Ovarian cancer is the leading cause of mortality from female reproductive cancer. No definite symptoms related with early-stage disease and no effective screening methods make its early detection difficult, which results in about two-third patients with advanced-stage ovarian cancer at the diagnosis. When we consider that 5-year survival rate is up to 90% in patients with early-stage ovarian cancer while it is less than 20% in those with advanced-stage disease, the development of effective screening tests and their applications in clinical setting are very important to improve the prognosis of ovarian cancer by early detection (1). Ovarian cancer, a cancerous growth arising from the ovary is the deadliest gynecologic malignancy. Symptoms are frequently very subtle early on and may include bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses. Most (> 90%) ovarian cancers are classified as "epithelial" and are believed to arise from the surface (epithelium) of the ovary. However, some evidence suggests that the fallopian tube could also be the source of some ovarian cancers. It is thought that these fallopian cancer cells can mimic ovarian cancer. Other types may arise from the egg cells (germ cell tumor) or supporting cells. Ovarian cancers are included in the category gynecologic cancer (2).Ovarian cancer is the seventh most common cancer, and it is the most common cause of mortality from gynecological cancers worldwide, with 238,619 incident cases in 2012 according to Globocan (http://globocan.iarc.fr/Default.aspx). In developing countries, it is ranked the second most common gynecological cancer, and constitutes the fourth most common of all cancers in women, with 17,755 incident cases in 2012. Essentially, the highest incidence rates of ovarian cancer are found in the developed countries. Northern Europe has the highest incidence rate (13.3 per 100,000 person-years), followed by Western Europe (11.3 per 100,000 person-years) and Northern America (10.7 per 100,000 person-years), whereas North Africa has the lowest incidence rate (2.6 per 100,000 person-years). The incidence rate of ovarian cancer in the entire Sudan has yet to be identified; however, in a hospital-based data set from the National Cancer Institute, Gezira University, Central Sudan and Radiation Isotopes Center in Khartoum, collected between 2000 and 2006, ovarian cancer accounted for 6.8% (949) of all recorded cancers (n = 226,652), and it was ranked the sixth most common cancer for both genders. Additionally, in a more recent data set (2009–2010) from the National Cancer Registry for Khartoum State alone, ovarian cancer was the fourth most common cancer in women, with an estimated incidence rate of 188 per 100,000 population, a gender-specific rate of 8.0 per 100,000 population, and an age-standardized rate (ASR) of 7.0 per 100,000 population. Furthermore, neither the morality rate for ovarian cancer nor the survival rate in Sudan has previously been described due to a lack of the availability of death certificates, the majority of patients presenting with advanced stage disease were not thoroughly investigated or treated symptomatically (3). In most cases, the exact cause of ovarian cancer remains unknown. The risk of developing ovarian cancer appears to be affected by several factors (4), Older women who have never given birth, and those who have a first or second-degree relative with the disease, have an increased risk. Hereditary forms of ovarian cancer can be caused by mutations in specific genes (most notably BRCA1 and BRCA2 genes of hereditary nonpolyposis colorectal cancer. Infertile women and those with a condition called endometriosis, and those who use postmenopausal estrogen replacement therapy are at increased risk (5).
Over 90% of ovarian neoplasms arise from the epithelial surface of the ovary, the rest from germ cells or stromal cells. The epithelial neoplasms are classified as serous (30–70%), endometrioid (10–20%), mucinous (5–20%), clear cell (3–10%), and undifferentiated (1%). The 5-year survival rates for these subtypes are 20–35%, 40–63%, 40–69%, 35–50%, and 11–29%, respectively (6, 7,8).
The updated, revised FIGO staging system combines the classification for ovarian, fallopian tube, and peritoneum cancer. It is based on findings made mainly through surgical exploration. (9). Epithelial tumors of the ovary and fallopian tube are further subclassified by histologic grading, which can be correlated with prognosis. This grading system does not apply to nonepithelial tumors. Two grading systems are applied. For nonserous carcinomas (most endometrioid and mucinous), grading is identical to that used in the uterus, based on architecture with a one-step upgrade if there is prominent nuclear atypia, as follows, GX: Grade cannot be assessed, G1: Well differentiated, G2: Moderately differentiated, G3: Poorly differentiated. (9).