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Perineal seeding of tumor cells from prostate cancer (PCa) is very rare, and no standard treatment exists for this atypical presentation with no evidence of distant metastases. Local excision or external beam radiotherapy are used as local salvage treatments for such perineal masses, including those occurring after biopsy, surgery, or interstitial brachytherapy. We report on a patient who presented no evidence of disease and no late urinary or gastrointestinal toxicities at 58 months after receiving high-dose-rate brachytherapy (HDR-BT) for perineal recurrence of PCa after radical prostatectomy and salvage external beam radiotherapy. To the best of our knowledge, this is the first case treated with HDR-BT in this scenario.

Purpose To analyse the survival outcomes and toxicity profile of patients treated with pulsed-dose-rate (PDR) brachytherapy (BT) after intensity-modulated radiation therapy (IMRT) for uterine cervical cancer in a single institution. Material and methods Between March 2011 and December 2014, 50 patients with histologically proven stages IB1-IVB cervical cancer were treated with IMRT followed by PDR-BT boost. Radiation treatment consisted of IMRT to pelvic with or without paraaortic lymph nodes to a total dose of 45-50.4 Gy. Weekly concomitant chemotherapy was administered to 45 patients. PDR-BT boost was delivered with a median dose of 30 Gy to the high-risk clinical target volume (HR-CTV) after a median time of 14 days since IMRT. Acute and late toxicity were evaluated by Radiation Therapy Oncology Group (RTOG) - European Organization for Research and Treatment of Cancer (EORTC) scoring criteria and Subjective Objective Management Analytic-Late Effects of Normal Tissues (SOMA-LENT) criteria. Results Two patients had tumour persistence at 6 months after the end of BT. After a median follow-up of 33 months, 6 distant metastases with or without regional relapse were observed. The 1- and 5-year progression-free survival was 83% (95% CI: 69-91%) and 76% (95% CI: 61-86%), whereas the 3- and 5-year overall survival was 91% (95% CI: 78-97%) and 76% (95% CI: 56-88%), respectively. Urinary and rectal toxicity higher than grade 2 was observed in 6.3% and 17% of patients, respectively. Five patients (10.6%) had grade 4 gastrointestinal toxicity requiring colostomy. Conclusions Our study confirms that the combination of IMRT and PDR-BT can be considered an effective treatment for cervical cancer, ensuring high local control, despite the high percentage of locally advanced disease.

The aim is to present the technical feasibility and efficacy of multiple re-irradiation (re-EBRT) for local recurrence of prostate cancer (PCa) using retrospective analysis of an updated series of patients who received ablative re-EBRT with stereotactic image-guided technique for isolated local recurrence of PCa. Eight patients received three RT courses (2 re-RTs); of those 2 received 4 RT courses (3 re-RTs). Local relapse in the prostate was assessed by multiparametric magnetic resonance and/ or choline positron emission tomography. Before treatment planning, all patients had been evaluated for late toxicity from previous RT according to RTOG/EORTC. Biochemical control was assessed according to Phoenix definition. Mean age at the third RT course was 68 (standard deviation, SD: 7.2); all patients had a good performance status. At diagnosis, four cases were classified as high risk PCa, three as intermediate and one as low per NCCN 2017. Biochemical progression free interval after first and second RT-course were 74 (IQR: 59.3-133.6) months and 33 (IQR: 20.8-53.1) months, respectively. Biochemical and radiological response was registered in all patients. At present, seven out of eight patients are disease free. Overall toxicity profile was good; no severe acute or late genitourinary or gastrointestinal events were recorded. Multiple RT courses with high precision technology and image guidance can be proposed as a possible salvage therapy for locally recurrent, low-burden PCa recurrence in adequately selected patients. Deeper understanding of radiobiological effects of hypofractionation and larger series of patients are warranted to fully evaluate the applicability of multiple RT courses in the setting of locally recurrent PCa.

Purpose To evaluate clinical results of catheter-based interstitial high-dose-rate (HDR) brachytherapy (BT) as adjuvant treatment in previously irradiated recurrent breast cancer. Material and methods Between January 2011 and September 2015, 31 consecutive patients with histologically confirmed recurrent breast cancer after conservative surgery and conventional whole breast radiotherapy, were retreated with a second conservative surgical resection and reirradiated with adjuvant interstitial HDR-BT. None of the brachytherapy implant was performed during the quadrantectomy procedure. A dose of 34 Gy in 10 fractions, 2 fractions per day, with a minimal interval of 6 hours was delivered. Results At the time of the implant, the median age of patients was 59.7 years (range, 39.3-74.9 years). The median time from first treatment until BT for local recurrence was 11.9 years (range, 2.5-27.8 years). The median interval between salvage surgery and BT was 3.6 months (range, 1-8.2 months). No acute epidermitis or soft tissue side effects higher than grade 2 were recorded, with good cosmetic results in all patients. Most of the patients presented grade 1-2 late side effects. Only one patient developed grade 3 liponecrosis. After a median follow-up of 73.7 months (range, 28.8-102.4 months), the overall survival and cancer specific survival were 87.1% and 90.3%, respectively; 5-year local control and 5-year progression-free survival rate were 90.3% and 83.9%, respectively. Conclusions Our preliminary analysis showed that HDR-BT is a feasible treatment for partial breast reirradiation offering very low complications rate and fast procedure. Higher patients' cohort is warranted in order to define the role of this treatment modality in the breast conservative management of local recurrence.

As part of the AIRC IG-13218 (NCT01913717), we analyzed data from patients with low- and intermediate-risk prostate cancer treated with extreme hypofractionated radiotherapy (RT) and simultaneous boost to the intraprostatic lesion. The aim of the study is to identify clinically meaningful information through the analysis of validated questionnaires testing gastrointestinal (GI) and genitourinary (GU) RT-related toxicity and their impact on quality of life (QoL). At the end of RT treatment, clinical assessment and prostate-specific antigen (PSA) measurements were performed every 3 months for at least 2 years and GI and GU toxicities were evaluated contextually. QoL of enrolled patients was assessed by International Prostate Symptoms score (IPSS), European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire—Core 30 (EORTC QLQ-C30), EORTC QLQ prostate specific (QLQ-PR25), and sexual activity by International Index of Erectile Function (IIEF-5). Patients’ score changes were calculated at the end of RT, at one month after RT and at 12 and 24 months. Sixty-five prospectively enrolled patients were analyzed. Extensive analysis of different QoL assessments showed that patients’ tolerance was satisfactory across all the considered time points, with no statistically significant change of QoL from baseline compared to that before RT. Overall survival and biochemical progression-free survival at 2-years were of 98% and 97%, respectively. Despite the toxicity of extreme hypofractionation was low and tumor control was encouraging, a longer follow-up is necessary to confirm our findings. The increasing dose to the dominant intraprostatic lesion does not worsen the RT toxicity and consequently does not affect patients’ QoL, thus questioning the possibility of an even more escalated treatment.

Purpose To evaluate toxicity and clinical outcomes in patients with eyelid tumour treated with contact high-dose-rate brachytherapy (HDR-BT). Material and methods Between April 2010 and August 2017, 10 consecutive patients with tumour of the eyelid underwent contact HDR-BT and custom-made surface mould. Every applicator was manually built using conventional thermoplastic material and standard plastic catheters. The median dose prescribed was 42 Gy (range, 30-48) with a median dose per fraction of 3.5 Gy (range, 2-4.5). The dose was delivered in a median of 12 fractions (range, 10-17) over a median of 16 days. In all cases, an ocular shield was placed to reduce the dose to the eye. Acute and late toxicity was evaluated according to RTOG toxicity criteria. Results We analyzed data of 9 of 10 patients (one patient was excluded because he did not give consent for investigation). The median age was 68 years (range, 31-88). According to the TNM-UICC staging system, 4, 1 and 4 patients were stage IA, IB and IC, respectively. Basal cell and sebaceous gland carcinomas were reported in 5 and 2 patients, respectively; other histological types were non-Hodgkin lymphoma and plasmacytoma. After a median follow-up of 51 months (range, 16-90), there was no evidence of local or distant recurrence. The treatment was very well tolerated. Most commonly acute reactions consisted of low grade (G1-G2) conjunctivitis and skin erythema. Only one patient required a temporary interruption of the treatment due to acute G2 conjunctivitis and G3 lid erythema. Only one G2 late toxicity was reported (corneal ulceration), without resulting in functional impairment or blindness. Conclusions Our results suggest that contact HDR-BT with a customized applicator is safe, effective and offers very good local control and can be considered for the treatment of eyelid tumours.

OBJECTIVE: To report preliminary results of a cutting edge extreme hypofractionated treatment with concomitant boost to the dominant lesion for patients with early stage prostate cancer (PCa). METHODS: AIRC-IG-13218 is a prospective Phase II trial started in June 2015. Patients with low and intermediate risk PCa who met the inclusion criteria underwent extreme hypofractionated radiotherapy to the prostate (36.25 Gy in 5 fractions) and a simultaneous integrated boost to the dominant intraprostatic lesion (DIL) to 37.5 Gy. The DIL was identified by a multiparamentric MRI (mpMRI) co-registered with planning CT. Toxicity was assessed according to CTCAE v4.0 and RTOG/EORTC criteria. The preliminary evaluation of the first 13 patients was required to confirm the feasibility of the treatment before completing the enrollment of 65 patients. RESULTS: The first 13 patients completed the treatment between June 2015 and February 2016. With a median clinical follow-up of 17 months (range 11–26), no Grade 3 or 4 early toxicity was reported. CONCLUSIONS: Our preliminary data about early toxicity of an extreme hypofractionated schedule with concomitant boost on the DIL are encouraging. The higher number of patients expected for the trial and a longer follow-up are needed to confirm these results. ADVANCES IN KNOWLEDGE: The use of mpMRI to identify and boost the DIL is an innovative and interesting approach to PCa. Our preliminary findings suggest that dose escalation using DIL boost and extremely hypofractionated radiotherapy regimens might be a safe approach, allowing for short and effective treatment of organ-confined PCa.

Aim: We report on acute toxicity, which is the secondary endpoint of a phase II clinical trial specifically addressed to assess the chronic toxicity of a hypofractionated scheme including a simultaneous integrated boost, with intensity modulated radiotherapy. Materials and methods: From 2/2012 to 12/2013 194 patients with early breast cancer entered a phase II study on hypofractionated radiotherapy including a boost dose to the tumor bed. All patients were operated on conservatively. The whole breast and the tumor bed are planned to receive a dose of 45 Gy and 50 Gy, respectively, in 20 fractions, over 4 weeks. Treatment plans are generated using the TomoDirect modality,which is available on Tomotherapy Hi-Art System (Madison,WI). Acute toxicity was evaluated according to the RTOG acute toxicity scale, up to 6 months after the treatment. Afterwards, chronic toxicity is evaluated using LENT/SOMA scale. Results: 95% of the volume of the breast and boost PTVs received 99% and 100% of the planned dose, as median values, respectively and 0.1% (median value) of the entire breast volume received 100% of the boost dose. The median maximum dose to the breast and to the boost PTVs was 113% and 103.3 %, respectively. At the end of treatment, the acute toxicity, was distributed as follows. As far as erythema was concerned, at the end of treatment, 58% of the patients experienced grade 1 erythema, which dropped to 23% one month later. Grade 2 erythema affected 37% of the cases, and after one month, it decreased to 2%.Only 1 patient (0.5%) complained of Grade 3 erythema at the end of the treatment, which rapidly disappeared afterwards. With regard to breast oedema, at the end of treatment grade 1 was observed in 16% of the cases, for whom it tended to remain stable after one month, while grade 2 oedema was noted in 4% of the cases, decreasing to 1.5% on the first month- follow-up visit. Regarding desquamation, dry desquamation ( grade 1) was observed in less than 10% of cases at the end of treatment, but it tended to increase to 17% one month later. Patchy moist desquamation (grade 2) was present in 1.9% of the patients at the end of radiotherapy, and in 1% of them, one month afterwards. Confluent desquamation (grade 3) was noted only in 1 patient (0.5%), who was receiving concomitant chemotherapy with cyclophospamide, methotrexate and fluoruracil: it was still present 1 month after the radiotherapy completion, as the patient continued to be on chemotherapy. No significantly different side effects were observed between the whole breast and the boost area. No patients experienced any lung and cardiac symptoms. Conclusion: The clinical results of this SIB hypofractionated scheme showed low acute toxicity. In spite of the high dose per fraction, with the tumor bed receiving an even higher dose /per fraction, acute toxicity was within the limit acknowledged by literature for conventional fractionation. This non-rotational treatment option allows us to deliver treatment with a traditional tangent-like dose, without spreading low doses to the adjacent structures. Chronic toxicity will be assessed after 2 years. Therefore, a longer follow-up is needed to assess the effective tolerance to the SIB schedule. Citation Format: Maria Cristina Leonardi, Anna Morra, Federica Cattani, Luigi Santoro, Samantha Dicuonzo, Raffaella Cambria, Rosa Luraschi, Alessia Bazani, Roberta Lazzari, Veronica Dell'Acqua, Roberto Orecchia. Simultaneous integrated boost incorporated into a hypofractionated regimen using tomoDirect: Acute toxicity assessment [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-07.

The integration of CT and multiparametric MRI (mpMRI) is a challenging task in high-precision radiotherapy for prostate cancer. A simple methodology for multimodal deformable image registration (DIR) of prostate cancer patients is presented.CT and mpMRI of 10 patients were considered. Organs at risk and prostate were contoured on both scans. The dominant intraprostatic lesion was additionally delineated on MRI. After a preliminary rigid image registration, the voxel intensity of all the segmented structures in both scans except the prostate was increased by a specific amount (a constant additional value, A), in order to enhance the contrast of the main organs influencing its position and shape. 70 couples of scans were obtained by varying A from 0 to 800 and they were subsequently non-rigidly registered. Quantities derived from image analysis and contour statistics were considered for the tuning of the best performing A.A = 200 resulted the minimum enhancement value required to obtain statistically significant superior registration results. Mean centre of mass distance between corresponding structures decreases from 7.4 mm in rigid registration to 5.3 mm in DIR without enhancement (DIR-0) and to 2.7 mm in DIR with A = 200 (DIR-200). Mean contour distance was 2.5, 1.9 and 0.67 mm in rigid registration, DIR-0 and DIR-200, respectively. In DIR-200 mean contours overlap increases of +13 and +24% with respect to DIR-0 and rigid registration, respectively.Contour propagation according to the vector field resulting from DIR-200 allows the delineation of dominant intraprostatic lesion on CT scan and its use for high-precision radiotherapy treatment planning. Advances in knowledge: We investigated the application of a B-spline, mutual information-based multimodal DIR coupled with a simple, patient-unspecific but efficient contrast enhancement procedure in the pelvic body area, thus obtaining a robust and accurate methodology to transfer the functional information deriving from mpMRI onto a planning CT reference volume.

Objective To report the image-guided hypofractionated radiotherapy (hypo-IGRT) outcome for patients with localised prostate cancer according to the new outcome models Trifecta (cancer control, urinary continence, and sexual potency) and SCP (failure-free survival, continence and potency). Patients and Methods Between August 2006 and January 2011, 337 patients with cT1–T2N0M0 prostate cancer (median age 73 years) were eligible for a prospective longitudinal study on hypo-IGRT (70.2 Gy/26 fractions) in our Department. Patients completed four questionnaires before treatment, and during follow-up: the International Index of Erectile Function-5 (IIEF-5), the International Prostate Symptom Score (IPSS), and the European Organization for Research and Treatment of Cancer prostate-cancer-specific Quality of Life Questionnaires (QLQ) QLQ-PR25 and QLQ-C30. Baseline and follow-up patient data were analysed according to the Trifecta and SCP outcome models. Cancer control, continence and potency were defined respectively as no evidence of disease, score 1 or 2 for item 36 of the QLQ-PR25 questionnaire, and total score of >16 on the IIEF-5 questionnaire. Patients receiving androgen-deprivation therapy (ADT) at any time were excluded. Results Trifecta criteria at baseline were met in 72 patients (42% of all ADT-free patients with completed questionnaires). Both at 12 and 24 months after hypo-IGRT, 57% of the Trifecta patients at baseline were still meeting the Trifecta criteria (both oncological and functional success according to the SCP model). The main reason for failing the Trifecta criteria during follow-up was erectile dysfunction: in 18 patients after 6 months follow-up, in 12 patients after 12 months follow-up, and in eight patients after 24 months. Actuarial 2-year Trifecta failure-free survival rate was 44% (95% confidence interval 27–60%). In multivariate analysis no predictors of Trifecta failure were identified. Missing questionnaires was the main limitation of the study. Conclusion The Trifecta and SCP classifications can be used as tools to report RT outcome.

Unfortunately, the denomination of the IEO was incorrectly published in the affiliation of this original.

Electronic portal imaging (EPI) is commonly used to identify and correct for inter-fraction variability in tangential breast irradiation. Based on the institutional policy, EPI registration is performed by either radiation oncologist or therapist. Little data is available on the inter-observer agreement in EPI registration among different health practitioners. The aim of our study was to analyze inter-observer agreement among radiation oncologists and therapists in the evaluation of EPI for breast cancer radiotherapy verification. EPI data of 40 patients treated with tangential fields were independently reviewed by a radiation oncologist (on-line, just before treatment) and off-line by junior and senior therapists. Displacement of each EPI image with respect to the digital reconstructed radiographs (DRRs) was quantified using manual EPI registration based on bony marks with the corresponding DRRs. Agreement between observers was evaluated using weighted Cohen's Kappa statistics. In 95% out of 720 EPI-DRR comparisons, the EPI-DRR misalignment was < 5 mm. The difference between observers was < 2 mm in 666 (92.5%) out of all 720 delta values. High inter-observer agreement was found, with weighted Cohen's Kappa values attesting evaluation overlaps ranging from moderate (among therapists) to almost perfect (among radiation oncologist and therapists). The high agreement among the observers demonstrated the precision of breast localization using EPI. These findings suggest that routine EPI-based patient set-up verification in breast cancer radiotherapy can be safely entrusted to trained therapists (supervision should be assured based on the local tasks definition). Our study might be useful in quality assurance and in the optimization of workload in the radiotherapy departments. They might allow for wider implementation of complex and evolving radiotherapy technologies.

To compare the toxicity of image-guided intensity-modulated radiotherapy (IG-IMRT) to the pelvis or prostate bed (PB) only. To test the hypothesis that the potentially injurious effect of pelvic irradiation can be counterbalanced by reduced irradiated normal tissue volume using IG-IMRT.Between February 2010 and February 2012, 208 patients with prostate cancer were treated with adjuvant or salvage IG-IMRT to the PB (102 patients, Group PB) or the pelvis and prostate bed (P) (106 patients, Group P). The Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria were used to evaluate toxicity.Median follow-up was 27 months. Toxicity G ≥ 2 in Group PB: in the bowel acute and late toxicities were 11.8% and 10%, respectively; urinary acute and late toxicities were 10.8% and 15%, respectively. Toxicity G ≥ 2 in Group P: in the bowel acute and late toxicities were both 13.2%; urinary acute and late toxicities were 13.2% and 15.1%, respectively. No statistical difference in acute or late toxicity between the groups was found (bowel: p = 0.23 and p = 0.89 for acute and late toxicity, respectively; urinary: p = 0.39 and p = 0.66 for acute and late toxicity, respectively). Of the clinical variables, only previous abdominal surgery was correlated with acute bowel toxicity. Dosimetric parameters that correlated with bowel toxicity were identified.The toxicity rates were low and similar in both groups, suggesting that IG-IMRT allows for a safe post-operative irradiation of larger volumes. Further investigation is warranted to exclude bias owing to non-randomized character of the study.Our report shows that modern radiotherapy technology and careful planning allow maintaining the toxicity of pelvic lymph node treatment at the acceptable level, as it is in the case of PB radiotherapy.

The aim of this study was to perform a detailed analysis of the air kerma values around a Liac mobile linear accelerator working in a conventional operating room (OR) for IORT. The Liac delivers electron beams at 4, 6, 8 and 10 MeV. A radiation survey to determine photon leakage and scatter consisted of air kerma measurements on a spherical surface of 1.5 m radius, centered on the titanium exit window of the accelerating structure. Measurements were taken using a 30 cm3 calibrated cylindrical ion chamber in three orthogonal planes, at the maximum electron energy. For each point, 10 Gy was delivered. At selected points, the quality of x‐ray radiation was determined by using lead sheets, and measurements were performed for all energies to investigate the energy dependence of stray radiation. The photon scatter contribution from the metallic internal patient‐shielding in IORT, used to protect normal tissues underlying the target, was also evaluated. At seven locations outside the OR, the air kerma values derived from in‐room measurements were compared to measurements directly performed using a survey meter. The results, for a delivered dose of 10 Gy, showed that the air kerma values ranged from approximately 6 μGy (upper and rear sides of the Liac) to 320 μGy (lateral to beam stopper) in the two orthogonal vertical planes, while values lower than 18 μGy were found in the horizontal plane. At 10 MeV, transmission behind 1 cm lead shield was found to be 42%. The use of internal shielding appeared to increase the photon scatter only slightly. Air kerma values outside the OR were generally lower than 1 mGy for an annual workload of 200 patients. Thus, the Liac can safely work in a conventional OR, while the need for additional shielding mainly depends on patient workload. Our data can be useful for centers planning to implement an IORT program using a mobile linear accelerator, permitting radiation safety personnel to estimate in advance the shielding required for a particular workload. PACS number: 87.55.ne, 87.56.bd

To retrospectively evaluate external beam reirradiation (re-EBRT) delivered to the prostate/prostatic bed for local recurrence, after radical or adjuvant/salvage radiotherapy (RT).32 patients received re-EBRT between February 2008 and October 2013. All patients had clinical/radiological local relapse in the prostate or prostatic bed and no distant metastasis. re-EBRT was delivered with selective RT technologies [stereotactic RT including CyberKnife(TM) (Accuray, Sunnyvale, CA); image-guidance and intensity-modulated RT etc.]. Toxicity was evaluated using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria. Biochemical control was assessed according to the Phoenix definition (NADIR + 2 ng ml(-1)).Acute urinary toxicity: G0, 24 patients; G1, 6 patients; G2, 2 patients. Acute rectal toxicity: G0, 28 patients; G1, 2 patients; and G2, 1 patient. Late urinary toxicity (evaluated in 30 cases): G0, 23 patients; G1, 6 patients; G2, 1 patient. Late renal toxicity: G0, 25 patients; G1, 5 patients. A mean follow-up of 21.3 months after re-EBRT showed that 13 patients were free of cancer, 3 were alive with biochemical relapse and 12 patients were alive with clinically evident disease. Four patients had died: two of disease progression and two of other causes.re-EBRT using modern technology is a feasible approach for local prostate cancer recurrence offering 2-year tumour control in about half of the patients. Toxicity of re-EBRT is low. Future studies are needed to identify the patients who would benefit most from this treatment.Our series, based on experience in one hospital alone, shows that re-EBRT for local relapse of prostate cancer is feasible and offers a 2-year cure in about half of the patients.

The purpose of this work was to evaluate the intrapatient tumor position reproducibility in a deep inspiration breath‐hold (DIBH) technique based on two infrared optical tracking systems, ExacTrac and ELITETM, in stereotactic treatment of lung and liver lesions. After a feasibility study, the technique was applied to 15 patients. Each patient, provided with a real‐time visual feedback of external optical marker displacements, underwent a full DIBH, a free‐breathing (FB), and three consecutive DIBH CT‐scans centered on the lesion to evaluate the tumor position reproducibility. The mean reproducibility of tumor position during repeated DIBH was 0.5±0.3mm in laterolateral (LL), 1.0±0.9mm in anteroposterior (AP), and 1.4±0.9mm in craniocaudal (CC) direction for lung lesions, and 1.0±0.6mm in LL, 1.1±0.5mm in AP, and 1.2±0.4mm in CC direction for liver lesions. Intra‐and interbreath‐hold reproducibility during treatment, as determined by optical markers displacements, was below 1 mm and 3 mm, respectively, in all directions for all patients. Optically‐guided DIBH technique provides a simple noninvasive method to minimize breathing motion for collaborative patients. For each patient, it is important to ensure that the tumor position is reproducible with respect to the external markers configuration. PACS numbers: 87.53.Ly, 87.55.km

Objectives To compare acute toxicity of prostate cancer image-guided hypofractionated radiotherapy (hypo-IGRT) with conventional fractionation without image-guidance (non-IGRT). To test the hypothesis that the potentially injurious effect of hypofractionation can be counterbalanced by the reduced irradiated normal tissue volume using IGRT approach. Materials and methods One hundred seventy-nine cT1-T2N0M0 prostate cancer patients were treated within the prospective study with 70.2 Gy/26 fractions (equivalent to 84 Gy/42 fractions, α/β 1.5 Gy) using IGRT (transabdominal ultrasound, ExacTrac X-Ray system, or cone-beam computer tomography). Their prospectively collected data were compared with data of 174 patients treated to 80 Gy/40 fractions with non-IGRT. The difference between hypo-IGRT and non-IGRT cohorts included fractionation (hypofractionation vs. conventional fractionation), margins (hypo-IGRT margins: 7 mm and 3 mm, for all but posterior margins; respectively; non-IGRT margins: 10 and 5 mm, for all but posterior margins, respectively), and use of image-guidance or not. Multivariate analysis was performed to define the tumor-, patient-, and treatment-related predictors for acute toxicity. Results All patients completed the prescribed radiotherapy course. Acute toxicity in the hypo-IGRT cohort included rectal (G1: 29.1%; G2: 11.2%; G3: 1.1%) and urinary events (G1: 33.5%; G2: 39.1%; G3: 5%). Acute toxicity in the non-IGRT patients included rectal (G1: 16.1%; G2: 6.3%) and urinary events (G1: 36.2%; G2: 20.7%; G3: 0.6%). In 1 hypo-IGRT and 2 non-IGRT patients, radiotherapy was temporarily interrupted due to acute toxicity. The incidence of mild (G1-2) rectal and bladder complications was significantly higher for hypo-IGRT ( P = 0.0014 and P P = 0.001) and higher PSA ( P = 0.046) are correlated with higher acute urinary toxicity. No independent factor was identified for acute rectal toxicity. No significant impact of IGRT system on acute toxicity was observed. Conclusions The acute toxicity rates were low and similar in both study groups with some increase in mild acute urinary injury in the hypo-IGRT patients (most probably due to the under-reporting in the retrospectively analyzed non-IGRT cohort). The higher incidence of acute bowel reactions observed in hypo-IGRT group was not significant in the multivariate analysis. Further investigation is warranted in order to exclude the bias due to the nonrandomized character of the study.

We report on a two-phase test performed to assess the ability of the ultrasound-based B-mode acquisition and targeting (BAT) trans-abdominal system to identify non-dedicated fiducial markers implanted into the prostate gland for subsequent image-guided radiotherapy. Although further investigation is warranted in order to identify the optimal echogenic marker and to define its potential use for image-guided radiotherapy in prostate cancer patients, we demonstrate the feasibility of the BAT system for the visualization of non-ultrasound-dedicated markers.

To present the technique and dose distribution of intraoperative radiotherapy (IORT) for prostate cancer.Pelvic lymphadenectomy, prostate IORT and radical retropubic prostatectomy was performed in 11 prostate cancer patients. Prostate thickness and rectum depth were measured with intraoperative ultrasound. IORT was delivered by a mobile linear accelerator in the operating room (electron beam, 12 Gy at 90% isodose).The mean preoperative probability of organ-confined disease was 10% (Memorial Sloan Kettering Cancer Center nomograms). Mean prostate thickness, width and length were 3.4 cm, 4.6 and 4.9 cm, respectively. Mean rectum depth was 3.3 cm. Mean doses to the posterior prostate capsule, 5-mm lateral prostate margins and at the subsequent uretheral stump area were 4.6 Gy, 8. 7 Gy and 11.3 Gy, respectively. Maximum mean rectal dose was 4.9 Gy.IORT appeared a feasible approach for prostate cancer, showing a satisfactory dose coverage to the prostate bed with relatively low rectal dose. However, high variability in dose distribution calls for further study of patient selection criteria and dosimetry.

To compare dose distribution for two techniques of 3-dimensional conformal radiotherapy (RT): 6-field technique (6F) and 2-dynamic arc therapy (2DA).Thirty nonmetastatic prostate cancer patients were included. In each patient, two treatment plans were prepared: with six coplanar fields (45 degrees , 90 degrees , 135 degrees , 225 degrees , 270 degrees , 315 degrees ) and with two dynamic lateral 100 degrees -wide arcs (40-140 degrees , 220-320 degrees ). Dose-volume histograms (DVHs) were computed and mean area under curve (AUC) values were calculated for the DVHs of Planning Target Volume (PTV), rectum, urinary bladder and femoral heads. Doses given to 30% of rectum (DR(30)), to 60% of rectum (DR(60)), to 50% of bladder (DB(50)), to 50% of femoral head (DF(50)) and to 95% of PTV (DPTV(95)) were reported as a percentage of the total dose.Mean DR(30) and DR(60) for 6F and 2DA were 75.8%, 51.5% and 72.2%, 37.2%, respectively. Mean DB(50) for 6F and 2DA were 68% and 64.2%, respectively. Mean right DF(50) for 6F and 2DA were 35.4% and 45.5%, respectively. Mean DPTV(95) for 6F and 2DA were 99% and 99.2%, respectively. Mean AUCs of DVHs of rectum and urinary bladder were significantly higher for 6F (this was more evident for small PTV and in the intermediate dose range). Mean AUC of DVHs of PTV and femoral heads were significantly higher for 2DA.Both 6F and 2DA offer good dose distribution for PTV. 2DA allows for significantly better sparing of rectum and urinary bladder with slightly worse femoral head dose distribution. Further study is warranted in order to establish the clinical relevance of these differences.

521 INTRAOPERATIVE RADIOTHERAPY FOR LOCALLY ADVANCED PROSTATE CANCER: THE EXPERIENCE OF THE EUROPEAN INSTITUTE OF ONCOLOGY Andrea Vavassori*, Mario Ciocca, Barbara Jereczek, Dario Zerini, Giovanni Ivaldi, Cristiana Fodor, Roberta Lazzari, Federica Cattani, Elena Rondi, Cristina Garibaldi, Raffaella Cambria, Victor Matei, Epifanio Scardino, Fabrizio Verweij, Gennaro Musi, Bernardo Rocco, Ottavio De Cobelli, Roberto Orecchia. Milan, Italy. INTRODUCTION AND OBJECTIVE: To present the technique adopted for intraoperative radiotherapy (IORT) for locally advanced prostate cancer. METHODS: Between June 2005 and February 2007, 24 patients (pts) with non-metastatic prostate cancer were treated with IORT before prostatectomy as part of their surgical procedure. Median