Colorectal cancer is the second most common cancer in Hong Kong, with over 4,000 new cases each year. Even if diagnosed early and surgically removed, over 50% of patients experience tumor recurrence or metastasis.
The reasons behind cancer recurrence
Why some patients experience recurrence while others survive has long been a mystery. The Faculty of Medicine at the University of Hong Kong has discovered cancer stem cells that drive colorectal cancer metastasis. Current chemotherapy drugs are ineffective against these cancer stem cells, leading to recurrence in patients. New treatments are needed to combat this.
The Department of Medicine at the Faculty of Medicine at the University of Hong Kong examined colorectal cancer cells from 27 patients and found the cancer stem cell marker CD26 in eight. Five of these patients experienced recurrence and metastasis to other organs eight to fifteen months after surgical resection. Metastasis to other organs is the main cause of death. The University of Hong Kong has discovered, for the first time in the world, that CD26+ cancer stem cells within tumors are key to cancer spread and recurrence. Early detection of cancer stem cells through blood tests allows for targeted treatment.
Conventional chemotherapy drugs cannot kill cancer stem cells.
Because conventional chemotherapy drugs cannot kill cancer stem cells, they can only kill active cells, and cancer stem cells are highly resistant to treatment and difficult to kill.
We conclude that conventional chemotherapy:
- Targets all active and rapidly multiplying cells
- Does not target specific cells
- Cancer stem cells possess the characteristics of stem cells that are resistant to treatment.
- Therefore, tumor shrinkage does not necessarily mean the death of all cancer cells.
