Hypofractionated Dose Escalated 3D Conformal Radiotherapy for Prostate Cancer: Outcomes from a Mono-Institutional Phase II Study.

BACKGROUND/AIM: Based on a radiobiological assumption of a low alpha/beta (α/ß) ratio for prostate cancer, hypofractionated radiotherapy has increasingly gained traction in the clinical practice and recent guidelines have confirmed the non-inferiority of this approach. Nevertheless, the largest studies that have used hypofractionation so far, employed image-guided radiation therapy/intensity modulated radiation therapy (IGRT/IMRT) facilities that might have overcome the radiobiological advantages, which remain to be fully confirmed. The aim of this trial was to evaluate the feasibility of a hypofractionated schedule delivered with 3D-Conformal Radiotherapy to prostate and seminal vesicles in combination with hormonal therapy. PATIENTS AND METHODS: The study included 97 consecutive patients with localized prostate cancer (PCa), irrespective of risk class, treated with a schedule of 62 Gy in 20 fractions over 5 weeks (4 fractions of 3.1 Gy each per week). According to National Comprehensive Cancer Network (NCCN) prognostic classification, patients were divided into a favourable group (19%), intermediate group (41%) and unfavourable group (40%). Early and late toxicities were scored using the radiation toxicity grading/European Organisation for Research and Treatment of Cancer (RTOG/EORTC) criteria. Additionally, the international prostate symptom index (IPSS) for benign prostate hypertrophy was used to evaluate obstructive urinary symptoms. Biochemical outcome was reported according to the Phoenix definition for biochemical failure. Hormonal therapy (HT) was administrated in 92% of patients. RESULTS: After a median follow-up of 39 months (range=25-52), maximum ≥G2 late genitourinary (GU) and gastrointestinal (GI) toxicities occurred in 8% and 11% patients, respectively. The corresponding figures for acute toxicities were 24% and 15%. Patients with higher IPSS score before enrolment had significantly worse urinary function after treatment. Only 2% of patients died from PCa. Biochemical non-evidence of disease (bNED) was 83% for all patients. CONCLUSION: Our study confirms that 3D conformal radiotherapy (3DCRT) remains a safe and effective method to deliver a dose-escalated hypofractionated regimen for PCa patients in all risk classes with acceptable toxicity rates and optimal biochemical control.

Geometric and dosimetric approach to determine probability of late cardiac mortality in left tangential breast irradiation: comparison between wedged beams and field-in-field technique.

PURPOSE: To evaluate the probability of late cardiac mortality resulting from left breast irradiation planned with tangential fields and to compare this probability between the wedged beam and field-in-field (FIF) techniques and to investigate whether some geometric/dosimetric indicators can be determined to estimate the cardiac mortality probability before treatment begins. METHODS AND MATERIALS: For 30 patients, differential dose-volume histograms were calculated for the wedged beam and FIF plans, and the corresponding cardiac mortality probabilities were determined using the relative seriality model. As a comparative index of the dose distribution uniformity, the planning target volume (PTV) percentages involved in 97-103% of prescribed dose were determined for the two techniques. Three geometric parameters were measured for each patient: the maximal length, indicates how much the heart contours were displaced toward the PTV, the angle subtended at the center of the computed tomography slice by the PTV contour, and the thorax width/thickness ratio. RESULTS: Evaluating the differential dose-volume histograms showed that the gain in uniformity between the two techniques was about 1.5. With the FIF technique, the mean dose sparing for the heart, the left anterior descending coronary artery, and the lung was 15% (2.5 Gy vs. 2.2 Gy), 21% (11.3 Gy vs. 9.0 Gy), and 42% (8.0 Gy vs. 4.6 Gy) respectively, compared with the wedged beam technique. Also, the cardiac mortality probability decreased by 40% (from 0.9% to 0.5%). Three geometric parameters, the maximal length, angle subtended at the center of the computed tomography slice by the PTV contour, and thorax width/thickness ratio, were the determining factors (p = .06 for FIF, and p = .10 for wedged beam) for evaluating the cardiac mortality probability. CONCLUSION: The FIF technique seemed to yield a lower cardiac mortality probability than the conventional wedged beam technique. However, although our study demonstrated that FIF technique improved the dose coverage of the PTV, the restricted number of patients enrolled and the short follow-up did not allow us to evaluate and compare the breast cancer survival rates of the patients.

Collection and evaluation of incidents in a radiotherapy department : a reactive risk analysis.

PURPOSE: to report on the use of an internal system for incident reporting. PATIENTS AND METHODS: from October 2001 until June 2009, data on incidents were collected in the radiotherapy department (RT) by means of an incident reporting worksheet. The risk analysis was based on the US Navy method of mishap cause investigation, the Human Factors Analysis and Classification System (HFACS). RESULTS: 37 incidents over 5,635 treatments were collected. Of the incidents, 20 involved deviation of the dose to the patient; only 6 showed clinical evidence of overdosage, while 2 of them showed permanent evidence of overdosage. There were 24 incidents that were classified as near misses (NM). Incorrect data input and use of an incorrect treatment field were the most common causes of the registered incidents. Reactive risk analysis showed how skill-based errors were associated with attention failure at the unsafe act level. Dose prescription and dose calculation are the most critical phases of the entire process. Most of the errors were discovered in set-up/treatment and during treatment visit/follow-up phases. The highest number of correction procedures was necessary in the phases of dose prescription and dose calculation. CONCLUSION: collecting and analyzing internal incidents improves the operative procedures used in the department.

Incidents analysis in radiation therapy: application of the human factors analysis and classification system.

The purpose of this investigation was to analyse incidents discovered in our radiation therapy department by means of human factor analysis and classification system (HFAC S). We adapted the original framework of the HFAC S and apply it to the analysis of incidents discovered in our radiotherapy department during a five-year period. Results showed that recurrent causal factors of incidents were attention failures and distracted/overconfidence behaviour as well as loss of situational awareness and mental fatigue. In our radiation therapy department the HFAC S allowed to highlight recurrent errors causal factors. Consequently we defined corrections factors for operators behaviour and implemented an operational protocol which improve operators attitude.

Three-dimensional conformal radiotherapy for locally advanced (Stage II and worse) head-and-neck cancer: dosimetric and clinical evaluation.

PURPOSE: To evaluate the dosimetric parameters of three-dimensional conformal radiotherapy (3D-CRT) in locally advanced head-and-neck tumors (Stage II and above) and the effects on xerostomia. METHODS AND MATERIALS: A total of 49 patients with histologically proven squamous cell cancer of the head and neck were consecutively treated with 3D-CRT using a one-point setup technique; 17 had larynx cancer, 12 oropharynx, 12 oral cavity, and 6 nasopharynx cancer; 2 had other sites of cancer. Of the 49 patients, 41 received postoperative RT and 8 definitive treatment. Also, 13 were treated with cisplatin-based chemotherapy before and during RT; in 6 cases, 5-fluorouracil was added. The follow-up time was 484-567 days (median, 530 days). RESULTS: One-point setup can deliver 96% of the prescribed dose to the isocenter, to the whole planning target volume, including all node levels of the neck and without overdosages. The mean dose to the primary planning target volume was 49.54 +/- 4.82 Gy (51.53 +/- 5.47 Gy for larynx cases). The average dose to the contralateral parotid gland was approximately 38 Gy (30 Gy for larynx cases). The maximal dose to the spinal cord was 46 Gy. A Grade 0 Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer xerostomia score corresponded to a mean dose of 30 Gy to one parotid gland. A lower xerostomia score with a lower mean parotid dose and longer follow-up seemed to give rise to a sort of functional recovery phenomenon. CONCLUSION: Three dimensional-CRT in head-and-neck cancers permits good coverage of the planning target volume with about 10-11 segments and one isocenter. With a mean dose of approximately 30 Gy to the contralateral parotid, we observed no or mild xerostomia.