## 1 Introduction  
Measurement of body surface area (BSA) plays a key role in several medical applications, including the treatment of burns [1] and the prescription of conventional cytotoxic chemotherapy drug dosages within systemic anti-cancer treatment (SACT). However, the use of BSA for calculating chemotherapy dosage has been heavily criticised, with potentially significant implications for the effectiveness of anti-cancer treatment [2; 3; 4; 5; 6]. Cytotoxic chemotherapy has been the mainstay of systemic treatment for malignancy for over 70 years. Several chemotherapy drugs have since been developed and found to be successful in combating a variety of cancers in paediatric and adult patients. However, conventional cytotoxic chemotherapy drugs are not tumour specific, and their administration can result in significant acute and chronic toxic effects to normal healthy tissue. Effectively determining the dosage of chemotherapy drugs is vital to balance the effectiveness of treatment with acceptable levels of toxicity to normal tissues, enabling patients to tolerate treatment and have better long-term treatment outcomes. Improvements in cancer survival and longer duration of treatment for individual patients may also lead to increasing numbers of patients developing treatment-related toxicities. Despite recent advances in anti-cancer treatment and the development of targeted agents and immunotherapeutics [7], which offer advantages in delivering growth inhibitory or cytotoxic effects in a more cell-specific manner, it is likely that cytotoxic chemotherapy will continue to be used into the foreseeable future [3]. Therefore, further research to optimise methods for determining chemotherapy dosage is warranted. BSA is currently the key anthropometric variable used to determine the cytotoxic drug dosage for patients receiving conventional chemotherapy as part of their cancer treatment. Investigations into BSA as a physiological quantity began in the late 19 th century, with the discovery that small animals utilise more oxygen and produce more heat relative to larger animals, due to having a larger surface area per unit mass [8]. These findings were subsequently applied to humans and led to the practice of describing the basal metabolic rate in terms of BSA rather than body weight [8]. Further exploration led to the observation of relationships between BSA and several physiological processes including, water turnover, blood volume, quantities of circulating plasma proteins and renal function, giving rise to the belief that BSA was correlated with the size and function of drug-metabolising organs [8]. In the mid-20 th century, both [PERSON] and [PERSON] [8; 9] conducted investigations to compare therapeutic dose ranges and maximum tolerated doses calculated based on body weight and BSA for humans and animals. Though the effective doses of some anti-cancer drugs were found to be more similar among mammals when calculated per unit surface area, there were still large differences across different drug types and species. Based on these findings, BSA was deemed reasonable and began being recommended for use in prescribing chemotherapy dosages by paediatrics and medical oncologists, rather than either being fixed or based on body weight [10; 11]. This remains the primary method of dose prescription to this day, for example within chemotherapy dosing in many clinical trials and is also the indicated method for dose calculation in drug package inserts or summary of product information data sheets. However, the continued use of BSA-based dosing remains controversial with methods of calculation not representative of patient variability and thus not truly individualised to patients. Inaccurate dose calculation for an individual may affect efficacy or tolerability as a result [12; 13; 14; 15]. Consequently, the need for improved methods of dose calculation and prescription have increased in recent years and remains a significant challenge within oncology [13; 16].