Types & Stages of Ovarian Cancer
Types of Ovarian Cancer
Different types of ovarian cancer are classified according to the type of cell from which they start:
Epithelial tumors – About 90 percent of ovarian cancers develop in the epithelium, the thin layer of tissue that covers the ovaries. This form of ovarian cancer generally occurs in postmenopausal women.
Germ cell carcinoma tumors –Making up about five percent of ovarian cancer cases, this type begins in the cells that form eggs. While germ cell carcinoma can occur in women of any age, it tends to be found most often in women in their early 20s. Six main kinds of germ cell carcinoma exist, but the three most common types are: teratomas, dysgerminomas, and endodermal sinus tumors. Many tumors that arise in the germ cells are benign.
Stromal carcinoma tumors – Ovarian stromal carcinoma accounts for about five percent of ovarian cancer cases. It develops in the connective tissue cells that hold the ovary together and those that produce the female hormones estrogen and progesterone. The two most common types are granulosa cell tumors and sertoli-leydig cell tumors. Unlike with epithelial ovarian carcinoma, 70 percent of stromal carcinoma cases are diagnosed in Stage I.
Stages of Ovarian Cancer
The stages of ovarian cancer are determined by how far the cancer has spread. The stage of ovarian cancer at diagnosis is the most important indicator of prognosis.
Stage I – Cancer is limited to one or both ovaries.
IA – Cancer is limited to one ovary and the tumor is confined to the inside of the ovary. No ascites containing malignant cells is present, and the surface of the tumor has not ruptured.
IB – Cancer is limited to both ovaries without any tumors on the ovaries’ outer surfaces. No ascites containing malignant cells is present, and the surface of the tumor has not ruptured.
IC – The tumor is classified as either Stage IA or IB and one or more of the following conditions exist: a tumor on the outer surface of one or both ovaries; at least one ruptured tumor; ascites or abdominal (peritoneal) washings containing malignant cells.
Stage II – The tumor involves one or both ovaries and extends to other pelvic structures.
IIA – The cancer has extended to and/or involves the uterus and/or the fallopian tubes.
IIB – The cancer has extended to the bladder or rectum.
IIC – The tumor is classified as either Stage IIA or IIB and one or more of the following conditions exist: a tumor on the outer surface of one or both ovaries; at least one ruptured tumor; ascites containing malignant cells or abdominal (peritoneal) washings containing malignant cells.
Stage III – The tumor involves one or both ovaries, and one or both of the following exist:
- The cancer has spread beyond the pelvis to the lining of the abdomen;
- The cancer has spread to the lymph nodes. The tumor is limited to the true pelvis but with histologically-proven malignant extension to the small bowel or omentum (peritoneum fold).
IIIB – The tumor is in one or both ovaries, and deposits of cancer are present in the abdomen that are large enough for the surgeon to see but do not exceed two cm in diameter. The cancer has not spread to the lymph nodes.
IIIC – The tumor is visible in one or both ovaries, and one or both of the following conditions exists:
- the cancer has spread to lymph nodes;
- the deposits of cancer exceed two cm in diameter and are found in the abdomen.
For more specific information about ovarian cancer, see the American Cancer Society’s Detailed Guide.
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