Daniel Malatek, PA-C
Department of Radiation Oncology – GI Service
The University of Texas MD Anderson Cancer Center
Hi. My name is Daniel Malatek. I'm a Physician's Assistant that works at the University of Texas MD Anderson Cancer Center in the GI Service of the Radiation Oncology Department. Today, we're going to talk about the late effects of radiation therapy.
At the conclusion of this lesson, the participant will be able to appreciate the risk of late effects of radiation therapy when treatments for the colo --- for colorectal cancer. You can identify organs at risk from pelvic radiation therapy; recognize acute and late effects of radiation therapy; and identify management strategies of late effects from radiation treatment.
The organs at risk when treated with pelvic radiation therapy are the colon, small bowel, the bladder, ureters, urethra, the genital organs and spinal cord, skin, soft tissue, muscles, bones, vasculature, nerves in the radiation field, and the lymph --- lymphatic system.
Now, there're two types of effects of radiation therapy, acute effects and late side effects. Most people suffer some acute side effects. They are self-limiting and usually resolve two to three weeks after treatments. They will occur with both external beam and brachytherapy treatments. And there is no way to determine who will or will not suffer side effects, or which side effects, as well as the severity of the side effects.
They include fatigue, nausea, vomiting, abdominal cramping and diarrhea, dysuria, hematuria, rectal bleeding, discharge, proctitis, and skin reactions that are similar to a sunburn.
Now, the management of the acute side effects, including fatigue har --- which is usually mild and managed with longer nightly sleep or a nap during the day. Exercise can also lessen the effects of fatigue. For nausea and vomiting, instructing the patient to eat bland small meals throughout the day, with or without antiemetics as needed, is the treatment choice. For abdomen cramping and diarrhea, having the patient avoid high fat and greasy foods, plus using antidiarrhea medication, such as loperamide and diphenoxylate with atropine, which is better for treatment of abdomen cramps.
For dysuria, phenazopyridine is used. It does not completely take away the burning with urination. However, it does help. If hematuria is observed by a patient, an ar --- a urinalysis with culture and sensitivity is obtained, and if positive for a urinary tract infection, the appropriate antibiotic therapy is prescribed. For radiation-induced proctitis, barrier creams are used, such as hydrocortisone cream ointment or suppositories, or pra --- pramoxine. For skin reactions, emollients are used, as recommended by the radiation oncologist and as needed throughout treatments.
Now, the late side effects of radiation therapy: Ten percent or less of patients suffer one or more late side effects. They can occur several months or many, many years after treatments. They can occur with both external beam radiation and brachytherapy. Unfortunately, there's no way to know which patients will suffer late side effects.
In no particular order, the most common side effects that happen in the late event are bone fractures, which growth arrest is believed to be caused by a combination of cellular injury to the chondrocytes and damage to the blood vessels. There's a possibility of small bowel obstructions, either partial or complete. And these are caused by inflammation or damage to muscles, nerves, and/or blood flow that's been damaged to the bowel or scar tissue.
Fistulas are caused by the damage or weakening of the tissue and linings of structures between organs. Sexual dysfunction is caused by damage to the blood vessels supplying the nerves responsible for erection in males, and it causes vaginal stenosis or fibrosis, shortening of the vaginal vault, and dryness, which can cause pain in females with sexual function. And non-function ovaries cause loss of hormones, thus, a loss of desire or interest in intercourse.
The infertility and sterility is caused by the destruction of immature oocytes in females. Radiation therapy affects any rapidly dividing cells. So, cells that produce sperm are quite sensitive to radiation damage. The vaginal stenosis and dryness is caused by scarring and fibrosis from radiation therapy and loss of hormones from non-functioning ovaries, as mentioned earlier.
There can also be chronic diarrhea or poor absorption of food. And this is caused by radiation damage to the small bowel, especially to the lining of the intestines. Radiation proctitis, which includes bowel urgency, bleeding, and --- and/or incontinence, is caused by radiation damage to the distal rectum, the anal canal, and sphincter muscles and nerves.
Now, there are some uncommon late effects of radiation therapy. These include recurrent urinary tract infections, strictures of the ureters or the urethra. And, this is caused by radiation damage to the lining of the urinary tract system. There can be long term fatigue, which is caused by the toxicity of radiation, and possibly lymphedema of the lower extremities, which is caused by scarring of the lymph vessels.
Now, note: since these are less common side effects, they shouldn't first be attributed to radiation treatments. Other causes should be investigated or ruled out. For example, if a patient's treatments are longer than ten years ago, a recurrent cancer or second primary cancer is possible. And these need to be ruled out before attrib --- ignoring these symptoms and attributing them to previous radiation.
The management of these uncommon late effects are as follows: For recurrent urinary tract infections, prophylactic antibiotics. Stricture of the urethra, dilatation is indicated. If there is stricture of the ureters, stents may have to be placed. Fatigue, a daily exercise regimen can help, and possibly referral to physical therapy. And lymphedema of the lower extremities, elevation helps, daily exercise, possibly physical therapy, and use of compression stockings is useful.
Now, let's go to the management of the more common late effects of radiation therapy. Chronic diarrhea or poor absorption of food is one of the common late side effects of radiation. It can usually be managed with diet changes that include going to foods that don't induce diarrhea, including low fiber, low fat, and high protein foods. And an example would be reducing the amount of salads the patient eats. Daily psyllium is used with only half the prescribed amount of water to help bulk stools in certain cases. And over-the-counter loperamide either is needed or prophylactically. For example, one tablet daily or twice daily can be used to help produce the amount of bowel movements per day.
Proctitis is treated with hydrocortisone cream, ointments, or suppositories. Usually no greater than a two-weeks' duration for each occurrence is recommended, or with pramoxine with or without hydrocortisone as needed. For bowel urgency and incontinence, sphincter tone strengthening is required, and this involves Kegel exercises. Also, a patient can do bowel training. And this is training your bowel to defecate at the same time period each day. Also, it's helpful for patients to investigate where bathrooms are when they're in new locations. And for long trips or where a bathroom is not ready available, adult diapers or prophylactic loperamide can be used.
Bone fractures usually occur at the sacrum or the pelvis, and they're usually insufficiency fractures. They can be treated with conservative treatment most times, which includes rest, no heavy lifting, pelvic rest, pain medications for pain for several weeks. In the event, the fracture does not heal, kyphoplasty can be considered. Also, an orthopedics consult is required if conservative treatments do not heal the fracture, so that surgical treatment options can be investigated.
For small bowel obstructions, this usually requires hospitalization for conservative treatments that includes bowel rest and nutritional supplementation. If not responsive to conservative treatments, or if there is a com --- a complete obstruction, surgery is indicated. Fistulas or holes are again treated with conservative treatments initially. However, if they do not resolve, surgery can be performed usually if necessary.
Now, dys --- sexual dysfunction can affect both males and females. In males, medications are available, such as sildenafil, tadalafil, etc., or surgical implants for erectile dysfunction. Psychotherapy is also useful for loss of desire and/or anxiety. Now to note, older males are usually at more of a risk for sexual dysfunction when they receive radiation treatments secondary to their other age-related factors that can already affect sexual function and libido.
For the management of late side effects in females of sexual dysfunction, dilator use for vaginal stenosis which causes dyspareunia is recommended two to three times weekly if not sexually active. For severe stenosis, surgery can be considered. For vaginal dryness and thinning, estrogen therapy or estrogen creams can be applied to the lining of the vagina, if not contraindicated for a hormonally sensitive cancer or other comorbidities. Psychotherapy is also available for loss of interest and/or anxiety. Hormonal replacement therapy can also be considered, if not contraindicated secondary to a hormonally sensitive cancer or other comorbidities.
For infertility and sterility, these things need to be addressed prior to start of radiation treatments. Once the testes and ovaries have received radiation, if there is damage, this cannot be reversed. Some options are sperm banking for males prior to treatments and egg harvesting for females prior to treatments. The female needs to remember she will need a surrogate for implantation of eggs, as the uterus in most females is atrophied following treatments and cannot carry a fetus to term. Ovarian relocation out of the radiation fields prior to treatments has been tried, but oftentimes this is not successful, secondary to the inadequate blood supply to the ovaries during this time.
When to refer to a specialist: You should consider referral to a specialist --- if trea --- if not responsive to conservative management for the following: persistent bowel dysfunction or symptoms of malabsorption, you should refer to a bowel management specialist and/or a dietitian. For urinary symptoms, erectile dysfunction, and decreased libid --- libido, a urologist who is familiar with treatment of these side effects. For vaginal stenosis, dryness, or dyspareunia and decreased libido in females, a gynecologist who is also familiar with cancer-related side effects should be refer --- consulted. For insufficiency fractures that do not respond to conservative treatments, refer to an orthopedist.
Referral is also indicated for fistulas and small bowel obstructions. This requires a surgeon to evaluate for treatment options. For rectal bleeding, a gastroenterologist should be consulted.
In summary, acute reactions from radiation therapy can usually be managed conservatively and will resolve in two to three weeks after treatment. The late side effects of radiation therapy are not common, but they do occur in a small percentage of patients. However, there are effective treatments for most of these late side effects. And remember, recurrent cancer or a second primary can mimic the less common side effects of radiation therapy, so should be given more attention. Thank you. That's the end of my talk for today. I appreciate your attention, and if you have any feedback, that would be appreciated.
Late Effects of Radiation Therapy video
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