Survival of patients with metastatic cancer has increased slightly in most tumour types over the past three decades. This is according to a study by UT-researcher Sabine Siesling in collaboration with the Integral Cancer Centre of the Netherlands (IKNL) and others. During the study period, more than eighty new drugs were introduced and survival in solid tumours was examined.
Overall, the researchers saw a modest increase in survival, which varies greatly by tumour type. In addition to improvements in treatments, the study points to the importance of prevention and early detection of cancer to reduce the number of patients with metastatic cancer. The results are based on figures from the Dutch Cancer Registry (NKR) and published in the Journal of the National Cancer Institute (JNCI). In the study, the researchers evaluated the 1- and 5-year survival of patients whose cancer had metastasised at diagnosis, and divided into two periods, 1989-1993 and 2014-2018.
Figure 1: Increase or decrease in 1- and 5-year survival, by tumour type, between 1989-1993 and 2014-2018 for cancer that had already metastasised at diagnosis. For breast cancer, for example, 5-year survival increased by 18 per cent from 14 to 32 per cent.
The study found that in patients with gastrointestinal stromal tumour (GIST) or neuroendocrine tumour - two rare cancers of the gastrointestinal tract - survival increased the most. Researcher Marianne Luyendijk (IKNL): 'This large increase is related to the introduction of drugs that are highly effective in these cancers, such as the drug imatinib (introduced in 2002) for GIST.' The 5-year survival rate for non-small cell lung cancer was 1 per cent 30 years ago. In the most recent research period of this study, it was only 7 per cent. Survival of other common cancers such as prostate, colon, and breast cancer also increased slightly.
Although more than 80 new drugs have been introduced since the 1990s, and treatment options for patients with metastatic cancer have expanded, achieving survival gains remains a challenge. Prof. Sabine Siesling (IKNL/ University of Twente): 'If we look at the figures of patients diagnosed up to and including 2018, survival gains seem limited. For certain subgroups, fortunately, a lot of progress has been made. And sometimes treatment is not primarily aimed at prolonging life, but at reducing symptoms.'
Figure 2: Changes in 5-year survival between 1989-1993 and 2014-2018, by tumour type, relative to the number of drugs introduced. In breast cancer, for example, 5-year survival increased by 18 per cent during a period when 17 new drugs were introduced.
In the study, the researchers looked at general trends and developments rather than a direct relationship between drugs and outcomes. To know how effective a drug is, you need more data than was highlighted in this study. Siesling: 'These historical data indicate that the results achieved in trials are not always also achieved in daily practice. To investigate the effectiveness, we also need, for instance, to chart at the individual level which patient received a particular drug, when a drug was administered and in what quantity. It is then at least as important to also look at what side effects occurred, and to what extent that hindered the use of the drug and affected the quality of life. What choice did a doctor and patient make in the process? What effect do new drugs introduced after 2018 have? Close monitoring of patients treated now in daily practice is necessary to see what effects drugs have outside the context of trials. These are relevant issues that we are looking at in other studies. Given the rising prices of new drugs, it is important to look at cost-effectiveness in addition. The limited survival additionally underlines the importance of good care in the palliative phase.'
In the study, researchers from IKNL, University of Twente, Erasmus University Rotterdam, UMC Groningen, -Antoni van Leeuwenhoek, Maastro / Maastricht University and Catharina Hospital collaborated.