While a connection between endometriomas and certain types of ovarian cancer does exist, it is important to understand that this occurrence is rare.
Understanding Endometriomas
Endometriomas are a specific type of ovarian cyst that forms as a result of endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus. They are often referred to as “chocolate cysts” due to their characteristic dark, thick, brownish fluid, which consists of old blood and cellular debris.
This old blood collects inside the cyst because, like the uterine lining, the tissue within an endometrioma responds to hormonal changes during the menstrual cycle by thickening and bleeding. However, unlike menstrual blood that exits the body, the blood inside an endometrioma becomes trapped. Endometriomas can vary significantly in size, ranging from small to quite large, and may affect one or both ovaries.
Common symptoms associated with endometriomas include chronic pelvic pain, which may worsen during menstruation, painful sexual intercourse, and heavy or irregular periods. Some individuals may also experience pain during bowel movements or urination, or struggle with infertility.
The Link to Ovarian Cancer
While endometriomas are benign growths, a small percentage of them can undergo malignant transformation into certain types of ovarian cancer. This transformation is considered rare, occurring in less than 1% to about 2-3% of women with ovarian endometriosis. The most common types of ovarian cancer associated with endometriosis are clear cell carcinoma and endometrioid ovarian cancer.
Research indicates that the risk of developing these specific ovarian cancer subtypes is increased in individuals with endometriosis, with some studies suggesting a two to three-fold higher risk for endometrioid and clear cell carcinomas. Factors such as long-standing endometriomas, larger cyst size, and postmenopausal status may be associated with a slightly elevated risk of malignant change. Despite these associations, it is important to emphasize that the overall lifetime risk of ovarian cancer remains low, even for those with endometriosis.
The exact mechanisms behind this transformation are still under investigation, but they are thought to involve genetic mutations within the endometriotic tissue itself, as well as the inflammatory environment surrounding the cysts. Atypical endometriosis, which shows abnormal cellular changes, is considered a potential precursor lesion for these cancers. However, most individuals with endometriomas will not develop ovarian cancer.
Identifying Suspicious Changes
Recognizing new or worsening symptoms is important for individuals with endometriomas, as these could signal a malignant change. While many symptoms of ovarian cancer overlap with those of endometriosis, such as persistent pelvic pain and bloating, there are distinctions. Endometriosis symptoms often fluctuate with the menstrual cycle, whereas symptoms indicative of cancer may be more consistent or progressively worsen over time, independent of the cycle.
Symptoms that warrant medical evaluation include a significant increase in persistent pelvic or abdominal pain, particularly if it is new or not related to menstruation. Other signs that should prompt a discussion with a healthcare provider include unexplained weight loss, new onset or worsening bloating that does not resolve, changes in bowel habits (such as persistent constipation or diarrhea), or changes in bladder habits (like increased frequency or urgency). Unusual vaginal bleeding, especially after menopause, is also a concern.
While these symptoms can be caused by many conditions, including endometriosis itself, their new appearance or progression should always be assessed by a medical professional.
Diagnosis and Follow-Up
Imaging techniques play a central role, with transvaginal ultrasound being a primary method to visualize the cysts, evaluate their size, and look for characteristics that might suggest malignancy, such as solid components, thickened walls, or abnormal blood flow. Magnetic resonance imaging (MRI) can provide more detailed anatomical information and is often used to further characterize ovarian masses and distinguish between benign and potentially malignant lesions.
Blood tests, such as CA-125, may be performed, but it is important to note that CA-125 levels can be elevated in many benign conditions, including endometriosis, and are not specific for cancer. A definitive diagnosis of malignancy often requires surgical removal of the cyst and subsequent pathological examination of the tissue under a microscope. This allows for precise identification of cancer cells. Regular follow-up with a gynecologist is important for individuals with endometriosis, especially those with endometriomas, to monitor for any changes and ensure timely intervention if needed. If cancer is confirmed, treatment approaches, which may include surgery, chemotherapy, or radiation, are tailored to the specific type and stage of the cancer.