Testing for Ovarian Cancer
Early diagnosis of ovarian cancer is rare because of the absence of symptoms in the early stages and the lack of reliable screening methods to detect ovarian cancer specifically. A Pap smear has no role to play in the detection of ovarian cancer unless it has metastasized to the cervix or vagina. Surgical diagnosis and staging should be done as soon as possible, with minimum pre-operative tests, when a pelvic mass is suspected to be ovarian cancer.
While a clinical history of vague gastrointestinal symptoms or abnormal vaginal bleeding may be correlated with ovarian cancer after it is diagnosed, it is rare where these symptoms immediately raise the concern ovarian cancer. High risk women should be monitored and the presence of these symptoms should prompt immediate investigation. Read more on ovarian cancer risks.
Methods to Diagnose Cancer of the Ovaries
Women with a personal or family history of breast, uterine or colon cancer, or those with a close family member (mother, daughter, or sister) affected with ovarian cancer may be at increased risk of contracting the disease. These women may be advised to go for genetic testing. Women with mutations in BRCA1 and BRCA2 genes need close monitoring as these are high-risk groups for ovarian cancer. Prophylactic oophorectomy may be done as a preventive measure against ovarian cancer in selected cases.
An abdominal mass, swelling, or presence of fluid in the abdomen (ascites) detected during a physical examination may be suggestive of ovarian cancer. A pelvic examination may reveal a unilateral or bilateral fixed mass or growth in the ovary. A mass may sometimes be felt in the abdomen.
- A complete blood count (CBC) and serum electrolyte tests are essential when ovarian cancer is suspected.
- Liver function tests (LFT) may be done to assess involvement of the liver.
- An elevated CA-125 in a postmenopausal woman may be suggestive of ovarian cancer. The levels of tumor marker or cancer associated antigen CA-125 in the blood may be used to detect ovarian cancer but the results are not always sufficiently sensitive or specific for ovarian cancer to be of much use as a screening method. Colon, pancreas, breast, stomach, or uterine cancers may also be associated with an elevated CA-125 value. A normal CA-125 level does not exclude the diagnosis of cancer either.
- A serum hCG level should be obtained in all women in whom pregnancy is a possibility.
- A serum alpha fetoprotein (AFP) and lactate dehydrogenase (LDH) measurement is advisable in young girls with a pelvic mass because of the likelihood of a cancerous germ cell tumor.
Imaging studies can help to detect a mass in the pelvis but they will not be able to confirm the diagnosis of ovarian cancer.
- Ultrasound may be helpful in detecting a pelvic mass. Transvaginal ultrasound (done by placing a probe in the vagina) provides better images than abdominal ultrasound.
- CT scan can help to show in more detail the size of the growth, lymph node enlargements, and metastasis to other organs.
- MRI (magnetic resonance imaging), in addition to being more expensive, may not have any advantages over a CT scan except in evaluation of pregnant patients by avoiding radiation exposure of the fetus.
- Chest x-ray may show spread of cancer to the lungs.
- PET (positron emission tomography) scans are sometimes done to detect spread of ovarian cancer. In this method a type of radioactive glucose is used for cancer detection.
- Mammography may be done as a screening procedure to exclude breast cancer, keeping in mind the link between ovarian cancer and breast cancer.
- A barium enema may be advised in patients to exclude colon cancer.
- Colonoscopy is preferred to barium enema to exclude metastasis to the colon.
Tissue samples for biopsy may be taken by means of laparoscopic surgery (through a tiny incision in the abdomen) when the tumor is small, or by a laparotomy (a larger incision is made to open the abdomen) in case of larger tumors.
Surgical staging is done at the time of surgery by sending the removed organs and tissues for microscopic examination.
A sample of tissue may be taken from the tumor and sent for analysis. Cancer cells found in the sample will confirm the diagnosis of ovarian cancer as well as determine the type of cancer. The stage and grade of the cancer can be determined by taking biopsies from various sites. Read more on ovarian cancer stages.
Passing a laparoscope (a thin tube with a light source, tiny camera and a magnifying device at the end) through a tiny incision in the abdomen allows for proper visualization of the ovary and other structures within the pelvis and abdomen. Tissue samples for biopsy may also be taken during a laparoscopic procedure.
A laparotomy may show obvious cancer in the ovaries or other structures in the abdomen. If cancer is suspected, surgery may be done for treatment of ovarian cancer. Samples for biopsy may be taken and staging of the cancer done at the time of surgery.
Removal of ascitic fluid from the abdomen as a means of testing for cancer cells is not routinely advised. Even with widespread intra-abdominal dissemination, false negative results are possible in a large number of cases. Also, there are more chances of cancer cell dissemination during the procedure.
Removal of fluid around the lungs in a pleural effusion for the purpose of testing for cancer cells may be recommended prior to surgery. If cancerous cells are found in the fluid, the patient is diagnosed with stage 4 cancer and the surgical procedure re-evaluated, keeping in mind the poor prognosis in these cases.