Exploring causes for declining prostate cancer mortality rates in the United States

The current evidence on statin use and prostate cancer prevention: are we there yet?

An increasing amount of data supports an inverse association between statin use and cancer risk. The findings for prostate cancer, particularly advanced disease, are the most promising of all cancers studied. Use of these agents seems to also be associated with improved prostate- cancer-specific survival, particularly in men undergoing radiotherapy, suggesting usefulness of statins in secondary and tertiary prevention. Some study results might be influenced by increased PSA screening and health-conscious behaviour in statin users but these factors are unlikely to completely account for observed beneficial effects. The epidemiological evidence is supported by preclinical studies that show that statins directly inhibit prostate cancer development and progression in cell-based and animal-based models. The antineoplastic effect of statins might arise from a number of cholesterol-mediated and non-cholesterol-mediated mechanisms that affect pathways essential for cancer formation and progression. Understanding these mechanisms is instrumental in drug discovery research for the development of future prostate cancer therapeutics, as well as in designing clinical trials to test a role for statins in prostate cancer prevention. Currently, sufficient data are lacking to support the use of statins for the primary prevention of prostate cancer and further research is clearly warranted. Secondary and tertiary prevention trials in men who have been diagnosed with prostate cancer might soon be performed.

A review of statin use and prostate cancer

Prostate cancer is the second most common cause of cancer and, when it metastasizes, has a high mortality rate. Statins may affect prostate cancer progression through cholesterol- and pleiotropic-mediated effects. The data on statin effects on prostate cancer has been mixed with benefit most likely occurring in reducing prostate cancer recurrence after radiation therapy and reduced mortality due to prostate cancer. More research is needed in this area to better characterize potential statin-mediated mechanisms that affect cancer. Also, future studies should report patients' anatomic/prognostic stage based on the updated staging system of the American Joint Committee on Cancer, which is a more effective predictor of recurrence and mortality than anatomic stage alone.

Attitudes and knowledge of primary care physicians regarding prostate cancer screening

Recently, several prospective randomized prostate cancer screening studies have been reported. We report the results of a questionnaire administered to primary care physicians (PCPs) to determine their attitudes on prostate cancer screening and compared these results to those obtained when the same questionnaire was administered to a different large cohort of PCPs in 2006 prior to the reporting of these randomized studies. A 24-item questionnaire designed to assess prostate cancer knowledge and screening attitudes was administered to PCPs within central Florida and those PCPs attending a state conference. Completed surveys were returned and analyzed. All reported p values were two-sided, and those p values less than 0.05 were considered to be statistically significant. Seven hundred and eighty PCPs received the study questionnaire, and 168 (22 %) PCPs returned the completed questionnaire. Sixty-eight percent of responders stated that they recommend prostate cancer screening to >75 % of their patients over the age of 50 years, up from 47 % in 2006 (p < 0.001). Seventy-four percent of responders felt screening was effective. The overall mean score of the knowledge survey was 66 %, which was similar to the cohort from 2006. Knowledge scores were not associated with screening attitudes and behaviors. On multivariate analysis, practice setting and percentage of Medicaid patients in the practice were associated with attitude scores. Our current findings imply that despite the recent landmark studies published on prostate cancer screening, PCPs' screening attitudes have changed minimally over the past 5 years.

Does urological cancer mortality increase with low population density of physicians?

PURPOSE

We examined the association between urological cancer mortality rates and the presence of physicians. We hypothesized that cancer mortality rates increase with a low physician population density since this would decrease the detection of cancers at an early stage.

MATERIALS AND METHODS

Mortality rates for prostate cancer, bladder cancer, kidney and renal pelvis cancer, and cancer at all sites for white patients in United States counties from 2003 to 2007 were obtained from the National Vital Statistics System. High and low rate groups of counties were reviewed for each type of cancer. The high rate groups consisted of 15 or 25 counties with the highest cancer mortality rates. The low rate groups consisted of counties, selected from the same states as high rate groups, with the lowest mortality rates. Levels of physicians per 10,000 general population, income, poverty and no health insurance were compared between the high and low cancer rate groups.

RESULTS

There was a statistically significant inverse association between physician population density levels and kidney and renal pelvis cancer mortality rates. The association was suggestive for bladder cancer and prostate cancer mortality but not for cancer at all sites. There was also a tendency for an inverse association between family income and cancer mortality rates.

CONCLUSIONS

Kidney and renal pelvis cancer mortality rates increased significantly with a low physician population density. We found a suggestive but not significant negative association between physician population density and mortality rates for prostate cancer and bladder cancer but not for cancer at all sites. Low family income was associated with higher cancer rates.

Statin Clinical Trial (REALITY) for prostate cancer: an over 15-year wait is finally over thanks to a dietary supplement

Support for a prescription statin clinical trial for the prevention or treatment of prostate cancer has been lacking, although recent data have provoked interest in such a study. The authors have initiated a pilot trial of red yeast rice (RYR) extract and prostate cancer. RYR significantly reduces low-density lipoprotein and is an option for statin-intolerant patients. RYR appears to be an adequate proxy for some statins as long as quality control is monitored. The REALITY (REduction in Active surveillance Lipid Indices Through Yeast of red rice) trial will be conducted in Toronto, Canada.

Prostate cancer mortality in Taiwanese men: increasing age-standardized trend in general population and increased risk in diabetic men

BACKGROUND

To evaluate the trend of prostate cancer mortality in Taiwanese general population and the association between diabetes and prostate cancer mortality.

MATERIALS AND METHODS

In the general population during 1995-2006, the trends of prostate cancer mortality were evaluated, followed by calculation of age-specific mortality rates for age 40-64, 65-74, and ≥ 75 years. A cohort of 102,651 diabetic men aged ≥ 40 years recruited in 1995-1998 was followed prospectively.

RESULTS

The trends of crude and age-standardized mortality from prostate cancer in the general population increased significantly (P < 0.0001). In the general population, 7,966 men aged ≥ 40 years died of prostate cancer, and aging was associated with increased risk. Age-specific prostate cancer mortality suggested significantly increasing trend for ages 65-74 and ≥ 75 years. A total of 321 diabetic men died of prostate cancer (crude mortality rate 41.9/100,000 person-years). Mortality rate ratios (95% confidence interval) showed higher risk of prostate cancer mortality in the diabetic patients, with magnitude increased with decreasing age: 1.55 (1.29-1.86), 2.68 (2.29-3.13), and 6.84 (5.34-8.75) for age ≥ 75, 65-74, and 40-64 years, respectively.

CONCLUSIONS

Prostate cancer mortality in the Taiwanese general population is increasing. Diabetic patients have a higher risk of prostate cancer mortality, which is more remarkable with decreasing age.

Micronutrients attenuate progression of prostate cancer by elevating the endogenous inhibitor of angiogenesis, platelet factor-4

Background

Longstanding evidence implicates an inadequate diet as a key factor in the onset and progression of prostate cancer. The purpose herein was to discover, validate and characterize functional biomarkers of dietary supplementation capable of suppressing the course of prostate cancer in vivo.

Methods

The Lady transgenic mouse model that spontaneously develops prostate cancer received a diet supplemented with a micronutrient cocktail of vitamin E, selenium and lycopene ad libitum. A proteomic analysis was conducted to screen for serum biomarkers of this dietary supplementation. Candidate peptides were validated and identified by sequencing and analyzed for their presence within the prostates of all mice by immunohistochemistry.

Results

Dietary supplementation with the combined micronutrients significantly induced the expression of the megakaryocyte-specific inhibitor of angiogenesis, platelet factor-4 (P = 0.0025). This observation was made predominantly in mice lacking tumors and any manifestations associated with progressive disease beyond 37 weeks of life, at which time no survivors remained in the control group (P < 0.0001). While prostates of mice receiving standard chow were enlarged and burdened with poorly differentiated carcinoma, those of mice on the supplemented diet appeared normal. Immunohistochemical analysis revealed marked amplifications of both platelet binding and platelet factor-4 within the blood vessels of prostates from mice receiving micronutrients only.

Conclusion

We present unprecedented data whereby these combined micronutrients effectively promotes tumor dormancy in early prostate cancer, following initiation mutations that may drive the angiogenesis-dependent response of the tumor, by inducing platelet factor-4 expression and concentrating it at the tumor endothelium through enhanced platelet binding.

Association between statins and prostate tumor inflammatory infiltrate in men undergoing radical prostatectomy

BACKGROUND

Cholesterol-lowering drugs known as statins have been reported to have significant anti-inflammatory properties. Given that inflammation may contribute to prostate cancer progression and that statins may reduce the risk for advanced prostate cancer, we investigated whether statin use was associated with reduced intratumoral inflammation in radical prostatectomy (RP) specimens.

METHODS

Inflammation within index tumors of 236 men undergoing RP from 1996 to 2004 was graded by a single pathologist as grade 0 (absent), 1 (mild: < or =10%), and 2 (marked: >10%). Preoperative statin use was analyzed by grouping subjects as statin users or nonusers. Type and dosage of statin was accounted for using dose equivalents with 20 mg simvastatin as reference. Logistic regression was used to determine the association between statin use and intratumoral inflammation controlling for age, race, body mass index, prostate-specific antigen, year of surgery, clinical stage, pathologic Gleason sum, surgical margin status, extracapsular extension, seminal vesicle invasion, prostate weight, time from prostate biopsy to RP, and nonsteroidal anti-inflammatory drug use.

RESULTS

Preoperative statin use was significantly associated with lower risk for any (grade > or =1) intratumoral inflammation (odds ratio, 0.31; 95% confidence interval, 0.10-0.98; P = 0.047) on multivariable analysis, with doses > or =20 mg simvastatin equivalents being more strongly associated (relative to nonuse; odds ratio, 0.22; 95% confidence interval, 0.06-0.79; P = 0.02).

CONCLUSION

In a cohort of men undergoing RP, statin use was associated with significantly lower risk of any inflammation within prostate tumors.

IMPACT

Given previous reports that inflammation is associated with advanced prostate cancer, and statin use is associated with decreased prostate cancer progression risk, our findings suggest that inhibition of inflammation within tumors may be a potential mechanism for purported anti-prostate cancer properties of statins.

The routine use of prostate-specific antigen for early detection of cancer prostate in India: Is it justified?

BACKGROUND

The use of prostate-specific antigen (PSA) for early detection of prostate cancer is a widely debated issue. The average Indian urologist is faced with the dilemma of whether PSA testing should be routinely offered to men over 50 years of age. The Urological Society of India is yet to issue any guidelines on PSA testing. This article attempts to explore scientific evidence dealing with this controversial subject.

MATERIALS AND METHODS

A MEDLINE search was performed using the words 'PSA screening', 'prostate cancer statistics', and 'PSA screening guidelines'. The relevant articles were then analysed for evidence regarding the utility of PSA screening.

RESULTS

Prostate cancer does not qualify to be categorized as a major health problem in India. The natural history of screen-detected cancer is not known. Prostate-specific antigen testing for early detection of prostate cancer has questionable benefits and has a potential to cause harm to asymptomatic individuals. There is no consensus amongst learned medical societies as to what should be the best approach for PSA testing. Most organizations caution against widespread PSA screening and emphasize on informed consent and patient counseling with regard to PSA testing. Randomized prospective trials are ongoing to assess to the true impact of screening on prostate cancer mortality.

CONCLUSIONS

There is no scientific rationale to advocate routine use of PSA for early detection of prostate cancer in Indian males. Results of randomized screening trials are awaited to clarify on this issue.