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'''Prostate specific antigen''', abbreviated '''PSA''', is marker that is quite [[specific]] for the prostate. | [[Image:Advanced prostate carcinoma - PSA - 2 -- very high mag.jpg|thumb|200px|[[Micrograph]] showing a PSA immunostain marking [[prostate carcinoma]].]] | ||
'''Prostate-specific antigen''', abbreviated '''PSA''', is marker that is quite [[specificity|specific]] for the prostate. | |||
==General== | ==General== | ||
*Quantity in the serum used to screen for [[prostate cancer]]. | *Quantity in the serum used to screen for [[prostate cancer]] and follow patients with a history of prostate cancer. | ||
*PSA [[immunostain]] useful for classifying a carcinoma as prostate carcinoma. | *PSA [[immunostain]] useful for classifying a carcinoma as prostate carcinoma. | ||
===Serum PSA=== | ===Serum PSA=== | ||
*Normal - typically < 4.0 ng/ | *Normal - typically <= 4.0 ng/ml. | ||
*Increases with age.<ref>{{cite journal |author=Ku JH, Ahn JO, Lee CH, ''et al.'' |title=Distribution of serum prostate-specific antigen in healthy Korean men: influence of ethnicity |journal=Urology |volume=60 |issue=3 |pages=475–9 |year=2002 |month=September |pmid=12350489 |doi= |url=}}</ref> | **[[Sensitivity]]: 82% (whites), 90% (blacks).<ref name=pmid8998182>{{Cite journal | last1 = Henderson | first1 = RJ. | last2 = Eastham | first2 = JA. | last3 = Culkin | first3 = DJ. | last4 = Kattan | first4 = MW. | last5 = Whatley | first5 = T. | last6 = Mata | first6 = J. | last7 = Venable | first7 = D. | last8 = Sartor | first8 = O. | title = Prostate-specific antigen (PSA) and PSA density: racial differences in men without prostate cancer. | journal = J Natl Cancer Inst | volume = 89 | issue = 2 | pages = 134-8 | month = Jan | year = 1997 | doi = | PMID = 8998182 }} | ||
</ref> | |||
**[[Specificity]]: 52% (whites), 38% (blacks).<ref name=pmid8998182/> | |||
*Increases with age.<ref name=pmid12350489>{{cite journal |author=Ku JH, Ahn JO, Lee CH, ''et al.'' |title=Distribution of serum prostate-specific antigen in healthy Korean men: influence of ethnicity |journal=Urology |volume=60 |issue=3 |pages=475–9 |year=2002 |month=September |pmid=12350489 |doi= |url=}}</ref> | |||
Age-normal: | |||
* | *40s - 2.5 ng/ml. | ||
*50s - 3.5 ng/ml. | |||
*60s - 4.5 ng/ml. | |||
*70s - 6.5 ng/ml. | |||
Note: | |||
*The units for PSA may also be μg/L; note that 1 μg/L = 1 ng/ml. | |||
====Prostate-specific antigen density==== | |||
:Abbreviated ''PSAD''. | |||
Normal is often considered to be: <0.15 ng/ml<sup>2</sup>. | |||
*Approximately 8% of individuals below the cut-point (0.15 ng/ml) have medium or high-grade cancer.<ref name=pmid12973074>{{Cite journal | last1 = Boulos | first1 = MT. | last2 = Rifkin | first2 = MD. | last3 = Ross | first3 = J. | title = Should prostate-specific antigen or prostate-specific antigen density be used as the determining factor when deciding which prostates should undergo biopsy during prostate ultrasound. | journal = Ultrasound Q | volume = 17 | issue = 3 | pages = 177-80 | month = Sep | year = 2001 | doi = | PMID = 12973074 }} | |||
</ref> | |||
*In another series, 48% of individuals with cancer had a PSAD >0.15 ng/ml<sup>2</sup>.<ref name=pmid22482342>{{Cite journal | last1 = Aganovic | first1 = D. | last2 = Prcic | first2 = A. | last3 = Kulovac | first3 = B. | last4 = Hadziosmanovic | first4 = O. | title = Influence of the prostate volume, prostate specific antigen density and number of biopsy samples on prostate cancer detection. | journal = Med Arh | volume = 66 | issue = 1 | pages = 41-4 | month = | year = 2012 | doi = | PMID = 22482342 }} | |||
</ref> | |||
*Differences between races have been noted in one study; in those without prostate cancer:<ref name=pmid8998182/> | |||
**0.19 +/- 0.03 ng/ml<sup>2</sup> (blacks). | |||
**0.11 +/- 0.01 ng/ml<sup>2</sup> (whites). | |||
PSAD is a better predictor than (unadjusted) serum PSA for: | |||
*Gleason score upgrading on [[prostatectomy]].<ref>{{cite journal |author=Sfoungaristos S, Katafigiotis I, Perimenis P |title=The role of PSA density to predict a pathological tumour upgrade between needle biopsy and radical prostatectomy for low risk clinical prostate cancer in the modified Gleason system era |journal=Can Urol Assoc J |volume=7 |issue=11-12 |pages=E722–7 |year=2013 |pmid=24282465 |pmc=3840515 |doi=10.5489/cuaj.374 |url=}}</ref> | *Gleason score upgrading on [[prostatectomy]].<ref>{{cite journal |author=Sfoungaristos S, Katafigiotis I, Perimenis P |title=The role of PSA density to predict a pathological tumour upgrade between needle biopsy and radical prostatectomy for low risk clinical prostate cancer in the modified Gleason system era |journal=Can Urol Assoc J |volume=7 |issue=11-12 |pages=E722–7 |year=2013 |pmid=24282465 |pmc=3840515 |doi=10.5489/cuaj.374 |url=}}</ref> | ||
* | *Benign prostate gland versus [[prostate cancer]].<ref name=pmid1371554>{{cite journal |author=Benson MC, Whang IS, Pantuck A, ''et al.'' |title=Prostate specific antigen density: a means of distinguishing benign prostatic hypertrophy and prostate cancer |journal=J. Urol. |volume=147 |issue=3 Pt 2 |pages=815–6 |year=1992 |month=March |pmid=1371554 |doi= |url=}}</ref><ref>{{cite journal |author=Verma A, St Onge J, Dhillon K, Chorneyko A |title=PSA density improves prediction of prostate cancer |journal=Can J Urol |volume=21 |issue=3 |pages=7312–21 |year=2014 |month=June |pmid=24978363 |doi= |url=}}</ref> | ||
====A forumla for PSAD==== | =====A forumla for PSAD===== | ||
Benson ''et al.'':<ref name=pmid1371554>{{cite journal |author=Benson MC, Whang IS, Pantuck A, ''et al.'' |title=Prostate specific antigen density: a means of distinguishing benign prostatic hypertrophy and prostate cancer |journal=J. Urol. |volume=147 |issue=3 Pt 2 |pages=815–6 |year=1992 |month=March |pmid=1371554 |doi= |url=}}</ref> | |||
:<math>PASD = \frac{serum PSA}{volume}</math> | :<math>PASD = \frac{serum PSA}{volume}</math> | ||
:<math>volume = \frac{1}{2} D1 | Where: | ||
:<math>volume = \frac{\pi}{6} H \times W \times L</math>.<ref>{{Cite journal | last1 = Eri | first1 = LM. | last2 = Thomassen | first2 = H. | last3 = Brennhovd | first3 = B. | last4 = Håheim | first4 = LL. | title = Accuracy and repeatability of prostate volume measurements by transrectal ultrasound. | journal = Prostate Cancer Prostatic Dis | volume = 5 | issue = 4 | pages = 273-8 | month = | year = 2002 | doi = 10.1038/sj.pcan.4500568 | PMID = 12627211 }} | |||
</ref> | |||
:H, W, L are the height, width and length. | |||
An alternate estimation of the volume is: | |||
:<math>volume = \frac{1}{2} D1 \times D2 \times D3</math>. | |||
:D1, D2, D3 are the major axes. | :D1, D2, D3 are the major axes. | ||
Notes: | |||
*The volume of an ellipsoid is: | *The volume of an ellipsoid is: | ||
::<math>\frac{4}{3}\pi D1 | ::<math>\frac{4}{3}\pi D1 \times D1 \times D3</math>. | ||
*As 1 cm<sup>3</sup> is equal to 1 ml, the units of PSAD are (ng/ml)/cm<sup>3</sup> or ng/ml<sup>2</sup>. | |||
===Immunostain=== | |||
*Relatively specific for prostate | |||
*May be found in normal pancreatic, salivary gland, Skene's glands and lactating breast tissue.<ref name=pmid21979599>{{cite journal |authors=Kelly P, McBride HA, Kennedy K, Connolly LE, McCluggage WG |title=Misplaced Skene's glands: glandular elements in the lower female genital tract that are variably immunoreactive with prostate markers and that encompass vaginal tubulosquamous polyp and cervical ectopic prostatic tissue |journal=Int. J. Gynecol. Pathol. |volume=30 |issue=6 |pages=605–12 |date=November 2011 |pmid=21979599 |doi=10.1097/PGP.0b013e31821713b6 |url=}}</ref> | |||
*In women, positive in up to 30-40% of breast cancers and also in tubulo-squamous polyps of the vagina. | |||
==Microscopic== | |||
Features - PSA immunostain: | |||
*Granular cytoplasmic staining. | |||
Notes: | |||
*May be very weak -- need to look at high power. | |||
<gallery> | |||
Image: Advanced prostate carcinoma - PSA -- high mag.jpg | Adv Pca - weak PSA - high mag. (WC) | |||
Image: Advanced prostate carcinoma - PSA -- very high mag.jpg | Adv Pca - weak PSA - very high mag. (WC) | |||
Image: Advanced prostate carcinoma - PSA - 2 -- high mag.jpg | Adv Pca - PSA - high mag. (WC) | |||
Image: Advanced prostate carcinoma - PSA - 2 -- very high mag.jpg | Adv Pca - PSA - very high mag. (WC) | |||
</gallery> | |||
==See also== | ==See also== | ||
*[[Prostate cancer]]. | *[[Prostate cancer]]. | ||
*[[Prostatic-specific acid phosphatase]]. | |||
==References== | ==References== |
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