0000000000321186
AUTHOR
F. Mazoyer
Absolute volume of the rectum and AUC from rectal DVH between 25Gy and 50Gy predict acute gastrointestinal toxicity with IG-IMRT in prostate cancer
International audience; Background: To determine whether dose/volume specific endpoints (DVSE) or Area under the rectal DVH curve (rAUC) better predict acute gastrointestinal (GI) toxicity in prostate cancer patients treated with IMRT in the era of daily image guidance (IG-IMRT). Methods: A set of DVSE was recorded from V25 to V75 (increments of 5Gy) (both in % and in cc) for 180 men. The rAUC was calculated for doses ranging between 25Gy and 50Gy (rAUC(25-50)). Univariate and multivariate logistic regressions were performed to determine the relationship between DVSE or rAUC(25-50) and the appearance of any acute GI toxicity. Results: The rates of acute grade 1 (G1), G2 and G3 GI toxicities…
Mapping of failures after radiochemotherapy in patients with non-metastatic esophageal cancer: A posteriori analysis of the dose distribution in the sites of loco-regional relapse.
Abstract Background and purpose We aimed to evaluate the patterns of loco-regional failure (LRF) after exclusive chemoradiotherapy (eCRT) for esophageal cancer with respect to planned dose and/or the incidental (unplanned) dose outside target volumes. Materials and methods Co-image registration of CT or 18 F-FDG PET-CT at the time of failure (tf) and at the time of CRT (t0) was performed in 34 patients with LRF. Dosimetric parameters with regard to local failure (LF), nodal failure (NF) and involved nodal stations (NS) were derived. Results Twenty-two patients (64.7%) had LF, the majority of which (95.5%) were located at the epicenter of the GTV of the primary tumor. The mean doses recalcul…
Multiparametric MRI and post implant CT-based dosimetry after prostate brachytherapy with iodine seeds: The higher the dose to the dominant index lesion, the lower the PSA bounce
Abstract Purpose To determine whether post-implant MRI-based dosimetry of the Dominant Intra-prostatic Lesion (DIL) could best predict the occurrence of PSA bounce after prostate brachytherapy. Methods and materials We selected 66 patients with a low risk prostate cancer treated with 125 I prostate brachytherapy as monotherapy. Post-implant dosimetry based on day 30 CT-scan and multiparametric MRI co-registration was generated: planned D 90, D 95, V 100, V 150 values were calculated for each DIL. Bounce was defined as a PSA elevation ⩾0.2ng/mL from the previous baseline value followed by a decrease to or below the prior nadir with no additional treatment. Results After a median follow-up of…
Focal or whole-gland salvage prostate brachytherapy with iodine seeds with or without a rectal spacer for postradiotherapy local failure: How best to spare the rectum?
International audience; PURPOSE: Salvage prostate permanent implant (sPPI) for postradiation local failure provides high rates of biochemical control. The cumulative dose delivered to the prostate and the rectum is still unknown. METHODS AND MATERIALS: We reviewed the postimplant CT-based dosimetry of 18 selected patients who underwent sPPI with I-125 seeds for isolated biopsy-proven local failure several years after external beam radiation therapy. Ten patients had whole-prostate sPPI, and 8 patients had multiparametric MRI-based focal sPPI. In 8 patients, hyaluronic acid (HA) gel was injected into the prostate rectum space. RESULTS: The median cumulative biological effective dose after EB…
Radiothérapie guidée par l’image des cancers prostatiques : concepts et implications
Resume La radiotherapie conformationnelle avec modulation d’intensite (RCMI) et la radiotherapie guidee par l’image sont deux evolutions technologiques qui, appliquees au modele des cancers prostatiques, ont permis de voir diminuer significativement la toxicite et les sequelles digestives et urinaires de la radiotherapie conformationnelle tridimensionnelle. Le benefice clinique majeur de ces techniques sur la diminution de la toxicite digestive et urinaire est indiscutable puisque les sequelles observees a dix ans sont devenues rares avec ces techniques (2 % de cas de toxicite digestive de grade 2 et 1 % de grade 3, 11 % de cas de toxicite urinaire de grade 2 et 5 % de grade 3). Si ces deux…
Impact of rectal distension on prostate CBCT-based positioning assessed with 6 degrees-of-freedom couch
International audience; Introduction: Prostate requires a daily correction of its 3-dimensional position in relation with rectal distension. In this study, we sought to determine whether rectal distension with respect to the rectal behavior might have an impact on prostate translations and/or rotations during prostate image guided radiation therapy using a 6 degrees-of-freedom (DOF) couch.Methods and materials: We reviewed the data from 39 patients with localized prostate cancer treated with protracted external radiation therapy using a 6 DOF couch. Before each fraction, a kilovoltage cone beam computed tomography (kV-CBCT) scan was performed. The automatic fusion algorithm was set to fuse …