Side Effects of Radiation

Side Effects of Pelvic Radiation for Gynecological Cancers

Note that radiation can be external or internal or HDR. The side effects of radiation are related to: the area treated (which normal organs are in the way, e.g. the bowel, bladder or rectum, see CT picture of organs affected by radiation here) the size of the radiation field or port (the larger the area, the more the side effects) the dose of radiation (the higher the dose, the more side effects) and whether chemotherapy is being given as well (generally more fatigue and diarrhea).

For a list of the most likely side effects from gynecologic radiation read the consent forms from the RTOG trials here. Read the nursing instruction sheets here.

Pelvic radiation normally causes bowel irritation (gas, cramps, looseness or diarrhea,) bladder irritation (frequency or burning,) vaginal irritation (itching or discharge,) skin irritation (mild sun burn) and fatigue. (In premenopausal women, radiation can cause ovarian function to stop and bring on menopausal symptoms.) Dose limits are set out in may protocols (e.g. RTOG 0116, RTOG 0418). For side effects involving the abdomen and upper pelvis go here and for a discussion or rectal problems go here, and for risk to pelvic bones go here.

The side effects usually start to show up after about 8 or 10 treatments and generally start fading away about a week or two after completing radiation, but it can take several months for all the side effects to wear off. As noted in the studies below about 20-40% of the women have mild side effects but only about 1-5% severe. (side effects from treating the abdomen are discussed here; go here for more studies on gyn pelvic side effects, and the scoring system.)

Radiation to the vagina can cause problems with sexual function as noted here and also here. There is a small risk of pelvic radiation increasing the risk of bone fractures (see here and here).

Side Effect Page from RTOG Consent Form (RTOG 97-08) External + Implant

Cancer treatments often have side effects. The treatment used in this program may cause all, some, or none of the side effects listed. In addition, there is always the risk of very uncommon or previously unknown side effects occurring.

Radiation Therapy: Possible side effects include tiredness, diarrhea, nausea, and vomiting, rectal irritation, urinary frequency, difficulty in urination, loss of public hair, reddening and irritation of the skin in the irradiated field, and depression of blood counts. Long-term side effects, although uncommon, may include malnutrition, rectal ulcer, bleeding or narrowing of the rectum, difficulty in urination, bloody urine, bowel obstruction, shortening of the vagina, vaginal vault necrosis (ulceration), and fistula formation (openings) between pelvic tissues.

The morbidity of treatment for patients with stage I endometrial cancer: results from a randomized trial
Carien L. Creutzberg International Journal of Radiation Oncology*Biology*Physics, 2001: 51:5 : 1246-1255

The Postoperative Radiation Therapy in Endometrial Carcinoma (PORTEC) trial included patients with endometrial cancer confined to the uterine corpus, either Grade 1 or 2 with more than 50% myometrial invasion, or Grade 2 or 3 with less than 50% myometrial invasion. Surgery consisted of an abdominal hysterectomy and oophorectomy, without lymphadenectomy. After surgery, patients were randomized to receive pelvic RT (46 Gy), or no further treatment. A total of 715 patients were randomized. Treatment complications were graded using the French–Italian glossary.

Results: The analysis was done at a median follow-up duration of 60 months. 691 patients were evaluable. Five-year actuarial rates of late complications (Grades 1–4) were 26% in the RT group and 4% in the control group (p < 0.0001). Most were Grade 1 complications, with 5-year rates of 17% in the RT group and 4% in the control group. All severe (Grade 3–4) complications were observed in the RT group (3%). Most complications were of the gastrointestinal tract. The symptoms resolved after some years in 50% of the patients. Grade 1–2 genitourinary complications occurred in 8% of the RT patients, and 4% of the controls. Bone complications occurred in 4 RT patients (1%). Seven patients (2%) discontinued their RT due to acute RT-related symptoms. Patients with acute morbidity had an increased risk of late RT complications (p = 0.001). The 4-field box technique was associated with a lower risk of late complications (p = 0.06).

Conclusion: Pelvic RT increases the morbidity of treatment in Stage I endometrial cancer. In the PORTEC trial, severe complications occurred in 3% of treated patients, and over 20% experienced mild (mostly Grade 1) symptoms. Patients with acute RT-related morbidity had an increased risk of late complications. As pelvic RT in Stage I endometrial carcinoma was shown to significantly reduce the rate of locoregional recurrence, but without a survival benefit, its use in the adjuvant setting requires careful patient selection (treating those at increased risk of relapse), and the use of treatment schemes with the lowest risk of morbidity.
see table below:

endomet_side_effects.gif (23788 bytes)