Endometrial cancer begins in cells within the endometrium, the tissue that lines the inside of a woman's uterus. The uterus is the hollow muscular organ in which a baby (fetus) develops. The outer muscular layer of the uterus is called the myometrium. The lower end of the uterus is the cervix, which leads to the vagina. Cancer can develop in the cervix and vagina, but endometrial cancer is the most common cancer affecting a women's reproductive system. This year about 47,000 U.S. women will be diagnosed with endometrial cancer.
Most endometrial cancers are adenocarcinomas, which begin in gland-like cells that produce mucus and other fluids. Examination of the cancer tissue under a microscope can help differentiate the cancer type and roughly predict tumor behavior. When cancer cells are closer in appearance to normal endometrial tissue, it is classified as a well differentiated cancer and this usually indicates that the cancer will not spread. On the other hand, when the cancer cells are distinctly different from normal cells, they are considered poorly differentiated and are most likely to invade the myometrium. From the myometrium, the cancer can spread to lymph nodes in the pelvis and chest and to other parts of the body, such as the lungs, liver, bones, brain and vagina.
Endometrial cancer (and other tumors) can spread (metastasize) from the place where it started (the primary tumor) in 3 ways. First, it can invade the normal tissue surrounding it. Second, cancer cells can enter the lymph system and travel through lymph vessels to distant parts of the body. Third, the cancer cells can get into the bloodstream and go to other places in the body. In these distant places, the endometrial cancer cells cause secondary tumors to grow.
To find out whether the cancer has entered the lymph system, a surgeon removes all or part of a lymph node near the primary tumor and a pathologist looks at it through a microscope to see if cancer cells are present. Several kinds of imaging can also be performed to determine if endometrial cancer has spread. These include chest x-rays, MRI and CT scans.
Despite significant improvements in the treatment of endometrial cancer, novel therapies and treatment strategies are needed.
Source: National Cancer Institute, 2015
Estimated new cases and deaths from endometrial cancer in the United States in 2015:
New cases: 54,870
Cancer of the endometrium is the most common gynecologic malignancy and accounts for an estimated 47,000 newly diagnosed cases in the United States in 2012. Endometrial cancer encompasses a broad range of histologic subtypes, with the most common being the endometrioid endometrial adenocarcinoma. Marked differences in clinical behavior have been observed in patients with endometrial cancers depending on the histologic subtype, the tumor grade and the extent of cancer spread. A classification system that groups endometrial cancers into Type I and Type II has been proposed to account for the divide in clinical behavior.
Type I endometrial cancers account for approximately 75-85% of endometrial cancers and tend to be of endometrioid histology, are most commonly diagnosed at stage I/II or are confined to the uterus and cervix. These tumors can present with a precursor lesion known as atypical hyperplasia, and are associated with unopposed estrogen exposures such as obesity, hormone replacement or tamoxifen use. For these patients, surgery is likely to be a curative procedure and lymph node staging is generally not pursued unless risk factors are present. The addition of vaginal radiation has been shown to reduce recurrence of some early stage cancers if certain risk factors are present. Overall, the recurrence risk for these women is between 2-7%.
Type I cancers, type II endometrial cancers present with a spectrum of histologies including uterine papillary serous carcinoma (UPSC), carcinosarcoma, clear cell carcinoma and high-grade endometrioid carcinoma. These cancers are high-grade by definition, tend to present with disease outside of the uterus (stage III or IV) and have a high propensity to develop recurrence after primary therapy. Common sites of metastasis include pelvic/para-aortic lymph nodes, vagina, lungs, liver and peritoneum. The upfront therapeutic approach to type II cancers frequently involves individualized multi-modality combinations of aggressive cytoreductive surgery, followed by platinum containing chemotherapy and pelvic or abdominal radiation. While this subset of patients accounts for only 15-25% of patients with endometrial cancer, patients with these tumors account for 75% of the mortality observed.
In the recurrent setting, type I and II endometrial tumors tend to be managed in a similar fashion. When a localized recurrence occurs, surgery and focused radiation is commonly employed and is sometimes followed by platinum- and taxane-based cytotoxic chemotherapy. With widespread or surgically inaccessible recurrent disease, chemotherapies provide the mainstay of therapy. While low-grade advanced stage or recurrent tumors are commonly refractory to cytotoxic agents, they may (20-30%) respond to hormonal therapies that modulate the progesterone or estrogen receptor. As type II cancers are high-grade and commonly (40-50%) present with extra-uterine spread, the risk of recurrence is markedly elevated in this population and further therapeutic modalities in the upfront setting are often warranted.
Correlative scientific investigations have utilized the type I and II distinctions to describe molecular signatures specific to the individual tumors types that may be key drivers of the neoplasia. By targeting specific overactive pathways with novel small molecule tyrosine kinase inhibitors (TKI) or antibody therapies, investigators hope to improve the therapeutic options for patients with endometrial cancer. Type I cancers have been shown to have molecular alterations via gene mutation, gene amplification or protein expression in KRAS, CTNNB1 and PTEN. In contrast, type II cancers have been shown to have 20-30% gene amplification in the HER2 (ERBB2) gene and a close to 90% frequency of mutation in the TP53 gene. Alterations in the phosphoinositol 3-Kinase (PI3K) pathway appear to affect both type I and II endometrial cancers through alterations in PTEN (50-80%) and PIK3CA (25-40%). With many promising signatures, clinical trials are currently in development.
Source: National Cancer Institute, 2015
Cancer research and treatments are constantly changing. Knowing the gene associated with your cancer can help doctors determine the most appropriate direction of care for you. To learn how you can find out more about genetic testing please visit http://www.massgeneral.org/cancer/news/faq.aspx
or contact the Cancer Center.
The mutation of a gene provides clinicians with a very detailed look at your cancer. Knowing this information could change the course of your care. To learn how you can find out more about genetic testing please visit http://www.massgeneral.org/cancer/news/faq.aspx
or contact the Cancer Center.