Population Screening for Prostate Cancer and Emerging Concepts for Young Men

Prostate Cancer: Biology, Incidence, Detection Methods, Treatment Methods, and Vaccines

Cancer of the prostate are cancers in which most incidences are slow-growing, and in the U.S., a record of 1.2 million new cases of prostate cancer occurred in 2018. The rates of this type of cancer have been increasing in developing nations. The risk factors for prostate cancer include age, family history, and obesity. It is believed that the rate of prostate cancer is correlated with the Western diet. Various advances in methods of radiotherapy have contributed to lowering morbidity. Therapy for hormone- refractory prostate cancer is making progress, for almost all men with metastases will proceed to hormone-refractory prostate cancer. Smoking cigarettes along with the presence of prostate cancer has been shown to cause a higher risk of mortality in prostate cancer. The serious outcome of incontinence and erectile dysfunction result from the cancer treatment of surgery and radiation, particularly for prostate- specific antigen detected cancers that will not cause morbidity or mortality. Families of patients, as well as patients, are profoundly affected following the diagnosis of prostate cancer. Poor communication between spouses during prostate cancer increases the risk for poor adjustment to prostate cancer. The use of serum prostate-specific antigen to screen for prostate cancer has led to a greater detection, in its early stage, of this cancer. Prostate cancer is the most common malignancy in American men, accounting for more than 29% of all diagnosed cancers and about 13% of all cancer deaths. A shortened course of hormonal therapy with docetaxel following radical prostatectomy (or radiation therapy) for high-risk prostate cancer has been shown to be both safe and feasible. Patients treated with docetaxel-estramustine had a prostate-specific antigen response decline of at least 50%. Cancer vaccines are an immune-based cancer treatment that may provide the promise of a non-toxic but efficacious therapeutic alternative for cancer patients. Further studies will elucidate improved methods of detection and treatment.

Robotic Transrectal Ultrasound Guided Prostate Biopsy

We present a robot-assisted approach for transrectal ultrasound (TRUS) guided prostate biopsy. The robot is a hands-free probe manipulator that moves the probe with the same 4 DoF that are used manually. Software was developed for three-dimensional (3-D) imaging, biopsy planning, robot control, and navigation. Methods to minimize the deformation of the prostate caused by the probe at 3-D imaging and needle targeting were developed to reduce biopsy targeting errors. We also present a prostate coordinate system (PCS). The PCS helps defining a systematic biopsy plan without the need for prostate segmentation. Comprehensive tests were performed, including two bench tests, one imaging test, two in vitro targeting tests, and an IRB-approved clinical trial on five patients. Preclinical tests showed that image-based needle targeting can be accomplished with accuracy on the order of 1 mm. Prostate biopsy can be accomplished with minimal TRUS pressure on the gland and submillimetric prostate deformations. All five clinical cases were successful with an average procedure time of 13 min and millimeter targeting accuracy. Hands-free TRUS operation, transrectal TRUS guided prostate biopsy with minimal prostate deformations, and the PCS-based biopsy plan are novel methods. Robot-assisted prostate biopsy is safe and feasible. Accurate needle targeting has the potential to increase the detection of clinically significant prostate cancer.

Atypical metastases from prostate cancer: 10-year experience at a single institution

OBJECTIVE

The purpose of the study was to retrospectively review the frequency, sites, and patterns of atypical metastases from prostate cancer and to determine whether any correlation exists between the atypical sites and biochemical or histologic variables.

MATERIALS AND METHODS

All available imaging studies of 620 consecutive patients with biopsy-proven prostate carcinoma seen at our institute between 1999 and 2009 were reviewed. Eighty-two patients (mean age, 72 years; age range, 58-87 years) with atypical sites of metastases were identified. Patients were separated into groups on the basis of the presence or absence of concurrent osseous metastasis and high or low Gleason grade, and metastatic patterns were compared using the Fisher exact test. The maximum prostate-specific antigen (PSA) level for each patient was recorded and correlated with metastatic pattern using the Mann-Whitney test.

RESULTS

The most frequent sites of atypical metastases were the lungs and pleura (40%, 33/82), liver (37%, 30/82), supradiaphragmatic lymph nodes (34%, 28/82), and adrenal glands (15%, 12/82). Supradiaphragmatic lymphadenopathy was more common in patients with osseous metastases (45%, 25/56) than in patients without concurrent osseous involvement (12%, 3/26; p < 0.05). There was no significant correlation between the other atypical metastatic sites and osseous metastases. Abdominal visceral metastasis occurred more frequently in patients with a high Gleason grade (25/43, 58%) than in patients with a low Gleason grade (9/29, 31%; p < 0.05). There was no significant correlation between metastatic pattern and PSA level.

CONCLUSION

The lungs and pleura, liver, supradiaphragmatic lymph nodes, and adrenal glands are the most common extranodal metastatic sites of prostate cancer. Supradiaphragmatic lymphadenopathy was strongly associated with concurrent osseous metastases.

Long-term oncological outcomes of men undergoing radical prostatectomy with preoperative prostate-specific antigen <2.5 ng/ml and 2.5-4 ng/ml

OBJECTIVES

Prostate-specific antigen (PSA) screening has increased the detection of small, organ-confined tumors, and studies suggest that these patients may have favorable outcomes following radical prostatectomy (RP). To date, there are limited data available on the outcomes of patients diagnosed with low PSA (≤ 4 ng/ml) who underwent RP. This study aimed to evaluate long-term oncological outcomes of patients undergoing RP with preoperative PSA <2.5 and 2.5-4 ng/ml compared with PSA 4.1-10 ng/ml.

MATERIALS AND METHODS

Data were analyzed from 3,621 men who underwent RP between 1988 and 2010 at our institution. Patients were stratified into 3 PSA groups: <2.5 ng/ml (n = 280), 2.5-4 ng/ml (n = 563), and 4.1-10 ng/ml (n = 2,778). Patient and disease characteristics were compared. Overall, biochemical disease-free (bDFS), and PCa-specific survivals were analyzed and compared between the groups. Multivariable analyses were conducted using proportional hazards model.

RESULTS

Compared with the 4.1-10 ng/ml PSA group, Gleason score >7, extracapsular extension, and non-organ-confined disease were less common in patients with PSA ≤ 4 ng/ml (all P < 0.001). The incidence of organ-confined disease was similar between the PSA < 2.5 and 2.5-4 ng/ml groups while perineural invasion (P = 0.050) and Gleason score ≥ 7 (P = 0.026) were more common in the 2.5-4 ng/ml PSA group. Estimated 10-year overall and PCa-specific survivals were comparable across all PSA groups, whereas bDFS was significantly lower in PSA 4.1-10 group (P < 0.001). bDFS was not statistically different between PSA <2.5 and 2.5-4 groups (P = 0.300). 10-year bDFS were 59.0%, 70.1%, and 76.4% in PSA 4.1-10, 2.5-4, and <2.5, respectively. For the PSA ≤ 4 ng/ml groups, age, race, margin status, pathologic stage, but not PSA were independent predictors of bDFS, whereas age, pathologic Gleason, and biochemical recurrence were associated with overall survival.

CONCLUSIONS

Long-term oncological outcomes (overall, bDFS, PCa-specific survivals) of patients presenting with low PSA (≤ 4 ng/ml) were excellent in this study. Compared with PSA 4.1-10 ng/ml, patients presenting with PSA ≤ 4 ng/ml had better bDFS outcomes. However, there was no difference in long-term outcomes between PSA <2.5 and 2.5-4 ng/ml.

ADAM17 regulates prostate cancer cell proliferation through mediating cell cycle progression by EGFR/PI3K/AKT pathway

A disintegrin and metalloprotease 17 (ADAM17) is a transmembrane protein that can cleave membrane anchored proteins to release soluble factors and regulate important biological phenomena in cancers. In the present study, we evaluated the effects of ADAM17 on the proliferation and on the cell cycle distribution of human prostate cancer cells. Experiments were also performed to gain insights into the possible mechanism of action of ADAM17. We used over-expression and RNAi strategy to investigate the function of ADAM17 in human prostate cancer cells. Changes in rate of proliferation and cell cycle profile were measured by growth curve, Cell Counting Kit-8 (CCK-8) assay, bromodeoxyuridine (BrdU) incorporation assay and cell cycle analysis. In addition, changes in expression of associated genes and proteins were studied by semiquantitative RT-PCR, western blotting and ELISA analysis. Ectopic over-expression of ADAM17 resulted in increased cell proliferation. We also showed that ADAM17 promoted G1 to S phase transition concomitantly with upregulation of cyclin E, CDK2 and downregulation of p21 and p27 proteins. ADAM17 over-expression cells showed that more TGF-α released to the supernatant and activated the EGFR/PI3K/AKT pathway. Conversely, silencing ADAM17 led to the opposite effect. Both siRNAs knockdown of ADAM17 and blocking the EGFR/PI3K/AKT pathway using specific inhibitor caused downregulation of cyclin E, CDK2, and upregulation of p21 and p27 in prostate cancer cells. Collectively, this study demonstrates that over-expression of ADAM17 might target cyclin E, CDK2, p21, and p27 to promote prostate cancer cell proliferation through activation of the EGFR/PI3K/AKT pathway.

Baseline prostate-specific antigen testing at a young age

CONTEXT

Prostate cancer screening is highly controversial, including the age to begin prostate-specific antigen (PSA) testing. Several studies have evaluated the usefulness of baseline PSA measurements at a young age.

OBJECTIVE

Review the literature on baseline PSA testing at a young age (≤60 yr) for the prediction of prostate cancer risk and prognosis.

EVIDENCE ACQUISITION

PubMed was searched for English-language publications on baseline PSA and prostate cancer for the period ending April 2011.

EVIDENCE SYNTHESIS

In most published series, median PSA levels in the general male population range from approximately 0.4 to 0.7 ng/ml in men in their 40s and from approximately 0.7 to 1.0 ng/ml in men in their 50s. Evidence from both nonscreening and screening populations has demonstrated the predictive value of a single baseline PSA measurement for prostate cancer risk assessment. Specifically, men with baseline PSA levels above the age-group-specific median have a greater risk of prostate cancer diagnosis during the next 20-25 yr. Additional studies confirmed that higher baseline PSA levels at a young age are also associated with a greater risk of aggressive disease, metastasis, and disease-specific mortality many years later.

CONCLUSIONS

Baseline PSA measurements at a young age are significant predictors of later prostate cancer diagnosis and disease-specific outcomes. Thus baseline PSA testing may be used for risk stratification and to guide screening protocols.

Trends in PSA, age and prostate cancer detection among black and white men from 1990-2006 at a tertiary care center

BACKGROUND

Prostate cancer is the most frequently diagnosed malignancy in men in the United States, with even higher prevalence and death rates among black men. The authors sought to compare trends in prostate-specific antigen (PSA), age, and prostate-cancer detection among black and white men in our region during a 16-year period.

METHODS

This was a retrospective study of patient archives between 1990 through 2006. Data collection was accomplished by examining patients' charts and electronic medical records. Data from 5570 patients, of whom 911 were black, were analyzed statistically by testing and comparing parameters over time.

RESULTS

During this 16-year period, mean age at the time of initial diagnostic prostate biopsy did not change in either group, despite what we had believed about the effects of patient education and screening campaigns. However, prostate-cancer detection rates did decrease during the time period studied. Over time, the authors also observed significant decreases in the sensitivity and specificity of PSA as a screening tool. Indeed, analysis of more recent cases demonstrated a positive predictive value comparable to a coin toss. While Gleason scores remained relatively stable over time, reporting of prostate intraepithelial neoplasia (PIN) and inflammation increased.

CONCLUSIONS

Using lower PSA thresholds, promoting younger screening age, and increasing efforts to educate the public have not seemed to influence age at time of diagnostic testing, which may reflect other factors such as usefulness of screening, physician referral patterns, patient compliance, and other sociodemographic issues. The usefulness of PSA as a screening tool appears to be diminishing.

Nerve growth factor signaling in prostate health and disease

The prostate is one of the most abundant sources of nerve growth factor (NGF) in different species, including humans. NGF and its receptors are implicated in the control of prostate cell proliferation and apoptosis and it can either support or suppress cell growth. The co-expression of both NGF receptors, p75(NGFR) and tropomyosin-related kinase A (trkA), represents a crucial condition for the antiproliferative effect of NGF; indeed, p75(NGFR) is progressively lost during prostate tumorigenesis and its disappearance represents a malignancy marker of prostate adenocarcinoma (PCa). Interestingly, a dysregulation of NGF signal transduction was found in a number of human tumors. This review summarizes the current knowledge on the role of NGF and its receptors in prostate and in PCa. Conclusions bring to the hypothesis that the NGF network could be a candidate for future pharmacological manipulation in the PCa therapy: in particular the re-expression of p75(NTR) and/or the negative modulation of trkA could represent a target to induce apoptosis and to reduce proliferation and invasiveness of PCa.

Protein quantification in complex mixtures by solid phase single-molecule counting

Here we present a procedure for quantifying single protein molecules affixed to a surface by counting bound antibodies. We systematically investigate many of the parameters that have prevented the robust single-molecule detection of surface-immobilized proteins. We find that a chemically adsorbed bovine serum albumin surface facilitates the efficient detection of single target molecules with fluorescent antibodies, and we show that these antibodies bind for lengths of time sufficient for imaging billions of individual protein molecules. This surface displays a low level of nonspecific protein adsorption so that bound antibodies can be directly counted without employing two-color coincidence detection. We accurately quantify protein abundance by counting bound antibody molecules and perform this robustly in real-world serum samples. The number of antibody molecules we quantify relates linearly to the number of immobilized protein molecules (R(2) = 0.98), and our precision (1-5% CV) facilitates the reliable detection of small changes in abundance (7%). Thus, our procedure allows for single, surface-immobilized protein molecules to be detected with high sensitivity and accurately quantified by counting bound antibody molecules. Promisingly, we can probe flow cells multiple times with antibodies, suggesting that in the future it should be possible to perform multiplexed single-molecule immunoassays.

Significant discrepancies between diagnostic and pathologic Gleason sums in prostate cancer: the predictive role of age and prostate-specific antigen

OBJECTIVES

To assess the discrepancies between diagnostic and pathologic Gleason sums and the predictive role of age and prostate-specific antigen (PSA) level on Gleason sum discrepancies.

METHODS

A total of 2963 patients receiving radical prostatectomy at Duke University from 1988 to 2006 were divided into two groups according to year of diagnosis: 1988 to 1999 and 2000 to 2006. The Gleason sum discrepancies were evaluated in the above groups. The predictive roles of diagnostic age (less than 50, 50 to 60, 60.1 to 70, and greater than 70 years), PSA level (less than 10, 10 to 20, and greater than 20 ng/mL), race, body mass index, and prostate weight on the discrepancies were analyzed.

RESULTS

Overall, 55.8% of diagnostic Gleason sums differed from those on final surgical pathology (58.6% in the 1988 to 1999 and 49.3% in the 2000 to 2006 groups). Diagnostic Gleason sums were undergraded in 41.2% of cases and overgraded in 12.8% of cases. Men older than 60 years were more likely to have their diagnostic Gleason sums undergraded than men younger than 50 (odds ratio in age groups less than 50, 50 to 60, 60.1 to 70, and greater than 70 years: 1.00, 2.30, 4.03, and 3.96, respectively). Biopsy Gleason sums in men with a high PSA level were more likely to be undergraded compared with the PSA group less than 10 ng/mL (odds ratio in PSA groups less than 10, 10 to 20, and greater than 20 ng/mL: 1.00, 2.11, and 3.64, respectively).

CONCLUSIONS

Significant discrepancies between diagnostic and pathologic Gleason sums remain in recent years. The rate of diagnostic Gleason sum undergrading was 3.2-fold that of overgrading. Advanced age and high PSA level were predictive of diagnostic Gleason sum undergrading, and caution should be exercised when recommending active surveillance in older men.

Submandibular Area Metastasis From Prostate Small Cell Carcinoma With Neuroendocrine Differentiation

Neuroendocrine differentiation in prostatic carcinomas generally confers a more aggressive clinical behavior and less favorable prognosis than usual prostatic carcinomas. In this article, we report a case of a 65-year-old man with prostatic carcinoma who had a metastasis of the submandibular area. His serum prostate-specific antigen level was reduced to below the normal range and carcinoembryonic antigen was increased. Pathologic specimens demonstrated a small cell carcinoma with neuroendocrine differentiation by immunohistochemical studies.

Are men with low selenium levels at increased risk of prostate cancer?

A meta-analysis was undertaken to quantitatively determine if men with low selenium levels were at increased risk of prostate cancer. PubMed, EMBASE and current contents were searched to identify relevant studies. The effect size was calculated by pooling the mean difference for serum, plasma and toenail selenium levels (95% confidence intervals) separately and combined using a random effects model. Meta-regression analysis explored possible sources of heterogeneity. Twenty epidemiologic studies were selected. Mean differences were: -5.55 microg/l (-9.82; -1.27; p=0.01), -0.01 microg/g (-0.03; 0.006; p=0.19), -0.52 microg/l (-4.63; 3.58; p=0.80) for serum, toenail and plasma studies, respectively. Overall, the pooled standardized mean difference between cases and controls was; -0.23 (-0.40; -0.05; p=0.01) indicating a possible inverse association between selenium levels and risk of prostate cancer. Differences in selenium levels between populations, a possible threshold effect and the relationship between selenium and the different stages of prostate cancer require further investigation.

Positive family history of prostate cancer not associated with worse outcomes after radical prostatectomy

OBJECTIVES

To determine the clinical outcomes in men with (FH) and without (NFH) a family history of prostate cancer after radical prostatectomy.

METHODS

We performed a retrospective analysis of 557 men with localized prostate cancer treated by radical prostatectomy between 1989 and 2000. We defined a positive FH as having one or more first-degree relatives such as a father or brother with prostate cancer. The clinical and pathologic features, as well as biochemical disease-free survival, defined as an undetectable prostate-specific antigen level (less than 0.2 ng/mL), were compared between the FH and NFH groups.

RESULTS

Compared with the NFH group, the FH men were younger at surgery (median 62 years versus 64 years, P = 0.01), had a lower median preoperative prostate-specific antigen level (7.2 ng/mL versus 7.8 ng/mL, P = 0.05), and were more likely to have only low-grade disease at the final pathologic evaluation (26.2% versus 17.8%, P = 0.05). At a median follow-up of 7.5 years (mean 7.6 +/- 2.9 years), 17% of the FH group had biochemical disease recurrence compared with 30% in the NFH group. The actuarial disease-free survival rate at 5 and 10 years for the two groups was 86% and 80% compared with 73% and 66%, respectively (P = 0.01). When controlled for pathologic variables in a multivariate analysis, FH was not an independent predictor of disease-free survival.

CONCLUSIONS

The association of improved disease-free survival in the FH patients may have been driven by an earlier age at diagnosis and more favorable pathologic features.