The dose of cytotoxic drugs is often calculated by the body surface area (BSA) or body weight. However, patiens after limb amputation cannot be estimated by standard calculation of BSA. This case shows patient after amputation of the arm and leg, treated for tonsil cancer by chemoradiotherapy. Cisplatin was administred weekly, 6 series with concomitant radiotherapy. The dose was adjusted to incomplet body constitution, according to modified BSA calculation. BSA was modified by the „rule of nines“, known from burn medicine, where every side of leg and every arm takes 9 % of the BSA. There was also involved modified renal function parameters (creatinine and cystatine C have a smaller production), and cisplatin kinetics respectively. This correction and its use in other cytotoxic drugs, pharmacokinetics and other factors (protein binding, metabolism, specific distribution, etc.) is discussed. Many of these questions are without clear answer.

Jan Dvorak works as a clinical pharmacist for 9 years, visiting Dpt. of Oncology and Dpt. of Neurology in the Hospital Ceske Budejovice (regional capital). He has a periodical outcomes at the Conference of Hospital Pharmacists, the biggest conference of pharmacists in the Czech Republic, and occasionally at other forums in CZ.