The Nephrogreen study – can dye help surgeons remove kidney tumours?

Currently, the standard protocol in the UK is to surgically remove part of the kidney for children with tumours in both kidneys or in children with tumours in one kidney who are predisposed to kidney cancers. Some doctors also think that part of the kidney should be removed in children with one-sided tumours who do not have a predisposition syndrome. However, it can be quite difficult to distinguish between healthy kidney and tumour tissue.

Indocyanine green is a dye which glows under near-infrared light. It has been used for several types of adult surgery. We know that kidney tumours in adults do not absorb indocyanine green at all. Surgeons can use this absence of dye to define the border between normal and cancerous tissue. This can give a real-time picture of the area of tumour. This delivers surgeons a detailed guide to removing only the cancerous part of the kidney.

Mr Max Pachl at Birmingham Children’s Hospital is pioneering the dye’s use in children's kidney cancer surgery. In this project, the research team are focusing on using indocyanine green for surgeries that remove only the kidney containing tumour. They aim to find evidence that shows children’s kidney tumours, like adults, do not absorb the indocyanine green dye, both to the naked eye and at a cellular level.

Using samples of kidney tissue which contains tumours, the researchers will add indocyanine green. The kidney and tumour will be studied under near-infrared light to show which areas glow. A surgeon will then remove the tumour from the kidney tissue and the boundaries will be reviewed to see if there is a difference to the naked eye. The team will then look at the border between normal and cancerous tissue with a microscope to see if there is a visible difference in the amount of indocyanine green dye at a cellular level. Mr Max Pachl hopes that introducing the dye to children’s cancer surgery can make the surgery easier and safer for children.