Local Failure After Accelerated Partial Breast Irradiation with Intraoperative Radiotherapy with Electrons: An Insight into Management and Outcome from an Italian Multicentric Study.

BACKGROUND: The aim of this work is to evaluate pattern of care and clinical outcome in a large series of patients with in-breast recurrence (IBR), after quadrantectomy and intraoperative radiation therapy with electrons (IOERT) as partial breast irradiation. PATIENTS AND METHODS: Patients with IBR after IOERT, treated with salvage surgery ± adjuvant reirradiation (re-RT), were selected from a multiinstitution database. Disease-free survival (DFS), overall survival (OS), cumulative incidence of second IBR, and distant metastases (DM) were estimated. RESULTS: A total of 224/267 patients from seven institutions were included. Primary tumors received 21 Gy. Median time to first IBR was 4.3 years (range 2.6-6.1 years). Salvage mastectomy and repeat quadrantectomy were performed in 135 (60.3%) and 89 (39.7%) patients, followed by adjuvant re-RT in 21/135 (15.5%) and 63/89 (70.8%), respectively. Median follow-up after salvage treatment was 4.1 years. Overall, 5- and 8-year outcomes were as follows: cumulative incidence of second IBR: 8.4% and 14.8%; cumulative incidence of DM: 17.1% and 22.5%; DFS: 67.4% and 52.5%; OS: 89.3% and 74.7%. The risk of second IBR was similar in the salvage mastectomy and repeat quadrantectomy + RT groups [hazard ratio (HR) 1.41, p = 0.566], while salvage mastectomy patients had greater risk of DM (HR 3.15, p = 0.019), as well as poorer DFS (HR 2.13, p = 0.016) and a trend towards worse OS (HR 3.27, p = 0.059). Patients who underwent repeat quadrantectomy alone had worse outcomes (second IBR, HR 5.63, p = 0.006; DFS, HR 3.21, p = 0.003; OS, HR 4.38, p = 0.044) than those adding re-RT. CONCLUSIONS: Repeat quadrantectomy + RT represents an effective salvage approach and achieved local control comparable to that of salvage mastectomy.

Adjuvant intraoperative radiotherapy for selected breast cancers in previously irradiated women: Evidence for excellent feasibility and favorable outcomes.

BACKGROUND: The present report provides preliminary outcomes with intraoperative radiotherapy delivered to women with breast cancer included in a re-irradiation program. MATERIALS AND METHODS: From October 2010 to April 2014, thirty women were included in a re-irradiation protocol by exploiting IORT technique. The median time between the two irradiations was 10 years (range 3-50). All patients underwent conservative surgery, sentinel lymph node excision and IORT with electron beam delivered by a mobile linear accelerator. Primary endpoint was esthetic result and consequential/late toxicity; secondary endpoints were local control (LC), disease free survival (DFS) and overall survival (OS). RESULTS: With a median follow up of 47 months (range 10-78), we analyzed 29 patients (1 lost at follow up). Twenty-seven patients (90%) had presented breast cancer local relapse or a new primary cancer in the same breast after a previous conservative surgery plus radiation treatment; three patients (10%) had previously received irradiation with mantle field for Hodgkin Lymphoma. Esthetic result was excellent in 3 pts (10%), good in 12 pts (41%), fair in 8 pts (28%) and poor in 6 pts (21%). 12 (41%) patients showed subcutaneous fibrosis at the last follow-up. LC, DFS and OS at five years was 92.3%, 86.3% and 91.2%, respectively. CONCLUSION: Although we analyzed a small number of patients, our results are satisfactory and this approach is feasible even if it could not be considered the standard treatment. Further clinical trials exploring IORT are needed to identify possible subgroups of patients that might be suitable for this type of approach.

AIRO Breast Cancer Group Best Clinical Practice 2022 Update.

INTRODUCTION: Breast cancer is the most common tumor in women and represents the leading cause of cancer death. Radiation therapy plays a key-role in the treatment of all breast cancer stages. Therefore, the adoption of evidence-based treatments is warranted, to ensure equity of access and standardization of care in clinical practice. METHOD: This national document on the highest evidence-based available data was developed and endorsed by the Italian Association of Radiation and Clinical Oncology (AIRO) Breast Cancer Group.We analyzed literature data regarding breast radiation therapy, using the SIGN (Scottish Intercollegiate Guidelines Network) methodology (www.sign.ac.uk). Updated findings from the literature were examined, including the highest levels of evidence (meta-analyses, randomized trials, and international guidelines) with a significant impact on clinical practice. The document deals with the role of radiation therapy in the treatment of primary breast cancer, local relapse, and metastatic disease, with focus on diagnosis, staging, local and systemic therapies, and follow up. Information is given on indications, techniques, total doses, and fractionations. RESULTS: An extensive literature review from 2013 to 2021 was performed. The work was organized according to a general index of different topics and most chapters included individual questions and, when possible, synoptic and summary tables. Indications for radiation therapy in breast cancer were examined and integrated with other oncological treatments. A total of 50 questions were analyzed and answered.Four large areas of interest were investigated: (1) general strategy (multidisciplinary approach, contraindications, preliminary assessments, staging and management of patients with electronic devices); (2) systemic therapy (primary, adjuvant, in metastatic setting); (3) clinical aspects (invasive, non-invasive and micro-invasive carcinoma; particular situations such as young and elderly patients, breast cancer in males and cancer during pregnancy; follow up with possible acute and late toxicities; loco-regional relapse and metastatic disease); (4) technical aspects (radiation after conservative surgery or mastectomy, indications for boost, lymph node radiotherapy and partial breast irradiation).Appendixes about tumor bed boost and breast and lymph nodes contouring were implemented, including a dedicated web application. The scientific work was reviewed and validated by an expert group of breast cancer key-opinion leaders. CONCLUSIONS: Optimal breast cancer management requires a multidisciplinary approach sharing therapeutic strategies with the other involved specialists and the patient, within a coordinated and dedicated clinical path. In recent years, the high-level quality radiation therapy has shown a significant impact on local control and survival of breast cancer patients. Therefore, it is necessary to offer and guarantee accurate treatments according to the best standards of evidence-based medicine.

Preliminary experience using oncoplastic techniques of reduction mammaplasty and intraoperative radiotherapy: report of 2 cases.

BACKGROUND: Since 2004 in the Department of Oncological Integrated Surgery at the National Institute for Cancer Research of Genoa, we have applied different techniques of reduction mammaplasty for a subgroup of 26 patients with medium- to large-sized and ptotic breasts who are candidates for conservative surgery. METHODS: In this series of patients, the choice between different techniques of breast reduction (superior or inferior pedicled or with free areola-nipple graft) depended only on cancer position. The chosen technique minimized reshaping and displacement of residual glandular flaps. In September 2009, the radiotherapists at the Institute began to apply intraoperative radiotherapy (IORT) to early breast cancer, and at the time of this report, more than 200 patients have been treated. RESULTS: This report describes two cases of reduction mammaplasty associated with this new and easily performed radiotherapy option (IORT) and discusses its advantages and cautions. CONCLUSIONS: Close collaboration between surgical oncologist, plastic surgeon, and radiotherapist is essential before and during surgery to obtain adequate tumor resection and good aesthetic results and to minimize postoperative complications.

Ten Daily Fractions for Whole Breast Cancer Irradiation: Long Term Results.

BACKGROUND/AIM: To report the feasibility and oncological outcomes in breast cancer patients treated with a short hypofractionated radiotherapy schedule. PATIENTS AND METHODS: We evaluated 380 breast cancer patients treated with ten daily fractions of radiotherapy up to 39 Gy on tumor bed. Primary endpoint was local relapse rate (LRR). Secondary endpoints were overall survival (OS) and metastasis-free survival (MFS). RESULTS: The median follow up was 5.0 years. Two- and 5-year LRR rates were 0.2 and 2%, respectively. Two- and 5-year MFS rates were 96.1% and 90.5%, respectively. Two and 5-year OS rates were 97.4% and 95%, respectively. CONCLUSION: This short schedule may represent an alternative option to standard mild hypofractionated radiotherapy in breast cancer patients due to its excellent feasibility and very low recurrence rate.

Accelerated partial breast irradiation via the mammosite catheter: preliminary reports of a single-institution experience.

Several studies have shown that the majority of in-breast recurrences following lumpectomy are at or near the original tumor site while ipsilateral breast recurrences further a field occur rarely. This suggests that the radiation dose could be delivered exclusively to the tumor bed, allowing larger fractions to be used without increasing toxicity and shortening the total treatment time. We investigated the use of the MammoSite irradiation system with a view to analyzing complications, cosmesis and patient comfort. Between 2004 and 2007 intracavity brachytherapy was given to 30 patients using the MammoSite device. The reference isodose was prescribed to the lumpectomy cavity with a 1 cm margin. Geometric parameters and anatomic position of the applicator after implantation were checked via CT, x-ray and ultrasound. Analysis was done for patient quality of life, cosmesis, early and late complications. Forty-nine patients received a proposal for MammoSite brachytherapy. Nine declined, 40 enrolled while 10 were excluded for various reasons (Table 5). A total of 30 patients were actually treated to 34 Gy (2 x 3.4 Gy) in 5 days. We observed 3 cases (10%) of infection within 3 months of implantation. Symptomatic seroma was seen in five patients (16.6%) at 6 months, in three (10%) at 12 months, and in just one patient (3.3%) at 18 months. Good to excellent cosmetic results were achieved in 75% by patient and physician ratings. Accelerated partial breast irradiation using the MammoSite catheter produces favorable short-term outcomes, limited toxic effects on skin, and optimal cosmetic results. Patient tolerance for the treatment is very high. Critical issues may regard the importance of good cavity conformance and adequate balloon-skin distance in avoiding possible dose excesses to the skin. For a selected patient group, this could be a valid alternative to conventional whole breast irradiation.

No Ink on Ductal Carcinoma In Situ: A Single Centre Experience.

BACKGROUND/AIM: A retrospective analysis of 388 patients with pure ductal carcinoma in situ (DCIS) was performed in order to test the correlation of clearance margin of resection and other host-, tumor- and treatment-related factors with ipsilateral breast tumor recurrence (IBTR). MATERIALS AND METHODS: The pathological analysis was performed according to a standardized protocol: positive margins had DCIS at the inked margin; close margins had tumor between 0.1 to 0.9 mm, or 1 to 1.9 mm, and negative margins were ≥2 mm. RESULTS: At a median follow-up of 90 months there were 26 IBTR (10 invasive and 16 DCIS). Both in univariate and multivariate analysis a significant difference was observed in IBTR by comparing positive versus close/negative margins of excision (p=0.05) and the number of re-operations (p=0.000). Moreover, the actuarial IBTR rates were significantly different in patients with a positive compared to close/negative margins (log-rank test, p=0.042) while the stratification by the margin width (0.1-0.9 mm; 1.0-1.9 mm; ≥2 mm) was not significant (log-rank test, p=0.243). CONCLUSION: The policy of "no ink on the tumor" can be translated from invasive to DCIS, because the actuarial IBTR rates were significantly different only in patients with a positive, compared to close/negative margins.

Simultaneous Integrated Boost in Once-weekly Hypofractionated Radiotherapy for Breast Cancer in the Elderly: Preliminary Evidence.

AIM: To evaluate once-weekly hypofractionated radiotherapy in elderly patients affected by early breast cancer, reporting acute and late toxicity profiles, and treatment feasibility. PATIENTS AND METHODS: Fifty patients were treated with a hypofractionated regimen: 28.5±2.5 Gy in five fractions at one fraction weekly. Simultaneous integrated boost (SIB) to the tumor bed in high-risk cases. INCLUSION CRITERIA: patients over 70 years old, pT1-2, N0-1a. Acute and late toxicities were assessed based on Radiation Therapy Oncology Group. RESULTS: The median follow-up was 20 months and the median patient age was 79 years. SIB was added for 22 patients (44%). Grade 3-4 acute cutaneous toxicities were not observed; grade 2 toxicity occurred only in four patients (8%). Late subcutaneous tissue toxicity consisted of grade 2 fibrosis in two patients (4%), grade 1 in five (10%) and grade 0 in 41(85%). CONCLUSION: Limiting fraction numbers with a safer profile may improve the management of breast cancer for the elderly.

Cardiotoxicity Assessment After Different Adjuvant Hypofractionated Radiotherapy Concurrently Associated with Trastuzumab in Early Breast Cancer.

AIM: To evaluate cardiotoxicity in patients with human epidermal growth factor receptor 2+ (HER2+) breast cancer (29 left-sided, 23 right-sided) treated with adjuvant whole-breast hypofractionated radiotherapy (HRT) concurrently administered with the humanized monoclonal antibody to HER2, trastuzumab. PATIENTS AND METHODS: From February 2008 to June 2017, 52 patients received three-dimensional conformal RT, with different HRT schemes. Echocardiogram monitoring was used to evaluate the decrease in left ventricular ejection fraction (LVEF). RESULTS: At a median follow-up of 5 years, cardiotoxicity was as follows: among the 15 patients treated with 46 Gy: grade (G) 2 in two (13%), G1 in three (20%), and G0 in 10 (67%);in those treated with 39 Gy (16 patients): G1 in five (31%), and G0 in 11 (69%);among the 21 patients treated with 35 Gy: G2 in one (5%), G1 in five (24%), and G0 in 15 (71%). CONCLUSION: Trastuzumab was shown to be a safe adjuvant treatment when administered with concomitant HRT since it did not increase cardiotoxicity in those with left-sided breast cancer. No differences in LVEF were observed between the HRT schemes.

Tumor Size-driven Dose of Intraoperative Radiotherapy for Breast Cancer: 18 Gy Versus 21 Gy.

AIM: To test whether a reduced total single dose of 18 Gy of intraoperative radiotherapy with electrons (IORT) may be tailored to safely treat patients in comparison with the standard dose of 21 Gy. (NCT01276938). PATIENTS AND METHODS: From October 2009 to December 2011, 199 females affected by breast cancer were treated with conservative surgery and IORT with two different exclusive doses, 18 or 21 Gy. RESULTS: The median follow-up was 91 months (16-104 months). Sixty-five patients (pT1a\b, pN0\mic, pMx, G1-G3) received 18 Gy and 134 patients (pT1c\2, pN0\mic, pMx, G1-G3) received 21 Gy. No significant difference in local recurrence-free survival or overall survival was detected in the 18 Gy-treated arm versus that treated with 21 Gy: 96.9% vs. 96.3%, p=0.72, and 96.9% vs. 95.5%, p=0.82, respectively at 5 years. CONCLUSION: The lower dose of 18 Gy achieved excellent results in terms of local toxicity and local control in early breast cancer.

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.

A Successful Therapeutic Challenge: Local Reirradiation of Breast Cancer with a Single Dose of 18 Gy Intraoperative Radiation Therapy (IORT).

After standard treatment of primary breast cancer, local relapse can develop in a previously irradiated region. The decision to refer a patient for a second radiotherapy must be thoroughly evaluated due to the increased risk of side effects. We report a case of a 43-year-old Caucasian female with a history of left breast lumpectomy and radiation treatment in 1990 for an invasive ductal carcinoma who presented with a locoregional recurrence 19 years later. After careful evaluation, the patient has undergone a second breast-conserving surgery and successful reirradiation with 18 Gy single dose of intraoperative radiation therapy (IORT).

Salvage Hypofractionated Radiotherapy in a Progressive Radiation-Induced Angiosarcoma: A Case Report.

We report a case of a long-term local control and survival achieved in a patient affected by radiation-induced angiosarcoma (RIA). A 57-year-old woman had a history of breast-conserving surgery and radiation therapy for primary breast cancer. Eight years after the mastectomy, multiple nodal progression was diagnosed as RIA and subsequentially treated by salvage lymph node dissection followed by adjuvant intensified radiotherapy to control the residual disease. Two and a half years later, the patient is alive and cancer-free. This experience shows that radiotherapy may have the potential to be a feasible and effective treatment to control RIA progression, and it may also play a role in the management of RIA as adjuvant.

Overview on cardiac, pulmonary and cutaneous toxicity in patients treated with adjuvant radiotherapy for breast cancer.

Conservative management of breast cancer represents the standard treatment for early disease. Breast conserving surgery associated with radiotherapy for stage I-II has been proven to be as equally effective as mastectomy in term of local control, distant disease, and overall survival. The growing minimal invasive surgical approach on the axillary region, and the new breast reconstructive techniques, will probably lead to a significant decrease of the rate of side-effects related to mastectomy. Therefore, the adverse events caused by adjuvant radiation still remain a challenge. Cutaneous, pulmonary and cardiac toxicity represent the main toxicities of adjuvant radiotherapy for breast cancer. Safety profile of radiation is strongly dependent on the multidisciplinary management of the single case (systemic treatment, endocrine therapy, surgery), individual characteristics (i.e., co-morbidities, age, habits), and radiation-related aspects. Radiation techniques development, and facilities implementation concerning organs-at-risk sparing systems (i.e., image-guided radiotherapy, tracking systems, respiratory gating), represent brand new tools for the clinical oncologist, that would certainly minimize toxicity profile in the next future. However, data reported from published literature will greatly help physicians, to give to the patients appropriate counseling regarding the efficacy and potential adverse events of treatments, thus optimizing the informed decision-making process.

Hypofractionated irradiation of infra-supraclavicular lymph nodes after axillary dissection in patients with breast cancer post-conservative surgery: impact on late toxicity.

BACKGROUND: The aim of the present work was to analyse the impact of mild hypofractionated radiotherapy (RT) of infra-supraclavicular lymph nodes after axillary dissection on late toxicity. METHODS: From 2007 to 2012, 100 females affected by breast cancer (pT1- T4, pN1-3, pMx) were treated with conservative surgery, Axillary Node Dissection (AND) and loco-regional radiotherapy (whole breast plus infra-supraclavicular fossa). Axillary lymph nodes metastases were confirmed in all women. The median age at diagnosis was 60 years (range 34-83). Tumors were classified according to molecular characteristics: luminal-A 59 pts (59%), luminal-B 24 pts (24%), basal-like 10 pts (10%), Her-2 like 7 pts (7%). 82 pts (82%) received hormonal therapy, 9 pts (9%) neo-adjuvant chemotherapy, 81pts (81%) adjuvant chemotherapy. All patients received a mild hypofractionated RT: 46 Gy in 20 fractions 4 times a week to whole breast and infra-supraclavicular fossa plus an additional weekly dose of 1,2 Gy to the lumpectomy area. The disease control and treatment related toxicity were analysed in follow-up visits. The extent of lymphedema was analysed by experts in Oncological Rehabilitation. RESULTS: Within a median follow-up of 50 months (range 19-82), 6 (6%) pts died, 1 pt (1%) had local progression disease, 2 pts (2%) developed distant metastasis and 1 subject (1%) presented both. In all patients the acute toxicity was mainly represented by erythema and patchy moist desquamation. At the end of radiotherapy 27 pts (27%) presented lymphedema, but only 10 cases (10%) seemed to be correlated to radiotherapy. None of the patients showed a severe damage to the brachial plexus, and the described cases of paresthesias could not definitely be attributed to RT. We did not observe symptomatic pneumonitis. CONCLUSIONS: Irradiation of infra-supraclavicular nodes with a mild hypofractionated schedule can be a safe and effective treatment without evidence of a significant increase of lymphedema appearance radiotherapy related.

Novel 10-fraction breast irradiation in prone and supine position: technical, dosimetric and clinical evaluation.

BACKGROUND: The aim of this study was to evaluate retrospectively the planned dose distribution and acute toxicity of adjuvant hypofractionated whole breast radiotherapy (RT) delivered in the prone vs. supine position. METHODS: Twenty-four patients were enrolled; 12 underwent adjuvant RT with a supine setup and 12 with a prone setup. We included patients according to breast volume (≥500 mL), disease stage (≤pT2/pN1), and clinical/biological features. Patients received a regimen of 35 Gy in 10 fractions for 2.5 weeks, and a concomitant boost of 3/4 Gy in 1 fraction/week. Target coverage was assessed by volume, V90, V95, V100, V103 and V105. Heart, LADCA and ipsilateral lung doses were evaluated according to volume, maximum dose, mean dose, V14, V10 and V5. We evaluated acute skin toxicity during RT, at the end of treatment, and after 1 month according to RTOG scales. RESULTS: Radiobiological equivalence was warranted with satisfactory BED values: considering α/ß = 4 for breast cancer, the 10-fraction schedule equaled 74 or 77 Gy depending on the boost dose (3 Gy vs. 4 Gy, respectively). Toxicity was low and similar for supine and prone treatments. Dose sparing was significant in the ipsilateral lung in the prone position (median Dmax: 28.7 Gy vs. 38.4 Gy; median Dmean: 0.8 Gy vs. 6.3 Gy; median V14: 0.6% vs. 13.5%; median V5: 0 vs. 19.3%, p<0.001). CONCLUSIONS: This novel 10-fraction schedule is feasible and well tolerated; the prone position allows better saving of OARs, with a statistically significant value for the ipsilateral lung.

Mono-institutional Italian experience with a double-lumen balloon-brachytherapy device for early breast cancer: results at a 5-year minimum follow-up.

AIMS AND BACKGROUND: To report the 5-year minimum follow-up in low-risk breast cancer patients treated with a double-lumen balloon-brachytherapy device in one mono-institutional Italian experience. Local control data and cosmetic outcomes were collected and analyzed. METHODS: Between October 2004 and December 2007, we treated 30 early stage breast cancer patients who underwent conservative surgery followed by adjuvant accelerated partial breast irradiation with a double-lumen balloon-brachytherapy system. Eligibility criteria for the protocol were based on the indications of the American Brachytherapy Society and the American Society of Breast Surgeons. The device was placed inside the lumpectomy cavity during surgery by open technique in all the patients. Computed tomography images and standard X-ray were used for treatment planning. The total irradiation dose was 34 Gy in 10 fractions of 3.4 Gy (twice daily) over 5 days to the lumpectomy cavity. RESULTS: Median follow-up was 80.5 months (range, 60-98). No patient developed local recurrence or distant metastasis. At the end of treatment, there was evidence of a symptomatic seroma in 83% of the total patients, with a yearly decreasing trend. However, the incidence of mild and moderate fibrosis progressively increased. Seventy-seven percent of the patients were satisfied with their cosmetic results. CONCLUSIONS: Our findings reinforce the hypothesis that an accelerated double-lumen balloon-breast brachytherapy catheter in selected low-risk patients is safe, and a favorable cosmetic outcome can be achieved.

Two different hypofractionated breast radiotherapy schedules for 113 patients with ductal carcinoma in situ: preliminary results.

AIM: To assess local control and cosmetic outcomes for two different hypofractionated radiotherapy schedules after breast-conserving surgery for ductal carcinoma in situ (DCIS). PATIENTS AND METHODS: A total of 113 breast-conserving operated patients with DCIS were treated from August 2006 to August 2011: 41 women received 46 Gy in 20 fractions of 2.3 Gy four times a week, for five weeks; the other 72 patients received 39 Gy in 13 fractions of 3 Gy four times a week for 3.5 weeks. Both schedules involved a concomitant boost to the tumor bed, with dose adjustment according to the surgical margins. RESULTS: The median follow-up is 30.5 months. Overall, the treatments were well-tolerated. The most common acute effect was erythema: grade 1 in 56.1% and 31.9% in the longer and in the shorter hypofractionated treatment, grade 2 in 9.8% and 0% of cases respectively. Late toxicity of fibrosis occurred at grade 1 in 19.6% and 15.3% respectively and at grade 2 in 0% and 2.8%. CONCLUSION: These results suggest that patients with DCIS can be safely treated with a shorter radiotherapy regimen.

On-line optimization of intraoperative electron beam radiotherapy of the breast.

PURPOSE: To optimize the dose delivery to the breast lumpectomy target treated with intraoperative electron beam radiotherapy (IOERT). MATERIALS AND METHODS: Two tools have been developed in our MU calculation software NEMO X to improve the dose homogeneity and the in-vivo dosimetry effectiveness for IOERT treatments. Given the target (tumor bed) thickness measured by the surgeon, NEMO X can provide auto dose normalization to cover 95% of the target volume with 95% of the prescription dose (PD) and a "best guess" of the expected dosimeter dose (EDD) for a deep seated in-vivo dosimeter. The tools have been validated with the data of 91 patients treated with IOERT on a LIAC mobile accelerator. In-vivo dosimetry has been performed with microMOSFETs positioned on the shielding disk inserted between the tumor bed and the chest wall. RESULTS: On average the auto normalization showed to provide better results if compared to conventional normalization rules in terms of mean target dose (|MTD-PD|/PD ≤ 5% in 95% vs. 53% of pts) and V107 percentage (left angle bracket V107 right angle bracket =19% vs. 32%). In-vivo dosimetry MOSFET dose (MD) showed a better correlation with the EDD guessed by our tool than just by assuming that EDD=PD (|MD-EDD|/EDD ≤ 5% in 57 vs. 26% of pts). CONCLUSIONS: NEMO X provides two useful tools for the on-line optimization of the dose delivery in IOERT. This optimization can help to reduce unnecessary large over-dosage regions and allows introducing reliable action levels for in-vivo dosimetry.

Focus on the actual clinical target volume irradiated with intraoperative radiotherapy for breast cancer.

AIM: Intraoperative radiotherapy (IORT) has been investigated as an exclusive adjuvant treatment option for early-stage breast cancer (BC). We analysed our experience on the technical aspects of this innovative approach in terms of identification of breast volume actually to be treated during IORT. PATIENTS AND METHODS: A total of 315 patients at low risk of breast cancer recurrence underwent IORT as exclusive treatment after breast-conservative surgery. To evaluate the breast volume actually irradiated with IORT, we considered a sample of eight patients, chosen retrospectively as having enough clips to identify the tumour bed and IORT site in computed-tomography (CT). The clinical target volume (CTV) was assessed for each patient with two different methods: the first, cc-IORT, was considered during surgery according to the chosen collimator diameter and glandular thickness, while the second, cc-CT, was evaluated through computed-tomography performed after surgery. The cc-CT CTV was obtained by contouring the cc-IORT on the CT section on the basis of the clips placed by the surgeon on the resection margins. RESULTS: In our experience, the 5-cm (50%) and the 6-cm (36%) diameter collimators have been the ones, used the most. The diameter of the collimator used did not appear to adversely affect the satisfactory aesthetic result. The comparison between CTVs showed that glandular breast volume contoured with CT (cc-CT) appeared to be three fold larger than the target identified at surgery and included in the area of chosen collimator (cc-IORT). CONCLUSION: The actual volume of breast gland irradiated with the IORT procedure appears to be larger than expected. This may be due to the area being prepared for IORT by placing tissue compactly.