TFE3 Translocation-Associated Renal Cell Carcinoma Presenting as Avascular Necrosis of the Femur in a 19-Year-Old Patient: Case Report and Review of the Literature.

In the United States, renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and 90-95% of all neoplasms arising from the kidney. According to the National Cancer Institute, 58 240 new cases and 13 040 deaths from renal cancer will occur in 2010. RCC usually occurs in older adults between the ages of 50 and 70 and is rare in young adults and children. We describe a case of a TFE3 translocation-associated RCC in a 19-year-old patient presenting as avascular necrosis of the femur. Due to the rarity of this malignancy, we present this case including a review of the existing literature relative to diagnosis and treatment.

Improvements in dose homogeneity for tangential breast fields from a selection of combinations of library compensators.

Individually paired physical compensators are used in our centre to improve dose homogeneity for radiotherapy to the whole breast. This technical note describes the further improvements that may be achieved when all possible combinations of individual compensators within the library are considered. A retrospective study of 78 patients using a total of 16 (left-sided) and 14 (right-sided) sets of library compensators was evaluated, and the results expressed in terms of the standard deviation of the differential dose-volume histogram and the dose range within the breast volume. The mean of the standard deviations was 3.17% (uncompensated), 2.16% (paired compensators) and 1.97% (combinations) and the mean homogeneity was 15.3%, 11.8% and 11.1%, respectively.

Randomized clinical trial comparing low power-slow heating versus high power-rapid heating noncontact neodymium:yttrium-aluminum-garnet laser regimens for the treatment of benign prostatic hyperplasia.

OBJECTIVES: To evaluate and compare the safety and effectiveness of two noncontact laser regimens for the treatment of human benign prostatic hyperplasia (BPH), and to assess the impact of the spatial distribution of the laser-induced lesions on treatment outcome. METHODS: This was a prospective, double-blind, randomized study that included 29 patients with BPH (both the patients and the study physician assistant in charge of the follow-up evaluation were blinded to the treatment rendered). The patients were randomized to receive either a 15 W for 180 s (15 patients) or 50 W for 60 s (14 patients) laser regimen (powers measured at the fiber tip). There were two study phases for each treatment group: the irradiated sites were not overlapping during the first phase (lesions 1.5 cm apart), and were overlapping during the second phase (lesion less than 1.0 cm apart). RESULTS: Morbidity was minimal in both groups. At 1 year of follow-up, there was significant improvement of the American Urological Association-7 symptom score, the peak urinary flow rate, and the postvoid residual in both treatment groups. These improvements were not statistically significantly different regardless of time or the phase of the study for the two treatment groups. There were 3 treatment failures, 2 of whom were later successfully re-treated with larger amounts of laser energy. Furthermore, the peak flows in the second phase of the study were statistically significantly higher than those in the first phase of the study, regardless of the treatment group. CONCLUSIONS: Our results suggest that both the 15 W for 180 s and the 50 W for 60 s are equally safe and effective treatments for BPH. Perhaps more importantly, they also suggest that the spatial distribution of lesions and overlapping of treated (irradiated) sites has significant impact on treatment outcome.

Nd: YAG laser thermocoagulation of the prostate: the barbecue effect.

OBJECTIVE: To determine systematically the depth of coagulation necrosis induced during Nd: YAG laser irradiation in the canine prostate model, and to define the correlation of laser dose with depth of the lesions. METHODS: We investigated the effect of various dosimetries on prostatic tissue of 17 mongrel canines using laser power in the range of 8 to 60 watts (W) at varying exposure times, from 20 to 300 seconds (S). Applied energy ranged from 1,000 to 5,500 Joules (J). RESULTS: Three distinct features were observed. First, deep coagulation necrosis was induced only with laser regimens of > or = 2,100J, suggesting that there is a threshold of energy that must be overcome in order to achieve significant coagulation depth. Second, the deepest coagulation necrosis was achieved with a low power slow-heating regimen (15W X 180S). Tissue surface changes appeared to be responsible for the reduced depth of coagulation necrosis seen with higher power regimens (> 20 W). Third, increasing the energy above 3,600J did not augment the depth of coagulation, suggesting that a steady state for temperature distribution is reached at that rate of heating. CONCLUSIONS: Our study suggests that in the canine prostate, a low power slow-heating regimen of 15W X 180S may yield larger volumes of coagulation necrosis than other regimens.

Comparison of thermocoagulation effects of low power, slow heating versus high power, rapid heating Nd: YAG laser regimens in a canine prostate model.

We compared the thermocoagulation effects of low power, slow heating (15 W x 180 seconds) versus high power, rapid heating (50 W x 60 seconds) laser regimens in the canine prostate. The study was performed in 20 mongrel canines. On each prostate, the low power regimen was delivered at the 2 and 4 o'clock positions, and the high power at the 8 and 10 o'clock positions. The laser power was measured at the fiber tip. Seven dogs (acute group) were sacrificed 1 hour after the procedure. The other 13 dogs (chronic group) were sacrificed at different time intervals from 3 days to 9 weeks after the procedure. The average depth of coagulation was significantly greater in lesions treated at low power (acute: 10.7 mm., chronic: 13.3 mm.) than in those treated at high power (acute: 8.5 mm., chronic: 11.6 mm.). Another potential benefit of the low power regimen observed in the study was preservation of the integrity and efficiency of the laser probe.