Practical considerations in setting up an intracoronary brachytherapy program: results of a multicenter survey.

PURPOSE: To identify logistic issues faced by radiation oncologists in initiating intracoronary radiation therapy (RT) and to delineate their role in these procedures. MATERIALS AND METHODS: Radiation oncologists from 12 sites (with combined experience of >500 cases) that participated in a randomized, double-blinded study of intracoronary RT completed a questionnaire that included demographics and experience, regulatory issues, scheduling and interaction with patients, time commitment, involvement of the radiation oncologist, and ideas for overcoming hurdles. RESULTS: Licensing was perceived as a substantial hurdle; Nuclear Regulatory Commission approval took more than 5 months at five of 12 sites. At two higher-volume sites, 10-20 procedures were performed per week; 75% of these radiation oncologists did not see the patient prior to the procedure and were not involved in obtaining informed consent. The mean time spent per case was 30-90 minutes; however, there were major concerns about case scheduling (<50% had any input in case scheduling) and after-hours coverage. Radiation oncologists performed fluoroscopy and cineangiography at most centers (92% and 83%); they also performed intracoronary contrast material injections (67%), interpreted intravascular ultrasonographic images (42%), and repositioned the intracoronary RT catheter (33%). CONCLUSION: The authors identify several issues that need to be addressed before intracoronary RT becomes a part of widespread clinical practice. Close collaboration between cardiologists and radiation oncologists at various levels is required to ensure that patients derive maximal benefit from this new technology.

External beam radiation therapy to prevent postangioplasty dialysis access restenosis: a feasibility study.

PURPOSE: To evaluate the feasibility and short-term side-effects of postangioplasty external beam radiation for patients with compromised arteriovenous dialysis accesses. MATERIALS AND METHODS: Ten patients with compromised arteriovenous dialysis accesses were studied. Following confirmation of access compromise by an angiogram, patients were treated by a standard angioplasty +/- stent deployment. The target volume incorporated a margin of 1 cm beyond the angioplastied segment. The first 5 patients were treated to a dose of 12 Gy in two 6-Gy fractions spaced 48 h apart, whereas the next 5 patients were treated to 8 Gy in two similarly separated 4-Gy fractions. Five of the patients had at least one prior access that had failed. The current access had been in use for 6-52 months, and 5 of the 10 patients had at least one episode of compromise involving the current access. The length of stenosis ranged from 2 to 9 cm (mean 4.4 cm). All patients were followed clinically for adequacy of dialysis; a radiological follow-up with a fistulogram was performed for all in 3-monthly intervals. Follow-up ranged from 4 to 10 months, with a median follow-up of 6 months. RESULTS: There were no procedure-related complications. Three patients developed a restenosis at the site of the original stenosis, and one patient developed a restenosis at the edge of the stent. As part of the natural history of this process, five patients have also developed new lesions elsewhere in the proximal veins requiring radiological intervention. None of the patients showed any radiation-related side effects, either in the skin/ soft tissues, or in the vasculature on follow-up angiograms. CONCLUSIONS: Several different radiotherapeutic approaches are being currently investigated to prevent postangioplasty restenosis. There are several issues involved with the use of endovascular brachytherapy in these patients. On the other hand, given the superficial location of the dialysis access, we believe that external beam radiation offers a safe and simple method of radiation therapy in this setting. The clinical efficacy of this modality needs to be established through a randomized phase III trial.

Palladium-103: a new radioactive source in the treatment of unresectable carcinoma of the pancreas: a phase I-II study.

Palladium-103 (Pd-103) is introduced in brachytherapy procedures because of its favorable physical properties, including its low energy, rapid dose fall-off, short half-life, and total cumulative dose delivery at a higher dose rate than iodine-125 (I-125) isotope. Intraoperative brachytherapy using I-125 pellets was reported to provide significant palliation and meaningful prolongation of life in highly selected patients with unresectable carcinoma of the pancreas. After considering some of the advantages of Pd-103 over I-125, we designed a phase I-II clinical trial to assess the feasibility of intraoperative Pd-103 in unresectable carcinoma of the pancreas to study the related morbidity when combined with chemotherapy and external beam radiation, and to evaluate the impact on palliation and local control rates. Between December 1989 and December 1993, 15 patients with biopsy-proven unresectable adenocarcinoma of the pancreas were treated with interstitial Pd-103 implants during laparotomy. In 13 patients the lesion was located in the head of the pancreas, in one patient in the uncinate process, and in one patient in the body of the pancreas. The stage distribution was as follows: T1 = 2; T2 = 6, and T3 = 7. In addition, all patients underwent biliary and gastric bypass. The mean number of Pd-103 pellets was 45; the mean total activity to obtain a matched peripheral dose (MPD) of 11,000 cGy was 68.9 mCi. The mean tumor volume encompassing the MPD was 16.5 cc. All patients received postoperative external beam radiation (4,500 cGy over 4 1/2 weeks) and chemotherapy (5-fluorouracil and mitomycin C). This combined treatment, consisting of intraoperative brachytherapy using Pd-103 and postoperative external beam radiation with chemotherapy, was well tolerated in all patients. These were no treatment-related mortalities, and no serious complications, such as bleeding or fistula formation. Pain relief was obtained within 3-6 weeks in 10 out of 12 patients presenting with pain. Survival ranged from 6 to 24 months (median 10 months). The study suggests that Pd-103 can be considered an alternative to I-125 for interstitial brachytherapy for unresectable carcinoma of the pancreas. Symptom relief appeared to occur faster and complications are significantly less. However, this study did not show any improvement in the median survival rate over I-125 due to the advanced stage cancer in the majority of patients in the study.

High dose-rate intraluminal irradiation in bronchogenic carcinoma. Technique and results.

Patients who present with symptomatic airway obstruction often have limited therapeutic options. Intraluminal irradiation has been used in an attempt to obtain sustained palliation. Patients treated with high dose-rate endobronchial irradiation have shown good to excellent palliation of symptoms, as well as a high rate of local control; however, these results have not always been devoid of complications. Some recent reports have shown a high incidence of morbidity, including an excessive incidence of fatal pulmonary hemorrhage. In this series, we report on 80 high dose-rate endobronchial treatments in 32 patients who were treated with remote afterloading endobronchial irradiation. All patients had endoscopic and histologic proof of tumor. Patients were divided into two groups. Group 1 consisted of 17 patients who were treated with endobronchial brachytherapy as a boost to primary external-beam irradiation. The remaining 15 patients comprised group 2 and were treated for endobronchial recurrence after prior irradiation with an external beam (main dose, 5,000 cGy). The endobronchial irradiation treatments were delivered using a high dose-rate remote afterloader. The standard dose per fraction was 500 cGy prescribed at a distance of 1 cm from the central axis of the catheter for a median of 3 fractions at weekly intervals. Treatment length averaged 5 cm; the median total dose was 1,500 cGy. The median follow-up for the entire group was 9.3 months, with a range of 6 to 24 months. Symptomatic improvement was attained in 15 of 15 patients presenting with hemoptysis, in 6 of 7 of those with cough, and in 10 of 10 who presented with dyspnea. In ten patients, follow-up endoscopy was performed, which revealed a pathologic complete response (by negative results on biopsies). At 6 months past the last brachytherapy, clinical and radiographic local control was obtained in 15/17 (88 percent) of the patients in group 1 and in 70 percent of the patients in group 2. All patients tolerated treatment well, without any acute or late complications, and there were no instances of fistula formation or fatal pulmonary hemorrhage. There was no association between the location of recurrence and complications. Fractionation, dose per fraction, and total combined dose appear to be important parameters in reducing complications.

A versatile method for planning stereotactic brain implants.

Our approach to planning stereotactic 125I brachytherapy of brain tumors has involved least-squares optimization of individual seed positions within the target contour, followed by repeated combining of seeds from nearest-neighbor catheters in order to achieve an acceptably low number of catheters and an acceptable-separation of entry points. In one option, the catheters diverge from an extra-cranial point that can be close to the skull if all catheters are to be placed through a small craniectomy to treat a larger-diameter target. In another option, catheters converge toward a point beyond the target, to facilitate perpendicularity at the skull surface if a separate opening is to be drilled for each catheter. In either case, the fact that seed orientations are known, permits including anisotropy in dose calculations. Trial seed locations are constrained to a target region defined on a 1-mm mesh, both in the initial optimization of single-seed catheters and in subsequent combinations followed by tune-up optimizations. In the optimization process, sum-of-squares contributions are weighted more heavily when the dose rate is lower than the target dose rate; the weighting imbalance falls short of keeping all target points above the target dose rate and requires targeting on a dose rate about 25% higher than the desired minimum dose rate.

Treatment planning for permanent and temporary percutaneous implants with custom made templates.

Nine patients who were presented at MSKCC with primary or recurrent pelvic or head and neck tumors and for whom surgery or further external radiation were excluded, were treated with percutaneous permanent or temporary implants, with individual pre-treatment planning and custom made templates. The tumor dose distributions achieved were as good as for implants performed at the time of surgical exploration. No serious complications have been encountered.