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The calculation of an accurate dose of chemotherapy for oncological patients reduces the possible medication errors and the toxicity of the body and so it improves the outcome of the treatment (survival). In oncological practice for the calculation of the dose of chemotherapy the human body surface area (BSA) is used. The human body surface area is determined by derived formulas, but it is not directly linked to the pharmacokinetics of the drugs. Pharmacokinetic studies have demonstrated that for the calculation of the chemotherapy dose the actual body weight should be taken into account rather than the ideal one. In the therapeutic dose determination the body fat mass has essential significance.
202 patients aged from 19 to 83 years with various tumor localizations underwent anthropometric measurements (height, weight, circumferences, fatfold thickness, the distance between the hills above the joint), the body mass index (BMI) and the BSA (according to the Mosteller formula).
The average weight of 99 men was 78.5 ± 16.4 kg and the mean body weight of 103 women was 70.1 ± 14.6 kg, statistically non-significantly different (F = 0.358, p = 0.551), but the independent-sample t-test arithmetical mean differed statistically significantly (t = 3.839, p <0.001). The oncological patients in the absolute and relative distribution of groups according to the body mass index in relation to the patients gender differed statistically significantly (χ2 =11.510, df = 4, p = 0.021). Half of the men had ideal weight (body mass), but only about 1/3 of women were with the ideal body weight. The men's average body mass index was 25.41 ± 4.73 kg/m2 and the women's average body massindex was 26.20 ± 5.90 kg/m2. After arithmetic calculation of the body surface area using a variety of formulas, men's BSA differs less than 1% compared to the calculated area of Mosteller formula. For women the differences are more than 1%. Distribution of patients in groups body fat content (%) of the patients shows that male and female patients were primarily from the group with excessive fat in the body, the body fat for men is 25% or more of the total body weight, but for the women it is over 32% of the total body weight. Correlation analysis showed that the body fat for men correlates with the body surface area, calculated using the Mosteller formula (r = 0.663, p <0.001) and the fat content for women correlates with the body surface area, calculated using the Mosteller formula (r = 0.760, p <0.001). The male body volume of the mean value was 75, 0 ± 17.1 dm3, the female body volume of the mean value was 68,6 ± 15.6 dm3. After the independent samples t-test between men and women in body volume arithmetical means differed statistically significantly (t = 2.437,p = 0.016).
Anthropometric measurements are suitable for the calculation of the doses of chemotherapy, but taking into account the correlation, it cannot be excluded that they reflect the same body surface area. The BMI does not feature the percentage of the fat mass of the whole body. Consequently, it is possible that the patient's body density is a more physiological parameter, which could be determined for comparison by using abdominal computer tomography. The body volume index (BVI) could be one of the most recent parameters for the more accurate calculation of chemotherapy for cancer patients. The Body Volume Index (BVI) is a new measurement for human obesity that has been proposed as an alternative to the Body Mass Index (BMI).