Nuclear Oncology

Prostate cancer is the most common cancer among men in the United States, prevalent mostly in men over 65 years of age and is fairly common among men aged 50 to 64 years. However, prostate cancer can occur in men under 50 years of age. The incidence of prostate cancer diagnosed in men in the United States has increased dramatically since 1990 due to the use of a blood test called prostate specific antigen (PSA). More recently, men under 65 years of age have shown a higher incidence of this disease.

Overview of treatment options

There are several options for treating a cancer that is confined to the prostate. Each option should be carefully considered, taking into account the advantages and disadvantages according to age, general health and personal preferences of each man.

Options historical standards include:

* Surgery (radical prostatectomy): An incision in the lower abdomen or through the perineum (between anus and scrotum), and removing the prostate. Surgery incomplete, in which the entire tumor can not be removed, can be followed by radiotherapy. After the procedure requires the patient to maintain a urinary catheter placed for several weeks. Possible side effects of surgery can include incontinence (inability to control urination) and impotence (inability to achieve erection). More recently, several institutions are using three small incisions to perform robot-assisted prostatectomy, resulting in shorter hospitalization and faster recovery. This may be preferable in selected patients, but not all.

* The external beam radiotherapy (EBT): a method for delivering a beam of high energy X rays at the tumor site. The beam is generated outside the patient (usually by a linear accelerator) and if directed to the tumor site. These X-rays can kill cancer cells and careful treatment planning allows you to leave the surrounding normal tissue without much effect. See the External beam radiation therapy.

* Watchful waiting: Careful observation without treatment and medical monitoring.
In the last 10 to 15 years have developed new advanced options. These newer options prevent or minimize some of the unpleasant side effects that sometimes occur with standard treatments. These options include:

* Radical prostatectomy with nerve protection: A surgical procedure in which the prostate is removed without cutting the critical nerves around that transmit signals between brain and penis to allow normal sexual functioning. A skilled and experienced surgeon may preserve sexual function in some patients if the procedure is performed successfully.

* Conformal radiotherapy External beam: Use advanced technologies to tailor therapy to each patient’s anatomical structures. With the help of computerized three-dimensional images of the prostate, bladder and rectum, can shape the radiation beam to conform to the shape of the prostate. Thus comes less radiation to surrounding normal tissues. Currently there are two levels of conformal radiation therapy: three-dimensional conformal radiotherapy and intensity modulated radiation therapy (IMRT). Both allow administering higher doses of radiation to the tumor while protecting surrounding normal organs. IMRT is considered the conformation of two options. For details see page Intensity Modulated Radiation Therapy.

* Image Guided Radiation Therapy : either the 3-D conformal radiotherapy or IMRT, using a daily guided imagery has been increased to improve performance due to movement of the body. Because the position of the prostate varies day to day depending on the contents of the bladder and rectum, the prostate’s position must be verified before each treatment. In one method, several reference markers, or small pieces of biologically inert metal such as gold, are placed in the prostate gland before the simulation. They take digital X-ray images that locate the metallic markers to verify the position of the prostate on a daily basis, immediately before treatment, and alignment and proper adjustment of the prostate in the field of planned high-dose radiation. Another method involves using ultrasound to locate the prostate before each treatment. Ask the patient to keep a full bladder as possible so that it can produce an ultrasound image of good, and also to move the lining of the bladder outside the field of radiation treatment. A third method involves the use of computed tomography (CT) of low doses of the prostate area, immediately before each treatment in the treatment chair to check the position of the prostate. Your doctor will tell you the type of IGRT will receive, depending on your specific case and the type of technology available at your treatment center.

* Proton Beam Therapy: A type of conformal radiation that bombards the affected tissue with protons instead of X-rays .

* Cryotherapy: A procedure that uses extremely low temperatures (-190 ° C) to freeze and destroy cancer cells. Some doctors have experienced good results with few complications using cryotherapy, but not others. For now, this procedure should be considered experimental as initial treatment for prostate cancer until it has made a longer follow-up of patients treated with this modality. This technique was developed as an alternative to surgery in patients with recurrent prostate cancer after radiotherapy.

* Brachytherapy: Radiation treatment that is provided in the prostate by placing radioactive material into the prostate.

* Low-dose brachytherapy (LDR) or treatment of permanent seed implantation: a maximum of one hundred small radioactive seeds are inserted into the prostate gland through the hollow needle guided by ultrasound. These radioactive seeds provide radiation continuously for a period of several weeks to months, and then become inactive. These seeds remain in the prostate forever. Although the implantation technique has been around for decades, recent advances in imaging technology have made it more effective. In order to plan the procedure, prior to implantation is performed imaging such as CT, MRI or ultrasound. The implant procedure is performed under conscious sedation or local anesthesia / regional. During the implantation procedure using ultrasound (or sometimes MRI) to better see the prostate gland. Through the use of needles, doctors can insert the seeds more carefully and transperineal (the area below the front of the anus and testicles) into the prostate. This is an outpatient procedure and may require the patient to maintain a urinary catheter placed for about a week. In some institutions are already available long-term results of up to 15 to 20 years. These results show that in specialized centers, radioactive seed implantation guided by ultrasound is highly effective in controlling prostate cancer and that has essentially the same results as surgery or external beam radiotherapy in patients with prostate cancer who have been selected properly.

* High Dose Brachytherapy (HDR): This technique was developed to supplement external radiation therapy in the treatment of patients with prostate cancer risk. Patients receive about five weeks of radiotherapy, followed by one to three sessions of high dose rate brachytherapy (HDR). In this treatment, radiation is administered to the prostate on a temporary basis through radioactive isotopes (usually iridium-192). This procedure requires hospitalization. First, are inserted between 12 and 18 holes catheters into the prostate using transperineal as ultrasound and x-ray guidance, while the patient is under general anesthesia. Then, perform a CT scan and treatment planning to determine the location and duration of placement of the iridium-192 source. When the patient receives treatment, these catheters are connected to the HDR machine that controls the supply of the radioactive source of Iridium-192 to specific areas in each of these catheters. Treatment usually lasts about 10 to 20 minutes per session, and the patient usually receives between three to four sessions over a period of two days. At the end of the last session, the catheters are removed from the patient and the patient is discharged from the hospital. While the catheters are in the prostate, the patient is asked to stay in bed and in the hospital during that period of two weeks. The patient has no permanent radioactive material when leaving the hospital, and may be required to maintain a urinary catheter for about a week. Using this technique alone (ie without external beam therapy) in patients at low risk, is still in experimental stages.