Research investigating measurement properties for evaluating the decongestive treatment effect on different edema characteristics (e.g. water volume, hardness of the skin, water content,..) at the level of the lower limbs is missing. Information about the clinical relevant change criteria after treatment for nearly all these edema characteristics, is not present and requires investigation.

To assess the merits of each treatment in a reproducible manner, a reliable way of measuring limb volume and other edema characteristics must be established, as the evaluation of treatment effects without appropriate tools might lead to biased treatment effects.

First of all, in clinical practice, it is of utmost importance to know which edema characteristics need to be evaluated in order to assess the clinical evolution of a patient with lymphedema during and after treatment. Secondly, in order to draw proper conclusions about the treatment effect, it is necessary that to know from which criterion (or cut-off value) one can speak of a real clinical change for a certain lymphedema characteristic. Given that the edema characteristics that are most responsive to treatment and their corresponding criteria for clinically significant and relevant changes at the lower limbs have never been investigated before, the need for this research is high.

Therefore, the research questions in this study are: Which measurement tool(s) are able to detect clinically relevant changes in the lymphedema characteristics after the intensive treatment and during the maintenance treatment? When can a clinician speak of a clinically relevant change?

Inclusion Criteria:

• Intensive treatment group

  • Unilateral or bilateral, primary or secondary LLL
  • No active metastases
  • If cancer-related lymphedema, time interval since surgery/ radiotherapy/ chemotherapy is ≥3 months
  • Objective diagnosis of lymphedema: ≥ 5% volume difference OR ≥ 2 minor/ 1 major criteria on lymphoscintigraphy OR presence of ICG dermal backflow
  • Age ≥ 18 years
  • Able to read, understand and speak Dutch
  • Planned to start with intensive decongestive lymphatic therapy at one or both legs

• Maintenance treatment group

  • See inclusion criteria 'intensive treatment group'
  • But: instead of patients planned to start with intensive lymphatic therapy, patients of this group should have ended their intensive treatment phase at least 3 months ago (= currently receiving maintenance decongestive lymphatic therapy)

Exclusion Criteria:

• Pregnant participants
• Presence of chronic venous insufficiency C4, C5, C6; deep venous thrombosis; post-thrombotic syndrome
• Presence of skin infections of wounds at the level of the lower limbs at the moment of inclusion

Intensive treatment group: Patients planned to start with intensive decongestive lymphatic therapy at one or both legs.

Maintenance treatment group: patienst who have ended their intensive treatment phase at least 3 months ago (= currently receiving maintenance decongestive lymphatic therapy)