Sometimes just keeping an eye on how the tumour behaves can be a good treatment option. Especially if the tumour is very small. Not all tumours grow quickly or spread and some are benign. Regular scans will be taken to actively monitor the tumour. The speed of tumour growth (size) will give your specialist a much better idea of how dangerous your tumour is. Active surveillance can be used as a treatment option alongside percutaneous biopsies (needle inserted into kidney, through the skin to remove suspicious cells), where you will hopefully be able to discover the type of tumour by looking at the cells under a microscope: this can provide information to predict how the tumour will behave. If a tumour grows rapidly over three to six months, it is much more likely to be malignant. A tumour size of approximately three centimetres is a common threshold where doctors decide that the kidney should be removed and biopsies taken from the tumour. There are advantages to not opting for surgery immediately, especially if the tumour stops growing and is benign.
Alternatively, some people may have multiple tumours, especially if they have a genetic condition such as Von Hippel-Lindau syndrome. Sometimes active surveillance is used to wait to discover the true number and location of tumours before committing to surgery. The number of operations over a lifetime should be minimised to reduce scar tissue and other complications. It is also preferable to avoid recovering from surgery to then discover there were other tumours developing.
Active surveillance is not for everyone and many people prefer to opt for surgery immediately. This will be a very personal decision and an important discussion to have with your specialist.