Brachytherapy is a type of radiotherapy, or radiation treatment, offered to certain cancer patients. There are two types of brachytherapy - high dose-rate (HDR) and low dose rate (LDR). Brachytherapy LDR is the most commonly used type for treating prostate cancer; can sometimes be referred to as 'seed implantation' or it may be called a 'pinhole' operation.
In LDR brachytherapy, small radioactive particles the size of a grain of rice (see Figure 1) are planted directly to the site of the tumor. These particles are known as 'seeds', and they can be inserted together together as a string, or individually. Because the seeds are inserted or planted directly into, or very close to the tumor, they give high doses of radiation to the tumor without affecting the normal healthy tissue around it. This means that the procedure is less damaging than conventional radiation therapy, where radioactive rays are sent from outside the body and have to pass through other tissues before it reaches the tumor.
In addition to seeds, a source of LDR-polymer encapsulation is also available. The feature source is 103 Pd along the full length of the device contained using a low Z polymer. The polymer construction and linear radioactive distribution of these sources creates a very homogeneous dose distribution.
LDR prostate brachytherapy (seed or line source implantation) is a proven treatment for local prostate cancer with low to high risk (when cancer is contained within the prostate). Under general anesthesia, radioactive seeds are injected through a fine needle directly into the prostate, so radiotherapy can destroy cancer cells. The seeds are planted permanently, so they remain in place but gradually become inactive because radioactivity decays naturally and safely from time to time. Unlike traditional surgery, LDR brachytherapy does not require an incision and is usually performed as a day procedure. Sometimes it takes one night stay in the hospital. Patients usually recover quickly from LDR brachytherapy, which means that most men can return to work or normal daily activities within a few days. As described below, LDR brachytherapy has a good side-effect profile with lower incontinence or impotence risk than other treatment options, and is becoming an increasingly popular alternative to major surgery (conventional radical prostatectomy or laparoscopic (hole surgery) of radical prostatectomy).
The isotopes used include iodine 125 (half 59.4 days) of palladium 103 (half-day 17) and cesium-131 ​​(half-life 9.7 days).
Video Prostate brachytherapy
Prosedur
When LDR prostate brachytherapy (seed or polymer source implantation) is performed, the ultrasound probe is inserted into the back (rectum), and an image of the probe is used to assess the size and shape of the prostate gland. This is done so that doctors can identify the best way to give the right radiation dose for each patient. Then the seeds are put into the exact location identified at the beginning of the procedure. This usually takes 1-2 hours. No surgical incisions required; on the contrary, radioactive seeds are inserted into the prostate gland using a needle that passes through the skin between the scrotum and rectum (perineum) and the ultrasound probe is used to guide them accurately to their final position. The needle is inserted into the target position and between 70 and 150 seeds are placed into the prostate. The needle is then removed. Figure 2 shows a device such as a grid used to guide the needle into the perineal area; coordinates or 'reference maps' on the grid or this template is used to determine the exact position in the prostate where the seed is placed. Figure 3 shows how the seed is positioned to target the tumor. Doctors use ultrasound and X-ray images to ensure the seeds are in the right place. Special computer software programs are used to ensure the prostate gland is completely covered by the exact dose of radiation (see Figure 4) to ensure that all cancer cells present in the prostate have been completely treated.
Once in place, seeds or sources slowly begin to release their radiation. When the source is active, the patient should consider some basic precautions. Travel and contact with adults is fine; however, during the first two months after seed implantation, young children and pregnant women should not be in direct contact with the patient for long periods - for example, children should not sit on the patient's knee for long periods. Sexual intercourse can start again in a few weeks. Sometimes seeds can be excreted in semen during ejaculation; if this happens, will usually occur in some first ejaculation, so it is advisable to use condoms for two or three first sexual intercourse after brachytherapy LDR.
Patients can usually return to normal activities and work within a few days. They should expect to be followed up after four to six weeks, and then every three months for a year, six months to five years, then every year.
Maps Prostate brachytherapy
Indication
LDR prostate brachytherapy (seed or polymer source implantation) is recommended as a treatment for patients whose cancer is at an early stage (stage of T1 to T2 cancer), and which has not spread beyond the prostate (local disease). Doctors use a combination of factors such as stage and cancer rates, PSA level, Gleason score and urine/bladder discharge test to help them decide whether the patient is suitable for LDR brachytherapy. Patients should ask their doctors about these different test results and how they affect the types of treatment they may offer. Brachytherapy LDR in combination with external beam radiotherapy can also be recommended for patients with end-stage cancer and higher PSA levels and Gleason scores.
Risks and benefits
Since its introduction in the mid-1980s, the brachytherapy (seed or polymer source implantation) prostate has become an established treatment option for patients with locally advanced disease. In the US alone, more than 50,000 eligible prostate cancer patients each year are treated using this method. Awareness of this treatment option has now spread to other parts of the world, and there is the widespread and rapidly growing use of this technique. In the UK, prostate brachytherapy is provided in most cancer centers and thousands of patients have been treated.
Clinical benefits
LDR prostate brachytherapy (seed or polymer source implantation) alone has been shown to be very effective for the treatment of early prostate cancer. The survival rate without an increase in mean PSA levels after LDR brachytherapy is similar to that achieved with external beam radiotherapy and radical prostatectomy. However, LDR brachytherapy has a lower risk of some complications associated with other treatment options.
Side effects
LDR prostate brachytherapy (seed or polymer source implantation) is a highly effective treatment for low-to-high-risk cancers, with patients quickly returning to normal activity. Although the patient may have problems (urinary incontinence or difficulty urinating) for the first 6 months or so after the implant, the problem is usually persistent and lasting, rarely occurs in about 1-2% of patients. Some patients (less than 10%) report an increase in bowel problems (diarrhea or urgency of the intestine), but again this usually settles without further treatment.
Erectile dysfunction (difficulty obtaining and/or maintaining an erection, impotence) is another side effect associated with all treatments for prostate cancer. Other treatments for prostate cancer cause problems with erectile dysfunction in 30-60% of men (as seen in Table 1), but this problem is much more common after LDR brachytherapy, and only occurs in about 10-30% of men under age 60 , which is strong before treatment.
In a 2006 study that looked at patients' quality of life, LDR brachytherapy was compared with other treatment options. Table 1 summarizes the more common side effects associated with each form of treatment and how this may affect patient recovery.
See also
- Brachytherapy
- Prostate cancer
References
External links
- Brachytherapy Group Pro Discussion and Support
- American Brachytherapy Society (USA)
- Canadian Prostate Cancer Network (Canada)
- National Prostate Cancer Coalition (USA)
- Prostate Brachytherapy Advisory Group (UK)
- Prostate Cancer Charity (UK)
- Prostate Cancer Foundation (USA)
- The Prostate Cancer Research Institute (USA)
- Prostate UK (UK)
- Prostate Cancer Research Vancouver Island Foundation (Canada)
Source of the article : Wikipedia
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