In almost thirty years, pharmaceutical companies have developed no less than twenty medicines to extend the life of patients with metastatic lung cancer. Nevertheless, the chance that these lung cancer patients were still alive after five years only increased by 7 percent in the period between 1989 and 2018, according to a study by the Comprehensive Cancer Center of the Netherlands (IKNL).
Lung cancer patients are not the only cancer patients who hardly seem to benefit from the introduction of new, often expensive medicines, the same study shows. Over the past 25 years, the average survival rate of patients with a metastatic form of cancer has increased slightly.
Little survival benefit
In the study, the researchers looked at the percentage of Dutch patients who were diagnosed with metastatic cancer between 2014 and 2018. They then looked at which of these patients was still alive one year later, and who was still alive five years after the diagnosis. The researchers compared these figures with data from patients who received a cancer diagnosis between 1989 and 1993.
“Many expensive medicines came onto the market during that period, but little survival benefit was achieved,” says lead researcher Sabine Siesling, who is a professor at the University of Twente. More than eighty new medicines have been developed in the past three decades.
Big differences
Every year, 21,000 patients in the Netherlands are diagnosed with the diagnosis that the cancer has already spread. Half of patients with metastases live six months or less after diagnosis. The figures from the IKNL show that the survival rate differs greatly per tumor type.
“Especially with less common tumors, the chance of survival has increased significantly,” says researcher Siesling. As in patients with neuroendocrine tumors (Net), for example, a rare form of cancer in the gastrointestinal tract. The chance that a person with Net is still alive five years after diagnosis has doubled in a quarter of a century. For this form of cancer, drugs have been proven to be effective.
The survival rate also increased in patients with breast and prostate cancer. The chance that a patient diagnosed with metastatic breast cancer was still alive after five years was 32 percent. Twenty-five years earlier, that chance was much lower, at 14 percent. With metastatic prostate cancer, the risk increased from 23 to 42 percent.
In the meantime, seventeen new medicines against breast cancer have been introduced. IKNL’s research shows that the total number of medicines developed per cancer type has no influence on the lifespan of patients.
The difference with the research results for other cancer types, such as pancreatic cancer and stomach cancer, is large. For those patient groups, the chance of survival remains small. For example, the survival rate of patients with metastatic pancreatic cancer only increased by 1 percent, despite the introduction of five new drugs.
Daily practice unruly
It is striking that some cancer drugs have a limited effect on the life expectancy of patients, says Siesling. Earlier drug research conducted in a clinical setting, required for the approval of the drugs, showed better results: “This shows that daily practice is more unruly.”
Siesling warns that in practice other factors also influence the survival rate of patients, such as additional illness or the time of diagnosis. Because the study was conducted at group level, these factors were not included in the study. The numbers also say nothing about the quality of life of the patients. In addition, new medicines were developed after 2018, which were not included in this study.
Due to the high cost of the drugs, Siesling argues for more research: “New drugs are still coming onto the market, which are very expensive. Only through proper monitoring do we know which medicines are really effective in daily practice.”
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