High dose proton and photon-based radiation therapy for 213 liver lesions: a multi-institutional dosimetric comparison with a clinical perspective.

BACKGROUND: Stereotactic radiotherapy (SRT) and Proton therapy (PT) are both options in the management of liver lesions. Limited clinical-dosimetric comparison are available. Moreover, dose-constraint routinely used in liver PT and SRT considers only the liver spared, while optimization strategies to limit the liver damaged are poorly reported. METHODS: Primary endpoint was to assess and compare liver sparing of four contemporary RT techniques. Secondary endpoints were freedom from local recurrence (FFLR), overall survival (OS), acute and late toxicity. We hypothesize that Focal Liver Reaction (FLR) is determined by a similar biologic dose. FLR was delineated on follow-up MRI. Mean C.I. was computed for all the schedules used. A so-called Fall-off Volume (FOV) was defined as the area of healthy liver (liver-PTV) receiving more than the isotoxic dose. Fall-off Volume Ratio (FOVR) was defined as ratio between FOV and PTV. RESULTS: 213 lesions were identified. Mean best fitting isodose (isotoxic doses) for FLR were 18Gy, 21.5 Gy and 28.5 Gy for 3, 5 and 15 fractions. Among photons, an advantage in terms of healthy liver sparing was found for Vmat FFF with 5mm jaws (p = 0.013) and Cyberknife (p = 0.03). FOV and FOVR resulted lower for PT (p < 0.001). Three years FFLR resulted 83%. Classic Radiation induced liver disease (RILD, any grade) affected 2 patients. CONCLUSIONS: Cyberknife and V-MAT FFF with 5mm jaws spare more liver than V-MAT FF with 10 mm jaws. PT spare more liver compared to photons. FOV and FOVR allows a quantitative analysis of healthy tissue sparing performance showing also the quality of plan in terms of dose fall-off.

Multicomponent T2 relaxometry reveals early myelin white matter changes induced by proton radiation treatment.

PURPOSE: To investigate MRI myelin water imaging (MWI) by multicomponent T2 relaxometry as a quantitative imaging biomarker for brain radiation-induced changes and to compare it with DTI. METHODS: Sixteen patients underwent fractionated proton therapy (PT) receiving dose to the healthy tissue because of direct or indirect (base skull tumors) irradiation. MWI was performed by a multi-echo sequence with 32 equally spaced echoes (10-320 ms). Decay data were processed to identify 3 T2 compartments: myelin water (Mw) below 40 ms, intra-extracellular water (IEw) between 40 and 250 ms, and free water (CSFw) above 250 ms. Both MWI and DTI scans were acquired pre (pre)-treatment and immediately at the end (end) of PT. After image registration, voxel-wise difference maps, obtained by subtracting MWI and DTI pre from those acquired at the end of PT, were compared with the corresponding biological equivalent dose (BED). RESULTS: Mw difference showed a positive correlation and IEw difference showed a negative correlation with BED considering end-pre changes (P < .01). The changes in CSFw were not significantly correlated with the delivered BED. The changes in DTI data, considering end-pre acquisitions, showed a positive correlation between fractional anisotropy and the delivered BED. CONCLUSION: MWI might detect early white matter radiation-induced alterations, providing additional information to DTI, which might improve the understanding of the pathogenesis of the radiation damage.

High-dose intensity-modulated radiation therapy as primary treatment of prostate cancer: genitourinary/gastrointestinal toxicity and outcomes, a single-institution experience.

PURPOSE: Prostatectomy, radiotherapy and watchful waiting are the main therapeutic options available for local stage of prostate cancer (PCa). We report our experience on 394 patients affected by prostate cancer primarily treated with high-dose, image-guided, IMRT, focusing on gastrointestinal, genitourinary toxicities and biochemical control. METHODS: From July 2003 to August 2014, 394 patients were treated with radical high-dose radiotherapy (HDRT) for prostate cancer; the mean total radiation dose was 79 Gy in standard fractions. Hormonal therapy (HT) was administered to 7.6% of low-risk patients, to 20.3% of intermediate-risk patients and to 72% of high-risk patients. Patients were evaluated for biochemical failure, local recurrence (LR) and metastases. RESULTS: Ninety-seven patients (26.65%) developed acute GU toxicity at the medium dose of 25.4 Gy, grade 1 (G1) or grade 2 (G2) in 94 cases. Only 16 patients (4.06%) reported chronic GU toxicity (G1 or G2), and one case developed G3 cystitis. No G3 GI acute and late toxicity were detected. Fifty-six (14.2%) patients experienced LR, 26 (6.6%) developed metastases and 70 patients (17.8%) were deceased. Gleason sum score > 7 was predictive for worse overall survival (GS = 7 was borderline) and for metastasis. No factors resulted predictive for local relapse. HT pre-RT had been demonstrated as a negative predictor for OS and DFS-DM. CONCLUSIONS: Data confirm the safety of HDRT for PCa. Treatment was efficient with low toxicity profile. Moreover, continued technologic advancements, as image-guided radiotherapy, could lead to further reduction in toxicity, thus increasing the therapeutic index.

Management of Leptomeningeal Metastases in Non-oncogene Addicted Non-small Cell Lung Cancer.

Brain metastases in non-small cell lung cancer (NSCLC) patients are more often detected due to imaging modalities improvements but also emerge because of improved treatments of the primary tumor which lead to a longer survival. In this context, development of leptomeningeal metastases (LM) is a devastating complication and its prognosis remains poor despite advances in systemic and local approaches. Histology characterization of NSCLC and molecular expression influence LM management. For those with "oncogene addiction," new generation epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) were developed to strongly penetrate the blood-brain barrier (BBB) with the aim to prevent central nervous system cancer dissemination, eventually impacting on LM appearance and its subsequent management. Systemic chemotherapy, often combined with intrathecal chemotherapy (when possible), was one of common indications for lung cancer patients affected by LM, without driver mutations and a good performance status but currently, with the advent of innovative systemic approaches treatment solutions in this subgroup of patients are rapidly evolving. Whole brain radiation therapy (WBRT) is the conventional treatment for patients with brain metastases. Furthermore, modern radiation techniques, as stereotactic radiotherapy (SRT), improve outcomes in those cases with a limited number of lesions. However, LM represent a minority of CNS metastases and few literature data are available to drive the radiotherapy approach. Considering all relevant progress made in this setting, after a literature review, the aim of this paper is to discuss about recent developments and therapeutic options in LM management of non-oncogene addicted NSCLC.