Why Do Early Ovarian Cancer Detection Tests Fail?

Current diagnostic tests for ovarian cancer are ineffective for early detection of the disease.

A study has found that in order to significantly lower the mortality rate for the ovarian cancer, tests need to detect tumors about 200-times smaller in mass than those currently used to assess potential new tests. However, the window of opportunity for treating these clinically undetectable cancers before they become life threatening is surprisingly long: about four years.

However, it is also difficult to design an effective test for this disease because there is more than one type of ovarian cancer. The most deadly, known as serous ovarian cancer, accounts for about 50 % of all cases of ovarian cancer and is responsible for at least 80 % of deaths from the disease. In contrast to other types of ovarian tumors, which can grow to be quite large before spreading to other locations, serous ovarian tumors usually metastasize before they are diagnosed.

In its early stages symptoms of ovarian cancer are vague, and often do not occur until the tumor is already several centimeters in diameter. At this point, it may have already spread to surrounding organs and tissues. Several studies have indicated that the current screening tests deliver many false-positive results and do not reduce mortality from the disease.

Biochemistry professor Patrick Brown, M.D., Ph.D. at the Stanford University, school of medicine, (Stanford, CA, USA) and team, which included scientists from the nonprofit Canary Foundation (Palo Alto, CA, USA), performed the study on early detection of ovarian cancer.

The Canary foundation is dedicated to the early detection of many types of cancer. "We are miles away from detecting the most deadly ovarian tumors at this early stage," said Prof. Brown "but now we have a chance of actually designing an effective test that will allow us to treat them before they become deadly."

Prof. Brown added that if a blood test were to be effective it would probably require identifying new markers that are not produced by normal cells. Other possible strategies might rely on new molecular imaging methods, or fluid samples from the uterus or vagina--in which tumor markers are likely to be more concentrated.

The early detection of ovarian cancer study was published in the July 28, 2009 issue of the open-access journal PLoS Medicine.

Related Links:
Stanford University, School of medicine
Canary Foundation
PLoS Medicine