Challenges in lower limb lymphoedema assessment based on limb volume change: Lessons learnt from the SENTIX prospective multicentre study.

Background: Lower limb lymphoedema (LLL) is the most disabling adverse effect of surgical staging of pelvic lymph nodes. However, the lack of standardisation of volumetric LLL assessment hinders direct comparison between the studies and makes LLL reporting unreliable. The aim of our study is to report outcomes from a prospective trial that have implications for LLL assessment standardisation.

Methods: In the prospective international multicentre trial SENTIX, a group of 150 patients with stage IA1-IB2 cervical cancer treated by uterine surgery with bilateral sentinel lymph node biopsy was prospectively evaluated by objective LLL assessment, based on limb volume change (LVC) using circumferrential limb measurements and subjective patient-reported swelling. The assessments were conducted in six-month periods over 24 months post-surgery.

Results: Patient LVC substantially fluctuated in both positive and negative directions, which were comparable in frequency up to ±14% change. Thirty-eight patients experienced persistent LVC increase >10% classified as LLL, with nine months median time to onset. Some 34.2% of cases experienced onset later than one year after the surgery. Thirty-three patients (22%) experienced transient oedema characterised as LVC >10%, which resolved without intervention between two consequent follow-up visits. No significant correlation between LVC >10% and a patient-reported swelling was observed.

Conclusions: Given that we observed comparable fluctuations of the the lower-limb volumes after surgical treatment of cervical cancer in both positive and negative direction up to ±14%, the diagnostic threshold for LLL diagnosis based on LVC should be increased to >15% LVC. The distinction of transient oedema from persistent LLL requires repeated measurements. Also, as one-third of LLL cases are diagnosed >1-year post-surgery, a sufficient follow-up duration needs to be ensured. Patient-reported swelling correlated poorly with LVC and should only be used as an adjunct to objective LLL assessment.

Trial Registration: ClinicalTrials.gov: NCT02494063.