Initial experience with steroatactic body radiation therapy for localized prostate cancer using helical tomotherapy

PURPOSE: Single-institution single-arm prospective study. Endpoint: To assess whether there are more than 5 % of men having grade 3 GU or any grade 3 GI acute toxicity during stereotactic body radiation therapy (SBRT) for prostate cancer using helical tomotherapy. METHODS: Since May 2012, 17 prostate cancer patients were treated with helical tomotherapy. The exclusion criteria used are the following: Gleason score ≥8, PSA >20 ng/ml, cT3b-4, IPSS ≥20 and history of acute urinary retention. CTV included the prostate gland and 1 cm of seminal vesicles in the low-risk group (LR) or the seminal vesicles completely in the intermediate (IR) and high-risk (HR) NCCN groups. CTV margins ranged from 2 to 8 mm, while PTV margins were 2 to 9 mm. Patients received eight fractions of 5.48 Gy (LR) or 5.65 Gy (IR, HR) on alternate days. Total equivalent doses at 2 Gy per fraction are 87.4 for LR and 92.3 Gy for IR-HR using an α/β value of 1.5. Correspondent figures for a α/β of 3 are 74.3 Gy and 78.2 Gy, respectively. Megavoltage CT (MVCT) for on-line correction was taken before every fraction. RESULTS: The patient distribution by risk group is 29, 47 and 24 % for LR, IR and HR, respectively. 82 % received neoadjuvant-concomitant hormonal therapy. Acute GU toxicity grade 1, 2 and 3 was found in 70, 6 and 0 % of men. GI toxicity was observed in 50, 0 and 0. After 136 MVCT, the standard deviation of the mean individual corrections in the anterior-posterior direction was 2.5 mm. CONCLUSION: SBRT for prostate cancer using helical tomotherapy is feasible. Initial results show an early toxicity profile no worse than SBRT delivered with robotic radiosurgery or conventionally fractionated radiotherapy (AU)

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Prognostic factors for acute toxicity in prostate cancer patients treated with high-dose hypofractionated radiotherapy

PURPOSE: To prospectively study acute genitourinary (GU) and gastrointestinal (GI) toxicity during hypofractionated radiotherapy. PATIENTS AND MATERIALS: One-hundred and seventy-one consecutive men with cT1-T3cN0cM0 prostate cancer were treated at 2.6 Gy/fraction to a total dose of 67.6 for low risk (EQD2 = 79 Gy) and 70.2 Gy for intermediate-high risk (EQD2 = 82 Gy) over 5.2-5.4 weeks (α/β 1.5). Acute toxicity was scored according to RTOG/EORTC toxicity extended criteria after completing a 22-item questionnaire (basal, weekly, at 6 months). RESULTS: Minimum and median follow-up were 36 and 54.2 months, respectively. GU toxicity grades 0, 1, 2 and 3 were found in 30.4, 37, 32 and 0.6 % of patients, respectively. The figures for grades 0, 1, 2 and 3 GI toxicity were 66, 24, 10 and 0 %. The highest degree of acute reactions was reached at 4-5 weeks. At 6 months, 15 % of patients had GU toxicity (11 % grade 1, 4 % grade 2) and 5.8 % GI toxicity (5.3 % grade 1, 0.5 % grade 2). Multivariate analysis shows that bladder volume receiving ≥65 Gy (V 65) is associated with an increased risk of GU complications (p = 0.017, HR = 1.143, 95 % CI = 1.025-1.276), while history of TURP is linked to lower risk (p = 0.002, HR = 0.310, 95 % CI 0.004-0.370). Mean rectal dose (p = 0.013, HR = 1.089, 95 % CI 1.018-1.116) and total dose (p = 0.019, HR = 0.734, 95 % CI 0.567-0.950) are significantly related to GI toxicity. CONCLUSIONS: This 5-week dose-escalation hypofractionated radiotherapy schedule that uses 3D-conformal radiotherapy without IGRT has resulted in <1 % grade 3 acute complications. Our study suggests that reducing the mean rectal dose and the bladder V 65 helps prevent acute toxicity. TURP before radiotherapy was associated with lower acute GU toxicity (AU)

Tumor volume delineation in headd and neck cancer with 18-fluor-fluorodeoxiglucose positron emission tomography: adaptative thresholdin method applied to primery tumors and metastatic lymph nodes

PURPOSE: There are several potential advantages of using 18-fluor-fluorodeoxiglucose (18F-FDG) PET for target volume contouring, but before PET-based gross tumor volumes (GTVs) can reliably and reproducibly be incorporated into high-precision radiotherapy planning, operator-independent segmentation tools have to be developed and validated. The purpose of the present work was to apply the adaptive to the signal/background ratio (R(S/B)) thresholding method for head and neck tumor delineation, and compare these GTV(PET) to reference GTV(CT) volumes in order to assess discrepancies. MATERIALS AND METHODS: A cohort of 19 patients (39 lesions) with a histological diagnosis of head and neck cancer who would undergo definitive concurrent radiochemotherapy or radical radiotherapy with intensity-modulated radiotherapy technique (IMRT), were enrolled in this prospective study. Contouring on PET images was accomplished through standardized uptake value (SUV)-threshold definition. The threshold value was adapted to R(S/B). To determine the relationship between the threshold and the R(S/B), we performed a phantom study. A discrepancy index (DI) between both imaging modalities, overlap fraction (OF) and mismatch fraction (MF) were calculated for each lesion and imaging modality. RESULTS: The median DI value for lymph nodes was 2.67 and 1.76 for primary lesions. The OF values were larger for CT volumes than for PET volumes (p < 0.001), for both types of lesions. The MF values were smaller for CT volumes than for PET volumes (p < 0.001), for both types of lesions. The GTV(PET) coverage (OF(PET)) was strongly correlated with the lesion volume (GTV(CT)) for metastatic lymph nodes (Pearson correlation = 0.665; p < 0.01). For smaller lesions, despite the GTV volumes were relatively larger on PET than in CT contours, the coverage was poorer. Accordingly, the MF(PET/CT) was negatively correlated with the lesion volume for metastatic lymph nodes. CONCLUSIONS: The present study highlights the considerable challenges involved in using FDG PET imaging for the delineation of GTV in head and neck neoplasms. The methods that rely mainly on SUV(max) for thresholding, as the RS/B method, are very sensitive to partial volume effects and may provide unreliable results when applied on small lesions (AU)

CTV to PTV margins for prostate irradiation. Three-dimensional quantitative assessment of interfraction uncertainties using portal imaging and serial CT scans

PURPOSE: To determine the magnitude of setup and organ motion errors from a subset of prostate cancer patients treated with conventional conformal radiotherapy, and to estimate the CTV-PTV margin according to published margin recipes. METHODS AND MATERIALS: Twenty prostate cancer patients were treated with external radiotherapy using electronic portal images (EPIs). Weekly treatment EPIs and pelvic CT scans were obtained. These data allowed interfractional analysis of prostate centre of mass motion and setup error. The margins needed to compensate these uncertainties were calculated. RESULTS: Tattoo localisation requires a margin of 9-10.5 mm (LR), 15.2-17.8 mm (anterior-posterior (AP)) and 10.6-12.4 mm (superior-inferior (S-I)). Systematic displacements due to prostatic motion, with standard deviations of 2.4 mm (LR), 4.2 mm (AP) and 3.1 mm (S-I) were found to be larger than setup errors (1.8, 3.0 and 1.7 mm respectively). CONCLUSIONS: Customised PTV margin definition has been possible through in-house measurements of geometrical clinical uncertainties involved in the conventional conformal radiotherapy process. Uncertainty measurements in our department have proved to be larger than those used in common practice. Additional margin reduction procedures are needed in order to accomplish conformal radiotherapy goals (AU)

Centralised treatment of soft tissue sarcomas in adults

The clinical research developed in specialised centres and oncologic cooperative groups has permitted various scientific societies to collect recommendations used in the treatment of soft tissue sarcomas (STS) and incorporate them into clinical practice guidelines (CPG). Some studies have been conducted in diverse healthcare ambits to assess the influence of CPG. This revision of the medical literature analyses the impact that healthcare management -centralised or otherwise- and clinical practice in conformity with CPG have on the clinical outcome variables of STS. Eight CPG have been identified, as well as 12 conformity studies or audits. These conformity studies and audits demonstrate that the grade of adaptation of medical interventions with CPG, medical healthcare in reference centres and procedures of referrals to these centres, as well as the process of organising healthcare teams into Sarcoma Committees, have a significant influence on clinical outcome. We can conclude that excellent healthcare of STS implies the adaptation of healthcare practice to CPG, the existence of Reference Centres guided by Sarcoma Committees, and the observance of strict referral procedures within the Healthcare Area (AU)

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