Easy measurement volumeter in detection of breast cancer related lymphedema: A validity study

Aim and Hypothesis: Breast cancer is the most common cancer among women. One of the most important complications of the breast cancer treatment is lymphedema which is characterized by protein rich subcutaneous fluid accumulation due to deteriorated lymph flow. Water displacement method is considered to be the gold standart method for the diagnosis of lymphedema. However, the standart volumeter is heavy, fragile. Furthermore an additional measuring container is needed to measure the volume of the displaced water. Difficulties in filling and emptying of the volumeter and using the same volumeter for different patients causes hygiene problems. These disadvantages necessitates a new model of volumeter. New volumeter that is designed by us is lighter, smaller and more sturdy. Also the easy measurement volumeter is easier to clean. Besides it has its own scale. In this study, validaty of this newly designed volumeter is investigated. Materials and Methods: At the first step of the validity study, volume of the standart cylinders was measured for three times with standart volumeter and easy measurement volumeter. Cylinders with known volumes (volumes change between 250 ml and 3000 ml) is slowly submerged into the both volumeters. Thereafter, the amount of water that is displaced was measured by weighing with a digital scale. In the second step, a total of 30 arm volumes of 15 volunteers were measured. Every volunteer immersed their right and left arms for three times until the top of the volumeter came to contact with axilla. Then displaced water was weighted and results were compared between two volumeters. At the third step, arms of the 28 patients with breast cancer related lymphedema was measured with each volumeter for one time and the means were compared. Datas are assessed with SPSS 22.0 software package program. Results: There was a high degree of consistency between measured volumes of cylinders of known volumes measured with standart volumeter and easy measure volumeter. The measured mean volumes with two volumeters was assessed with paired sample t test. Sig.(P value) was 0,927 and was higher than alpha=0,05 which means there was no difference between measurements of both volumeters. The variance of measurements of the devices was assessed with Levene's test for equality of variances. Sig.(P value) was obtained as 0,981. According to this result null hypothesis can not be rejected which signifies there is no difference in variances of measurements between two volumeters. Likewise, paired sample t test was used to evaluate the differences between the means of the measurements in healthy volunteers group. No difference was detected between the means of arm volumes measured with standart volumeter and newly designed volumeter (sig= 0,105). Additionally, there was no significant difference between variances of measurements between two volumeters which is evaluated with Levene's test of equality(sig=0,932). The measurements between two volumetres are also consistent in lymphedema patients group (involved arm sig=0,842 and normal arm sig=0,075) There was a significant correlation between the body mass index and mean arm volumes that is measured by standart volumeter and ''Easy Measurement Volumeter''. Conclusion: Our study revealed newly designed '' Easy Meeasurement Volumeter'' is valid in terms of measuring arm volume. This volumeter has the advantages of containing its own scale for volume measurement also it is smaller, lighter and easier to clean. Simple measure volumeter is appropriate for using in daily practise. If the production cost can be lowered, we aim to use this volumeter for self-measurement at home.