Prostate cancer

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Important: In their effort to be who they are, many male to female transsexuals find it difficult or simply ignore the fact that there is a continuing need for regular testing to detect the presence of prostate cancer. Early detection is the only way to prevent its spread.


Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. The cancer cells may metastasize (spread) from the prostate to other parts of the body, particularly the bones and lymph nodes. Prostate cancer may cause pain, difficulty in urinating, problems during sexual intercourse, or erectile dysfunction. Other symptoms can potentially develop during later stages of the disease.

Rates of detection of prostate cancers vary widely across the world, with South and East Asia detecting less frequently than in Europe, and especially the United States.[1] Prostate cancer tends to develop in men over the age of fifty and although it is one of the most prevalent types of cancer in men, many never have symptoms, undergo no therapy, and eventually die of other causes. This is because cancer of the prostate is, in most cases, slow-growing, symptom free and men with the condition often die of causes unrelated to the prostate cancer, such as heart/circulatory disease, pneumonia, other unconnected cancers, or old age. Many factors, including genetics and diet, have been implicated in the development of prostate cancer. The presence of prostate cancer may be indicated by symptoms, physical examination, prostate specific antigen (PSA), or biopsy. There is controversy about the accuracy of the PSA test and the value of screening. Suspected prostate cancer is typically confirmed by taking a biopsy of the prostate and examining it under a microscope. Further tests, such as CT scans and bone scans, may be performed to determine whether prostate cancer has spread.

Treatment options for prostate cancer with intent to cure are primarily surgery and radiation therapy. Other treatments such as hormonal therapy, (Not the same as HRT) chemotherapy, proton therapy, cryosurgery, high intensity focused ultrasound (HIFU) also exist depending on the clinical scenario and desired outcome.

The age and underlying health of the man, the extent of metastasis, appearance under the microscope, and response of the cancer to initial treatment are important in determining the outcome of the disease. The decision whether or not to treat localized prostate cancer (a tumor that is contained within the prostate) with curative intent is a patient trade-off between the expected beneficial and harmful effects in terms of patient survival and quality of life.

Classification

Main article: Prostate

Prostatelead.jpg

The prostate is a part of the male reproductive organ that helps make and store seminal fluid. In adult men, a typical prostate is about three centimeters long and weighs about twenty grams.[2] It is located in the pelvis, under the urinary bladder and in front of the rectum. The prostate surrounds part of the urethra, the tube that carries urine from the bladder during urination and semen during ejaculation.[3] Because of its location, prostate diseases often affect urination, ejaculation, and rarely defecation. The prostate contains many small glands which make about twenty percent of the fluid constituting semen.[4] In prostate cancer, the cells of these prostate glands mutate into cancer cells. The prostate glands require male hormones, known as androgens, to work properly. Androgens include testosterone, which is made in the testes; dehydroepiandrosterone, made in the adrenal glands; and dihydrotestosterone, which is converted from testosterone within the prostate itself. Androgens are also responsible for secondary sex characteristics such as facial hair and increased muscle mass.

An important part of evaluating prostate cancer is determining the stage, or how far the cancer has spread. Knowing the stage helps define prognosis and is useful when selecting therapies. The most common system is the four-stage TNM system (abbreviated from Tumor/Nodes/Metastases). Its components include the size of the tumor, the number of involved lymph nodes, and the presence of any other metastases.

The most important distinction made by any staging system is whether or not the cancer is still confined to the prostate. In the TNM system, clinical T1 and T2 cancers are found only in the prostate, while T3 and T4 cancers have spread elsewhere. Several tests can be used to look for evidence of spread. These include computed tomography to evaluate spread within the pelvis, bone scans to look for spread to the bones, and endorectal coil magnetic resonance imaging to closely evaluate the prostatic capsule and the seminal vesicles. Bone scans should reveal osteoblastic appearance due to increased bone density in the areas of bone metastasis—opposite to what is found in many other cancers that metastasize.

Computed tomography (CT) and magnetic resonance imaging (MRI) currently do not add any significant information in the assessment of possible lymph node metastases in patients with prostate cancer according to a meta-analysis.[5] The sensitivity of CT was 42% and specificity of CT was 82%. sensitivity of MRI was 39% and the specificity of MRI was 82%. For patients at similar risk to those in this study (17% had positive pelvic lymph nodes in the CT studies and 30% had positive pelvic lymph nodes in the MRI studies), this leads to a positive predictive value (PPV) of 32.3% with CT, 48.1% with MRI, and negative predictive value (NPV) of 87.3% with CT, 75.8% with MRI.

After a prostate biopsy, a pathologist looks at the samples under a microscope. If cancer is present, the pathologist reports the grade of the tumor. The grade tells how much the tumor tissue differs from normal prostate tissue and suggests how fast the tumor is likely to grow. The Gleason system is used to grade prostate tumors from 2 to 10, where a Gleason score of 10 indicates the most abnormalities. The pathologist assigns a number from 1 to 5 for the most common pattern observed under the microscope, then does the same for the second-most-common pattern. The sum of these two numbers is the Gleason score. The Whitmore-Jewett stage is another method sometimes used. Proper grading of the tumor is critical, since the grade of the tumor is one of the major factors used to determine the treatment recommendation.

Signs and symptoms

Early prostate cancer usually causes no symptoms. Often it is diagnosed during the workup for an elevated PSA noticed during a routine checkup. It's highly advised to avoid sexual intercourse for 3 days prior to a PSA test because that does affect the outcome of the test. Sometimes, however, prostate cancer does cause symptoms, often similar to those of diseases such as benign prostatic hypertrophy. These include frequent urination, increased urination at night, difficulty starting and maintaining a steady stream of urine, blood in the urine, and painful urination. Prostate cancer is associated with urinary dysfunction as the prostate gland surrounds the prostatic urethra. Changes within the gland, therefore, directly affect urinary function. Because the vas deferens deposits seminal fluid into the prostatic urethra, and secretions from the prostate gland itself are included in semen content, prostate cancer may also cause problems with sexual function and performance, such as difficulty achieving erection or painful ejaculation.[6]

Advanced prostate cancer can spread to other parts of the body, possibly causing additional symptoms. The most common symptom is bone pain, often in the vertebrae (bones of the spine), pelvis, or ribs. Spread of cancer into other bones such as the femur is usually to the proximal part of the bone. Prostate cancer in the spine can also compress the spinal cord, causing leg weakness and urinary and fecal incontinence.[7]

Diagnosis

The only test that can fully confirm the diagnosis of prostate cancer is a biopsy, the removal of small pieces of the prostate for microscopic examination. However, prior to a biopsy, several other tools may be used to gather more information about the prostate and the urinary tract. Cystoscopy shows the urinary tract from inside the bladder, using a thin, flexible camera tube inserted down the urethra. Transrectal ultrasonography creates a picture of the prostate using sound waves from a probe in the rectum.

Biopsy

If cancer is suspected, a biopsy is offered. During a biopsy a urologist or radiologist obtains tissue samples from the prostate via the rectum. A biopsy gun inserts and removes special hollow-core needles (usually three to six on each side of the prostate) in less than a second. Prostate biopsies are routinely done on an outpatient basis and rarely require hospitalization. Fifty-five percent of men report discomfort during prostate biopsy.[8] Tissue samples can be then stained for the presence of PSA and other tumor markers in order to determine the origin of maligant cells that have metastasized.[9]

PCA3

Another potential non-invasive method of early prostate tumor detection is through a molecular test that detects the presence of cell-associated PCA3 mRNA in urine. PCA3 mRNA is expressed almost exclusively by prostate cells and has been shown to be highly over-expressed in prostate cancer cells. PCA3 is not a replacement for PSA but an additional tool to help decide whether, in men suspected of having prostate cancer, a biopsy is really needed. The higher the expression of PCA3 in urine, the greater the likelihood of a positive biopsy, i.e., the presence of cancer cells in the prostate.

Prostate mapping

Prostate mapping is a method of diagnosis that may be accurate in determining the precise location and aggressiveness of a tumor. It uses a combination of multi-sequence MRI imaging techniques and a template-guided biopsy system, and involves taking multiple biopsies through the skin that lies in front of the rectum rather than through the rectum itself. The procedure is carried out under general anesthetic.[10]

Screening

Prostate cancer screening is an attempt to find unsuspected cancers. Screening tests may lead to more specific follow-up tests such as a biopsy, where small cores of the prostate are removed for closer study. Prostate cancer screening options include the digital rectal exam and the prostate-specific antigen (PSA) blood test. Screening for prostate cancer is controversial because it is expensive and is not at all clear whether the benefits of screening outweigh the risks of follow-up diagnostic tests and cancer treatments and the unnecessary worry for the patient that often ensues.

Prostate cancer is usually a slow-growing cancer, very common among older men. In fact, most prostate cancers never grow to the point where they cause symptoms, and most men with prostate cancer die of other causes before prostate cancer has an impact on their lives. The PSA screening test may detect these small cancers that would never become life-threatening. Doing the PSA test in these men may lead to overdiagnosis, including additional testing and treatment. Follow-up tests, such as prostate biopsy, may cause pain, bleeding and infection. Prostate cancer treatments may cause urinary incontinence and erectile dysfunction. A large randomized study in which 76,000 men were randomized to receive either PSA screening or conventional care found that more men that underwent PSA screening were diagnosed with prostate cancer, but that there was no difference in mortality between the two groups.[11]

The results from two of the largest randomized trials regarding the efficacy of screening have now been published.[12] In one of these trials, the death rate from prostate cancer was actually higher in the group that had total screening compared to the control group that had only normal rates of screening. The other showed some benefit from screening, but the reduction in deaths was minor compared to the level of intervention needed to prevent it.

Management

Treatment for prostate cancer may involve active surveillance, surgery, radiation therapy including brachytherapy (prostate brachytherapy) and external beam radiation therapy, High-intensity focused ultrasound (HIFU), chemotherapy, cryosurgery, hormonal therapy, or some combination. Which option is best depends on the stage of the disease, the Gleason score, and the PSA level. Other important factors are the man's age, his general health, and his feelings about potential treatments and their possible side-effects. Because all treatments can have significant side-effects, such as erectile dysfunction and urinary incontinence, treatment discussions often focus on balancing the goals of therapy with the risks of lifestyle alterations.

The selection of treatment options may be a complex decision involving many factors. For example, radical prostatectomy after primary radiation failure is a very technically challenging surgery and may not be an option.[13] This may enter into the treatment decision.

If the cancer has spread beyond the prostate, treatment options significantly change, so most doctors that treat prostate cancer use a variety of nomograms to predict the probability of spread. Treatment by watchful waiting/active surveillance, HIFU, external beam radiation therapy, brachytherapy, cryosurgery, and surgery are, in general, offered to men whose cancer remains within the prostate. Hormonal therapy and chemotherapy are often reserved for disease that has spread beyond the prostate. However, there are exceptions: radiation therapy may be used for some advanced tumors, and hormonal therapy is used for some early stage tumors. Cryotherapy (the process of freezing the tumor), hormonal therapy, and chemotherapy may also be offered if initial treatment fails and the cancer progresses.[14]

Prognosis

Prostate cancer rates are higher and prognosis poorer in developed countries than the rest of the world. Many of the risk factors for prostate cancer are more prevalent in the developed world, including longer life expectancy and diets high in red meat and reduced-fat dairy products to which vitamin A palmitate has been added.[15] (People that consume larger amounts of meat and dairy also tend to consume fewer portions of fruits and vegetables. It is not currently clear whether both of these factors, or just one of them, contribute to the occurrence of prostate cancer.[16]) Also, where there is more access to screening programs, there is a higher detection rate. Prostate cancer is the ninth-most-common cancer in the world, but is the number-one non-skin cancer in United States men. Prostate cancer affected eighteen percent of American men and caused death in three percent in 2005.[17] In Japan, death from prostate cancer was one-fifth to one-half the rates in the United States and Europe in the 1990s.[18] In India in the 1990s, half of the people with prostate cancer confined to the prostate died within ten years.[19] African-American men have 50–60 times more prostate cancer and prostate cancer deaths than men in Shanghai, China.[20] In Nigeria, two percent of men develop prostate cancer and 64% of them are dead after two years.[21]

In patients that undergo treatment, the most important clinical prognostic indicators of disease outcome are stage, pre-therapy PSA level and Gleason score. In general, the higher the grade and the stage the poorer the prognosis. Nomograms can be used to calculate the estimated risk of the individual patient. The predictions are based on the experience of large groups of patients suffering from cancers at various stages.[22]

References

  1. IARC Worldwide Cancer Incidence Statistics—Prostate. JNCI Cancer Spectrum. Oxford University Press (December 19, 2001). Retrieved on 2007-04-05 through the Internet Archive
  2. Aumüller, G. (1979). Prostate Gland and Seminal Vesicles. Berlin-Heidecool.lberg: Springer-Verlag. 
  3. Moore, K.; Dalley, A. (1999). Clinically Oriented Anatomy. Baltimore, Maryland: Lippincott Williams & Wilkins. 
  4. Steive, H. (1930). "Männliche Genitalorgane", Handbuch der mikroskopischen Anatomie des Menschen. Vol. VII Part 2. Berlin: Springer, 1–399. 
  5. Smith JA, Chan RC, Chang SS, et al. (2007). "A comparison of the incidence and location of positive surgical margins in robotic assisted laparoscopic radical prostatectomy and open retropubic radical prostatectomy". J. Urol. 178 (6): 2385–9; discussion 2389–90. doi:10.1016/j.juro.2007.08.008. PMID 17936849.
  6. Miller, DC; Hafez, KS, Stewart, A, et al. (2003). "Prostate carcinoma presentation, diagnosis, and staging: an update from the National Cancer Data Base". Cancer 98: 1169. doi:10.1002/cncr.11635. PMID 12973840.
  7. van der Cruijsen-Koeter, IW; Vis AN, Roobol MJ, Wildhagen MF, de Koning HJ, van der Kwast TH, Schroder FH (July 2005). "Comparison of screen detected and clinically diagnosed prostate cancer in the European randomized study of screening for prostate cancer, section rotterdam". Urol 174 (1): 121–5. doi:10.1097/01.ju.0000162061.40533.0f. PMID 15947595.
  8. Essink-Bot, ML; de Koning HJ, Nijs HG, Kirkels WJ, van der Maas PJ, Schroder FH (June 17 1998). "Short-term effects of population-based screening for prostate cancer on health-related quality of life". J Natl Cancer Inst 90 (12): 925–31. doi:10.1093/jnci/90.12.925. PMID 9637143.
  9. Chuang AY, Demarzo AM, Veltri RW, Sharma RB, Bieberich CJ, Epstein JI (2007). "Immunohistochemical Differentiation of High-grade Prostate Carcinoma From Urothelial Carcinoma". The American Journal of Surgical Pathology 31 (8): 1246–1255. doi:10.1097/PAS.0b013e31802f5d33. PMID 17667550.
  10. Sartor AO, Hricak H, Wheeler TM, et al. (December 2008). "Evaluating localized prostate cancer and identifying candidates for focal therapy". Urology 72 (6 Suppl): S12–24. doi:10.1016/j.urology.2008.10.004. PMID 19095124.
  11. Gerald L. Andriole, M.D., Robert L. Grubb, III, M.D., Saundra S. Buys, M.D., David Chia, Ph.D., Timothy R. Church, Ph.D., Mona N. Fouad, M.D., Edward P. Gelmann, M.D., et al. (2009-03-18). "Mortality Results from a Randomized Prostate-Cancer Screening Trial". The New England Journal of Medicine 360: 1310. doi:10.1056/NEJMoa0810696. PMID 19297565. Retrieved on 2009-03-19.
  12. http://www.nytimes.com/2009/03/19/health/19cancer.html?em
  13. Mouraviev V, Evans B, Polascik TJ (2006). "Salvage prostate cryoablation after primary interstitial brachytherapy failure: a feasible approach". Prostate Cancer Prostatic Dis. 9 (1): 99–101. doi:10.1038/sj.pcan.4500853. PMID 16314889.
  14. Prostate Cancer At A Glance. ShaveMagazine.com.
  15. http://yedda.com/questions/Low_fat_milk_causes_prostate_cancer_7351021963170/
  16. ACS :: What Are The Risk Factors for Prostate Cancer?
  17. Jemal, A; Murray T; Ward E; Samuels A; Tiwari RC; Ghafoor A; Feuer EJ; Thun MJ (Jan-February 2005). "Cancer statistics, 2005". CA Cancer J Clin 55 (1): 10–30. doi:10.3322/canjclin.55.1.10. PMID 15661684. Erratum in: CA Cancer J Clin. 2005 Jul-Aug;55(4):259.
  18. Wakai, K (February 2005). "Descriptive epidemiology of prostate cancer in Japan and Western countries". Nippon Rinsho 63 (2): 207–12. PMID 15714967. Review.
  19. Yeole, BB; Sunny L (Jun-December 2001). "Population based survival from prostate cancer in Mumbai (Bombay), India". Indian J Cancer 38 (2–4): 126–32. PMID 1259345.
  20. Hsing, AW; Tsao L, Devesa SS (January 1 2000). "International trends and patterns of prostate cancer incidence and mortality". Int J Cancer 85 (1): 60–7. <60::AID-IJC11>3.0.CO;2-B doi:10.1002/(SICI)1097-0215(20000101)85:1<60::AID-IJC11>3.0.CO;2-B. PMID 10585584.
  21. Osegbe, DN (April 1997). "Prostate cancer in Nigerians: facts and nonfacts". J Urol 157 (4): 1340–3. doi:10.1016/S0022-5347(01)64966-8. PMID 9120935.
  22. Di Blasio CJ, Rhee AC, Cho D, Scardino PT, Kattan MW (2003). "Predicting clinical end points: treatment nomograms in prostate cancer". Semin Oncol 30 (5): 567–86. doi:10.1016/S0093-7754(03)00351-8. PMID 14571407.

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