Comparison of hematologic toxicity between 3DCRT and IMRT planning in cervical cancer patients after concurrent chemoradiotherapy: a national multi-center study.

PURPOSE: To compare the incidence and severity of acute and chronic hematologic toxicity (HT) in patients treated with three-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) for curative treatment of cervical cancer and to ascertain the dosimetric parameters of two techniques associated with acute and chronic HT. MATERIALS AND METHODS: A total of 127 patients with cervical cancer receiving concomitant pelvic radiotherapy (RT) and cisplatin were evaluated. Pelvic bone marrow (BM) was contoured for each patient and divided into five sub-regions: lumbosacrum (LS), ilium (IL), lower pelvis (LP), pelvis (P), and whole pelvis (WP). The volume of each BM region receiving 10, 20, 30, and 40 Gy was calculated (V10, -V20, -V30, and -V40). The lowest level of hemoglobin, leukocyte, neutrophil, and platelet counts were obtained during chemoradiotherapy and six months after RT. The nadir values were graded according to Common Terminology Criteria for Adverse Events (version 3.0). RESULTS: Grade 2 or greater acute anemia, leukopenia, neutropenia, thrombocytopenia was observed in 2%, 41.5%, 12% ,and 0% in 3DCRT group and in 27%, 53%, 24.5%, and 4.5% in IMRT group, respectively. Grade 2 or greater chronic anemia, leukopenia, neutropenia, and thrombocytopenia was observed in 11%, 10%, 6%, and 0% in 3DCRT group and in 11%, 9%, 4.5%, and 0% in IMRT group, respectively. LS-V30, 40; IL-V10, 20, 30, 40; LP-V10, 20 ,40; P-V10, 20, 30, 40, and TP-V10, 20, 30, 40 were significantly reduced with IMRT planning compared to 3DCRT planning. Logistic regression analysis of potential predictors showed that none of the dosimetric parameters were significant for predicting acute and chronic HT. CONCLUSION: The present findings showed that IMRT planning reduced irradiated BM volumes compared to 3DCRT planning. However, no difference between the two techniques was observed in terms of acute and chronic HT. Further studies are needed to confirm these results.

Coverage of axillary lymph nodes with high tangential fields in breast radiotherapy.

The aim of this study is to evaluate the coverage of axillary nodal volumes with high tangent fields (HTF) in breast radiotherapy and to determine the utility of customised blocking. The treatment plans of 30 consecutive patients with early breast cancer were evaluated. The prescription dose was 50 Gy to the whole breast. Axillary level I-II lymph node volumes were delineated and the cranial border of the tangential fields was set just below the humeral head to create HTF. Dose-volume histograms (DVH) were used to calculate the doses received by axillary nodal volumes. In a second planning set, HTF were modified with multileaf collimators (MLC-HTF) to obtain an adequate dose coverage of axillary nodes. The mean doses of the axillary nodes, the ipsilateral lung and heart were compared between the two plans (HTF vs MLC-HTF) using a paired sample t-test. The doses received by 95% of the breast volumes were not significantly different for the two plans. The doses received by 95% of the level I and II axillary volumes were 16.79 Gy and 11.59 Gy, respectively, for HTF, increasing to 47.2 Gy and 45.03 Gy, respectively, for MLC-HTF. Mean lung doses and per cent volume of the ipsilateral lung receiving 20 Gy (V20) were also increased from 6.47 Gy and 10.47%, respectively, for HTF, to 9.56 Gy and 16.77%, respectively, for MLC-HTF. Our results suggest that HTF do not adequately cover the level I and II axillary lymph node regions. Modification of HTF with MLC is necessary to obtain an adequate coverage of axillary levels without compromising healthy tissue in the majority of the patients.

The application of positron emission tomography/computed tomography in radiation treatment planning: effect on gross target volume definition and treatment management.

AIMS: To analyse the effect of the use of molecular imaging on gross target volume (GTV) definition and treatment management. MATERIALS AND METHODS: Fifty patients with various solid tumours who underwent positron emission tomography (PET)/computed tomography (CT) simulation for radiotherapy planning from 2006 to 2008 were enrolled in this study. First, F-18 fluorodeoxyglucose (FDG)-PET and CT scans of the treatment site in the treatment position and then a whole body scan were carried out with a dedicated PET/CT scanner and fused thereafter. FDG-avid primary tumour and lymph nodes were included into the GTV. A multidisciplinary team defined the target volume, and contouring was carried out by a radiation oncologist using visual methods. To compare the PET/CT-based volumes with CT-based volumes, contours were drawn on CT-only data with the help of site-specific radiologists who were blind to the PET/CT results after a median time of 7 months. RESULTS: In general, our PET/CT volumes were larger than our CT-based volumes. This difference was significant in patients with head and neck cancers. Major changes (> or =25%) in GTV delineation were observed in 44% of patients. In 16% of cases, PET/CT detected incidental second primaries and metastatic disease, changing the treatment strategy from curative to palliative. CONCLUSIONS: Integrating functional imaging with FDG-PET/CT into the radiotherapy planning process resulted in major changes in a significant proportion of our patients. An interdisciplinary approach between imaging and radiation oncology departments is essential in defining the target volumes.

Dosimetric comparison of intensity modulated pelvic radiotherapy with 3D conformal radiotherapy in patients with gynecologic malignancies.

PURPOSE: Before initiating an intensity modulated radiotherapy (IMRT) program for gynecologic malignancies we prospectively evaluated the potential benefits of IMRT by dose volume histogram comparison of IMRT and 3D conformal radiotherapy plans. METHODS: Plans of ten consecutive patients with cervical and endometrial cancer were evaluated. For each patient a 4-field box technique was compared to an IMRT plan. Both plans were normalized to deliver 50.4 Gy to the PTV in six patients and 45 Gy in the remaining four. Isodose distributions and dose volume histograms were compared in seven dose levels. RESULTS: IMRT reduced the volume of small bowel receiving more than 45 Gy in all patients. The average absolute volume of small bowel receiving 45 Gy was significantly reduced from 318 cc to 33 cc. No significant increase in the volume of small bowel receiving less than 20 Gy was observed. Rectum, bladder and bone marrow volumes receiving high doses were also significantly reduced with IMRT. CONCLUSIONS: IMRT significantly reduces the volume of normal tissues irradiated to high doses without compromising the target coverage. This may potentially lead to a reduction in treatment related toxicities.

Implantation of fiducial markers for image guidance in prostate radiotherapy: patient-reported toxicity.

The purpose of this study was to evaluate patient-reported morbidity of implanted fiducial markers used for image guidance in prostate radiotherapy. Three fiducial markers were implanted under transrectal ultrasound guidance to 177 patients who were referred to our department for definitive radiotherapy between June 2005 and January 2008. No local anaesthesia was administered. Patients were asked to complete a questionnaire about the possible side effects of this invasive procedure. 135 patients completed the questionnaire at a median of 57 weeks after the procedure. Pain during the procedure was assessed with the Wong-Baker Faces Pain Rating Scale. Patients were also asked to compare the pain with the diagnostic biopsy. Although haematuria, rectal bleeding and fever were reported by 15%, 4% and 2% of the 135 patients, respectively, no major toxicity necessitating any intervention was observed. The mean pain score reported by the patients was 1.7 (range, 0-5). 87% of patients reported less (or comparable) pain than the diagnostic biopsy. In conclusion, implantation of fiducial markers for image guidance in prostate radiotherapy is a safe and well-tolerated procedure.

Impact of percent positive random biopsies on biochemical outcome in prostate cancer patients treated with external beam radiotherapy with or without androgen deprivation.

PURPOSE: To identify the prognostic factors for biochemical outcome in patients with localized prostatic adenocarcinoma treated with external beam radiotherapy (EBRT) with or without androgen deprivation (AD) and to investigate the impact of percent positive prostate core biopsies (PCB%). METHODS: From 1998 through 2003, 333 patients with newly diagnosed localized prostate cancer were retrospectively analyzed. The patients were treated in two institutions with definitive EBRT to a median dose of 72 Gy and 80% of them received short- or long-term AD. Biochemical failure was defined using ASTRO criteria with 3 consecutive rises in prostate specific antigen (PSA). RESULTS: Median follow up was 36 months. Gleason score, initial PSA, risk grouping, PCB%, AD and total duration of AD were found to be significant predictors for biochemical outcome in univariate analysis. Independent predictors for PSA failure on multivariate analysis were PCB% and duration of AD. Among 3 risk groups, in the intermediate risk group the biochemical control was significantly better in patients with < 67% positive core biopsies. In the subgroup analysis of patients who received a prostatic dose or= 67% positive core biopsies. These significant differences did not exist in patients receiving > 70.2 Gy and long-term hormonal therapy. CONCLUSION: Our results suggest that high PCB% could be a predictor of biochemical relapse, especially in the intermediate risk group. The role of PCB% in prostate cancer should be investigated in further trials.