Endometrial cancer forms in the tissues lining the uterus. The majority of women with early-stage endometrial cancer (meaning the cancer has not yet spread outside the uterus) will be cured simply by the surgical removal of the uterus. However, some women who are presumed to have early-stage disease will actually have higher-stage disease on final post-surgery pathological examination of the tumor.
To date, there has been no consensus on the optimal way to identify those women with presumed early-stage disease who will need further staging and treatment. For women with low-grade disease, there are surgeons who opt to remove no pelvic lymph nodes during surgery, while others choose to remove all nearby lymph nodes. Now, the results of a study by Memorial Sloan-Kettering Cancer Center investigators, published in the May 2009 issue of Gynecologic Oncology [PubMed Abstract], demonstrate that a procedure known as sentinel lymph node (SLN) biopsy provides an accurate way to determine whether or not a tumor has spread. The use of SLN may help physicians avoid overtreating potentially low-risk patients and undertreating patients with more advanced cancer.
Endometrial Cancer Treatment
Endometrial cancer is initially diagnosed prior to surgery with either an endometrial biopsy or an outpatient surgical procedure called dilation and curettage (D&C). Doctors use the tissue obtained to determine the stage and grade of the tumor. There are four stages of endometrial cancer, with stage 1 representing no spread outside the uterus, and stage 4 representing spread to the bladder and/or bowel or beyond the pelvis. The grade describes how malignant the cells look under the microscope, escalating in severity from grade 1 to grade 3.
The most common surgical treatment for all stages of endometrial cancer is the removal of the uterus (total hysterectomy). In women who have a preoperative diagnosis of grade 1 endometrioid endometrial cancer -- one of the most common forms of the disease -- it is unlikely that the cancer will metastasize, or spread, to the pelvic lymph nodes. These women have a very high cure rate and consequently do not usually require further treatment after surgery.
But it has been shown that approximately 10 to 15 percent of women who receive a presurgery diagnosis of grade 1 endometrial cancer will actually have higher-grade lesions (grades 2 and 3) when the entire primary tumor is examined after being removed. Women with grade 2 and 3 lesions may have higher stage tumors that require additional therapies such as chemotherapy or radiation therapy to kill the tumor cells that have spread.
Pelvic Lymph Node Removal and Sentinel Lymph Node Mapping
The function of lymph nodes is to help to drain fluids and fight infection. Among women with grade 1 endometrial cancer who are treated by surgeons who routinely remove all the pelvic lymph nodes (total lymphadenectomy), a majority will have received unnecessary treatment, as they will be found to have disease that is confined to the uterus. For these women, the removal of the pelvic lymph nodes may result in lymphedema, a potentially lifelong condition characterized by swelling, in this case in the groin and legs. But of equal concern, for those women with a preoperative diagnosis of grade 1 endometrial cancer treated by surgeons who routinely remove no lymph nodes during surgery, some 10 to 15 percent will not have their metastatic cancer properly diagnosed and treated.
