Prostate-specific antigen levels in relation to cadmium exposure and zinc intake: results from the 2001-2002 National Health and Nutrition Examination Survey.

BACKGROUND: Cadmium exposure has been suggested as a risk factor for prostate cancer, and experimental literature suggests that the carcinogenic effect of cadmium is modified by the presence of zinc. We evaluated total prostate-specific antigen (PSA) levels in relation to urinary cadmium concentrations and dietary zinc intake. METHODS: PSA levels were determined in 1,320 men over the age of 40 in the 2001-2002 National Health and Nutrition Examination Survey (NHANES). Urinary cadmium concentrations were measured in about one-third of the sample population, whereas dietary zinc intake was based on participants' 24-hr recall. Information on all three variables was available for 422 men in the 2001-2002 NHANES survey. We performed linear regressions to evaluate the relationships these factors after accounting for age and other covariates. RESULTS: Little evidence for an association between cadmium and elevated PSA level was observed. However, the data provide suggestive evidence for an interaction between zinc intake and cadmium exposure (P for interaction=0.09). Among men with zinc intake less than the median level of 12.67 mg/day, an increase in 1 microg/g creatinine cadmium exposure was associated with a 35% increase in PSA level. In contrast, among men with greater than median zinc intake, little evidence for an association between cadmium and PSA was found. CONCLUSIONS: These findings suggest a protective effect of zinc intake on cadmium-induced prostatic injury, and may provide further rationale for investigating the impact of these factors individually and jointly on the etiology of prostate cancer.

Clinical relevance of genetic instability in prostatic cells obtained by prostatic massage in early prostate cancer.

We investigated whether genetic lesions such as loss of heterozygosity (LOH) are detected in prostatic cells obtained by prostatic massage during early diagnosis of prostate cancer (CaP) and discussed their clinical relevance. Blood and first urine voided after prostatic massage were collected in 99 patients with total prostate-specific antigen (PSA) between 4 and 10 ng ml(-1), prior to prostate biopsies. Presence of prostatic cells was confirmed by quantitative RT-PCR analysis of PSA mRNA. Genomic DNA was analysed for LOH on six chromosomal regions. One or more allelic deletions were found in prostatic fluid from 57 patients analysed, of whom 33 (58%) had CaP. Sensitivity and specificity of LOH detection and PSA free to total ratio <15% for positive biopsy were respectively 86.7 and 44% (P=0.002) for LOH, and 55 and 74% (P=0.006) for PSA ratio <15%. Analysis of LOH obtained from prostatic tumours revealed similar patterns compared to prostatic fluid cells in 86% of cases, confirming its accuracy. The presence of LOH of urinary prostatic cells obtained after prostatic massage is significantly associated with CaP on biopsy and may potentially help to identify a set of patients who are candidates for further prostate biopsies.

Adherence to a low-fat diet in men with prostate cancer.

OBJECTIVES: To evaluate, in a feasibility study, the adherence to a low-fat diet by men with prostate cancer. Evidence is growing that a low-fat diet affects the development and course of prostate cancer. To design preventive and therapeutic interventions, it is important to know whether men will adhere to these nutritional recommendations, particularly when motivated by the diagnosis of prostate cancer. METHODS: Men with elevated prostate-specific antigen levels, most of whom were recently treated for prostate cancer, were randomized to one of four dietary regimens for which they received nutritional counseling: a low-fat diet (15% fat or less) with supplements (vitamin E and selenium), a low-fat diet (15% fat or less) without the supplements, the supplements alone, and a control group. Adherence was evaluated by the change in weight, fat intake, free fatty acids, cholesterol, high-density and low-density lipoproteins, and triglycerides during a 12-month period. RESULTS: The mean age of the 48 participants was 66 years. For those counseled about a low-fat diet, the mean change in the percentage of energy (kilocalories) in the diet from fat was greater after 3 months (-8.6% versus +2.1%, P <0.001) and 12 months (-9.8% versus -1.6%, P = 0.001). Three months after starting the intervention, those randomized to low-fat dietary counseling had lost 2 kg, on average, compared with 0.8 kg lost by those who did not receive this counseling (P = 0.09). At 12 months, those receiving low-fat counseling had lost 2.8 kg, on average, compared with 0.5 kg gained among the other groups (P = 0.02). CONCLUSIONS: With appropriate counseling, men with prostate cancer can adhere to a low-fat dietary intervention for a 12-month period.

Influence of digital rectal massage on urinary prostate-specific antigen: interest for the detection of local recurrence after radical prostatectomy.

BACKGROUND: Following radical prostatectomy, urinary prostate-specific antigen (uPSA) may originate from periurethral glands or from recurrent carcinomatous prostatic cells. We evaluated massage of the urethro-vesical anastomosis as a uPSA-releasing method for the detection of local recurrence. METHODS: PSA was assessed (PSA IMx, Abbott Diagnostic, Rungis, France) in serum and in the first voided urine before and after massage in 59 patients: 7 after cystoprostatectomy for bladder cancer, 22 with prostate in situ, and 30 after radical prostatectomy for prostate cancer. RESULTS: No significant changes of uPSA were induced by the massage in cystoprostatectomy patients and in 4 radical prostatectomy patients with a negative biopsy of the anastomosis. In contrast, a significant increase of uPSA was observed after massage in the patients with prostate in situ and in 6 radical prostatectomy patients with biopsy-proven local relapse. CONCLUSIONS: uPSA before and after massage of the prostatic fossa may constitute a new and efficient tool for the detection of local recurrence, if these preliminary results are confirmed on a larger scale.