Neoadjuvant androgen ablation in localized carcinoma of the prostate. (57/1081)

BACKGROUND: An increased awareness of prostate cancer has led to a rise in the detection of this disease at a clinically localized stage at presentation. This article discusses the role of neoadjuvant hormonal ablation at this earlier stage to decrease tumor bulk and thus enhance survival. METHODS: Outcomes from each primary modality for localized treatment of prostate cancer with and without neoadjuvant androgen deprivation (NAAD) are reviewed. RESULTS: Survival benefit using NAAD has not yet been demonstrated from prostatectomy. Long-term hormonal deprivation provides an improved time to progression and has decreased distant metastatic and biochemical failure for poor-risk patients undergoing external-beam radiation. The toxicities of brachytherapy can be decreased with NAAD. CONCLUSIONS: NAAD with radical prostatectomy is considered to be investigational. The duration of NAAD needs to be delineated for poor-prognosis patients who are treated with external-beam radiation therapy, but the approach improves the local toxicity of brachytherapy.  (+info)

The evolving role of prostate brachytherapy. (58/1081)

BACKGROUND: The publication of several large studies with long-term results on the use of prostate brachytherapy has resulted in increased use of this option for patients with localized prostate cancer. METHODS: A historical review of brachytherapy as an approach to prostate cancer management is provided, as well as a general summary of the implant technique and the results to date according to patient risk. The effects of combination therapies for specific patient groups are also reviewed. RESULTS: A recent 12-year follow-up reported no failures after 10 years, and 75% of recurrences occurred with-in the first 5 years. Patients at low risk for failure based on stage, grade, and prostate-specific antigen (PSA) parameters are likely to have disease confined to the prostate. Those with more advanced disease are likely to have a lower probability of cure with brachytherapy as monotherapy. Complications involve primarily the urinary tract. Ideal candidates have a PSA of =10, Gleason score of =7, and low-volume/low-stage disease (stage T1c or T2a). Patients with more-advanced disease are candidates for brachytherapy combined with external-beam radiation therapy (EBRT). For high-risk men with multiple adverse prognostic features, consideration should be given to clinical trials investigating innovative treatment combinations (eg, the addition of androgen blockade, and EBRT). CONCLUSIONS: The rarity of failures after 5 years and the absence of recurrence after 10 years suggest a that brachytherapy for localized prostate cancer can provide durable disease control. Future improvements in pathologic tools may lead to selection of patients more likely to respond well to brachytherapy.  (+info)

An analytic dosimetry study for the use of radionuclide-liposome conjugates in internal radiotherapy. (59/1081)

A dosimetric analysis has been performed to evaluate the potential of liposome systems as carriers of radionuclides in internal radiotherapy. METHODS: Pharmacokinetic data for a variety of liposome constructs (multilamellar vesicles [MLV]; small unilamellar vesicles [SUV]; and sterically stabilized liposomes, monosialoganglioside [G(M1)]-coated) were used to obtain tumor and normal-organ absorbed dose estimates for (67)Cu, (188)Re, (90)Y, and (131)I. Dosimetry was performed for two tumor models: subcutaneous Ehrlich ascites tumor, growing intramuscularly, and C26 colon carcinoma, growing intrahepatically. Dose estimates were obtained using the MIRD schema. Tumor doses were obtained assuming local deposition of electron energy; photon contributions were incorporated assuming spheric tumor geometry. With the conservative assumption that intravenously administered liposomes achieve rapid equilibration with the red marrow extracellular fluid volume, red marrow absorbed dose estimates were obtained from blood kinetics. RESULTS: For intramuscular tumors, absorbed dose ratios for tumor to red marrow ranged from 0.93 ((131)I-MLV) to 13.9 ((90)Y-SUV). Tumor-to-liver ratios ranged from 0.08 ((188)Re-MLV) to 0.92 ((188)Re-SUV); corresponding values for tumor to spleen were 0.13 ((90)Y-MLV) and 0.54 ((188)Re-G(M1)). The optimal combination of radionuclide and liposome system was obtained with (90)Y-SUV. Tumor-to-liver ratios for the G(M1)-coated construct were greatest when the tumor was intrahepatic (1.13 for (90)Y). For a given liposome system, absorbed dose ratios for tumor to normal tissue exhibited up to a twofold variation depending on the radionuclide selected. CONCLUSION: This study provides a dosimetric evaluation for the use of some liposome systems as carriers in targeted radionuclide therapy. Although much further work must be undertaken before any clinical application is considered, these results suggest that radionuclide targeting using liposomes is feasible and may have the advantage of reduced red marrow absorbed dose.  (+info)

High dose rate interstitial brachytherapy in soft tissue sarcoma: technical aspects and results. (60/1081)

BACKGROUND: Radiation is essential for function preservation in the management of soft tissue sarcoma (STS). One of the advantages of brachytherapy is that it allows for specific localization of radiation dose to the tumor bed. We examined the results of our clinical experiences with immediate postoperative high dose rate (HDR) brachytherapy and external beam radiation treatment (EBRT) for STS. METHODS: A total of 17 patients (11 primary and six recurrent) between 1995 and 1999 were included in this review. The inclusion criteria for HDR and EBRT were as follows: (1) high-grade tumor, (2) low-grade tumor of > or = 10 cm, (3) recurrent tumor, (4) tumor abutting or invading critical structures and (5) positive margin. The catheters (six French) were placed parallel to the long axis of the tumor with a 1-1.5 cm spacing in between. If necessary, muscle or gel-foam was placed over the critical structures to maintain a minimum space of 0.5 cm from the catheters. On postoperative day 6, patients received HDR (2-3 Gy/fraction x6, twice daily). Three weeks later, patients received EBRT (total 36-60 Gy). The follow-up duration was between 13 and 60 months (median 31 months). RESULTS: There was no local failure within the radiation field in any of the patients. One patient required wound revision for delayed healing after brachytherapy. During EBRT, most patients experienced only mild erythema (grade 1 or 2 skin reaction). In long-term follow-up, there were no patients with neuropathy or significant fibrosis. CONCLUSIONS: Our results suggest that immediate postoperative HDR with a total dose of 12-18 Gy over 3 days is an effective treatment combined with EBRT in the management of STS.  (+info)

High-dose-rate endobronchial brachytherapy in endobronchial metastatic malignant chondroid syringoma. (61/1081)

A 65-year-old man with malignant chondroid syringoma (MCS) was found to have pulmonary metastases in the form of multiple pulmonary nodules 4 years after wide excision and adjuvant radiotherapy of a primary abdominal wall tumor. Atelectasis of the lingula due to obstructive endobronchial metastasis, resistant to combination chemotherapy, led us to perform high-dose rate (HDR) endobronchial brachytherapy for the first time in this rare tumor with a favorable response. This case emphasizes the role of HDR brachytherapy as a palliative procedure in endobronchial tumors not responding to other treatment modalities, even those considered to be radioresistant.  (+info)

The pattern of restenosis and vascular remodelling after cold-end radioactive stent implantation. (62/1081)

BACKGROUND: Edge restenosis is a major problem after radioactive stenting. The cold-end stent has a radioactive mid-segment (15.9 mm) and non-radioactive proximal and distal 5.7 mm segments. Conceptually this may negate the impact of negative vascular remodelling at the edge of the radiation. METHOD AND RESULTS: ECG-gated intravascular ultrasound with three-dimensional reconstruction was performed post-stent implantation and at the 6-month follow-up to assess restenosis within the margins of the stent and at the stent edges in 16 patients. Angiographic restenosis was witnessed in four patients, all in the proximal in-stent position. By intravascular ultrasound in-stent neointimal hyperplasia, with a >50% stented cross-sectional area, was seen in eight patients. This was witnessed proximally (n=2), distally (n=2) and in both segments (n=4). Echolucent tissue, dubbed the 'black hole' was seen as a significant component of neointimal hyperplasia in six out of the eight cases of restenosis. Neointimal hyperplasia was inhibited in the area of radiation: Delta neointimal hyperplasia=3.72 mm3 (8.6%); in-stent at the edges of radiation proximally and distally Delta neointimal hyperplasia was 7.9 mm3 (19.0%) and 11.4 mm3 (25.6%), respectively (P=0.017). At the stent edges there was no significant change in lumen volume. CONCLUSIONS: Cold-end stenting results in increased neointimal hyperplasia in in-stent non-radioactive segments.  (+info)

Prophylaxis of restenosis with (186)re-labeled stents in a rabbit model. (63/1081)

BACKGROUND: Intraluminal beta-irradiation has been shown to decrease neointimal proliferation after angioplasty in experimental models. The purpose of this study was to test the technical feasibility and biological effects of (186)Re-labeled stents. METHODS AND RESULTS: Thirty-four New Zealand White rabbits were fed a 0.5% cholesterol diet before balloon angioplasty and insertion of Palmaz stents in the infrarenal aorta. The animals were killed 7 weeks after stent implantation. Two of 34 animals died prematurely (aortic leak, pneumonia). Control stents (n=7) were compared with (186)Re stents (2.6 MBq [n=6], 8.1 MBq [n=5], 16.0 MBq [n=6], and 25.3 MBq [n=8]). Stent application was successful in all cases. No thrombus occlusion was observed. After 7 weeks, neointima formation was 2.2+/-0.2 mm(2) in the control group. In the treatment groups, a dose-dependent neointima reduction was detectable (0.5+/-0.5 mm(2) [2.6 MBq], 0.4+/-0.4 mm(2) [8.1 MBq], and 0 mm(2) [16.0 MBq, 25.3 MBq]). No induction of neointimal formation was observed at the edges of the stents. Radiation resulted in delayed reendothelialization. CONCLUSIONS: (186)Re stents were capable of reducing neointima formation in a dose-dependent fashion. (186)Re stents did not cause late thrombosis or neointimal induction at the stent margins in the observation period of 7 weeks.  (+info)

Geographical miss during catheter-based intracoronary beta-radiation: incidence and implications in the BRIE study. Beta-Radiation In Europe. (64/1081)

OBJECTIVES: We sought to determine the incidence and causes of geographical miss (GM) and to evaluate its impact on edge restenosis after intracoronary beta-radiation therapy. BACKGROUND: Edge restenosis is a limitation of intracoronary beta-radiation therapy. Geographical miss is the situation in which the radiation source does not fully cover the injured segment and may lead to edge restenosis. METHODS: We analyzed 175 vessels treated according to the Beta-Radiation In Europe (BRIE) study protocol. The effective irradiated segment (EIRS) and both edges were studied with quantitative coronary angiography. The edges of the EIRS that were injured constituted the GM edges. Restenosis was defined as diameter stenosis >50% at follow-up. Geographical miss was determined by simultaneous electrocardiographic-matched, side-by-side projection of the source and balloons deflated at the injury site, in identical angiographic projections surrounded by contrast. RESULTS: Geographical miss affected 41.2% of the edges and increased edge restenosis significantly compared with non-GM edges (16.3% vs. 4.3%, respectively, p = 0.004). Restenosis was increased both in the proximal (p = 0.05) and distal (p = 0.02) GM edges compared with noninjured edges. Geographical miss associated with stent injury significantly increased edge restenosis (p = 0.006), whereas GM related to balloon injury did not significantly increase edge restenosis (p = 0.35). The restenosis in the EIRS was similar between vessels with and without GM (24.3% and 21.6%, respectively, p = 0.8). CONCLUSIONS: Geographical miss is strongly associated with restenosis at the edges of the EIRS. This effect is more prominent when caused by stenting. Geographical miss does not increase restenosis in the EIRS.  (+info)