Radiotherapy is one of the common methods of cancer treatment. Conventional radiotherapy can cause certain side effects, such as weakness, fatigue, dizziness, headache, and anorexia, and can also cause some degree of skin reactions.
Radiation damage to tissues and organs is related to the following factors:
- Tissue sensitivity to radiation (degree of damage): generally proportional to the proliferative capacity of cells, i.e. the more reproducible the tissue is, the more sensitive it is.
- Lymphatic tissues, bone marrow, testes, ovaries, and small intestine epithelium are the most sensitive to radiation and most vulnerable to damage;
- Followed by skin epithelium, cornea, oral and nasal cavities, crystals, stomach and bladder epithelium;
- The least sensitive tissues are muscle, bone, and nerve tissue.
- Area of tissue irradiated and single dose: The larger the area irradiated and the higher the dose, the greater the damage to the tissue.
- Patient’s general condition: The presence or absence of concurrent diseases, such as cachexia, infectious diseases, and cardiopulmonary and vascular diseases, affects the degree of response to radiation.
- Age is also a factor, with adolescents being more sensitive than adults, but sensitivity increasing again in older age.
- The advent of linear gas pedals and conformal techniques: including 3D conformal radiotherapy and intensity-modulated conformal radiotherapy, both of which are now the most mainstream techniques in prostate cancer radiotherapy, allow large doses of radiation to reach the pelvis while reducing damage to normal tissues such as the anterior rectal wall, prostatic urethra, femoral head, and bladder neck, i.e., achieving a precise strike
- Application of image-guided technology: The application of image-guided technology during the implantation of radioactive material in the prostate overcomes the blindness of the original implantation technique, maximizing the dose of radiotherapy to the prostate while protecting the surrounding normal tissue. This results in improved tumor control and reduced side effects.
Traditional prostate radiation therapy, in which radiation is directed to the pelvis, not only kills prostate cancer cells, but also affects adjacent organs, such as the rectum and bladder, causing problems with urination and defecation.
But since the early 1980s, 2 important advances have been made in radiation therapy for prostate cancer:
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The current advances in radiotherapy techniques, which can achieve radical cure for limited prostate cancer and are relatively less invasive than surgery, are gaining more and more attention for these new radiotherapy techniques.
The side effects of radiotherapy are related to the single dose, the total dose, the radiotherapy regimen, and the volume irradiated. Conventional radiotherapy causes more complications, but nowadays conformal radiotherapy or intensity-modulated conformal radiotherapy is mostly used, and the incidence of side effects is much lower.
Common complications of external radiotherapy
The common toxicities in the acute phase of external radiotherapy (i.e., external exposure) include: urinary frequency, urinary urgency, nocturia, hematuria, diarrhea, a sensation of falling, urgency, blood in the stool, and perianal skin erosion, etc. These symptoms usually disappear gradually after a few weeks of radiotherapy and are reversible. The most obvious late toxic side effect is rectal bleeding, but the incidence of blood in the stool that seriously affects life and requires surgical treatment is less than 1%.
Other possible complications, such as hemorrhagic cystitis, can occur, but the condition can improve with conservative treatment. The most recent retrospective study confirmed that radiotherapy for prostate cancer increases the risk of rectal and bladder cancer: the risk of rectal cancer is about 1.7 times higher compared with radical surgery, and the risk of bladder cancer is about 2.34 times higher compared with a healthy population.
Common complications of brachytherapy
Complications of brachytherapy (ie, internal exposure) include both short-term and long-term complications. Complications that occur within 1 year are usually defined as short-term complications, whereas those that occur after 1 year are considered long-term complications. These complications are mainly related to the urinary tract, rectum, and sexual function.
Short-term complications include urinary frequency, urgency, thin urine lines, or mild pain, which can last 2 to 6 weeks and are relieved by symptomatic treatment, occasionally requiring catheter placement. Some patients may also experience rectal irritation such as increased frequency of stools and urgency, as well as proctitis (mild blood in the stool, intestinal ulcers, or even prostatic rectal fistula).
Long-term complications are more common with chronic urinary retention, urethral stricture, and urinary incontinence (which occurs in less than 1% of cases).
So, what should you look for after brachytherapy?
1. Do not lift heavy objects or exercise vigorously
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Do not lift heavy objects or exercise vigorously for 3 to 4 days after treatment. This is because vigorous exercise can cause bladder bleeding, and although there is usually no significant effect on the body, it is best to exercise after the bleeding has stopped.
2. Do not ride a bicycle or other activities that put pressure on the prostate
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For 6 months after treatment, do not do any activities that may put pressure on the prostate, such as bicycling, horseback riding, and motorcycle riding. This is because the particle implant needle can cause damage to the blood vessels around the prostate, and repeated multiple shocks can cause swelling and damage to the prostate.
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3. Avoid contact with children and pregnant women for a short period of time
Contact with children and pregnant women should be avoided for 2 months after treatment. However, there is little effect on others, such as simply hugging, eating together, etc., because the particles decay quickly, the energy is very low, and the implantation is so precise that almost all of the energy is absorbed by the prostate.
4. Use condoms for sex
Sex can be had at any time after treatment. Condoms are currently recommended because the semen is not radioactive and there is no effect on the sexual partner if there is blood in the semen. The probability of the particles entering the vagina is minimal because the decay is rapid and therefore there is little risk.
5. Oral antimicrobials to prevent infection
Oral antimicrobials are generally required for 1 week after treatment. Although particle implantation does not usually cause serious infection, it is a surgical procedure that occasionally leads to urethral infection or prostatitis in some patients and therefore requires anti-inflammatory therapy.
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