Permanent prostate brachytherapy preplanned technique: The modern Seattle method step-by-step and dosimetric outcomes.

PURPOSE: To describe, step-by-step, the current Seattle preplan technique, and report the dosimetric outcomes on 1,131 consecutively such treated prostate brachytherapy patients. METHODS AND MATERIALS: One thousand one hundred thirty one patients with prostate cancer were treated with iodine-125 ((125)I), palladium-103 ((103)Pd), or cesium-131 ((131)Cs) using a preplanned template-guided transrectal ultrasound-guided approach between January 2005 and August 2007. Day one computed tomography (CT) scans were taken for postimplantation dose-volume histogram evaluations. Postoperative prostate contours were drawn by one author (DN) on CT images taken on postoperative day one. RESULTS: The volume of prostate receiving 100% of prescription dose (V(100)) and percent dose to 90% of the prostate (%D(90)) were 95% and 106% for 558 monotherapy (125)I implants, 91% and 102% for 327 (103)Pd implants, and 97% and 111.5% for 13 (131)Cs implants, respectively. The median V(100) and percent D(90) were 91% and 101% for five boost (125)I implants, 92% and 104% for 228 boost (103)Pd implants. The median rectal volume receiving 100% of prescription dose (RV(100)) for (125)I, (103)Pd, and (131)Cs monotherapy implants were 0.3, 0.13, and 0.38cc, and for (125)I and (103)Pd boost implants were 0.16 and 0.13cc, respectively. No patient received an RV(100) of >0.92cc. CONCLUSIONS: Modern preplanned template and ultrasound-guided prostate brachytherapy can consistently result in excellent prostate dosimetry and rectal sparing.

Simplifying intensity-modulated radiotherapy plans with fewer beam angles for the treatment of oropharyngeal carcinoma.

The first aim of the present study was to investigate the feasibility of using fewer beam angles to improve delivery efficiency for the treatment of oropharyngeal cancer (OPC) with inverse-planned intensity-modulated radiation therapy (IP-IMRT). A secondary aim was to evaluate whether the simplified IP-IMRT plans could reduce the indirect radiation dose. The treatment plans for 5 consecutive OPC patients previously treated with a forward-planned IMRT (FP-IMRT) technique were selected as benchmarks for this study. The initial treatment goal for these patients was to deliver 70 Gy to > or = 95% of the planning gross tumor volume (PTV-70) and 59.4 Gy to > or = 95% of the planning clinical tumor volume (PTV-59.4) simultaneously. Each case was re-planned using IP-IMRT with multiple beam-angle arrangements, including four complex IP-IMRT plans using 7 or more beam angles, and one simple IMRT plan using 5 beam angles. The complex IP-IMRT plans and simple IP-IMRT plans were compared to each other and to the FPIMRT plans by analyzing the dose coverage of the target volumes, the plan homogeneity, the dose-volume histograms of critical structures, and the treatment delivery parameters including delivery time and the total number of monitor units (MUs). When comparing the plans, we found no significant difference between the complex IP-IMRT, simple IP-IMRT, and FP-IMRT plans for tumor target coverage (PTV-70: p = 0.56; PTV-59.4: p = 0.20). The plan homogeneity, measured by the mean percentage isodose, did not significantly differ between the IP-IMRT and FP-IMRT plans (p = 0.08), although we observed a trend toward greater inhomogeneity of dose in the simple IP-IMRT plans. All IP-IMRT plans either met or exceeded the quality of the FP-IMRT plans in terms of dose to adjacent critical structures, including the parotids, spinal cord, and brainstem. As compared with the complex IP-IMRT plans, the simple IP-IMRT plans significantly reduced the mean treatment time (maximum probability for four pairwise comparisons: p = 0.0003). In conclusion, our study demonstrates that, as compared with complex IP-IMRT, simple IP-IMRT can significantly improve treatment delivery efficiency while maintaining similar target coverage and sparing of critical structures. However, the improved efficiency does not significantly reduce the total number of MUs nor the indirect radiation dose.

A zero PSA slope in posttreatment prostate-specific antigen supports cure of patients with long-term follow-up after external beam radiotherapy for localized prostate cancer.

PURPOSE: To determine whether the rate of change in prostate-specific antigen (PSA) in patients treated with external beam radiotherapy for localized prostate cancer improves our ability to define which patients are likely to be cured of their disease. METHODS AND MATERIALS: Patients treated between 1987 and 1995 at the University of California, San Francisco and the University of Michigan for localized prostate cancer with external beam radiotherapy and without hormonal ablation were evaluated for this study. The PSA slope was calculated for 199 patients who were disease free by the American Society for Therapeutic Radiology and Oncology consensus definition for at least 4 years and at last follow-up. Patients were categorized into groups defined by no increase, minimal increase, modest increase, and a definite increase in change in PSA level, corresponding to slopes of 0.0-0.1, >0.1-0.5, and >0.5 ng/mL/y, respectively. RESULTS: Fifty-four percent of the patients displayed a non-increasing PSA (Group 1), 23% had a minimal increase (Group 2), 17% had a modest increase (Group 3), and 6% had a definite increase (Group 4). Patients with a non-increasing PSA slope had a significantly longer time to nadir (median 47.8, 31.6, 29.9, and 23.3 months for Groups 1-4, respectively, p = 0.0001) and a lower median PSA nadir (median 0.30, 0.40, 0.55, and 1.00 ng/mL for Groups 1-4, respectively, p = 0.0006). CONCLUSION: On the basis of PSA kinetics, we believe that a group of patients can be defined who appear to be cured of localized prostate cancer (i.e., have a zero slope). These patients have a lower and later PSA nadir, as well as a more substantial proportional effect of external beam radiotherapy on their PSA level. Patients with a definite increase in PSA slope are erroneously labeled disease free by the American Society for Therapeutic Radiology and Oncology consensus definition.