Extreme-hypofractionated RT with concomitant boost to the DIL in PCa: a 5-year update on oncological and patient-reported outcomes for the phase II trial "GIVE ME FIVE".

AIM: The present work reports updated oncological results and patients-reported outcomes at 5 years of phase II trial "Short-term high precision RT for early prostate cancer with SIB to the dominant intraprostatic lesion (DIL) for patients with early-stage PCa". METHODS: Data from patients enrolled within AIRC IG-13218 (NCT01913717) trial were analyzed. Clinical and GU/GI toxicity assessment and PSA measurements were performed every 3 months for at least 2 years after RT end. QoL of enrolled patients was assessed by IPSS, EORTC QLQ-C30, EORTC QLQ-PR25, and IIEF-5. Patients' score changes were calculated at the end of RT and at 1, 12, and 60 months after RT. RESULTS: A total of 65 patients were included. At a median follow-up of 5 years, OS resulted 86%. Biochemical and clinical progression-free survival at 5 years were 95%. The median PSA at baseline was 6.07 ng/ml, while at last follow-up resulted 0.25 ng/ml. IPSS showed a statistically significant variation in urinary function from baseline (p = 0.002), with the most relevant deterioration 1 month after RT, with a recovery toward baseline at 12 months (p ≤ 0.0001). A numerical improvement in QoL according to the EORTC QLQ-C30 has been reported although not statistically significant. No change in sexual activity was recorded after RT. CONCLUSIONS: The study confirms that extreme hypofractionation with a DIL boost is safe and effective, with no severe effects on the QoL. The increasing dose to the DIL does not worsen the RT toxicity, thus opening the possibility of an even more escalated treatment.

Post-operative KEloids iRradiation (POKER): does the surgery/high-dose interventional radiotherapy association make a winning hand?

PURPOSE: To report the results involving post-operative interventional radiotherapy (POIRT) in a homogenous cohort of patients affected by keloid and treated at a single institution with the same fractionation schedule. PATIENTS AND METHODS: Inclusion criteria were: surgery with a histopathological diagnosis of keloid, subsequent high-dose rate interventional radiotherapy (HDR-IRT)-12 Gy in 4 fractions (3 Gy/fr) twice a day-and follow-up period ≥ 24 months. RESULTS: One-hundred and two patients and a total of 135 keloids were eligible for the analyses. Median follow-up was 64 [IQR: 25-103] months. Thirty-six (26.7%) recurrences were observed, 12-months and 36-months cumulative incidence of recurrence were 20.7% (95% CI 12.2-28.5) and 23.8% (95% CI 14.9-31.7) respectively. History of spontaneous keloids (HR = 7.00, 95% CI 2.79-17.6, p < 0.001), spontaneous cheloid as keloid cause (HR = 6.97, 95% CI 2.05-23.7, p = 0.002) and sternal (HR = 10.6, 95% CI 3.08-36.8, p < 0.001), ear (HR = 6.03, 95% CI 1.71-21.3, p = 0.005) or limb (HR = 18.8, 95% CI 5.14-68.7, p < 0.001) keloid sites were significantly associated to a higher risk of recurrence. CONCLUSIONS: The findings support the use of surgery and POIRT as an effective strategy for controlling keloid relapses. Further studies should focus on determining the optimal Biologically Effective Dose and on establishing a scoring system for patient selection.

Correction to: Late toxicity of image-guided hypofractionated radiotherapy for prostate: non-randomized comparison with conventional fractionation.

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

Late toxicity of image-guided hypofractionated radiotherapy for prostate: non-randomized comparison with conventional fractionation.

PURPOSE: To evaluate the incidence and predictors for late toxicity and tumor outcome after hypofractionated radiotherapy using three different image-guided radiotherapy (IGRT) systems (hypo-IGRT) compared with conventional fractionation without image guidance (non-IGRT). METHODS AND MATERIALS: We compared the late rectal and urinary toxicity and outcome in 179 prostate cancer patients treated with hypo-IGRT (70.2 Gy/26 fractions) and 174 non-IGRT patients (80 Gy/40 fractions). Multivariate analysis was performed to define predictors for late toxicity. 5- and 8-year recurrence-free survival (RFS) and overall survival (OS) were analyzed. RESULTS: Mean follow-up was 81 months for hypo-IGRT and 90 months for non-IGRT group. Mainly mild late toxicity was observed: Hypo-IGRT group experienced 65 rectal (30.9% G1/G2; 6.3% G3/G4) and 105 urinary events (56% G1/G2; 4% G3/G4). 5- and 8-year RFS rates were 87.5% and 86.8% (hypo-IGRT) versus 80.4% and 66.8% (non-IGRT). 5- and 8-year OS rates were 91.3% and 82.7% in hypo-IGRT and 92.2% and 84% in non-IGRT group. Multivariate analysis showed that hypo-IGRT is a predictor for late genitourinary toxicity, whereas hypo-IGRT, acute urinary toxicity and androgen deprivation therapy are predictors for late rectal toxicity. Advanced T stage and higher Gleason score (GS) were correlated with worse RFS. CONCLUSIONS: A small increase in mild late toxicity, but not statistically significant increase in severe late toxicity in the hypo-IGRT group when compared with conventional non-IGRT group was observed. Our study confirmed that IGRT allows for safe moderate hypofractionation, offering a shorter overall treatment time, a good impact in terms of RFS and providing potentially more economic health care.

Reporting combined outcomes with Trifecta and survival, continence, and potency (SCP) classification in 337 patients with prostate cancer treated with image-guided hypofractionated radiotherapy.

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.

Image guided hypofractionated radiotherapy and quality of life for localized prostate cancer: prospective longitudinal study in 337 patients.

PURPOSE: We prospectively analyzed quality of life in a cohort of patients with prostate cancer undergoing a course of hypofractionated image guided radiotherapy. MATERIALS AND METHODS: Between August 2006 and January 2011, 337 patients with a median age of 73 years who had cT1-T2N0M0 prostate cancer were eligible for this prospective, longitudinal study of hypofractionated image guided radiotherapy (70.2 Gy/26 fractions) using 1 of 3 image guided radiotherapy modalities (transabdominal ultrasound, x-ray or cone beam computerized tomography) available in our radiation oncology department. Patients completed 4 questionnaires before treatment, and 6, 12 and 24 months later, including the International Index of Erectile Function-5, International Prostate Symptom Score, and EORTC (European Organization for Research and Treatment of Cancer) prostate cancer specific QLQ-PR25 and QLQ-C30. RESULTS: Patient followup was updated to at least the last questionnaire time point. Median followup was 19 months. Significant deterioration in erectile function on the International Index of Erectile Function-5 was documented with time only in patients without androgen deprivation (p = 0.0002). No change with time was observed in urinary symptom related quality of life on the QLQ-PR25 or International Prostate Symptom Score. Slight deterioration in QLQ-PR25 bowel symptom related quality of life was observed (p = 0.02). Overall QLQ-C30 Global Health Status improved with time (p = 0.03). On univariate analysis it significantly correlated with the maximum RTOG (Radiation Therapy Oncology Group)/EORTC urinary and bowel late toxicity scores after radiotherapy. CONCLUSIONS: The regimen of hypofractionated image guided radiotherapy with multiple imaging modalities adopted in our radiation oncology department for localized prostate cancer might be a successful strategy for dose escalation with a limited impact on different aspects of quality of life with time.

Deep inspiration breath-hold technique guided by an opto- electronic system for extracranial stereotactic treatments.

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 ± 0.3 mm in laterolateral (LL), 1.0 ± 0.9 mm in anteroposterior (AP), and 1.4 ± 0.9 mm in craniocaudal (CC) direction for lung lesions, and 1.0 ± 0.6 mm in LL, 1.1 ± 0.5 mm in AP, and 1.2 ± 0.4 mm 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.

Ultrahypofractionated radiotherapy for localized prostate cancer with simultaneous boost to the dominant intraprostatic lesion: a plan comparison.

OBJECTIVE: To compare different stereotactic body techniques-intensity-modulated radiotherapy with photons and protons, applied to radiotherapy of prostatic cancer-with simultaneous integrated boost (SIB) on the dominant intraprostatic lesion (DIL). METHODS: Ten patients were selected for this planning study. Dosimetric results were compared between volumetric modulated arc therapy, intensity-modulated radiation therapy (IMRT), and intensity-modulated proton therapy both with two (IMPT 2F) and five fields (IMPT 5F) planning while applying the prescription schemes of 7.25 Gy/fraction to the prostate gland and 7.5 Gy/fraction to the DIL in 5 fractions. RESULTS: Comparison of the coverages of the planning target volumes showed that small differences exist. The IMPT-2F-5F techniques allowed higher doses in the targets; conformal indexes resulted similar; homogeneity was better in the photon techniques (2%-5%). Regarding the organs at risk, all the techniques were able to maintain the dose well below the prescribed constraints: in the rectum, the IMPT-2F-5F and IMRT were more efficient in lowering the intermediate doses; in the bladder, the median dose was significantly better in the case of IMPT (2F-5F). In the urethra, the best sparing was achieved only by IMPT-5F. CONCLUSIONS: Stereotactic radiotherapy with SIB for localized prostate cancer is feasible with all the investigated techniques. Concerning IMPT, the two-beam technique does not seem to have a greater advantage compared to the standard techniques; the 5-beam technique seems more promising also accounting for the range uncertainty.

Physical and clinical implications of radiotherapy treatment of prostate cancer using a full bladder protocol.

PURPOSE: To assess the dosimetric and clinical implication when applying the full bladder protocol for the treatment of the localized prostate cancer (PCA). PATIENTS AND METHODS: A total of 26 consecutive patients were selected for the present study. Patients underwent two series of CT scans: the day of the simulation and after 40 Gy. Each series consisted of two consecutive scans: (1) full bladder (FB) and (2) empty bladder (EB). The contouring of clinical target volumes (CTVs) and organs at risk (OAR) were compared to evaluate organ motion. Treatment plans were compared by dose distribution and dose-volume histograms (DVH). RESULTS: CTV shifts were negligible in the laterolateral and superior-inferior directions (the maximum shift was 1.85 mm). Larger shifts were recorded in the anterior-posterior direction (95% CI, 0.83-4.41 mm). From the dosimetric point of view, shifts are negligible: the minimum dose to the CTV was 98.5% (median; 95%CI, 95-99%). The potential advantage for GU toxicity in applying the FB treatment protocol was measured: the ratio between full and empty bladder dose-volume points (selected from our protocol) is below 0.61, excluding the higher dose region where DVHs converge. CONCLUSION: Having a FB during radiotherapy does not affect treatment effectiveness, on the contrary it helps achieve a more favorable DVH and lower GU toxicities.

Use of machine learning methods for prediction of acute toxicity in organs at risk following prostate radiotherapy.

PURPOSE: The goal of this study is to investigate the advantages of large scale optimization methods vs conventional classification techniques in predicting acute toxicity for urinary bladder and rectum due to prostate irradiation. METHODS: Clinical and dosimetric data of 321 patients undergoing prostate conformal radiotherapy were recorded. Gastro-intestinal and genito-urinary acute toxicities were scored according to the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) scale. Patients were classified in two categories to separate mild (Grade < 2) from severe toxicity levels (Grade > 2). Machine learning methods at different complexity were implemented to predict toxicity as a function of multiple variables. The first approach consisted of a large scale optimization method, based on genetic algorithms (GAs) and artificial neural networks (ANN). The second approach was a binary classifier based on support vector machines (SVM). RESULTS: The ANN and SVM-based solutions showed comparable prediction accuracy, exhibiting an area under the receiver operating characteristic (ROC) curve of 0.7. Different sensitivity and specificity features were measured for the two approaches. The ANN algorithm showed enhanced sensitivity if combined with appropriate classification criteria. CONCLUSIONS: The results demonstrate that high sensitivity in toxicity prediction can be achieved with optimized ANNs, that are put forward to represent a valuable support in medical decisions. Future studies will be focused on enlarging the available patient database to increase the reliability of toxicity prediction algorithms and to define optimal classification criteria.

Adjuvant high-dose-rate interstitial brachytherapy for malignant peripheral nerve sheath tumor of the foot: a case report.

Soft tissue sarcomas of the foot are extremely rare and can therefore be misdiagnosed as benign diseases, and be prematurely removed with an unplanned excision. The standard treatment is a wide local excision with an addition of radiotherapy as an alternative to a radical resection (e.g., below-knee or foot amputation). We report on a patient with primary malignant peripheral nerve sheath tumor in the foot plantar soft tissue, who had no evidence of the disease and no severe late toxicity higher than grade 2, 40 months after receiving amputation of toes and adjuvant interstitial high-dose-rate brachytherapy (HDR-BT). To the best of our knowledge, only a few cases were treated with HDR-BT with this scenario. From our findings, HDR-BT could be a safe and quick treatment option for these types of lesions.

Multidisciplinary team approach for Merkel cell carcinoma: the European Institute of Oncology experience with focus on radiotherapy.

OBJECTIVE: To review the therapeutic strategy in Merkel cell carcinoma (MCC) treated with radiotherapy (RT) discussed in a multidisciplinary tumour board. METHODS: Clinical records of patients with a diagnosis of MCC and with an indication to undergo RT at the European Institute of Oncology between 2003 and 2018 were reviewed retrospectively. RESULTS: Twenty-six patients were included in the analysis (median age 65 years, range 42-87). Nineteen received adjuvant RT, 4 exclusive RT, and the remainder palliative RT. Intensity-modulated RT was used in 13 cases, a 3D conformal technique in 11 cases, and stereotactic RT in 2 cases. No major toxicities were recorded. The median relapse-free survival (RFS) after adjuvant RT was 20.5 months, while for unknown primary MCC, it was 23 months. In the adjuvant setting, median polyomavirus-positive RFS was 21.5 months (range 1-49) and median polyomavirus-negative RFS was only 14 months (range 4-45). Overall, RFS of polyomavirus-positive and polyomavirus-negative patients was 10.5 and 8 months, respectively. After adjuvant RT, only 1 out of 10 patients had a recurrence in the RT field. At the time of data collection, 16 patients were alive with no evidence of disease, 1 patient was alive with advanced status of disease, 8 patients died of disease progression, and 1 patient died of other causes. CONCLUSIONS: The management of unknown primary and polyomavirus-positive cases, which had a better prognosis in our series, may benefit from a multidisciplinary approach, given the limited data available regarding optimal treatment.

Finding safe dose-volume constraints for re-irradiation with SBRT of patients with prostate cancer relapse: The IEO experience.

AIM: The primary aim of this study is to provide preliminary indications for safe constraints of rectum and bladder in patients re-irradiated with stereotactic body RT (SBRT). METHODS: Data from patients treated for prostate cancer (PCa) and intraprostatic relapse, from 1998 to 2016, were retrospectively collected. First RT course was delivered with 3D conformal RT techniques, SBRT or volumetric modulated arc therapy (VMAT). All patients underwent re-irradiation with SBRT with heavy hypofractionated schedules. Cumulative dose-volume values to organs at risk (OARs) were computed and possible correlation with developed toxicities was investigated. RESULTS: Twenty-six patients were included. Median age at re-irradiation was 75 years, mean interval between the two RT courses was 5.6 years and the median follow-up was 47.7 months (13.4-114.3 months). After re-irradiation, acute and late G ≥ 2 GU toxicity events were reported in 3 (12%) and 10 (38%) patients, respectively, while late G ≥ 2 GI events were reported in 4 (15%) patients. No acute G ≥ 2 GI side effects were registered. Patients receiving an equivalent uniform dose of the two RT treatments < 131 Gy appeared to be at higher risk of progression (4-yr b-PFS: 19% vs 33%, p = 0.145). Cumulative re-irradiation constraints that appear to be safe are D30% < 57.9 Gy for bladder and D30% < 66.0 Gy, D60% < 38.0 Gy and V122.1 Gy < 5% for rectum. CONCLUSION: Preliminary re-irradiation constraints for bladder and rectum have been reported. Our preliminary investigation may serve to clear some grey areas of PCa re-irradiation.

3D-conformal hypofractionated radiotherapy for prostate cancer with daily transabdominal ultrasonography prostate localization: toxicity and outcome of a pilot study.

AIMS AND BACKGROUND: To evaluate the feasibility, toxicity and patient outcome of hypofractionated 3-dimensional conformal radiotherapy for low- and intermediate-risk prostate cancer, using daily an ultrasound targeting system (BAT). METHODS: Between May 2005 and October 2006, 25 patients (cT1-T2, GS < or = 7, mean initial PSA = 7.06 ng/ml) received a dose of 72 Gy in 30 fractions. Only the prostate was included in the clinical target volume. Immediately before each radiotherapy session, BATTM ultrasound alignment was performed. Acute and late toxicity was evaluated according to the Radiation Therapy Oncology Group criteria; the Phoenix definition (PSA = nadir + 2 ng/ml) was applied to define biochemical failure. BAT localization data were provided for 300 out of 750 procedures. RESULTS: No interruptions in 3-dimensional conformal radiotherapy due to toxicity were registered. There was no acute rectal toxicity in 52% of patients; 28% had G1, 16% had G2, and 1 patient had a G3 event. No acute urinary toxicity was observed in 28% of the patients. G1 toxicity occurred in 40%, G2 in 28%, and G3 in 1 patient; no G4 event was observed. With an average follow-up of 45 months, one biochemical relapse was observed; late toxicity showed an excellent profile: 78% of the patients had no rectal toxicity, 16% had G1, and 1 patient had G2 toxicity. Most of the patients (68%) had no late urinary complications, whereas 32% had G1 toxicity. Localization data showed systematic and random errors in relation to some procedure biases. CONCLUSIONS: Promising tumor control and toxicity profile were observed with this mildly hypofractionated BAT-based 3-dimensional conformal radiotherapy.

Salvage high-dose-rate interstitial brachytherapy for perineal recurrence of prostate cancer after surgery and radiotherapy: a case report.

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.

High-dose-rate Brachytherapy as Adjuvant Local rEirradiation for Salvage Treatment of Recurrent breAst cancer (BALESTRA): a retrospective mono-institutional study.

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.

Phase II prospective trial "Give Me Five" short-term high precision radiotherapy for early prostate cancer with simultaneous boost to the dominant intraprostatic lesion: the impact of toxicity on quality of life (AIRC IG-13218).

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.

Evaluation of late rectal toxicity after conformal radiotherapy for prostate cancer: a comparison between dose-volume constraints and NTCP use.

PURPOSE: To analyze the reliability of different methods used in evaluating the risk of late rectal toxicity. PATIENTS AND METHODS: The treatment plans of 57 patients treated at the authors' institute between September 1999 and September 2000 for localized prostate cancer using three-dimensional conformal radiotherapy (3D-CRT) were analyzed retrospectively. The expected rate of late rectal toxicity was analyzed (a) by means of the dose-volume histogram (DVH) constraints; (b) by calculating the normal-tissue complication probability (NTCP) using the Lyman-Kutcher-Burman (LKB) model with the radiobiological parameters of either Emami (1991; for toxicity of grade >or= 2) or Rancati (2004; for toxicity of grade >or= 2 and >or= 3). Patients were divided into high-/low-risk (HR/LR) groups and the results were compared to the clinical outcome. RESULTS: (a) The HR percentages were 24% and 5% for radical and postsurgical 3D-CRT, respectively. When applying high-dose constraints only, HR percentages were 18% and 5%, respectively. (b) In the case of the NTCP (grade >or= 2), Emami (1991) HR rates were 16% and 11%, and Rancati (2004) HR rates 29% and 11%, for radical and postsurgical treatment, respectively. Only one case with higher-grade toxicity was found. The reported clinical toxicity was 17.8% and 6.7% for grade >or= 2 toxicity, and 3.7% and 0.7% for grade >or= 3 toxicity, for radical and postsurgical treatment, respectively. CONCLUSION: This study demonstrated that there is an agreement between the toxicity rate evaluated by DVH constraints and by the LKB model and the clinical outcome. In this case, the use of the LKB model can be as reliable as the use of DVH constraints.

Radiation survey around a Liac mobile electron linear accelerator for intraoperative radiation therapy.

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 microGy (upper and rear sides of the Liac) to 320 microGy (lateral to beam stopper) in the two orthogonal vertical planes, while values lower than 18 microGy 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.

Mould-based surface high-dose-rate brachytherapy for eyelid carcinoma.

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.