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Cyberknife is an emerging treatment for early stage prostate cancer. Between October 2012 and January 2014, 32 patients were treated in our institution. Prescribed dose was 35-36.25 Gy in five fractions. Biochemical response was observed in 22 patients. Four patients experienced G2 acute genitourinary toxicity and in two cases we recorded G3 acute GU toxicity. 5 patients experienced G2 acute proctitis. At last follow up visit, all patients were still alive. 29 remained free of disease at last follow up appointment, while three developed a biochemical recurrence. Our experience confirms the efficacy and safety of Cyberknife for localized prostate cancer. [ABSTRACT FROM AUTHOR]

Purpose: To compare and evaluate different dosimetric techniques and devices for the QA of VMAT plans created by two treatment planning systems (TPSs). Methods: A total of 50 VMAT plans were optimized for treatment of anatomical sites of various complexities by two TPSs which use rather different approaches to VMAT optimization. Dosimetric plan verifications were performed both as part of commissioning and as patient specific QA of clinical treatments. Absolute point doses were measured for all plans by a micro ion chamber inserted in a dedicated water-filled cylindrical phantom. Delivered dose distributions were verified by four techniques based on different detectors: radiographic and gafchromic films, two systems based on 2D diode arrays and an ion chamber array. Gamma index analysis with various tolerance levels (3%, 3 mm and 3%, 2 mm) was used to analyze differences between calculated and delivered doses. Sensitivity to possible delivery errors was also evaluated for three of the considered devices introducing ±3 mm shifts along the three directions and a 3° gantry offset. Results: Ion chamber measured point doses were within 3% of calculated ones for 48 out of 50 values. For delivered dose distribution, the average fraction of passed gamma values using 3% and 3 mm criteria was above 95% for both TPSs and all detectors except gafchromic film which yielded on average of 91.4%. For 49 out of 50 plans, a pass-rate above 94% was obtained by at least one of the four techniques. Shrinking the tolerance to 3% and 2 mm, the average pass-rate by all detectors (except film) was still above 95% for one of the two TPSs, but lower for the other one. The detector sensitivity to 3 mm shifts and to gantry angle offset was strongly plan and partially detector dependent: the obtained pass-rate reduction ranged from 2% to 30%. Conclusions: The presented results for VMAT plans QA assess the reliability of the delivered doses for both TPSs. The slightly lower pass-rate obtained for one of the considered TPS can be attributed to a higher level of complexity of the optimized plans. The results by different dosimetric techniques are coherent, apart from a few measurements by gafchromic films. The detector sensitivity to delivery errors, being strongly plan dependent, is not easy to evaluate. [ABSTRACT FROM AUTHOR]

Prescription of ablative doses in pancreas SBRT requires steep dose fall-off to fulfill OARs dose limits. Both geometric errors and organ deformation may lead to OARs doses violation. We aimed at evaluating effects of intra-fraction errors and inter-fraction deformation on OARs doses, investigating their predictability in terms of target-to -OAR proximity Twenty patients, treated for pancreatic cancer in 5 fraction prescribing 40Gy/50Gy to PTV/GTV, were considered. Plan optimization required for duodenum, stomach and bowel V35Gy< 0.5 cc. Target-to-OAR proximity was quantified for each patient computing the expansion-intersection volume (EIV) on the planning CT (pCT), as the intersection between the PTV expanded by 5 mm and duodenum, stomach and bowel. All patients were treated at a frameless robotic radiosurgery system using fiducial real time respiratory tracking modality. Residual tracking errors were extracted for 100 fractions using the system log-files. Standard uncertainties (mean values + 2 standard deviations) along the three directions (SI, LR; AP) were used as descriptive statistics. To simulate the effects of tracking errors on OARs doses, a perturbed plan was created modifying each CK beam coordinates by the corresponding errors and a perturbed dose distribution was calculated. Inter-fraction OARs deformation was evaluated acquiring pre-fraction CT scans with a maximum of 2 repeated scans per patient. Deformed OARs were contoured by the same physician who contoured the pCT. Planned doses were re-calculated on the deformed anatomy using the fiducials alignment center, to rigidly register the pCT to each pre-fraction scan. OARs constraints of perturbed plan and deformed anatomy were considered met at V35 Gy < 1 cc. EIV values ranged from 0.5 to 28 cc (median 9.6 cc). Tracking errors standard uncertainties ranged from 0.6 mm to 7.2 mm, with respective median values 3.5 mm (SI), 2.4 mm (LR), 2.0 mm (AP). For plans perturbed by tracking errors, OARs constraints were violated only in 2 / 20 patients (V35Gy respectively 1.4 cc and 1.2 cc). For these two patients, EIV values were above 25 cc, and errors uncertainties were above 5 mm along at least one direction. The recalculated doses on deformed OARs, contoured on repeated CT scans, showed constraints violation in 13/20 cases with V35Gy values up to 5 cc (median 2.1 cc). The 7 patients for whom constraints were still met on the deformed anatomy (V35Gy<1cc) showed EIV values below 1.5 cc. CK tracking errors have small effects on OAR doses, but attention must be paid to minimize these errors for patients with large EIV values. Although OARs deformation has larger effects, constraints were still met in 33% of patients. EIV is a promising parameter to predict who is at risk of exceeding OARs constraints during pancreas SBRT, needing plan adaptation. [ABSTRACT FROM AUTHOR]

In view of the possible relation between pancreatic function and cystic fibrosis (CF) gene mutations, a detailed study on Italian patients was performed. Seventy pancreatic insufficient and 48 pancreatic sufficient patients were included after very accurate characterisation of their pancreatic and digestive function, all performed in the same CF centre. The CF gene deletion F508 was tested to define the patients' genotypes. The results confirm that the mutation correlates with pancreatic insufficiency, and is recessive to other, as yet unreported, mutant alleles that determine pancreatic sufficiency. An indication that duodenal bicarbonate output is more severely reduced in the presence of deletion F508 is also presented. The data are discussed in relation to a hypothesis on the primary effects of CF gene deletion F508. [ABSTRACT FROM PUBLISHER]

Salvage radiotherapy (SRT) is one of the most widely used approaches in case of biochemical recurrence after radical prostatectomy for prostate cancer. Macroscopic recurrence within the prostate bed in this scenario is often detected through PSMA PET/CT or Magnetic resonance imaging (MRI). Stereotactic salvage radiotherapy (SSRT) has been proposed as a method to improve disease control by dose escalation in these patients. STARR is a prospective trial exploring clinical outcomes after SSRT on macroscopic recurrence within prostate bed after radical prostatectomy. STARR trial is a prospective multicenter study enrolling subjects affected by prostate bed macroscopic recurrence. All relapses were detected by Choline, PSMA CT-PET or MRI performed after a post prostatectomy PSA rise above 0.2 ng/ml. All patients with regional or distant metastatic disease were excluded. SSRT consisting in a total dose of 35 Gy in 5 fractions every other day was administered on macroscopic relapse defined through CT-PET and/or MRI co-registration with planning CT. Androgen Deprivation therapy (ADT) was not prescribed. A PSA nadir <0.2 ng/ml and <50% of baseline, respectively, were defined as complete biochemical response (CBR) or biochemical response (BR). Sixty-one patients were enrolled between March 2021 and November 2023. The current analysis included 50 enrolled patients at the promoting institution with > 3 months of follow up. After a median follow up of 10 months (95% CI = 7-17), Acute genitourinary and gastrointestinal toxicity occurred in 4 (3 G1 and 1 G2), and 5 patients (3 G1 and 2 G2), respectively. Late genitourinary and gastrointestinal toxicity were identified in 7 (all G1) and 1 patient (G2), respectively. BR and CBR were detected at 3 months in 41 (82%) and 23 (46%) cases, respectively. Seven recurrences were detected (3 biochemical and 4 metastatic recurrences detected through PSMA PET-CT) Forty-six patients (92%) were free from ADT at the end of follow up. SSRT yielded optimal results in terms of safety, with only mild adverse events. Biochemical outcomes are promising, with a significant benefit in terms of clinically meaningful outcomes (i.e. new distant metastases occurrence and need for ADT start). [ABSTRACT FROM AUTHOR]

Following reports of improved efficacy in vertebral metastases, Stereotactic Body Radiotherapy has been increasingly applied for local palliation and disease control in non-spinal bone metastases. However, its use in the management of rib metastases (RM) has been traditionally limited due to purported risk of iatrogenic fracture, possibly resulting in impaired pain control. For this reason, SBRT in this setting has been scarcely reported in literature. The aim of our study is to evaluate pain control and local failure rates in RM treated with SBRT. We collected data from a cohort of RM patients treated from October 2014 to December 2023 with SBRT. Clinical and treatment-related data were collected. Pain Control (PC) was defined as absence or reduction of pain allowing for decreased medication intake. Local Failure (LF) was defined as radiologic progression on follow-up imaging. Univariable analysis with the log-rank test and multivariable analysis with the Cox model were performed to investigate predictors of PC and LF. Data from 55 patients accounting for 64 RM were collected. Median age was 70 (range = 37-78) years. Most represented primary tumors were prostate (41%, n = 26) and non-small cell lung cancer (21%, n = 13). Baseline pain before SBRT was reported in 26 (41%) lesions, requiring daily opioid intake in 12 cases (20%). SBRT was delivered with C-arm (92%, n = 59) and robotic-arm (8%, n = 5) Linac using the following regimens: 16 Gy/1 fraction, 24 Gy/2 fractions, 24-30 Gy/3 fractions, 30-55 Gy/5 fractions. Median EQD2 (assuming an α/β = 10) was 47 Gy (range = 35-96.25). Median follow-up was 14 (range = 1-76) months. PC was 87% at 6 months and 82% at 1 year. Age> 70 (P = 0.002), EQD2 ≤40 Gy (P = 0.009) and baseline pain (P = 0.004) were correlated with impaired PC although only EQD2 ≤40 Gy (P = 0.007) and baseline pain (P = 0.012) proved significant at multivariate analysis. LF rate was 2.0% at 6 months and 4.8% at 1 year. Median OS was 60 (95% CI= 25-70) months. No predictive factors of LF were identified at statistical analysis. Pain flare was observed in 1 patient. No rib fracture and/or skin fibrosis was observed. SBRT for RM is associated with low rates of local failure and durable pain control. Administration of SBRT before the onset of symptoms and use dose intensive regimens may result in improved pain control. [ABSTRACT FROM AUTHOR]