Growing evidence suggests that obesity, an established cause of renal cell cancer (RCC), may also be associated with a better prognosis. To evaluate the association between RCC survival and obesity, we analyzed a large cohort of patients with RCC and undertook a meta-analysis of the published evidence. We collected clinical and pathologic data from 1,543 patients who underwent nephrectomy for RCC between 1994 and 2008 with complete follow-up through 2008. Patients were grouped according to BMI (kg/m 2 ): underweight <18.5, normal weight 18.5 to <23, overweight 23 to <25 and obese !25. We estimated survival using the Kaplan-Meier method and Cox proportional hazard models to examine the impact of BMI on overall survival (OS) and cancer-specific survival (CSS) with adjustment for covariates. We performed a meta-analysis of BMI and OS, CSS and recurrence-free survival (RFS) from all relevant studies using a random-effects model. Kidney cancer incidence has been rising steadily world-wide with a 2.6% annual increase in the US between the years 1997 and 2007 1 and a 6.0% annual increase in South Korea between the years 1999-2007. 2 Accounting for 85% of all kidney cancer in adults, renal cell carcinoma (RCC) has a relatively poor prognostic outlook with no major breakthrough in primary treatment. However, overall survival (OS) rate has been increasing, with 5-year relative survival rate reaching 74.7% among men and 75.3% among women in South Korea during [2003][2004][2005][2006][2007]2 probably due to earlier diagnosis through improved diagnostic tools and detection of slow growing or even nonlethal RCC. Novel therapeutic approaches are needed, and there is indeed evidence that, for some cancers, lifestyle factors such as physical activity, diet and obesity, may also influence recurrence and survival after cancer diagnosis. 3 Overweight and obesity is one of few established causes for RCC, 4,5 accounting for an estimated 40% of all cases in the US and 30% in Europe. 6,7 Paradoxically, patients with higher body mass index (BMI) also had a significantly better RCC prognosis than those with lower BMI in several studies. [8][9][10][11][12][13][14][15] However, a possible association between obesity and RCC survival has not been yet generally accepted as causal and there has been no comprehensive systematic review of this association. We therefore analyzed a large cohort of Korean patients with RCC and then undertook a comprehensive meta-analysis of all informative studies published until recently.
Material and Methods
Study cohortWe identified 1,543 patients who underwent initial radical (n ¼ 1,259) or partial (n ¼ 284) nephrectomy for RCC at the
In patients with PSA level and no previous biopsy, 3-T MRI that is performed before transrectal ultrasound-guided biopsy may contribute to the detection of prostate cancer.
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