New Study Shows Four-Year Window for Early Detection of Ovarian Cancer

Every year approximately 190,000 women worldwide are diagnosed with ovarian cancer. 140,000 of these women will die from the disease. Early detection of ovarian cancer is the key to saving their lives, but there are currently no tests available that discover it during the early stages.

A new study by Howard Hughes Medical Institute researchers addresses the issue of early detection. On Monday, July 27, 2009, Dr. Patrick O. Brown of Stanford University in California and Dr. Chana Palmer of the Canary Foundation, San Jose, California, published a report in the July 2009 issue of PLoS Medicine (Public Library of Science) announcing new findings that are the first step in developing the much-needed tests for early detection of ovarian cancer.

Why Ovarian Cancer is So Deadly
Most ovarian cancer deaths involve the difficult to detect serous ovarian cancer tumor. The tumor begins when a cell on the surface of the ovary or inside the Fallopian tube genetically mutates, allowing it to grow and spread around the body. If the tumor is discovered while still confined to its original location, there is an 80% chance of survival. However, this type of ovarian cancer tumor is too small to detect in the early stages and usually does not cause symptoms until is has already spread to the pelvis or beyond to the stomach, liver and other distant organs. Once it has spread that far, there is only about a 15% chance of survival.

Studying the Early Stages of Ovarian Cancer
The goal of the study by Dr. Brown and Dr. Palmer was to map out the progression and growth of the serous ovarian cancer tumor. The team gathered data from cases where microscopic or minuscule tumors were discovered in the ovaries and fallopian tubes surgically removed from healthy women who were genetically predisposed to developing ovarian cancer. By analyzing the measurements of the hidden tumors, along with data on clinically evident tumors, the doctors were able to create a mathematical model to describe the early stages of serous ovarian cancer.

The study's findings include such previously unknown information as:

Serous ovarian cancer tumors do not spread for a period of four years.

Early stage serous ovarian cancer tumors average less than 0.3 centimeters in diameter and spend 90% of the four year period at a diameter of less than 0.9 centimeters.

Many advance stage serous ovarian cancer tumors (cancer stages III and IV) were 1 centimeter or less in diameter.

90% of occult (hidden) serous ovarian cancer tumors were not detected during surgery or gross (naked eye) examination and were only visible through use of a microscope.

Ovarian cancer is twice as likely to begin in the Fallopian tubes than in the ovaries.

Late stage serous ovarian cancer tumors double in volume every 2.5 months.

On average, serous ovarian cancer exists in the body for 8 years before it progresses to stage III (advanced cancer) and 9 years before it is clinically diagnosed.

To cut the mortality rate of serous ovarian cancer by half, annual early detection screenings would have to detect tumors 0.5 centimeters in diameter, if not smaller. (That is approximately one thousandth the size of the current average for ovarian cancer tumor detections.)

Creating a Test for Early Detection of Ovarian Cancer
Now that they know what to look for, the research team is working to develop a test that will detect serous ovarian cancer during the four year time period before it begins to spread. One area of focus is the search for a protein or other biomarker that is specific to ovarian cancer tumors. They are also hoping to learn if any information that would show the presence of a tumor is passed through the female reproductive system into the vagina where it could be collected by means of a vaginal swab.