New Perspectives for Diagnosis and Treatment of Prostate Cancerby Stiven Benson Doctor
Prostate cancer is now a major public health problem. It is the second most frequently diagnosed cancer in men today, as it is the 4th leading cause of death by cancer in men in Western countries, including Portugal. Although there are no concrete numbers regarding our country, we know that in the U.S. alone, for example, 28,900 men died of prostate cancer in 2003. Diagnosed in 2005 were in the same country 230,110 men with prostate cancer, that number will raise to 380,000 by 2025. The risk of a man Western be diagnosed with cancer of the prostate lifetime is 16.6%. In European die per day, 247 men due to this pathology. Studies show that the incidence of prostate cancer has been increasing in recent decades. The causes are not clear and, although the more aggressive strategies for early diagnosis may partly explain this increase, not to exclude other causes related to nutrition, lifestyle, and the environment.
The incidence of prostate cancer increases with age, which is not a disease of the young man. However, we have seen the emergence of this neoplasm in ever earlier ages. Most guidelines also recommends annual screening beginning at age 50, or age 45 in the case of high-risk groups such as individuals of black race or those with 1st degree relatives with a history of prostate cancer. However, a growing number of cases below 50 years, so many urologists recommend regular consultation after 40 years.
We continue to ignore the causes of this type of cancer. Our knowledge is incomplete regarding risk factors. Apart from age, and family history, other factors seem to be important. Indeed the risk for developing prostate cancer appears to vary from population to population being much more common in Western countries like the United States, Canada and Europe than, for example, in Asian countries. On the other side, the risk is higher in individuals of black race.
Generally prostate cancer develops without any symptoms manifesting only a very advanced stage (widespread), since without the possibility of cure. Contrary to what most people judges rarely occurring urinary symptoms at an early stage. In fact, today, 80% of cases are diagnosed by routine medical examinations conducted in apparently healthy individuals without any complaints Hence the importance of early diagnosis, ie a stage of localized prostate disease, even without symptoms, but curable . The diagnosis is suggested by the alteration of one of the following exams: DRE, PSA blood assay (prostate specific antigen) and trans-rectal ultrasound prostate. The digital rectal examination is a very easy and simple, which consists of prostatic digital palpation (with finger) via anal, which can provide important information about the volume, consistency and limits prostate. Unfortunately some men still delay their trip to the urologist afraid of this examination. PSA is a substance produced by normal prostate but whose blood values rise when prostatic diseases, particularly in the case of prostate cancer. It is important to note that an elevated PSA does not necessarily mean the existence of a prostate cancer, although it is necessary to exclude it.
The elevation of PSA occurs on average up to five years prior to detection of any fault to the DRE. Nowadays they use special types of PSA, free PSA and PSA complexes, or who seek to increase specificity in the detection of prostate cancer, i.e. decrease the cases of false positives. Finally, the trans-rectal ultrasound prostate, although not recommended by all urologists, offers us important information such as the existence of prostatic nodules suspected, or commitment limits gland. When any of these tests reveals changes that become suspect, we must confirm the diagnosis of cancer by performing a prostate biopsy. This is a technique which consists in collecting various fragments of the prostate via trans-rectal, which are then sent for histological evaluation in order to determine the existence or not of cancer. It is a simple test, very well tolerated by the patient and which is ambulatory without any admission to only local anesthesia.
The treatment of prostate cancer depends essentially on two parameters: the age of the patient and the tumor. The older patients, ie with a life expectancy less than 10 years, are usually treated with hormone therapy, i.e. therapy with hormonal suppression since prostate cancer is hormone depending on the stimulation by androgens such as testosterone. This suppression can be achieved with hormonal castration (removal of the testes) or chemically that inhibit the production or action of testosterone). It is a type of treatment that works only temporarily (2-4 years), but eventually allows the patients of this age die with their cancer and its not cancer.
When patients have a life expectancy exceeding 10 years or younger, must offer the patient a treatment with curative intentions, which is only possible if the disease is localized to the prostate. There are only three types of curative treatments for prostate cancer. That is considered more effective radical prostatectomy, which consists of surgical removal of the prostate and seminal vesicles. Allows survival after 10 years more than 90%, but with two major side effects: some degree of erectile dysfunction reaching 50 to 90% of patients and some urinary incontinence, usually transitory, within the first month but which may be permanent among 3 to 10% of patients.
As an alternative to surgery, some patients opt for radiotherapy method, with less compromise of sexual function and without impact on urinary continence, but cure rates lower than surgery and does not devoid of significant side effects and also disabling such as stems rectum cystitis lies, or alteration of intestinal transit. Recently introduced a third type of treatment, prostate brachytherapy, interstitial a form of radiation therapy, which consists of the introduction of radioactive seeds in the prostate gland under anesthesia). This is a method that showed cure rates superimposable to radical prostatectomy, in well-differentiated cancers, but with far fewer side effects, and it is increasingly preferred by patients. In the U.S., where it has existed for about 15 years, is chosen by more than half of the patients.
Patients with metastatic disease (when the cancer has spread to other areas of the body) are treated with hormone therapy. Hormonal therapy, although not curative, can lead to long term remission, allowing an excellent quality of life. However, with time, prostate cancer can progress despite hormonal therapy. It is not clear why this happens, but it evolves into a state referred to as prostate cancer hormone-resistant, in which about 70% of patients have bone metastasis.
The skeleton is the main target of this type of cancer metastasis and as the disease reaches this stage there is no standard effective therapy and generally patients have severe and debilitating bone pain and intense compression fractures or neurological structures which are associated with a decreased survival. However, recent research in this area has made great progress, motivating a renewed optimism. In recent years there have been some important new treatments, designing new ways to treat these patients and metastatic hormone-resistant. In addition to the substantial improvement in the treatment of pain through the use of novel analgesics, we now have two new drugs with proven results. The first is zoledronic acid, the class of bisphosphonates (a class of drugs that help rebuild and strengthen the bone). This drug has shown efficacy in a significant reduction of pain caused by bone metastases, and a decrease and delay the onset of complications such as bone metastases of fractures and the need for palliative radiotherapy.
The introduction of zoledronic acid consisted in a new and effective treatment of the complications of bone metastasis of prostate cancer. Are ongoing studies indicate the possibility of using this drug in an earlier stage in order to prevent the appearance of bone metastases in patients at risk. A second recently introduced drugs to treat hormone-resistant patients is docetaxel, a type of chemotherapy shown to increase survival in these patients significantly improving quality of life, and forming a new hope for patients hormone-resistant.
One of the most fascinating in prostate cancer is the chemoprevention, which consists in regular administration of chemicals, natural or synthetic, in order to prevent the appearance and Development also for prostate cancer. Some natural products such as lycopene (abundant in tomatoes), the phytosterols (abundant in soy), selenium, or vitamins A and D, have shown promising results. One of the most interesting studies in this area was the Prostate Cancer Prevention Trial, which showed a 25% reduction in the risk of developing prostate cancer in men who were taking daily 5 mg of finasteride, a drug that inhibits the activity of prostatic testosterone level , have been used for many years in benign prostatic hyperplasia. Another study, the REDUCE study, attempts to show similar results with another drug: dutasteride. The results are expected this year. This is certainly an area for future in oncology, which just now is taking its first steps.
In conclusion, although prostate cancer is very common, we now have many treatment alternatives, even in the later stages of the disease, enabling the patient with prostate cancer look to the future with hope.
Created on Dec 31st 1969 19:00. Viewed 0 times.
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