Your body evacuates the chemicals from chemotherapy mainly through your urine. Active residue from the medication stays in the body for 72 hours after administration, hence the need to observe certain precautions.
Additionally, your ankles or fingers may swell because you are retaining water and salt. This is known as oedema. The cortisone treatment preceding chemotherapy or associated with anti-hormone therapy is the most frequent cause of this phenomenon, though some kinds of chemotherapy are themselves directly responsible for water/salt retention.