Background: Intraoperative Irradiation Therapy (IORT) refers to the delivery of radiation during surgery and needs the computed- thickness of the target as one of the most significant factors.Objective: This paper aimed to compute target thickness and design a radiation pattern distributing the irradiation uniformly throughout the target.Material and Methods: The Monte Carlo code was used to simulate the experimental setup in this simulation study. The electron flux variations on an electronic board’s metallic layer were studied for different thicknesses of the target tissue and validated with experimental data of the electronic board.Results: Based on the electron number for different Poly Methyl Methacrylate (PMMA) phantom thicknesses at various energies, 6 MeV electrons are suitable to determine the target thickness. Uniformity in radiation and corresponding time for each target were investigated. The iso-dose and percentage depth dose curves show that higher energies are suitable for treatment and distribute uniform radiation throughout the target. Increasing the phantom thickness leads to rising radiation time based on the radiation time corresponding to these energies. The tissue thickness of each section is determined, and the radiation time is managed by scanning the target. Conclusion: Calculation of the thickness of the remaining tissue and irradiation time are needed after incomplete tumor removal in IORT for various remaining tissues. The patients should be protected from overexposure to uniform irradiation of tissues since the radiation dose is prescribed and checked by an oncologist.

Background: Ductal Carcinoma In Situ (DCIS) which has recently been renamed into Ductal Intraepithelial Neoplasia (DIN), is a malignant cell proliferation without invasion to basement membrane of ducts or lobules of breast. DCIS consists 20-30% of newly diagnosed breast cancers in some Western countries due to higher diagnosis resulting from screening by mammography. Relative Risk (RR) of invasive ductal carcinoma is 8-10 times in DCIS, although high grading lesions and positive or close surgical margins are two important predictive factors in DCIS recurrences. The adjuvant radiotherapy has decreased the rate of ipsilateral local recurrence about 60%. In this article, we evaluated the recurrence rate as DCIS as well as invasive breast cancer in patients with DCIS undergoing breast conserving surgery (BCS) and intraoperative electron radiotherapy (IOERT). Methods: Data were derived from Cancer Research Center database from 38 pure DCIS cases who had received intraoperative radiation therapy between 2012– 2017. Intraoperative electron radiotherapy (IOERT) was performed according to Iran's intraoperative radiation therapy consensus. Conclusion: There is not a lot of data on the effectiveness of IOERT in DCIS management. Although there are not large number of cases in our study, the local recurrence (13. 1%) was only event in our study with 31 months median follow up with no contralateral metastasis, distant metastasis, or death. Results: The median age of the patients was 55 years and median histological lesion size was 1. 8 centimeters. Number of extracted lymph nodes had a median of 1 and all extracted nodes were negative. Hormonal therapy was performed in 42. 1% of patients. IOERT was done as radical full exposure for 86. 9% of cases and as boost dose for 13. 1% of cases, who needed to complete radiotherapy by external beam. One case in the group received boost dose and 4 cases in the group received full dose had recurrence. The median follow-up of patients was 31 months. Pathology of recurrence was reported as DCIS in 3 cases and invasive breast cancer in 2 of them.

Background: Breast conserving surgery (BCS) and its following radiotherapy is an accepted therapeutic method for patients with invasive lobular carcinoma (ILC) and invasive ductal carcinoma (IDC). Objectives: The aim of this study was to investigate the effect of intraoperative electron radiotherapy on women with breast cancer (invasive lobular and ductal carcinoma). Methods: Between August 2013 and September 2017, 968 patients, who were referred to Cancer Research Center, Shahid Beheshti University of Medical Sciences with invasive breast cancer, were treated with breast-conserving surgery and radiotherapy. Of those, 426 patients received a tumor bed boost with intraoperative electron radiotherapy (IOERT) during lumpectomy (58 patients with pure invasive lobular carcinoma, 239 patients with pure invasive ductal carcinoma, and 129 patients with other diagnoses). 542 patients received a tumor bed boost with conventional external beam radiotherapy post lumpectomy (24 patients with pure invasive lobular carcinoma, 418 patients with pure invasive ductal carcinoma, and 100 patients with other diagnoses). The patients were followed up to 49 months. A comprehensive list of clinical and pathologic features was evaluated for all patients. We retrospectively analyzed outcomes of breast cancer treated with boost intraoperative electron radiotherapy (pure ILC and IDC groups) and in other group treated with boost conventional external beam radiotherapy (pure ILC group). Results: None of the ILC patients had recurrence in the two groups. The four-year survival rate for ILC patients was 100%, but in the IDC group the survival rate was 97%. Survival analyses showed patients with IDC had a higher risk of ipsilateral breast tumor recurrence (IBTR) and metastasis. Conclusions: Overall, the rates of IBTR and metastasis in the ILC boost IOERT group were significantly low. This finding suggests that IOERT technique deployment in ILC had no inferiority compared with the control group.

Background: In the large breast tumors or locally-advanced breast cancers, breast conserving surgery (BCS) after neoadjuvant chemotherapy (NACT) had an acceptable local control, but greater risk of recurrence. Adding boost dose radiation to whole breast radiotherapy is involved with a reduced risk of recurrence. Boost radiotherapy can be delivered in 3 methods, including (1) external beam radiotherapy (EBRT), (2) intraoperative radiotherapy with electron (IOERT), and (3) intraoperative radiotherapy with low-kV X-ray (IOXRT). Objectives: This study compared the outcomes of these 3 methods with each other. Methods: Within 60 months, 217 unselected breast cancer patients in Cancer Research Center of Shahid Beheshti were under treatment with BCS after NACT. They received boost dose radiation in 3 groups; 115 patients in the EBRT group, 39 patients IOXRT group, and 63 patients in the IOERT group. All of them received WBRT after surgery. Results: The patients had large tumors or stage 3 breast cancer. Local recurrences were 1 (2. 5%) in IOXRT, 2 (3. 2%) in IOERT, and 1 (0. 9%) in EBRT groups. Systemic recurrences were 4 (10. 3%) in IOXRT, 10 (15. 9%) in IOERT, and 16 (13. 9%) in EBRT groups. Deaths were 3 (7. 7%) in IOXRT, 2 (3. 2%) in IOERT, and 10 (6. 9%) in EBRT groups. Patients with any events were 4 (10. 3%) in IOXRT, 11 (17. 5%) in IOERT, and 33 (15. 2%) in the EBRT group. Death due to distant metastases was lower in IOERT group, but it was not significant. No significant difference was observed in disease-free survival (DFS) among 3 groups. IOXRT group had non-significant, lower events, and better DFS. Especially, in non-PCR (non-pathologic complete response) patients, multivariate COX analysis showed better outcome (DFS) in IOXRT group (HR = 0. 50), although it was not significant (P = 0. 53). Conclusions: Intraoperative radiotherapy (IORT or IOXRT) as tumor bed boost during BCS after NACT had at least non-inferiority compared with EBRT. In non-PCR patient, IOXRT group had non-significant better outcomes (DFS).

Background: Intraoperative radiation therapy (IORT) is a novel approach to breast cancer (BC) treatment. Objectives: In this study, we compared the cellular and molecular effects of IORT-treated post-lumpectomy wound fluid (seroma) at the point of IOERT versus IOxRT on the BC cell line. Methods: Immortalized human BC cell lines: MCF-7, MDA-MB-231, and MCF10 were incubated with seroma from 3 groups of patients (as a pilot study). The first group received Intraoperative electron radiation therapy (IOERT, Boost dose=12Gy), the second one received IOERT (Radical dose=21Gy), and the third group was prescribed Intraoperative x-ray radiation therapy (IOxRT, X-ray=20Gy). Cellular and molecular tests were used to investigate how cells are influenced by the IORT-treated seroma. Results: We evaluated the effects of dose-time and source-dependent IORT-treated seroma on BC cell lines. In this study, weobserved that IOxRT-treated seroma has the most significant effects on the reduction of proliferation, induced cell cycle arrest, and apoptosis. Furthermore, inhibited migration and invasion of BC cell lines were compared to IOERT-treated seroma. Conclusions: Although this is a pilot study, we suggest that at 24 h, the IORT (specifically IOxRT)-treated seroma may play an important protective role in the breast tumor bed, which is followed by local recurrence decreases.

Background: Invasive lobular carcinoma (ILC) differs from invasive ductal carcinoma (IDC) in genomic profile, clinicopathologic behavior, and response to treatment. Despite favorable profile, ILC is susceptible to recurrence. Thus, most of studies did not include ILC in intraoperative radiotherapy (IORT) trials or considered it as a cautionary criteria, especially in accelerated partial breast irradiation (APBI). Objectives: In this study, we compared treatment outcome between breast cancer patients with ILC and IDC treating with breast conserving surgery and intraoperative electron radiotherapy (IOERT). Methods: A total of 191 patients with early breast cancer treated with breast conserving surgery and IOERT were included in the study. This study compared outcome of 42 ILC patients with 135 IDC patients. Fourteen patients were mixed type. ILC was a suitable criterion, as well. Local recurrence and disease-free survival were endpoints of study. Results: Median follow-up was 23. 17 month and 21. 17 month for IDC and ILC, respectively. Univariate analysis was done according to age, pathologic, and biologic factors and multivariate analysis was according molecular subtype. There were 3 patients with local recurrence. Two patients were in the IDC group and another one was the ILC group. There was no significant difference between two groups. The 4-year disease-free survival (DFS) was 95. 45% and 97. 40% for ILC and IDC, respectively. Conclusions: In this study, there was no significant difference in in-breast tumor recurrence (IBTR) and DFS between two groups. It was seem lobular carcinoma can be used for APBI and it may be a suitable criterion as the IDC.