*4.2.2.2 Late GI toxicity*

*Translational Research in Cancer*

after termination of RT.

better than the bowels.

(IMRT) [62].

*4.2.1.1 Acute radiation cystitis*

*4.2.1.2 Late genito-urinary toxicity*

following brachytherapy [63].

*4.2.2.1 Acute RT toxicity*

*4.2.2 Gastro-intestinal (GI) toxicity*

termination of the treatment.

*4.2.1 Genito-urinary (GU) system toxicity*

receiving 40–50 Gy. The toxic effect of RT depends on the age for ovaries; exposure to 20 Gy usually results in ovarian insufficiency in an adult woman. The influence of RT on the vagina depends on the location (superior, medial, inferior, posterior or the anterior wall). While the proximal vagina seems to be resistant to high doses (>100 Gy), the distal and the posterior walls are susceptible to atrophy and stenosis. While the rectum and the urinary bladder can be treated with low risk with 45–50 Gy RT, the small intestine shows severe toxic effects against <30 Gy, depending on the treated volume. These toxic effects of RT are known to be related to the treated tissue amount, fraction number and dose, previous surgeries, concurrent

chemotherapies, co-morbid conditions and the smoking status [61].

Acute toxicity is defined as conditions that develop in the course of RT.

Sub-acute toxicity is defined as conditions that develop between 4 and 12 weeks

Late toxicity is defined as the irreversible reactions that develop 3 months after

The patient is asked to come to the treatment with a full urinary bladder with the aim of moving away the bowels as the urinary bladder can tolerate RT relatively

This is among the most common RT-induced complications. The patients present with urinary symptoms (dysuria, frequency, urgency and nocturia). Infectious cystitis should be excluded. The symptoms usually recover spontaneously within 1–2 weeks. Genitor-urinary complaints were reported to be seen less frequently when adjuvant therapy was performed with intensity-modulated radiation therapy

This toxic effect of RT emerges as the urinary bladder epithelium and the micro-vascular circulation are affected. Fibrosis and collagen accumulate under the epithelium and the muscle layer, and the urinary bladder capacity decreases. This effect leads to over-activity and contraction of the urinary bladder resulting in urge incontinence. In the PORTEC-1 study, while grade 3–4 toxicity was not observed,

Hematuria and ulcer formation are the late GU findings. Recurrent urinary bladder stones may be formed. Ureto-vaginal or vesico-vaginal fistulae may also develop

Gastro-intestinal toxicity may develop during RT or later and impair the quality of life of the patients through leading to restrictions in the daily lives of the patients.

As the small intestine epithelium shows a rapid proliferation, it is affected to a higher extent by RT. While nausea and vomiting are seen at the beginning of the

the rate of grade 1–2 genito-urinary complication was 5% higher [11].

**164**

Late effects may develop between 6 months and several years in most patients. The pathophysiology includes chronic enteropathy with mucosal atrophy and loss of mucin-producing goblet cells. Fibrosis in the intestinal walls causes dysmotility and acute obstruction. There are no techniques that do not cause late intestinal complications, including IMRT. The late toxic intestinal effects include chronic diarrhea, malabsorption, recurrent ileus, mucosal ulcer, telangiectasias and rectal proctopathy.
