Koichi Wadasaki

Results of a preliminary study using hypofractionated involved-field radiation therapy and concurrent carboplatin/paclitaxel in the treatment of locally advanced non-small-cell lung cancer

BackgroundWe aimed to evaluate the feasibility and efficacy of hypofractionated involved-field radiation therapy (IFRT) omitting elective nodal irradiation (ENI) with concurrent chemotherapy for locally advanced non-small-cell lung cancer (NSCLC).MethodsBetween July 2004 and July 2006, ten patients with locally advanced NSCLC were included in this study. One had stage IIIA and 9 had stage IIIB disease. The treatment consisted of IFRT in fractions of 2.5 Gy and weekly carboplatin (CBDCA)/paclitaxel (PTX). Hypofractionated IFRT with a median total dose of 65 Gy with median percent total lung volume exceeding 20 Gy (V20) of 20.2%, and a median of five courses of chemotherapy with weekly CBDCA (area under the curve, 1.5−2.0)/PTX (30−35 mg/m2) were given to all patients.ResultsThe median survival time and the 1-, 2-, and 3-year overall survival rates were 29.5 months and 90.0%, 58.3%, and 43.8%, respectively. No elective nodal failure was encountered during the median follow up of 18.2 months. No acute or late toxicities of grade 3 or worse were observed. No in-field recurrence occurred in the group with a total dose of 67.5 Gy or more, but there was such recurrence in 83.3% of those in the group with less than 67.5 Gy.ConclusionHypofractionated IFRT with weekly CBDCA/PTX was a feasible treatment regimen. Hypofractionated IFRT with a total dose of 67.5 Gy or more could be a promising modality to improve the treatment results in patients with locally advanced NSCLC.

Evaluation of the basic properties of the BANGkit? gel dosimeter

We evaluated the basic properties of a commercially available BANGkit gel dosimeter, which is a normoxic type of BANG gel. This gel-kit has the same composition as the BANG 3 gel, but is fully oxygenated. To exclude oxygen, oxygen scavenging ascorbic acid and copper sulfate as a catalyst are used. The properties that we examined are the effects of the concentrations of copper sulfate and ascorbic acid on the response, the reproducibility, the long-term stability, the temperature effect at irradiation and the dose-rate effect. In our results, the excellent linear fit of the R2-dose response in a dose range for clinical use and its reproducibility were observed. The precision of a linear fit was preserved for about 3 weeks. The temperature at irradiation showed a significant effect on the dose response. Although the dose-rate dependence in the high-dose range was observed, it was negligible for the clinical dose range up to 270 cGy. In conclusion, this gel dosimeter is thought to be utilizable in clinical practice, while we have to pay attention to the temperature during the entire measurement processes, and additionally there is room for improvement in the linearity and the dose-rate dependence in the high-dose range.

Treatment results of adjuvant radiotherapy and salvage radiotherapy after radical prostatectomy for prostate cancer.

BackgroundThe indications for and the efficacy of radiation therapy after radical operation for patients with prostate cancer are not clear. We analyzed the treatment results of adjuvant radiotherapy and salvage radiotherapy after radical prostatectomy.MethodsBetween September 1997 and November 2004, 57 patients received adjuvant radiotherapy or salvage radiotherapy after radical prostatectomy. Fifteen patients received radiation therapy because of positive margins and/or extracapsular invasion in surgical specimens (adjuvant group). Forty-two patients received radiation therapy because of rising prostate-specific antigen (PSA) during follow-up (salvage group). Radiation therapy was delivered to the fossa of the prostate ± seminal vesicles by a three-dimensional (3-D) conformal technique to a total dose of 60–66 Gy (median, 60 Gy). Biochemical control was defined as the maintenance of a PSA level of less than 0.2 ng/ml.ResultsThe median follow-up period after radiation therapy was 33 months (range, 12–98 months). Three-year biochemical control rates were 87% for the adjuvant group and 61% for the salvage group. For patients in the salvage group treated without hormone therapy, the preradiation PSA value was the most significant factor for the biochemical control rate. The 3-year biochemical control rate was 93% in patients whose preradiation PSA was 0.5 ng/ml or less and 29% in patients whose preradiation PSA was more than 0.5 ng/ml. No severe adverse effects (equal to or more than grade 3) were seen in treated patients.ConclusionRadiation therapy after radical prostatectomy seemed to be effective for adjuvant therapy and for salvage therapy in patients with a preradiation PSA of 0.5 ng/ml or less. Also, radiation to the fossa of the prostate ± seminal vesicles, to a total dose of 60–66 Gy, using a three-dimensional (3-D) conformal technique, seemed to be safe.

Computed tomography-based three-dimensional dosimetry of intracavitary brachytherapy for cervical cancer

PurposeThe aim of this study was to show the results of computed tomography (CT)-based dosimetry of intracavitary brachytherapy for cervical cancer.Materials and methodsA total of 20 patients with cervical cancer underwent intracavitary brachytherapy with external beam radiation therapy. The prescribed dose of brachytherapy was 6 Gy per fraction to point A. In every fraction a CT scan was performed after applicator insertion and three-dimensional (3D) dosimetry was done. The tumor dose was evaluated using D90 (the minimum dose delivered to 90% of the volume), and the doses of risk organs were evaluated using D2cc (the minimum dose in the most irradiated 2 cm3 of the volume).ResultsThe mean D90 for the clinical target volume (CTV) was 7.0 Gy (range 4.8–9.8 Gy). There was a negative correlation between the volume and the D90 for the CTV. The mean D2cc doses for the rectum and bladder were 6.0 Gy (range 3.9–9.0 Gy) and 6.5 Gy 5 Gy 2.9–9.0 Gy), respectively.ConclusionCT-based 3D dosimetry of intracavitary brachytherapy for cervical cancer was useful for evaluating the doses of the CTV and the organs at risk. In cases with a large CTV, CTV D90 was often lower than the point A dose, and modulation of the prescribed dose might have to be considered.

Relationship between sentinel lymph nodes and postoperative tangential fields in early breast cancer, evaluated using SPECT/CT.

Single-photon emission computed tomography/computed tomography (SPECT/CT) demonstrates the precise location of the sentinel lymph nodes (SLNs) in patients with breast cancer. We evaluated the relationship between SLNs and postoperative tangential fields by using SPECT/CT images. Subjects included 72 patients with early breast cancer who underwent SPECT/CT of the SLNs and received whole-breast irradiation with tangential fields after partial mastectomy. The SLN locations evaluated by using SPECT/CT images were entered into the treatment-planning CT image with a 5-mm-diameter sphere. A 15-mm-diameter sphere including the 5-mm treatment margin around the SLNs was defined as PTV-SLN. The PTV-SLN doses with tangential irradiation were evaluated and expressed as the percentage of the prescribed dose. In 69 patients, SLNs were detected by using SPECT/CT; 68 SLNs were located at axillary lymph node Level I, and one was located at Level II. A total of 62 SLNs (90%) were determined to be located inside the tangential fields on the digitally reconstructed radiography (DRR) images. The median doses of SLN center, mean PTV-SLN dose, and PTV-SLN D95 (the minimum dose delivered to 95% of the volume) were 94.1% (range, 15.3–101.9%), 93.7% (range, 29.3–104.0%) and 84.8% (range, 6.8–99.8%). The D95 for the SLNs with treatment margins were ≤90% of the prescribed doses in more than half of the cases. Modification of the individual treatment fields seemed to be necessary to ensure coverage of the SLNs in whole-breast irradiation.

Time-Adjusted Internal Target Volume: A Novel Approach Focusing on Heterogeneity of Tumor Motion Based on 4-Dimensional Computed Tomography Imaging for Radiation Therapy Planning of Lung Cancer

PURPOSE To consider nonuniform tumor motion within the internal target volume (ITV) by defining time-adjusted ITV (TTV), a volume designed to include heterogeneity of tumor existence on the basis of 4-dimensional computed tomography (4D-CT). METHODS AND MATERIALS We evaluated 30 lung cancer patients. Breath-hold CT (BH-CT) and free-breathing 4D-CT scans were acquired for each patient. The tumors were manually delineated using a lung CT window setting (window, 1600 HU; level, -300 HU). Tumor in BH-CT images was defined as gross tumor volume (GTV), and the sum of tumors in 4D-CT images was defined as ITV-4D. The TTV images were generated from the 4D-CT datasets, and the tumor existence probability within ITV-4D was calculated. We calculated the TTV80 value, which is the percentage of the volume with a tumor existence probability that exceeded 80% on ITV-4D. Several factors that affected the TTV80 value, such as the ITV-4D/GTV ratio or tumor centroid deviation, were evaluated. RESULTS Time-adjusted ITV images were acquired for all patients, and tumor respiratory motion heterogeneity was visualized. The median (range) ITV-4D/GTV ratio and median tumor centroid deviation were 1.6 (1.0-4.1) and 6.3 mm (0.1-30.3 mm), respectively. The median TTV80 value was 43.3% (2.9-98.7%). Strong correlations were observed between the TTV80 value and the ITV-4D/GTV ratio (R=-0.71) and tumor centroid deviation (R=-0.72). The TTV images revealed the tumor motion pattern features within ITV. CONCLUSIONS The TTV images reflected nonuniform tumor motion, and they revealed the tumor motion pattern features, suggesting that the TTV concept may facilitate various aspects of radiation therapy planning of lung cancer while incorporating respiratory motion in the future.

Clinical features of prostate-specific antigen bounce after 125I brachytherapy for prostate cancer

Abstract The aim of this study was to analyse the clinical features of prostate-specific antigen (PSA) bounce and the difference between biochemical failure and large-magnitude PSA bounce. The cases of 352 patients with prostate cancer who underwent brachytherapy were analysed. PSA bounce was defined as an increase in PSA of ≥0.2 ng/ml above an initial PSA nadir, with subsequent decline to or below that initial nadir without treatment. PSA bounce +2 was defined as an increase in PSA of ≥2.0 ng/ml above the nadir with subsequent decline to or below that initial nadir without treatment. We analysed the rates, time to onset, and predictive factors for PSA bounce and PSA bounce +2. The median follow-up period at the time of evaluation was 82 months. One hundred and seventeen patients had PSA bounce; of them, 10 had PSA bounce +2. Biochemical failure occurred in 29 patients. The median times to onset of PSA bounce, PSA bounce +2, and biochemical failure were 20, 17.5 and 51 months, respectively. Younger age at implant and larger prostate volume were significant predictive factors for PSA bounce. Age was a significant factor for PSA bounce +2, and PSA bounce +2 patients were significantly younger than biochemical failure patients. The maximum duration from the date of PSA bounce +2 to the date when PSA level decreased was 12 months. Age at implant, time to onset, and 1-year follow-up after an increase in PSA level of ≥2 ng/ml above nadir level are useful for distinguishing between biochemical failure and PSA bounce +2.

An unusual unilocular mesothelial cyst of the pleura: a case report.

A 79-year-old woman was found to have an abnormal shadow on chest radiography. Computed tomography demonstrated a pleural mass. The F-18 fluorodeoxyglucose positron emission tomography (FDG PET) was performed to determine whether the pleural mass was benign or malignant. The histologic examination of the resected mass showed a unilocular mesothelial cyst of the pleura. The FDG PET findings of a mesothelial cyst of the pleura have not yet been previously reported. The FDG PET findings of a mesothelial cyst in the pleura reflected the microscopic findings of the resected mass. The FDG PET findings, therefore, seem to be useful in the diagnosis of mesothelial cysts.