The earliest finding of indocyanine green lymphography in asymptomatic limbs of lower extremity lymphedema patients secondary to cancer treatment: the modified dermal backflow stage and concept of subclinical lymphedema.

Background: Early diagnosis and treatment are as important for management of secondary lymphedema following cancer treatment as in primary cancer treatment. Indocyanine green lymphography is the modality of choice for routine follow-up evaluation of patients at high risk of developing lymphedema after cancer therapy.

Methods: Fifty-six limbs of 28 so-called unilateral secondary lower extremity lymphedema patients who underwent indocyanine green lymphography were compared with dermal backflow patterns of indocyanine green lymphography on 28 asymptomatic limbs and assessed using leg dermal backflow stage.

Results: Of 28 asymptomatic limbs of secondary lower extremity lymphedema patients, the dermal backflow patterns were detected in 19 limbs but were absent in nine limbs. Significant differences were seen between asymptomatic limbs with dermal backflow patterns (n=19) and limbs without them (n=9): age, 51.4±15.3 years versus 34.8±12.7 years (p=0.007); body weight, 75.1±7.9 kg versus 50.1±5.3 kg (p=0.012); body mass index, 23.1±4.2 versus 19.7±1.8 (p=0.005); leg dermal backflow stage of asymptomatic limb, 1.2±0.4 versus 0.0±0.0 (p<0.001); and leg dermal backflow stage of symptomatic limb, 3.5±0.6 versus 2.8±0.8 (p=0.033).

Conclusions: The splash pattern is the earliest finding on indocyanine green lymphography of asymptomatic limbs of secondary lower extremity lymphedema patients. The leg dermal backflow stage allows early diagnosis of secondary lower extremity lymphedema even in a subclinical stage. The concept of subclinical lymphedema could play an important role in early diagnosis and prevention of lymphedema after cancer treatment.

Clinical Question/level Of Evidence: Diagnostic, V.