Introduction to Endometriosis  

Endometriosis is the abnormal growth of endometrial tissue, similar to the endometrium (inner layer), outside the uterus. Endometrial tissue is shed each month during menstruation. Areas of endometrial tissue found in ectopic locations are called endometrial implants. These lesions are most commonly found on the ovaries, the uterine tubes, the surface of the uterus, the bowel, and on the membrane lining of the pelvic cavity (i.e. the peritoneum). They are less commonly found to involve the vagina, cervix, and bladder. Rarely, endometriosis can occur outside the pelvis.

Stöppler & Schiel (2021) define endometriosis as an abnormal growth of cells (endometrial cells) similar to those that form the inside of the uterus, but in a location outside of the uterus. Endometriosis is most commonly found on other organs of the pelvis. The exact cause of endometriosis has not been identified. Endometriosis is more common in women who are experiencing infertility, but the condition does not necessarily cause infertility. Most women with endometriosis have no symptoms. However, when women do experience signs and symptoms of endometriosis they may include:

• Pelvic pain that may worsen during ovulation and or menstruation
• Painful intercourse
• Painful bowel movements or urination
• Infertility

The stages of endometriosis

Endometriosis is classified into four stages (I-minimal, II-mild, III-moderate, and IV-severe) and the stage will depend on the exact location, extent, and depth of the endometriosis implants. The stage will also depend on the presence and severity of scar tissue, and the size of endometrial implants in the ovaries. Most cases of endometriosis are classified as minimal or mild, which means there are superficial implants and mild scarring. Moderate and severe endometriosis typically result in cysts and severe scarring. The stage of endometriosis is not related to the degree of symptoms a woman experiences; however, fertility is common with stage IV endometriosis.

The incidence and prevalence of endometriosis

Endometriosis occurs in 6-10% of US women, and approximately 4 per 1000 women are hospitalized with this condition each year. The definitive diagnosis requires a biopsy or needs to be seen through laparoscopy or laparotomy (Wanyoike: 2017). In 2019, it is estimated that about 61 880 women in the US will be diagnosed with endometrial cancer, making this the fourth most common cancer in women in the US. The survival rate is high, with about 81% of women alive five years after diagnosis of endometrial cancer. However, certain subtypes of endometrial cancer have a less favourable prognosis. In 2019, there were 12,160 expected deaths from endometrial cancer in the U.S.   It has recently been reported that endometrial cancer incidence is increasing in the U.S. and worldwide.

Does endometriosis increase a woman’s risk of getting cancer?

Some studies have hypothesised that women with endometriosis have an increased risk for ovarian cancer, known as epithelial ovarian cancer (EOC). This risk is higher in women with endometriosis and primary infertility (those who have never conceived a pregnancy). The use of oral contraceptive pills (OCPs), which may be used to treat endometriosis, appears to reduce this risk. The reasons for the association between endometriosis and ovarian epithelial cancer are not clearly understood. One theory is that the endometriosis implants undergo malignant transformation to cancer. Another possibility is that endometriosis may be related to other genetic or environmental factors which increase a women’s risk of developing ovarian cancer.

Prevention of Cancer

Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cancer cases is lowered. Hopefully, this will lower the number of deaths caused by cancer. To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases a woman’s chance of developing cancer is called a cancer risk factor; anything that decreases the chance of developing cancer is called a cancer protective factor. Cancer risk factors can be avoided, but many cannot. For example, both smoking and inheriting genes are risk factors for some types of cancer, but smoking can be avoided. Regular exercise and a healthy diet can help to avoid some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk, but it does not mean that you will not get cancer.

Endometriosis is a mesmerizing disease that we strive to understand fully. Molecular techniques cleared up many aspects of this disease: from pathogenesis to recognition of distinct disease variants like deep infiltrating endometriosis. The perception that endometriosis is a cancer precursor has been clarified. The knowledge that mutations are present in endometriosis-associated cancers can be found in adjacent endometriosis lesions (Dawson; Fernandez; Anglesio; Yong & Carey: 2018).

New genetic data suggest that endometriosis may be benign neoplasm that invades locally and rarely metastasises. Further research will help clarify distinct deviations, which result in this phenotype. With regards to identifying patients who may be at risk of developing endometriosis-associated cancers, uniting of molecular, pathological, and heritage markers may define a high-risk group that might benefit from risk-reducing strategies.

The Prevention of Endometriosis-Associated Ovarian Cancers (EAOCs)

Endometriosis in women during their reproductive age is high and may cause dysmenorrhea, chronic pelvic pain, infertility, and cancer. The knowledge we have gained about neoplastic diseases and modern technology will help us applying molecular science to identify the etiology of endometriosis and the patients with endometriosis (Pearce; Stram & Ness, et al. Population distribution of lifetime risk of ovarian cancer in the United States. Cancer Epidemiology Biomarkers: 2015. https://www.ncbi.nim.nih.gov/pmc/articles/PMC5813919/). [Accessed 8 February 2021]).