Contrary to popular belief, metastases begin to grow long before the cancerous tumor is clinically detectable.
Up to 80% of metastatic colorectal cancers are likely to have spread to distant locations before the initial tumor grew larger than the size of a poppy seed, according to a new study conducted by researchers at Stanford University School of Medicine.
Identifying these at-risk patients would allow better assessment of early treatments, such as systemic chemotherapy, to kill cancer cells that hide far from the initial location of the tumour.
“This discovery is quite surprising”
“This discovery is quite surprising,” says Christina Curtis, professor of medicine and genetics at Stanford. “In the majority of cases of metastatic colorectal cancer analyzed in this study, the cancer cells had already spread and started growing long before the primary tumor was clinically detectable. This indicates that metastatic competence was achieved very early. after the cancer is born. This runs counter to the prevailing assumption that metastasis occurs late.”
Researchers speculate that cancers acquire the ability to metastasize through the gradual accumulation of molecular changes over time. These changes allow cancer cells to escape from surrounding tissues, enter the bloodstream, and establish themselves in new places.
17,000 deaths
In France, screening for colorectal cancer is still very insufficient, according to Public Health France. The latest data for the period 2017-2018 show that only 32.1% of men and women aged 50 to 74 who should take this step take part. The participation rate was 33.5% for the 2016-2017 period and around 31-32% for previous periods, figures well below the European benchmark of 45%.
Colorectal cancer is one of the most common and deadliest cancers. In 2018, this pathology affected approximately 43,000 French people (23,000 men and 20,000 women) and caused 17,000 deaths (9,000 men and 8,000 women). While detected early, colorectal cancer can be cured in 9 out of 10 cases.
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