Ten-year Follow-up Study of Grenz Ray Treatment for Lentigo Maligna and Early Lentigo Maligna Melanoma

Abstract

Radiotherapy is often used to treat lentigo maligna. However, the long-term efficacy and safety of radiotherapy approaches have not been thoroughly evaluated. We aimed to evaluate the long-term efficacy and safety of ultrasoft X-ray/Grenz ray treatment in those patients. A total of 161 lesions from 159 patients received treatment with Grenz ray between 2005 and 2007. Follow-up of recurrence was performed 10 years after the final treatment. In the study setting, the cure rates were 97% for primary therapy with Grenz ray alone and 100% when Grenz ray was combined with partial or radical excision. The treatment is well tolerated, simple to perform, and has an excellent cosmetic outcome, with 94% of patients pleased with the results. Grenz ray is painless, effective, and safe for use when surgery is not feasible. Thus, Grenz ray can be considered as a standard treatment option for lentigo maligna.

Keywords: lentigo maligna; lentigo maligna melanoma; radiotherapy; Grenz ray.

Fig. 1

Lentigo maligna recurrence. Clinical 10-year follow-up; 1-mm light-brown macula 2.5 cm from the surgical scar. (A) Dermatoscopy with light-brown pigmentation arranged in lines; (B) histological recurrence with melanocytic atypia (Hematoxylin eosin staining).

Fig. 2

Box-plot of the treatment groups according to the radiation dose. Primary Grenz ray (GR), non-radical surgery and GR, and radical surgery and GR were evaluated.

Fig. 3

A 77-year-old woman with hyperpigmentation. (A) Ten-year follow-up with hyperpigmentation. (B) Basal hyperpigmentation was observed histologically, but no recurrence was detected, and melanocytes were normal (Hematoxylin eosin staining).