Uterine polyps, also known as endometrial polyps, are growths that form on the inner lining of the uterus (the endometrium). These growths are common, especially in women approaching or past menopause. While the vast majority of uterine polyps are non-cancerous (benign), a small percentage can harbor precancerous or cancerous cells. Understanding the nature of these growths and the factors that influence their risk is important for appropriate medical management.
Defining Uterine Polyps and Their Prevalence
Uterine polyps develop from an overgrowth of the endometrial tissue. They vary significantly in size, ranging from a few millimeters to several centimeters, and may attach to the uterine wall by a thin stalk or a broad base. This excessive tissue growth is thought to be stimulated by estrogen, a hormone that regulates the monthly thickening of the endometrium.
Polyps are a common gynecological finding, with prevalence estimated between 10% and 24% in women undergoing certain uterine procedures. While they can occur at any age, they are most frequently diagnosed in women in their 40s and 50s. Common signs include irregular menstrual bleeding, spotting between periods, or unusually heavy menstrual flow. Bleeding after menopause is an important symptom that warrants immediate investigation.
Assessing the Likelihood of Malignancy
The vast majority of uterine polyps are benign, meaning they are not cancerous, with studies consistently showing that over 95% fall into this category. The overall risk of a polyp containing malignancy (precancerous changes or actual cancer) is low, generally cited in the range of 1.3% to 2.73% of all removed polyps. This low overall risk means initial diagnoses are not cause for immediate alarm, but a thorough assessment is still necessary.
The risk of malignancy is not uniform, and several factors increase the probability of finding a cancerous or precancerous lesion. Menopausal status is a significant risk factor; the malignancy rate is notably higher in postmenopausal women (reaching close to 5%) compared to premenopausal women (around 1%). The presence of symptoms, especially abnormal uterine bleeding, also raises the risk, with symptomatic polyps showing a higher malignancy rate than those discovered incidentally.
Analysis of the tissue may show three findings: a benign polyp, precancerous cells (atypical hyperplasia), or endometrial carcinoma. Atypical hyperplasia is an important finding because it represents a significant risk for cancer development if left untreated. Other patient factors that increase the potential for malignancy include older age, high body mass index (BMI), high blood pressure, diabetes, and the use of the breast cancer drug Tamoxifen.
Specific characteristics of the polyp also factor into the risk assessment. Polyps larger than 2.25 centimeters may have an increased chance of malignancy, often prompting removal. If initial imaging shows the endometrial lining thickness is greater than 11 millimeters, it may be associated with a higher risk of cancerous change. These factors help clinicians prioritize which polyps require immediate removal and detailed pathological examination.
Diagnostic Tools for Evaluation
Diagnosis usually begins with an imaging study to visualize the uterine cavity. Transvaginal ultrasound (TVUS) is a common initial screening tool, using a slender device placed in the vagina to create images of the uterus. This technique can reveal a thickened endometrial lining or suggest the presence of a growth.
To obtain a clearer view, Saline Infusion Sonography (SIS), or sonohysterography, may be performed. During this procedure, sterile salt water is gently injected into the uterus through a thin tube, slightly expanding the cavity. This technique outlines the polyp by separating it from the uterine wall, making it easier to see its size, number, and location on the ultrasound image.
The most definitive step for both diagnosis and treatment is hysteroscopy. This procedure involves inserting a thin, lighted telescope directly into the uterus, allowing the physician to visually inspect the lining. If a polyp is seen, hysteroscopy allows for targeted removal and collection of the tissue for a pathology report. The pathology report provides the final, conclusive determination of whether the polyp is benign, precancerous, or malignant.
Treatment and Post-Removal Management
The decision to treat a uterine polyp depends on several factors, including symptoms, menopausal status, and risk factors for malignancy. For small, asymptomatic polyps, particularly in premenopausal women, watchful waiting may be an option, as some polyps can spontaneously regress. However, if the polyp is causing symptoms like abnormal bleeding, or if there is suspicion of malignancy, removal is generally recommended.
Surgical removal, known as a polypectomy, is the standard treatment method and is most effectively performed during a hysteroscopy. The hysteroscopic approach allows the doctor to visually guide instruments to precisely remove the polyp, often reducing the risk of recurrence. Removal is also frequently recommended for women experiencing infertility, as polyps can interfere with implantation.
A crucial component of post-removal management is the mandatory histopathological examination of the removed tissue. This analysis confirms the nature of the growth and determines if further treatment is necessary. Patients with precancerous or malignant cells require careful follow-up and discussion regarding subsequent monitoring or additional interventions. Since polyps can recur, follow-up imaging may be recommended to monitor the uterine lining.