Radiation kills cancer cells by damaging the DNA. Tumor cells often have impaired repair mechanisms that are normally found in healthy cells. Thus, tumor cells can be inherently sensitive to radiation effects. Damage to DNA can occur by direct interaction of radiation with a cell’s DNA or indirectly by the creation of free radicals that are produced by the interaction of radiation and water within the cell.
Radiation oncologists use linear accelerators to deliver radiation to a patient. Linear accelerators are treatment machines that selectively create high-energy radiation beams which are then directed at a specific target.

Epidemiology of Ovarian Cancer

There are three primary types of ovarian cancer. Epithelial ovarian cancer comprises approximately 80%-90% of ovarian cancer and will be the subject of this review. Germ and stromal tumors represent the remaining 10-20%.
There are numerous risk factors for ovarian cancer and can include lower number of pregnancies, nulliparity and infertility [3]. Oral contraceptive use has been shown to reduce the risk of ovarian cancer [4]. Women who have a family history of breast cancer or ovarian cancer are at increased risk. Gene mutations in BRCA1 and BRCA2 have been observed in many of these families. Hereditary non-polyposis colon cancer (HNPCC) is a genetic syndrome that has been associated with colon, endometrial and ovarian cancer.

Detection/Screening

Routine screening for ovarian cancer has not been recommended because there have been no reliable markers for detecting early epithelial ovarian cancer [1,5] although routine gynecologic care should still be recommended. The tumor marker CA-125 has been found to be helpful in ovarian cancer screening. The combination of a pelvic exam, transvaginal ultrasound and a blood test for CA-125 can be offered for women who are symptomatic or at high risk

Clinical Presentation

Epithelial ovarian cancer does not present with specific signs or symptoms. Patients most commonly present with abdominal distention, however, heartburn, nausea, and lower abdominal pain can also manifest [5].
Ovarian cancer is often metastatic or spread beyond the ovaries at presentation and confined to the ovary in only 23% of cases [6]. The peritoneum is a multilayered membrane which lines the abdominal cavity, and supports and covers the organs within it. The most common route of spread is through the peritoneum (transperitoneal) and the disease is confined to the abdominal cavity in 85% of patients [6]. However, ovarian cancer may also spread through the blood or lymphatics.