraoperative radiotherapy and hypofractionated postmastectomy radiotherapy for early stage breast cancer.

STUDY REGISTRATION NUMBER

INPLASY2020110115.

Changing Patterns of Distant Metastasis in Patients With Lower Rectal Cancer Undergoing Intraoperative Radiotherapy

BACKGROUND/AIM

Local radiotherapy for primary tumors may increase the incidence of distant metastasis. However, the patterns of target organs have not been clarified yet.

PATIENTS AND METHODS

In our randomized controlled trial examining the oncological efficacy of intraoperative radiotherapy (IORT) for advanced lower rectal cancer, the details of the metastatic organs were evaluated.

RESULTS

In the IORT group (38 patients), 2 patients had metastasis in the liver and lung simultaneously, 9 in the liver, and 4 in the lung. In the control group (38 patients), 3 had metastasis in the lung, and 2 in the liver. The IORT group tended to have liver metastases more frequently (p=0.058). Among patients with liver metastases, distant metastasis-free intervals were significantly shorter in the IORT group, however, no significant difference was observed among patients with lung metastases.

CONCLUSION

After curative rectal cancer surgery with IORT, liver metastasis may be increased and accelerated.

Targeted Intraoperative Radiotherapy Is Non-inferior to Conventional External Beam Radiotherapy in Chinese Patients With Breast Cancer: A Propensity Score Matching Study

Purpose: To investigate the efficacy of targeted intraoperative radiotherapy (TARGIT) vs. conventional external beam radiotherapy (EBRT) in Chinese patients with breast cancer. Methods: We retrospectively analyzed breast cancer patients who underwent breast-conserving surgery (BCS) at our hospital between April 2009 and October 2017. Patients were divided into TARGIT group and EBRT group according to different radiotherapy methods. TARGIT was performed with low-energy X-rays emitted by the Intrabeam system to deliver a single dose of 20 Gy to the applicator surface. Propensity score matching was performed at 1:1. The Kaplan-Meier method was used to calculate the locoregional recurrence (LR), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) of the two groups, and the log-rank test was run to analyse between-group difference before and after matching. Results: A total of 281 patients were included, with a median follow-up of 43 months. Of them, 82 were included in the TARGIT group and 199 in the EBRT group. Using the risk-adapted approach, 6.1% of patients received supplemental EBRT in the TARGIT group. The 5-year LR rate was 3.2% in the TARGIT group and 3.1% in the EBRT group (P = 0.694), the 5-year DMFS rates were 100 and 96.7%, respectively (P = 0.157); the 5-year DFS rates were 96.8 and 94.2% (P = 0.604); and the 5-year OS rates were 97.6 and 97.8% (P = 0.862). After matching which eliminated interference from imbalanced baseline factors, 128 matched patients were analyzed by the Kaplan-Meier method. The 5-year LR rate was 2.3% in the TARGIT group and 1.6% in the EBRT group; the 5-year DMFS rates were 100 and 98.4%, respectively; the 5-year DFS rates were 97.7 and 98.4%; and the 5-year OS rates were 98.4 and 98.4% (P = 0.659, 0.313, 0.659, 0.987). There was no significant difference in efficacy between TARGIT group and EBRT group. Conclusion: TARGIT and EBRT have similar 5-year outcomes in selected Chinese breast cancer patients undergoing BCS, and it can be used as an effective alternative to standard therapy, with substantial benefits to patients. The results need to be further confirmed by extending the follow-up time.

Impact of intraoperative radiotherapy on the perioperative period of patients after breast-conserving surgery

BACKGROUND

To investigate the effect of intraoperative radiotherapy (IORT) in the perioperative period of patients after breast-conserving surgery (BCS).

METHODS

The clinical data of 100 patients with early breast cancer undergoing breast-conserving surgery (BCS) followed by treatment with IORT using the Intrabeam system (Carl Zeiss Meditec, Oberkochen, Germany) (BCS + IORT group, n=100) between June 2016 and December 2019 were analyzed and compared with the data of 60 matched patients who only underwent breast-conserving therapy over the same period (BCS group, n=60). The surgical settings and postoperative acute complications between the groups were assessed.

RESULTS

There was no significant statistical difference between the groups in terms of age, tumor size, grading, lymph node status, hormone receptor status, and human epidermal growth factor receptor 2 (HER-2) status (P>0.05). The BCS + IORT group had a significantly longer surgery duration (P<0.05), but there was no significant statistical difference in terms of intraoperative blood loss, amount of bleeding, drainage tube removal time, postoperative length of hospitalization, incision suture removal time, or incidence of postoperative complications (P>0.05).

CONCLUSIONS

IORT using the Intrabeam system safely delivers radiation therapy, is well-tolerated, has acceptable acute toxicity, and does not significant increase the risk of surgery or the incidence of perioperative complications.

Neoadjuvant chemotherapy combined with intraoperative radiotherapy is effective to prevent recurrence in high-risk non-small cell lung cancer (NSCLC) patients

Background

Basal cell hyperplasia (BCH) and squamous metaplasia (SM) in the small bronchi distant from the tumor is associated with a high risk of non-small cell lung cancer (NSCLC) recurrence. Here, we assessed whether neoadjuvant chemotherapy (NAC), intraoperative radiotherapy (IORT), or adjuvant chemotherapy (AC) is effective to prevent recurrence in NSCLC patients (n=171) with different premalignant lesions in the small bronchi

Methods

BCH, SM, and dysplasia (D) were identified in the samples of lung tissue distant from the tumor. NSCLC patients were treated by surgery, different combinations of NAC and IORT, and AC.

Results

Based on the type of bronchial lesions, NSCLC patients were classified into four groups: BCH⁺SM⁻D⁻ (55.6%, 95/171), BCH⁺SM⁺D⁻ (26.3%; 45/171), BCH⁻SM⁺D⁺ (6.4%, 11/171), and BCH⁻SM⁻D⁻ (11.7%, 20/171). During 5 years, recurrent carcinoma was found in 13.4% (23/171) of patients and represented by metachronous metastases in the thoracic lymph nodes (82.6%, 19/23) and by a relapse in the bronchial stump (17.4%, 4/23). Recurrence was frequent in BCH⁺SM⁺D⁻ patients (87.0%, 20/23), rare in BCH⁺SM⁻D⁻ and BCH⁻SM⁻D⁻ patients (13.0%, 3/23), and absent in BCH⁻SM⁺D⁺ patients (0/23). The 5-year recurrence-free survival was also shorter in BCH⁺SM⁺D⁻ patients (HR 27.35; 95% CI: 6.31−118.48; P<0.0001). In the high-risk (BCH⁺SM⁺D⁻) group, recurrence occurred mainly in cases without NAC and IORT (88.2%, 15/17) and was absent (0/15) when these therapies were combined. NAC- and IORT-negative patients also showed poor overall survival (HR 4.35; 95% CI: 1.96−9.66; P<0.0001) and tended to have decreased recurrence-free survival (P=0.075). Importantly, the recurrence rate was not different between AC-treated and AC-naïve BCH⁺SM⁺D⁻ patients.

Conclusions

The combination of NAC and IORT is an effective strategy to prevent recurrence in high-risk NSCLC patients.

Safety and efficacy of INTRABEAM intraoperative radiotherapy for invasive thymoma

Intraoperative radiotherapy (IORT) has been used to treat different residual solid tumors after tumor removal and has shown many advantages over other treatment methods. However, the use of IORT for invasive thymoma has not been reported. Therefore, in this study, we tried to determine the safety and efficacy of INTRABEAM IORT for the treatment of invasive thymoma.Among the patients admitted to our hospital from September to December 2016 who were diagnosed with invasive thymoma, 14 were selected as study subjects. With medical histories taken beforehand, 8 of these patients were diagnosed with Masaoka stage IIA and 6 with Masaoka stage IIB; furthermore, 5 of the patients were diagnosed with myasthenia gravis (MG). INTRABEAM radiation (8-10 Gy, low energy) was delivered to the postoperative tumor bed of each patient during surgery. The intra- and postoperative complications were observed and evaluated, and the improvement in symptoms was assessed. An additional 23 patients with stage II thymoma undergoing radical surgery from April to August 2016 were chosen as the control group.One month after the operation, only 1 patient in the IORT group had cough, increased levels of leucocytes and neutrophils, and pulmonary inflammation on chest computed tomography. Reactive inflammation and pleural effusion in the 2 groups were similar (P > .05). There was no significant difference between the 2 groups in the improvement of myasthenia gravis (P > .05). Postoperative chest computed tomography and routine blood examination at 3 and 12 months showed that all the patients recovered, with normal hemogram levels and no pulmonary fibrosis around the radiation field. In addition, ultrasonic cardiography and electrocardiography demonstrated no significant difference before or after surgery within the IORT group. At the end of the follow-up, all the patients were alive, no relapse or remote metastasis was observed in the IORT group, and 2 inpatients in the control group had experienced relapse at 24 and 26 months. There was a significant difference in disease-free survival between the 2 groups (P = .00).It is safe to administer low-energy INTRABEAM IORT at a dose of approximately 10 Gy in patients with stage II invasive thymoma. INTRABEAM IORT does not significantly increase operation- or radiation-related complications and has no significant effect on vital organs such as the lungs and heart. Its long-term efficacy is worth expecting.

Update on intraoperative radiotherapy for early-stage breast cancer

Intraoperative radiotherapy (IORT) is a practical and feasible alternative or an adjunct to whole-breast external beam radiation therapy (EBRT) for adjuvant treatment of breast cancer. A large number of experiments have proved IORT is non-inferior for treating early breast cancer due to its advantages, including precise radiotherapy, protection of healthy tissues and organs and sound cosmetic effects. IORT can use both electron beams and X-rays. Some aspects of the clinical use of IORT are still controversial, and extensive trails are ongoing. In this article, we review the published evidence and some ongoing clinical practice to introduce IORT in breast cancer treatment.

Margin assessment before intraoperative radiotherapy during breast conserving surgery-Does the addition of MarginProbe decrease the need for addition of fractionated whole breast radiation?

When performing Breast Conserving Surgery (BCS) with Intraoperative Radiation Therapy (IORT), positive resection margin necessitates not only re-lumpectomy-but also the addition of fractionated whole breast radiation. This retrospective study of 106 patients undergoing BCS and IORT aims to evaluate intraoperative margin assessment use in our center, and the contribution of the MarginProbe device (MP) to achieving negative surgical margins. Eleven out of 106 lumpectomy specimens had a total of 17 margins positive for tumor cells. Intraoperative gross pathology identified 6 (43%) involved margins, MarginProbe detected 8 (50%), and their combined use allowed for detection of 12 (70.5%) involved margins. In conclusion, the adjunctive use of intraoperative gross pathology and MarginProbe reduced the number of lumpectomies with positive resection margins by more than 50%, decreasing the need for re-lumpectomy and the addition of whole breast radiation.

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

INTRODUCTION

Intraoperative radiotherapy (IORT) based on low-kV photons may be an option for early breast cancer patients. Following Targit trial results some of those patients should undergo whole breast irradiation (WBRT) additionally.

MATERIAL AND METHODS

Since April 2010, IORT has been applied to early breast cancer patients. One hundred and fifty patients were prospectively followed up and examined to evaluate the side effects (pain, fibrosis, breast edema, telangiectasias). We present the results 3 years post-treatment. WBRT was given to 82 (54.7%) patients.

RESULTS

Tumor cavity fibrosis grade II and more was observed in 18 (12%) patients, as grade III only in 2 (1.33%) patients. Breast tissue fibrosis outside tumor cavity grade II was observed only in 2 (1.33%) patients. Breast edema was present in 10 (6.66%) patients. WBRT administration led to increased frequency of higher grade tumor cavity fibrosis (P < .0001), breast fibrosis (P < .0001), breast edema (P = .003), and occurrence of telangiectasias (P = .03), with no influence on pain reported by patients. In case of WBRT, tumor location (P = .026) and size of the irradiated breast (P = .015) were independent risk factors for higher degree of breast fibrosis, as seroma evacuation 6 months post-WBRT (P = .036) was the only independent risk factor for higher level of tumor cavity fibrosis in multiple regression.

CONCLUSIONS

The cosmetic result after IORT is good and comparable to other accelerated partial breast irradiation techniques. Administration of WBRT post-IORT in breast cancer patients increases the level of fibrotic changes, breast edema and telangiectasias 3 years post-treatment, but with no influence on pain.

Intraoperative radiotherapy with electrons as partial breast irradiation in limited stage breast cancer: Early term clinical and cosmetic outcomes

Purpose

We aimed to report the experience of intraoperative electron radiation therapy (IOERT) with Mobetron (Intraop Medical Incorporated, Santa Clara, CA, USA) as a partial breast irradiation (PBI) for patients with early-stage breast cancer and explanation of IOERT application and present early clinical and cosmetic result.

Materials and Methods

Between November 2012 and February 2014, in Ankara Oncology Hospital, Radiation Oncology Clinic, was performed IOERT as a PBI with a single dose of 21 Gy for 21selected patients. Median tumor size was 1.5 cm (range, 0.6-2.8 cm). Median treatment duration was 2.04 min (range, 1.26-2.44 min). According to final pathology, two patients were found to have close margin and mastectomy was applied. Three cases (two were N1 mic and one case had perineural invasion and tumor size was >2 cm) received whole breast irradiation.

Results

Median follow-up time was 3 years (range, 26-42 months). One patient died because of nonbreast cancer reason, all of the other patients (except one) alive without disease. There was no Grade 3 or 4 toxicities related to the IOERT. Good or excellent cosmesis was revealed 79% (15/19) and 95% (18/19), by physician and patient, respectively.

Conclusion

IOERT, for patients with early-stage breast cancer as a part of breast-conserving treatment, offer patients better cosmetic results with less skin toxicity and increases comfort of patients by shortening duration of treatment time.

Effect of intraoperative radiotherapy for early breast cancer on 10-year recurrence rates and overall survival

The aim of this study was to evaluate 10-year local control and overall survival of IORT for early breast cancer treatment. We analyzed 68 patients submitted to breast conservative surgery and IORT, in the accelerator room of the Radiotherapy Service in South Brazil. In the long-term follow-up, we had 17.6% of patients with ipsilateral breast cancer recurrence, 2.9% with regional recurrence, 2.9% with contralateral breast recurrence, and 5.9% with distant metastasis. The 10-year overall survival was 82.8%. Our data show high local recurrence rates, however, good overall survival in early breast cancer patients treated with breast-conserving surgery and intraoperative radiotherapy with electron beams in the long-term follow-up.

Acute Toxicity and Early Oncological Outcomes After Intraoperative Electron Radiotherapy (IOERT) as Boost Followed by Whole Breast Irradiation in 157 Early Stage Breast Cancer Patients-First Clinical Results From a Single Center

Introduction: Breast conserving surgery (BCS) followed by postoperative whole breast irradiation (WBI) is the current standard of care for early stage breast cancer patients. Boost to the tumor bed is recommended for patients with a higher risk of local recurrence and may be applied with different techniques. Intraoperative electron radiotherapy (IOERT) offers several advantages compared to other techniques, like direct visualization of the tumor bed, better skin sparing, less inter- and intrafractional motion, but also radiobiological effects may be beneficial. Objective of this retrospective analysis of IOERT as boost in breast cancer patients was to assess acute toxicity and early oncological outcomes. Material and Methods: All patients, who have been irradiated between 11/2014 and 01/2018 with IOERT during BCS were analyzed. IOERT was applied using the mobile linear accelerator Mobetron with a total dose of 10 Gy, prescribed to the 90% isodose. After ensured woundhealing, WBI followed with normofractionated or hypofractionated regimens. Patient reports, including diagnostic examinations and toxicity were analyzed after surgery and 6-8 weeks after WBI. Overall survival, distant progression-free survival, in-breast and contralateral breast local progression-free survival were calculated using the Kaplan-Meier method. Furthermore, recurrence patterns were assessed. Results: In total, 157 patients with a median age of 57 years were evaluated. Postoperative adverse events were mild with seroma and hematoma grade 1-2 in 26% and grade 3 in 0.6% of the patients. Wound infections grade 2-3 occurred in 2.2% and wound dehiscence grade 1-2 in 1.9% of the patients. Six to eight weeks after WBI radiotherapy-dependent acute dermatitis grade 1-2 was most common in 90.9% of the patients. Only 4.6% of the patients suffered from dermatitis grade 3. No grade 4 toxicities were documented after surgery or WBI. 2- and 3-year overall survival and distant progression-free survival, were 97.5 and 93.6, and 0.7 and 2.8%, respectively. In-breast recurrence and contralateral breast cancer rates after 3 years were 1.9 and 2.8%, respectively. Conclusion: IOERT boost during BCS is a safe treatment option with low acute toxicity. Short-term recurrence rates are comparable to previously published data and emphasize, that IOERT as boost is an effective treatment.

Solitary adrenal metastasis from advanced gastric cancer invading duodenal bulb with situs inversus totalis: A case report

RATIONALE

Situs invsersus totalis (SIT) is a rare anomaly featured by complete inversion of abdominal and thoracic organs. Adrenal metastasis is often encountered as part of advanced systemic dissemination, which is usually unresectable. Few published cases reported the adrenal metastasis from gastric cancer with SIT and the treatment of gastrectomy combined with adrenalectomy, especially with intraoperative radiotherapy (IORT).

PATIENT CONCERNS

A 61-year-old SIT man found a mass on the right clavicle and the biopsy revealed a metastatic cancer. Around 14 years ago, he had a rectal cancer resection surgery and no sign of occurrence. Five months later, the patient had a pain in his right low abdomen and abdominal CT found a right adrenal mass.

DIAGNOSES

Gastroscopy and the pathology revealed the gastric antrum cancer invading the duodenal bulb. Abdominal enhanced CT suspected the adrenal mass as a hematoma, but positron emission tomography computed tomography suspected it as the metastases of gastric cancer which is consistent with the pathology results. Finally, the SIT patient was diagnosed with primary gastric cancer invading duodenal bulb with solitary right adrenal metastasis.

INTERVENTIONS

The patient was treated with curative distal gastrectomy and Billroth-II anastomosis with D2 lymphadenectomy. A total 18 Gy intraoperative radiotherapy (IORT) using low energy x-rays by Intrabeam were given after resection.

OUTCOMES

The patient had liver metastasis in the seventh month after surgery but there is no sign of local recurrence until now.

LESSONS

Gastric cancer with adrenal metastasis, especially with SIT is rare and intractable. The result suggested that active surgical treatment for resectable gastric cancer and solitary adrenal metastatic tumor, especially in combination with IORT may be an option in controlling local relapse and prolonging survival in selected patients.

Patient preferences for adjuvant radiotherapy in early breast cancer are strongly influenced by treatment received through random assignment

OBJECTIVE

TARGIT-A randomised women with early breast cancer to receive external beam radiotherapy (EBRT) or intraoperative radiotherapy (TARGIT-IORT). This study aimed to identify what extra risk of recurrence patients would accept for perceived benefits and risks of different radiotherapy treatments.

METHODS

Patient preferences were determined by self-rated trade-off questionnaires in two studies: Stage (1) 209 TARGIT-A participants (TARGIT-IORTn = 108, EBRTn = 101); Stage (2) 123 non-trial patients yet to receive radiotherapy (pre-treatment group), with 85 also surveyed post-radiotherapy. Patients traded-off risks of local recurrence in preference selection between TARGIT-IORT and EBRT.

RESULTS

TARGIT-IORT patients were more accepting of IORT than EBRT patients with 60% accepting the highest increased risk presented (4%-6%) compared to 12% of EBRT patients, and 2% not accepting IORT at all compared to 43% of EBRT patients. Pre-treatment patients were more accepting of IORT than post-treatment patients with 23% accepting the highest increased risk presented compared to 15% of post-treatment patients, and 15% not accepting IORT at all compared to 41% of pre-treatment patients.

CONCLUSIONS

Breast cancer patients yet to receive radiotherapy accept a higher recurrence risk than the actual risk found in TARGIT-A. Measured patient preferences are highly influenced by experience of treatment received. This finding challenges the validity of post-treatment preference studies.

Output factors of ionization chambers and solid state detectors for mobile intraoperative radiotherapy (IORT) accelerator electron beams

Purpose

The electron energy characteristics of mobile intraoperative radiotherapy (IORT) accelerator LIAC^® differ from commonly used linear accelerators, thus some of the frequently used detectors can give less accurate results. The aim of this study is to evaluate the output factors (OFs) of several ionization chambers (IC) and solid state detectors (SS) for electron beam energies generated by LIAC^® and compare with the output factor of Monte Carlo model (MC) in order to determine the adequate detectors for LIAC^®.

Methods

The OFs were measured for 6, 8, 10, and 12 MeV electron energies with PTW 23343 Markus, PTW 34045 Advanced Markus, PTW 34001 Roos, IBA PPC05, IBA PPC40, IBA NACP‐02, PTW 31010 Semiflex, PTW 31021 Semiflex 3D, PTW 31014 Pinpoint, PTW 60017 Diode E, PTW 60018 Diode SRS, SNC Diode EDGE, and PTW 60019 micro Diamond detectors. Ion recombination factors (k_sat) of IC were measured for all applicator sizes and OFs were corrected according to k_sat. The measured OFs were compared with Monte Carlo output factors (OF_MC).

Results

The measured OFs of IBA PPC05, PTW Advanced Markus, PTW Pinpoint, PTW microDiamond, and PTW Diode E detectors are in good agreement with OF_MC. The maximum deviations of IBA PPC05 OFs to OF_MC are −1.6%, +1.5%, +1.5%, and +2.0%; for PTW Advanced Markus +1.0%, +1.5%, +2.0%, and +2.0%; for PTW Pinpoint +2.0%, +1.6%, +4.0%, and +2.0%; for PTW microDiamond −1.6%, +2%, +1.1%, and +1.0%; and for PTW Diode E −+1.7%, +1.7%, +1.3%, and +2.5% for 6, 8, 10, and 12 MeV, respectively. PTW Roos, PTW Markus, IBA PPC40, PTW Semiflex, PTW Semiflex 3D, SNC Diode Edge measured OFs with a maximum deviation of +5.6%, +4.5%, +5.6%, +8.1%, +4.8%, and +9.6% with respect to OF_MC, while PTW Diode SRS and IBA NACP‐02 were the least accurate (with highest deviations −37.1% and −18.0%, respectively).

Conclusion

The OFs results of solid state detectors PTW microDiamond and PTW Diode E as well as the ICs with small electrode spacing distance such as IBA PPC05, PTW Advanced Markus and PTW Pinpoint are in excellent agreement with OF_MC. The measurements of the other detectors evaluated in this study are less accurate, thus they should be used with caution. Particularly, PTW Diode SRS and IBA NACP‐02 are not suitable and their use should be avoided in relative dosimetry measurements under high dose per pulsed (DPP) electron beams.

Interstitial Surgical Cavity Sizing Applicators for the Treatment of the Breast Lumpectomy Cavity with Intraoperative Radiation Therapy

Surgical cavity sizing applicators were developed for utilization prior to intraoperative radiation therapy (IORT) of the breast lumpectomy cavity with the Zeiss INTRABEAM (Carl Zeiss Meditec AG, Jena, Germany) device. The use of these applicators minimizes the number of sterilizations of the treatment applicator, which is currently limited to 100 sterilizations per applicator. This maximizes the number of patients who can be treated with each applicator, resulting in cost savings for the treating institution.

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.

Intraoperative radiotherapy for the treatment of thyroid cancer: a pilot study

We preliminarily evaluated the clinical feasibility and efficacy of intraoperative radiotherapy in patients with thyroid carcinoma. Nine thyroid cancer patients received intraoperative radiotherapy using an Intrabeam system. The dose was 3-4 Gy and the irradiation time ranged from 1 min 32 s to 7 min 33s. One case was a primary thyroid carcinoma, while the other cases were recurrent disease. Adverse effects, recurrence and survival were analyzed. In one patient, poorly differentiated thyroid carcinoma recurred 5 months after treatment, one patient developed a postoperative tracheal skin fistula, and one patient developed a wound infection. Because the affected areas were treated with both surgical resection and then radiotherapy, it is difficult to know which of those led to the adverse effects. Nonetheless, our results indicate that intraoperative radiotherapy can relieve the symptoms associated with thyroid cancer and improve the quality of life for these patients. It thus appears feasible to treat thyroid cancer patients with intraoperative radiotherapy.

Intraoperative Radiotherapy for Breast Cancer

Intraoperative radiotherapy (IORT) for early stage breast cancer is a technique for partial breast irradiation. There are several technologies in clinical use to perform breast IORT. Regardless of technique, IORT generally refers to the delivery of a single dose of radiation to the periphery of the tumor bed in the immediate intraoperative time frame, although some protocols have performed IORT as a second procedure. There are two large prospective randomized trials establishing the safety and efficacy of breast IORT in early stage breast cancer patients with sufficient follow-up time on thousands of women. The advantages of IORT for partial breast irradiation include: direct visualization of the target tissue ensuring treatment of the high-risk tissue and eliminating the risk of marginal miss; the use of a single dose coordinated with the necessary surgical excision thereby reducing omission of radiation and the selection of mastectomy for women without access to a radiotherapy facility or unable to undergo several weeks of daily radiation; favorable toxicity profiles; patient convenience and cost savings; radiobiological and tumor microenvironment conditions which lead to enhanced tumor control. The main disadvantage of IORT is the lack of final pathologic information on the tumor size, histology, margins, and nodal status. When unexpected findings on final pathology such as positive margins or positive sentinel nodes predict a higher risk of local or regional recurrence, additional whole breast radiation may be indicated, thereby reducing some of the convenience and low-toxicity advantages of sole IORT. However, IORT as a tumor bed boost has also been studied and appears to be safe with acceptable toxicity. IORT has potential efficacy advantages related to overall survival related to reduced cardiopulmonary radiation doses. It may also be very useful in specific situations, such as prior to oncoplastic reconstruction to improve accuracy of adjuvant radiation delivery, or when used as a boost in higher risk patients to improve tumor control. Ongoing international clinical trials are studying these uses and follow-up data are accumulating on completed studies.

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.

Wound fluids affect miR-21, miR-155 and miR-221 expression in breast cancer cell lines, and this effect is partially abrogated by intraoperative radiation therapy treatment

Breast cancer is the most common malignant disease occurring in women. Conservative breast cancer surgery followed by radiation therapy is currently the standard treatment for this type of cancer. The majority of metastases occur within the scar, which initiated a series of studies. As a result, clinical trials aimed to assess whether localized radiotherapy, as intraoperative radiotherapy (IORT), may more effective in inhibiting the formation of local recurrence compared with the standard postoperative whole breast radiotherapy. The present study determined the role of postoperative wound fluids (WFs) from patients diagnosed with breast cancer subsequent to breast conserving surgery or breast conserving surgery followed by IORT on the expression of three microRNAs (miRNAs), consisting of miR-21, miR-155 and miR-221, in distinct breast cancer cell lines that represent the general subtypes of breast cancer. It was determined that the miRNAs responsible for breast cancer progression, induction of tumorigenesis and enrichment of the cancer stem cell phenotype, which is responsible for resistance to tumor therapy, were highly upregulated in the human epidermal growth factor receptor 2-positive breast cancer SK-BR-3 cell line following stimulation with WFs. It is worth emphasizing, that those changes were more significant in WFs collected from patients after surgery alone. The BT-549 cell line showed altered expression only of miR-155 following incubation with WFs. Notably, this change was not associated with IORT. Additionally, it was indicated that both WFs and RT-WF strongly downregulated the expression of miR-21, miR-155 and miR-221 in basal/epithelial and luminal subtypes of breast cancer. It was concluded that the present study contributes to an increased understanding of the role of surgical WFs and IORT treatment in the regulation of miRNA expression. This may enable the development of the current knowledge of breast cancer biology subsequent to IORT treatment and substantially to improve the therapy in the future.

Immunotherapy Combined with Large Fractions of Radiotherapy: Stereotactic Radiosurgery for Brain Metastases-Implications for Intraoperative Radiotherapy after Resection

Brain metastases (BM) affect approximately a third of all cancer patients with systemic disease. Treatment options include surgery, whole-brain radiotherapy, or stereotactic radiosurgery (SRS) while chemotherapy has only limited activity. In cases where patients undergo resection before irradiation, intraoperative radiotherapy (IORT) to the tumor bed may be an alternative modality, which would eliminate the repopulation of residual tumor cells between surgery and postoperative radiotherapy. Accumulating evidence has shown that high single doses of ionizing radiation can be highly efficient in eliciting a broad spectrum of local, regional, and systemic tumor-directed immune reactions. Furthermore, immune checkpoint blockade (ICB) has proven effective in treating antigenic BM and, thus, combining IORT with ICB might be a promising approach. However, it is not known if a low number of residual tumor cells in the tumor bed after resection is sufficient to act as an immunizing event opening the gate for ICB therapies in the brain. Because immunological data on tumor bed irradiation after resection are lacking, a rationale for combining IORT with ICB must be based on mechanistic insight from experimental models and clinical studies on unresected tumors. The purpose of the present review is to examine the mechanisms by which large radiation doses as applied in SRS and IORT enhance antitumor immune activity. Clinical studies on IORT for brain tumors, and on combined treatment of SRS and ICB for unresected BM, are used to assess the safety, efficacy, and immunogenicity of IORT plus ICB and to suggest an optimal treatment sequence.

Intraoperative radiotherapy: Patient selection, management, and follow-up

Intraoperative partial breast radiotherapy is an alternative or an adjunct to fractionated whole breast irradiation for the administration of adjuvant radiotherapy in breast cancer following breast conserving surgery. Establishing intraoperative radiotherapy as a therapeutic modality requires a multidisciplinary approach to patient selection, workup, surgery, radiation protocols, chemotherapy, and patient follow up. In this article, we review the published evidence for best clinical practice, as a guide to the introduction of intraoperative radiotherapy for breast cancer treatment.