Faculty Bibliography

Epidemiologic and experimental data suggest that soy consumption may prevent prostate cancer and be beneficial for men with prostate cancer. Soy intake and risk of prostate cancer are inversely correlated; soy isoflavones inhibit growth of prostate cancer cells and reduce prostate carcinogenesis in animal models. We tested the hypothesis that soy consumption reduces biochemical recurrence after radical prostatectomy in a randomized controlled clinical trial with a soy protein supplement versus a casein-based placebo in men at increased risk for PSA failure in the first 2 years after radical prostatectomy. PSA was tested at 2-month intervals in year 1 and every 3 months in year 2. Eligibility criteria were: Gleason sum of >8, extra-capsular extension, seminal vesicle invasion, positive surgical margins, positive lymph nodes, and/or a preoperative PSA of >20 ng/ml. Biochemical recurrence was defined a priori as reaching a PSA value of alpha0.07 ng/ml, confirmed twice. A two-year PSA failure rate in eligible subjects of approximately 30% was expected, based on data from NYU and previous literature. With a planned sample size of 128 evaluable subjects per arm, the study had 80% power to detect a 50% reduction in PSA failure rate at a 2-sided significance level of 0.05. The soy protein isolate and placebo (generously provided by Solae LCC, St Louis, MO) were identical in composition, except for the protein source (19.2-19.8 g protein/day); the soy product provided daily 23.5 mg genistein and 40.9 mg total isoflavones (aglycone equivalents); the placebo was devoid of any soy-specific constituents. Accrual did not reach the intended level and 172 subjects were randomized and enrolled, of whom 142 were evaluable (completed two years on study or developed confirmed recurrence within two years). Soy protein consumption did not alter recurrence rate or time-to-recurrence (TTR). Of the 74 evaluable subjects in the soy arm 22 (30%) recurred as did 22 (32%) of the 68 subjects in the placebo arm recurred. The!

Purpose: To retrospectively assess the relationships between a number of magnetic resonance (MR) imaging features and growth rate of solid renal masses in patients undergoing active surveillance. Materials and Methods: This retrospective study was institutional review board approved, with waiver of informed consent. This study was HIPAA compliant. Forty-four patients (mean age, 70 years +/- 13 [standard deviation]; 31 men, 13 women) with 47 solid renal masses measuring at least 1 cm who underwent two contrast material-enhanced MR imaging studies at least 3 months apart were included. The initial MR imaging study was evaluated independently by two radiologists for an array of imaging features, with differences resolved by consensus. Later, the two readers in consensus measured tumor volume on the first and last study to calculate tumor doubling time (DT). Associations between MR imaging features and DT were assessed by using generalized estimating equations and mixed model analyses. Interreader agreement was assessed with k coefficients. Results: kappa coefficients ranged from 0.62 to 0.92. Mean DT of the 47 masses was 530 days. Five (11%) masses decreased in size. Twenty-five of 47 masses were classified as slow growing on the basis of a DT of more than 2 years. There was significantly slower growth among masses showing homogeneity on T2-weighted images (P = .036) and a nearly significant slower growth rate among masses showing homogeneity on postcontrast images (P = .065) and hypointensity on T2-weighted images (P = .074). There was a significant correlation between initial volume and growth rate among lesions larger than 3 cm (r = 0.79, P = .041) but not among smaller lesions (r = -0.02, P = .911). Multivariate analysis identified age (odds ratio = 0.92, P = .015) and homogeneity on T2-weighted images (odds ratio = 4.47, P = .037) as independent predictors of slow growth. Conclusion: The results suggest MR imaging features may have a role in predicting growth rate of solid renal masses during active surveillance. (c) RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11111074/-/DC1.