Rare cancer patients have a lower chance of survival

People with a rare form of cancer have a lower chance of survival than other cancer patients. This turns out from a recently published study published in the European Journal of Cancer and conducted by Dutch researchers affiliated with the Comprehensive Cancer Center of the Netherlands and various academic hospitals. The authors looked at figures from the Dutch Cancer Registry for the past 25 years.

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A type of cancer is called ‘rare’ if it affects fewer than 6 in 100,000 people per year. Rare cancers are relatively more common in patients up to and including 34 years of age.

There are about 260 types of cancer, of which about 220 are rare, says researcher Saskia Duijts, co-author of the article: “People often don’t know that there are so many different types of rare cancer. In total, the people with a rare cancer, added together, are a larger group than the group of patients who get breast cancer every year.”

One in five people diagnosed with cancer has a rare form of cancer. This concerns about 23,000 people in the Netherlands every year, the researchers conclude.

Most research is done on the ‘big five’: breast, prostate, skin, colon and lung cancer. Less is known about rare cancers. This concerns, for example, head and neck tumors, brain tumors, tumors of the male genital organs or peritoneal cancer. The chances of survival for these groups have increased little or not at all in recent years.

The survival rate (5 years after diagnosis) in the most common cancers has increased from an average of 57 percent to 70 percent over the past 25 years. The survival rate (5 years after diagnosis) for the rare cancers is lagging behind, rising from 46 percent to 53 percent.

But, say the researchers, it is difficult to draw firm conclusions because of the small numbers of patients involved in each rare cancer type.

The authors cite delay in diagnosis and late initiation of treatment as the main reasons for lower survival rates for this group. Designating centers of expertise for each rare cancer could help to get a diagnosis and correct treatment more quickly. Due to the small numbers per specific tumor type, collaboration with other countries is necessary to collect more knowledge, the researchers say.

Marga Schriek of it Patient platform Rare Cancers recognizes the picture that emerges from the study. She sees little progress for the group of patients with a rare cancer. Schrieks: “Our 2021 poll of 2,027 respondents shows that a third of respondents were misdiagnosed, resulting in a delay in treatment. Patients then end up in the hospital in a cancer stage that is too high, which means that they have less chance of survival. There is ignorance among doctors, but sometimes also shame among patients to go to the doctor, for example with penile and anal cancer.”

Knowledge and experience

Schrieks agrees with the researchers that centers of expertise for rare cancers could help. But then the patients have to end up there, Schrieks: “Doctors sometimes seem not to know that there is an expertise center and then start a treatment themselves. Patients with a rare cancer should be treated properly by someone with the most knowledge and experience in that field. Concentration of the right care is really necessary here. There must be central control at this point, otherwise the survival chances for this group of patients will remain lower.”

According to Schrieks, research into rare cancers is lagging behind because it is not interesting for the industry to research such small groups of patients. Schrieks: “We call on both research funders and the industry to enter into discussions with us to bring about a change in this.”

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