Why would my oncologist weigh me in kilograms?

Standard measurement: Kilograms are the standard scientific unit for measuring mass or weight. All drug doses are based on kilograms. Pounds are the common unit of weight for Americans, but the rest of the world uses kilograms.

To calculate doses: Most of the research involving doses of chemotherapy has been reported in kilograms (and a related measure, body surface area, which is calculated from weight and height). It's simply easier to calculate doses if patient's weight has been measured in kilograms already. Of course, I'm assuming that you are in America or the U.K. If you're in Europe, he's simply being normal!