Image-guided intensity-modulated radiotherapy for patients with locally advanced gastric cancer: a clinical feasibility study.

BACKGROUND: The aim of this study was to determine the medical and technical feasibility of intensity-modulated radiotherapy (IMRT) in high-risk nonmetastatic gastric cancer stage II and III after primary gastrectomy and D2 lymphadenectomy. METHODS AND MATERIALS: A prospective nonrandomized phase II trial was performed on 25 consecutive patients with gastric cancer with high risk (T3-4, N1-3, G2-3, R0-1). The dose delivered was 45 Gy (1.80 Gy per fraction) in IMRT technique. Concurrent 5-fluorouracil-based chemotherapy at 225 mg/m(2) was administered as a continuous intravenous infusion. Primary endpoints were acute gastrointestinal toxicity (CTC 4.0) and technical feasibility of IMRT in regard to dose planning and radiation delivery. RESULTS: Early acute events were defined as clinical and chemical adverse effects of IMRT and concurrent chemotherapy during treatment. By definition, 90 days after the end of IMRT has been evaluated as acute-phase toxicity. No patient had grade 4 or higher acute adverse events. Clinical grade 3 toxicity occurred in two patients (8%) with diarrhea and in one case (4%) with nausea. Hematological changes with grade 3 occurred in three cases (12%) with hemoglobin decrease, in five cases (25%) as leukopenia, and in one case (4%) with thrombocytopenia. The mean dose for liver was 16 Gy and the percentage volume exceeding 30 Gy (V30) was 21%. Mean dose for right and left kidney was 9 and 13 Gy, respectively, and V20 was 9% and 13%, respectively. Heart received a median dose of 15 Gy and V40 was 17%. The mean dose to the bowel was 11 Gy and V40 was 6%. Spinal cord had at maximum 33 Gy in median. Specifics of dose distribution, including the coverage, for the target region were as follows: minimum was 33 Gy, maximum 48.6 Gy, and mean dose 44.6 Gy. The prescribed dose (45 Gy) covered 99% and 95% of planning target volume (OTV) in 66% and 92% of cases, respectively. Median PTV was 15.77 ml (range, 805-3,604 ml). CONCLUSIONS: The data support the practical feasibility of IMRT in adjuvant treatment in high-risk gastric cancer in the postoperative setting as a proof of principle. Acute toxicity has been tolerable.

Potentials of on-line repositioning based on implanted fiducial markers and electronic portal imaging in prostate cancer radiotherapy.

BACKGROUND: To evaluate the benefit of an on-line correction protocol based on implanted markers and weekly portal imaging in external beam radiotherapy of prostate cancer. To compare the use of bony anatomy versus implanted markers for calculation of setup-error plus/minus prostate movement. To estimate the error reduction (and the corresponding margin reduction) by reducing the total error to 3 mm once a week, three times per week or every treatment day. METHODS: 23 patients had three to five, 2.5 mm Ø spherical gold markers transrectally inserted into the prostate before radiotherapy. Verification and correction of treatment position by analysis of orthogonal portal images was performed on a weekly basis. We registered with respect to the bony contours (setup error) and to the marker position (prostate motion) and determined the total error. The systematic and random errors are specified. Positioning correction was applied with a threshold of 5 mm displacement. RESULTS: The systematic error (1 standard deviation [SD]) in left-right (LR), superior-inferior (SI) and anterior-posterior (AP) direction contributes for the setup 1.6 mm, 2.1 mm and 2.4 mm and for prostate motion 1.1 mm, 1.9 mm and 2.3 mm. The random error (1 SD) in LR, SI and AP direction amounts for the setup 2.3 mm, 2.7 mm and 2.7 mm and for motion 1.4 mm, 2.3 mm and 2.7 mm. The resulting total error suggests margins of 7.0 mm (LR), 9.5 mm (SI) and 9.5 mm (AP) between clinical target volume (CTV) and planning target volume (PTV). After correction once a week the margins were lowered to 6.7, 8.2 and 8.7 mm and furthermore down to 4.9, 5.1 and 4.8 mm after correcting every treatment day. CONCLUSION: Prostate movement relative to adjacent bony anatomy is significant and contributes substantially to the target position variability. Performing on-line setup correction using implanted radioopaque markers and megavoltage radiography results in reduced treatment margins depending on the online imaging protocol (once a week or more frequently).

Thermoradiotherapy using interstitial self-regulating thermoseeds: an intermediate analysis of a phase II trial.

OBJECTIVE: Thermoradiotherapy in the treatment of prostate cancer is based on a variety of experimental and clinical phase I data which have proven the synergistic effects of this combination. We report on a phase II trial in a special hyperthermia research group (SFB 273) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to determine feasibility, acute toxicity and efficacy of this combination for prostate cancer. METHODS: 57 patients with localized prostate cancer were treated with interstitial hyperthermia using cobalt-palladium thermoseeds and conformal radiation between July 1997 and December 2000. Thermoseeds were placed into the prostate homogeneously. Hyperthermia was created using a magnetic field and was delivered in six sessions once weekly for one hour. 3D-conformal radiotherapy of 68.4Gy was given simultaneously in daily fractions of 1.8Gy. RESULTS: Intraprostatic temperatures were between 42 and 46 degrees C. No major side effects were observed during hyperthermia. Median follow-up was 36 months (range 3-72 months). Median PSA value decreased from 11.6ng/ml to 2.4ng/ml 3 months after treatment, to 1.3ng/ml 12 months after treatment and to 0.55ng/ml 2 years after therapy. CONCLUSION: Interstitial hyperthermia is feasible, well tolerated and led to a steep decrease of PSA values. Combining effective interstitial hyperthermia with conformal radiotherapy may be an exciting innovative treatment option for prostate cancer.

Interstitial hyperthermia using self-regulating thermoseeds combined with conformal radiation therapy.

OBJECTIVE: The combination of hyperthermia and radiation in the treatment of malignancies is based on a variety of experimental data which have proven the synergistic effects of these two treatment modalities. We planned a phase II trial in a special hyperthermia research group (SFB 273) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) to determine feasibility, acute toxicity and efficacy of this combination for prostate cancer. METHODS: A total of 57 patients with localized prostate cancer were treated with interstitial hyperthermia using cobalt-palladium thermoseeds and conformal radiation between July 1997 and December 2000. Thermoseeds were placed into the prostate homogeneously. Hyperthermia was created using a magnetic field and was delivered in six sessions once weekly. 3D-conformal radiotherapy of 68.4Gy was given simultaneously in daily fractions of 1.8Gy. RESULTS: Intra-prostatic temperatures were between 42 and 46 degrees C. No major side effects were observed during hyperthermia. Median follow-up was 12 months (range: 3-26 months). Median prostate specific antigen (PSA) value decreased from 11.6 to 2.4 ng/ml 3 months after treatment, to 1.3ng/ml 12 months after treatment and to 0.55 ng/ml 2 years after the therapy. CONCLUSION: Interstitial hyperthermia is feasible, well tolerated and led to a steep decrease of PSA values. Our current follow-up is too short to comment about efficacy. Combining effective interstitial hyperthermia with conformal radiotherapy may be an exciting innovative treatment option for prostate cancer.