Severity of internal lymphedema in unilateral or bilateral radiotherapy patients: An exploratory study

Bilateral elective nodal irradiation (ENI) is part of the standard treatment for most head and neck cancers (HNC) that are treated with primary (chemo)radiotherapy. Recent studies indicate that unilateral radiotherapy can reduce radiation-related toxicities and improve quality of life. This study examines whether there is a difference in the prevalence and severity of internal lymphedema between patients with unilateral or bilateral radiotherapy.

Internal lymphedema was scored on available laryngoscopy videos, using the revised Patterson scale, in patients included in a previous prospective study comparing uni- versus bilateral radiotherapy. Analysis was performed by descriptively comparing the variation in location and severity of internal lymphedema, and by calculating rank biserial correlation coefficients.

Out of 100 potentially eligible patients, 41 patients with available good-quality laryngoscopy videos were included. Of these, twenty-three patients were treated with unilateral radiotherapy and 18 with bilateral radiotherapy. The median internal lymphedema score for all patients was 7 (range: 0-24). For the patients with unilateral radiotherapy, the median was 6 (range: 0-19), compared to 9.5 (range: 0-24) for the bilateral group. Nine patients had no internal lymphedema, six in the unilateral group and three in the bilateral group. The rank biserial correlation coefficients showed a negative correlation between lymphedema and unilateral radiotherapy for all regions in the larynx (range -0.19 to -0.63), and for the total lymphedema score -0.92 (95 % CI -0.97 to -0.82).

Internal lymphedema prevalent and severity are lower after unilateral radiotherapy for head and neck cancer, compared to the current standard of care bilateral radiotherapy.