[Volumetrics: an indispensable complementary test in lymphology]

In patients with lymphedema, the volume of the affected limb is rarely measured in routine practice or may only be appreciated by a method giving a result in centimetres, an incorrect unit for volume quantification. Measurement of limb volume allows early diagnosis of lymphedema, long before the clinical signs appear. Two methods exhibit excellent reproducibility: the water displacement method which is the gold standard, with an accuracy of 0.7% and reproducibility of 1.3%, and the perimetric method, which has a good intraclass coefficient of correlation of 0.99. The water displacement method is the gold standard because it is the only one that gives the exact volume of the limb, including its extremity (hand or foot), but it has the drawback of requiring water. The perimetric method has two drawbacks: it does not include the hand or foot in the volume measure, and therefore gives an approximate volume of the affected limb, and it requires a computer to calculate the cone volumes. Taking, as an example of limb volume measurement, the case of patients operated for breast cancer, a difference between the post and pre postoperative volumes of < or = 100 mL is reassuring, a difference > 100 and < or = 250 mL requires regular surveillance, and a difference exceeding 250 mL is an indication for drainage and elastic compression. When the preoperative limb volume is unknown, the volume of the ipsilateral limb can be used.