Câncer de próstata - Coluna #11
Prostate cancer is the development of cancer in the prostatea gland in the male reproductive system. Factors that increase the risk of prostate cancer include older age, a family history of the disease, and race.
Prostate cancer screening is controversial. Many cases are managed with active surveillance or watchful waiting. Early prostate cancer c61 Prostatakrebs has no clear symptoms. Sometimes prostate cancer does cause symptoms, often similar to those of diseases such as benign prostatic hyperplasia. These include frequent urination, nocturia increased urination at nightdifficulty starting and maintaining a steady stream of urine, hematuria blood in the urineand dysuria painful urination.
A study based on the Patient Care Evaluation in the US found that about a third of patients diagnosed with prostate cancer had one or more such symptoms, while two-thirds had no symptoms. 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 c61 Prostatakrebs urethra, and secretions from the prostate gland c61 Prostatakrebs are included in semen content, prostate cancer may also cause problems with sexual function and performance, such as difficulty achieving erection or painful ejaculation.
Metastatic prostate cancer that has spread to other parts of the body can cause additional symptoms. The most common symptom is bone painoften in the vertebrae bones of the spinepelvisor ribs. Spread of cancer into other c61 Prostatakrebs such as the femur is usually to the proximal or nearby part of the bone. Prostate cancer in the spine can also compress the spinal cordcausing tingling, leg weakness and urinary and fecal incontinence. A complete understanding of the causes of prostate c61 Prostatakrebs remains elusive.
Prostate cancer is very uncommon in men younger than 45, but becomes more common with advancing age. The average age at the time of diagnosis is Men who have first-degree family members with prostate cancer appear to have double the risk of getting the disease compared to men without prostate cancer in the family.
In the United States inthere were an estimatednew cases of prostate cancer and 30, deaths due to prostate cancer. Genetic background may contribute to prostate cancer risk, as suggested by associations with race, family, and specific gene variants.
Men c61 Prostatakrebs have a first-degree relative father or brother with prostate cancer have twice the risk of developing c61 Prostatakrebs cancer, and those with two first-degree relatives affected have a fivefold greater risk compared with men with no family history. No single gene is responsible for prostate cancer; many different genes have been implicated. Two large genome-wide association studies linking single-nucleotide polymorphisms SNPs to prostate cancer were published in This SNP explains part of the increased prostate cancer risk of African American men as compared to American men of European descent, since the C c61 Prostatakrebs is much more prevalent in the latter; this SNP is located in the promoter region of the MSMB gene, thus affects the amount of MSMB protein synthesized and secreted by epithelial cells of the prostate.
Finally, obesity  and elevated blood levels of testosterone  may increase the risk for prostate cancer. Consuming fruits and vegetables has been found to be of little benefit c61 Prostatakrebs preventing prostate cancer. Lower blood levels of vitamin D may increase the risk of developing prostate cancer.
Folic acid supplements c61 Prostatakrebs no effect on the risk of developing prostate cancer. There are also some links between prostate cancer and medications, c61 Prostatakrebs procedures, and medical conditions. Infection or inflammation of the prostate prostatitis may c61 Prostatakrebs the chance for prostate cancer while another study shows infection may help prevent prostate cancer by increasing blood flow to the area.
In particular, infection with the sexually transmitted infections chlamydiagonorrheaor syphilis seems to increase risk. C61 Prostatakrebs virus has been proposed in several studies to have a potential role in prostate cancer, but as of the evidence was inconclusive.
Although there is some evidence from prospective cohort studies that frequent ejaculation may reduce prostate cancer risk,  there are no results from randomized controlled trials concluding that this benefit exists. The prostate is a part of the male reproductive system that c61 Prostatakrebs make and store seminal fluid.
In adult men, a typical prostate c61 Prostatakrebs about 3 centimeters long and weighs about 20 grams. The prostate surrounds part of the urethrathe tube that carries urine from the bladder during urination and semen during ejaculation. In prostate cancer, the cells of these prostate glands mutate into cancer cells. C61 Prostatakrebs prostate glands require male hormonesknown as androgensto work properly. Androgens include testosteronewhich is made in the testes ; dehydroepiandrosteronemade in the adrenal glands ; and dihydrotestosteronewhich is converted from testosterone within the prostate itself.
Androgens are also responsible for secondary sex characteristics such as facial hair and increased muscle mass. C61 Prostatakrebs prostate cancers are classified as adenocarcinomas c61 Prostatakrebs, or glandular cancers, that begin when normal semen-secreting prostate gland cells mutate into cancer cells.
The region of prostate gland where c61 Prostatakrebs adenocarcinoma is most common is the peripheral zone. Initially, small clumps of cancer cells remain confined to otherwise normal prostate glands, a condition known as carcinoma in situ or prostatic intraepithelial c61 Prostatakrebs PIN.
Although there is no proof that PIN is a cancer precursor, it is closely associated with cancer. Over time, these cancer cells begin to multiply and spread to the surrounding prostate tissue the stroma forming a tumor. C61 Prostatakrebs, the tumor c61 Prostatakrebs grow large enough to invade nearby organs such as the seminal vesicles or the rectumor the c61 Prostatakrebs cells may develop the ability to travel in the bloodstream and lymphatic system.
Prostate cancer is considered a malignant tumor because it is a mass of cells that can invade other areas of the body. This invasion of other organs is called metastasis. Prostate cancer most commonly metastasizes to the boneslymph nodesand may invade rectum, bladder and lower ureters c61 Prostatakrebs local progression. The route of metastasis to bone is thought to be venous as the prostatic venous plexus draining the prostate connects with c61 Prostatakrebs vertebral veins.
The prostate is a zinc -accumulating, citrate -producing organ. The c61 Prostatakrebs ZIP1 is responsible for the active transport of zinc into prostate cells. One of the zinc's important roles is to change the metabolism of c61 Prostatakrebs cell in order to produce citrate, an important component of semen.
The process of zinc accumulation, alteration c61 Prostatakrebs metabolism, and citrate production is energy inefficient, and prostate c61 Prostatakrebs sacrifice enormous amounts of energy ATP in order to accomplish this task.
Prostate cancer cells are generally devoid of zinc. This allows prostate cancer cells to save energy not making citrate, and utilize the new abundance of energy to grow and spread. The absence of zinc is thought to occur via a silencing of the gene that produces the transporter protein ZIP1. The cause of the epigenetic silencing is unknown. Strategies which transport zinc into transformed prostate cells effectively eliminate these cells in animals. Unfortunately, oral ingestion of zinc is ineffective since high concentrations of zinc into prostate cells is not possible without the active transporter, ZIP1.
Loss c61 Prostatakrebs cancer suppressor genes, early in the prostatic carcinogenesis, have been localized to chromosomes 8p10q13qand 16q. P53 mutations in the primary prostate cancer are relatively low and are more frequently seen in metastatic settings, hence, p53 mutations are a late event in the pathology of prostate cancer.
RUNX2 is a transcription factor that prevents cancer cells from undergoing apoptosis thereby contributing to the development of prostate cancer. The androgen receptor helps prostate cancer cells to survive and is a target for many anti c61 Prostatakrebs research studies; so far, inhibiting the androgen receptor has only c61 Prostatakrebs to be effective in mouse studies. The American Cancer Society 's position regarding early detection by PSA c61 Prostatakrebs is "Research has not yet proven that the potential benefits of testing outweigh the harms of testing and treatment.
Starting at age 50, 45 if C61 Prostatakrebs American or brother or father suffered from condition before age 65 talk to your doctor about the pros and cons of testing so you can decide if testing is the right choice for you. There are also several other tests c61 Prostatakrebs can be used to gather more c61 Prostatakrebs about the prostate and the urinary tract. Digital rectal c61 Prostatakrebs DRE may allow a doctor to detect prostate abnormalities.
Cystoscopy shows the urinary tract from inside the bladder, c61 Prostatakrebs a thin, flexible camera tube inserted down the urethra. Transrectal ultrasonography creates a picture of the prostate using sound waves c61 Prostatakrebs a probe in the rectum.
But the c61 Prostatakrebs test that can fully confirm the diagnosis of prostate cancer is a biopsythe removal of small pieces of the prostate for microscopic examination. Ultrasound US and magnetic c61 Prostatakrebs imaging MRI are the two main imaging methods used for prostate cancer detection. Urologists use transrectal ultrasound during prostate biopsy and can sometimes c61 Prostatakrebs a hypoechoic area c61 Prostatakrebs or structures that reflect relatively less of the ultrasound waves directed at them.
As ultrasound has poor tissue resolution, it is generally not used clinically. Prostate MRI has better soft tissue resolution than ultrasound. MRI c61 Prostatakrebs those who are at low risk might help people choose active surveillance; in those who are at intermediate risk it may help c61 Prostatakrebs determining the stage of disease, while in those who are at high risk it might help find bone disease.
Prostate MRI is also used for surgical planning for men undergoing robotic prostatectomy. It has c61 Prostatakrebs shown to help c61 Prostatakrebs decide whether to resect or spare the neurovascular bundle, determine return to urinary continence, and help c61 Prostatakrebs surgical difficulty. If cancer is suspected, a biopsy is offered expediently. 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 c61 Prostatakrebs in less than a second.
Prostate biopsies are routinely done on an outpatient basis and rarely require hospitalization. Antibiotics should be used to prevent complications like feverurinary tract infectionsand sepsis  even if c61 Prostatakrebs most appropriate course or dose of the antibiotic is still undefined.
The tissue samples are then examined under a microscope to determine whether cancer cells are present, and to evaluate the microscopic features or Gleason score of any cancer found. Prostate specific membrane antigen is a transmembrane carboxypeptidase and c61 Prostatakrebs folate hydrolase activity. Tissue samples can be stained for the presence c61 Prostatakrebs PSA and other tumor markers in order to determine c61 Prostatakrebs origin of malignant cells that have metastasized.
The oncoprotein BCL-2 is c61 Prostatakrebs with the development of androgen-independent prostate cancer, due to its high levels of expression in androgen-independent tumours in advanced stages of the pathology.
The upregulation of BCL-2 after androgen ablation in prostate carcinoma cell lines and in a castrated-male rat model further established a connection between BCL-2 expression and prostate cancer progression.
The expression of C61 Prostatakrebs by immunohistochemistry may be a significant predictor of patient outcome for men with prostate cancer. An important part of evaluating prostate cancer is determining the stageor how far the cancer has spread. Knowing the stage helps define prognosis and is useful when selecting therapies. Its components include the size of the tumor, the number of involved lymph nodesand 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.
Several tests can be used c61 Prostatakrebs look for evidence of spread. Medical specialty professional organizations recommend against the use of PET scansCT scansor bone scans when a physician stages early prostate cancer with low risk for metastasis. 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.
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.