The study could help recommend the best treatment for women with early-stage mucinous ovarian cancer

A global study of mucinous ovarian cancer could help oncologists recommend the best treatment for women who are diagnosed with the disease early.

By looking through a microscope for two different “invasion patterns” — the way cancer cells invade ovarian tissue — oncologists can better predict which patients may have better or worse outcomes and tailor treatment accordingly. The result was reported in a paper published today Clinical Cancer Researcha journal of the American Association for Cancer Research.

“Mucous ovarian cancer is a rare type of ovarian cancer. It actually has more in common with gastrointestinal cancer and can be difficult to diagnose and difficult to treat once it has spread beyond the ovaries,” says lead author Nicki Meagher, who has just completed his PhD in the Molecular Oncology group at the UNSW School of Clinical Medicine.

She says that observing which of the two types of invasion patterns the cancer cells form could help specialists decide on treatment strategies.

We have shown for the first time that women with early disease – that is, with tumors that have not spread beyond the ovaries – have a much poorer chance of surviving in the first two years after diagnosis if they suffer from what is known as an infiltrate invasive pattern .

Knowing this early in the disease allows us to identify patients who might benefit from additional chemotherapy after surgery to remove their ovaries.”

Nicki Meagher, lead author

The two invasion patterns are defined by the way the cancer cells self-organize when viewed under the microscope. The infiltrative invasion pattern associated with poorer health outcomes demonstrates that cancer cells spread unevenly and randomly in ovarian tissue. The other pattern is known as expansil, in which cells expand through tissue in a more orderly fashion and is associated with better prognosis.

Previous studies had suggested that the infiltrative invasive pattern was associated with poorer patient outcomes, but no study had a large enough number of patients with early-stage cancer to reach statistical significance.

But the current study, which involved more than 100 researchers in Australia, the UK, Canada, Asia, Europe and the US, was able to test this hypothesis on a much larger scale by examining tissue from 604 patients. In addition to the invasion patterns, the researchers also looked for the expression of 19 genes, including THBS2 and TAGLN.

Professor Susan Ramus, who oversaw the global study and leads the Ovarian Tumor Tissue Analysis Consortium, says guidelines for treating women with early-stage mucinous ovarian cancer vary worldwide due to limited data on infiltrative invasion patterns related to survival rates.

“For example, in some parts of the world, an infiltrative pattern has been recognized as an important characteristic and determines what treatment these women receive,” says Professor Ramus.

“In other cases, all patients are recommended the same course of treatment. We hope that after this large study, treatment guidelines can be adjusted and that we can target treatment to women with these more severe signs, even if they are diagnosed at the early stages.”

The researchers also found that women with higher expression of two genes, THBS2 and TAGLN, in their tumors had poorer overall survival.

“We’re hoping that this can help explain some of the biology, potentially later on,” Ms. Meagher says.

“Another avenue could be that knowing how these genes are expressed could help in the development of targeted drugs.”

The researchers are part of a broad network of experts who want to conduct a validation study to further investigate these genomic markers as the basis for a targeted treatment strategy.