Fighting a rare battle

Cancer is not a single disease; it is hundreds. Cancers of the lung, breast, prostate, and colon are the most common forms of the disease, and account for about half of all diagnoses. But less common forms of cancer also account for about half of diagnoses, and these are not as well studied. Some of them are extremely rare, with only a few people diagnosed each year. Patients with these rare cancers have not had the same improvements in survival outcomes as those with more common cancers, largely because there has been less focus on research and the development and testing of new treatment options.

But the Canadian Cancer Trials Group (CCTG) is working to change that. Headquartered at the Queen’s Cancer Research Institute, CCTG is a collaborative network of researchers, physicians, scientists, and statisticians who are advancing cancer research through clinical trials. And CCTG’s priority is to address the gap in rare cancer research.

“When people hear the term rare cancers, they rightly assume these cancers are uncommon,” says Dr. Janet Dancey, the Director of CCTG and a Professor in the Department of Oncology.Dr Janet Dancey

“But collectively, rare cancers are quite common. About a quarter of people diagnosed with cancer will be diagnosed with a rare cancer.”

Rare-cancer research has some inherent challenges. Pharmaceutical companies are more interested in developing drugs for common cancers. The reason for this is economic: the more patients who suffer from a condition, the greater the potential sales for a treatment. But rare-cancer research also presents practical problems. 

“One of the challenges is scientific. It takes time and interest to understand the biology of rare cancers. There are fewer people looking at them in the lab to understand their biology and what drives a cell to become a cancer cell in a rare cancer,” says Dr. Dancey. 

But there is an even more basic challenge. Rare cancers are, well, rare. So, it can be difficult to find enough participants to conduct a clinical trial. That is where CCTG’s network comes into play. With more than 2,100 participating researchers at 85 universities and hospitals, CCTG’s reach allows for recruitment across Canada and beyond. 

Consider the case of uveal melanoma. Each year, roughly one person in 200,000 is diagnosed with the condition. It is the most common cancer of the eye, but in a city of Kingston’s size, a year could pass without a single suitable candidate for a clinical trial. Yet across Canada, nearly 200 people will be diagnosed in that time frame, and CCTG’s network enables more of them to participate in clinical trials.

“We have always done rare-cancer trials, but about five years ago, we decided to make a specific effort to grow the portfolio, support those trials, and develop the international collaborations necessary to execute them,” says Dr. Dancey. 

“We have almost tripled our portfolio of trials for patients with a rare cancer, and a number of them have already defined new treatments for rare cancers.”

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