Radiation Therapy and Its Correlation With Urinary Incontinence

Introduction:

Urination is essential for maintaining a healthy life. Toxic metabolic byproducts are eliminated by this process. In childhood, babies don't have any control over urination. Gradually voluntary control over the process of urination is developed. But, the sudden passage of urine during physical activity has a social and psychological impact. Different medical conditions may induce such situations. Radiation therapy of the pelvic floor is known as pelvic radiation therapy. Such types of radiation therapy are responsible for urinary incontinence.

What Is Urinary Incontinence?

Urinary incontinence is the leakage of urine accidentally. In such cases, patients complain of involuntary urine leakage during physical activity. This is most commonly seen in women. Different types of urinary inconsistency are seen based on several situations and pathological conditions.

1. Etiology:

The causative factors for urinary incontinence are:

• Stress Urinary Incontinence: This type of urinary inconsistency occurs due to a sudden increase in intraabdominal pressure. Such things usually occur during coughing, sneezing, and exertion. This is also seen in sports persons during sports activity or in pregnant women. Persons can predict the leakage of urine. Urethral sphincter or pelvic floor weakness is the root cause of this type of urinary inconsistency.

• Urge Urinary Incontinence: This type of urinary leakage is related to urinary urgency. Bladder dysfunctions are the root cause of this type of urinary incontinence. Increased bladder activity, bladder hypersensitivity, and poor detrusor compliance are responsible for such situations. Such type of incontinence is seen in elderly people.

• Mixed Urinary Incontinence: This type of urinary inconstancy occurs due to a combination of both stress and urgency.

• Overflow Urinary Incontinence: This type of urinary inconsistency occurs due to an overdistended bladder. Overproduction of urine in diseases like diabetes is one of the main reasons for this type of urinary incontinence. Over-distension of the bladder is another reason behind it. Bladder outlet obstruction is responsible for over-distension of the bladder. Such type of bladder outlet obstruction happens due to pathological factors like Skene's gland cyst (cyst in the Skene's gland which is located at the lower end of the urethra), presence of the Mullerian duct remnants, urethral diverticulum (presence of unwanted sac in the urethra), and ectopic ureterocele (presence of extra tube in the urinary system). Cervical carcinoma, vaginal cancer, and urethral carcinoma are also associated with bladder obstruction.

• Functional Urinary Incontinence: Such types of urinary inconsistency occur due to environmental factors or physical barriers to toileting. In such cases, the urinary tract functions normally, but physical or cognitive impairment causes leakage of the urine. Functional conditions like dysfunctional voiding and external sphincter pseudo-dyssynergia (unusual contraction of the sphincter during voiding) are also related to this. Neurological disorders like spinal cord injury, multiple sclerosis, degenerative changes in the pelvic floor muscles, and Parkinson's disease may also cause bladder obstruction.

What Is Pelvic Radiation Therapy?

Radiation is a high-energy ray that is used to kill cancer cells. Different types and doses of radiation are used for the treatment of different cancers. Sometimes it is used in combination with chemotherapy and surgical therapy.

There are two types of radiation therapy. In external beam radiation therapy (EBRT), radiation is given from outside the body; in internal radiation therapy, a small source of radiation is placed inside the body close to the malignant tissue.

Radiation therapy of the pelvic floor is indicated in situations like cervical cancer, endometrial cancer, prostate cancer, urinary bladder cancer, and colorectal cancer.

What Is the Relation Between Pelvic Radiation Therapy and Urinary Incontinence?

Urinary incontinence associated with pelvic radiation therapy increased fibrosis in the levator ani, and urogenital diaphragm muscles are related to pathological changes in the muscles of the pelvic floor. The cells exposed to ionizing radiation are damaged by the oxidative stress associated with radiation therapy. Also, nucleic materials of the cells, such as DNA and chromatin fibers, are damaged. Such damage kills not only the cancer cell but also the healthy cells around them. Damage to the blood vessels results in a chronic condition known as radiation fibrosis syndrome. Injury to the vascular endothelium and the formation of an increased amount of high-density myofibroblasts are responsible for this. These changes lead to acute and chronic symptoms of the urinary tract. Also, changes like increased fibrosis in the levator ani and urogenital diaphragm muscles can be noticed in men. Structural changes in the muscles are responsible for the functional changes. A decrease in contractility is one of the major causes of leakage of urine during activity.

What Are the Different Treatment Options?

Different treatment options for urinary incontinence are:

1. Low-dose estrogen can be applied to the vaginal wall, which can help improve blood supply and reduce the symptoms of lower urinary tract symptoms. Also, medications like anticholinergic drugs can be used, which help reduce voiding symptoms. Apart from this, drugs like alpha-adrenergic agonists (e.g., Phenylpropanolamine), beta 3-adrenergic receptor agonists (Mirabegron), and serotonin–noradrenaline reuptake inhibitors (Duloxetine) can be used for this condition. Specifically, anticholinergic drugs are used in radiation-induced urinary incontinence. Such drugs improve micturition, nighttime urination, and episodes of urinary urgency.

2. Stress incontinence surgery can be performed in severe cases. Burch colposuspension is a standard procedure performed for repositioning the muscle that connects the bladder to the urethra. Insertion of narrow ribbon-like structure, such as a mid-urethral sling, is inserted under the urethra. Such slings support the bladder neck to withstand urinary pressure. Also, the insertion of the artificial urinary sphincter and circumferential spiral urethral sling is useful in such cases.

3. The application of electrical stimulus in the pelvic floor muscles is useful.

Conclusion:

Sudden leakage of urine during physical activity is known as urine incontinence. Overactivity of the detrusor muscles, obstruction in the urinary tract, and bladder hypersensitivity are associated with leakage of urine. Pelvic floor radiation therapy is indicated in the treatment of conditions like cervical cancer, endometrial cancer, and prostate cancer. Fibrosis of pelvic floor muscles and changes in functionality are the usual complications of pelvic radiation therapy. These changes lead to urinary incontinence. Surgical interventions, along with the application of medications, can help treat such conditions.