FC3 Assessment of growth rate of melanomas based on sequential dermatoscopic images
Introduction The aim of this study was to estimate the average growth rate of cutaneous melanomas in comparison with melanocytic nevi.
Methods Matched-pairs case-control study. Morphometric analyses of sequential dermatoscopic images. 59 patients with 63 primary melanomas were included. Sequential images of melanocytic nevi as controls were available for 55 melanomas. The main outcome measure is the average growth rate (mm2) per month.
Results The mean patient's age was 50.2 years (SD±15.8). Thirty-five (55.6%) melanomas were invasive. The mean monthly growth rate of melanomas (n=63) was 0.43 mm2 (SD±0.9) with a mean relative increase of size of 33.7% (SD±50.2). For melanomas the average size at baseline was 25.6 mm2 (SD±14.5) and 32.0 mm2 (SD±16.7) after follow-up (P<0.01). The mean monthly growth rate for melanoma in situ was 0.25 mm2 (SD±0.7) and 0.58 mm2 (SD±1.0) for invasive melanomas (P=0.15). There were no significant correlations between mean monthly growth rate and age of patient, anatomic site, and size of the melanoma at baseline. The mean increase of size was significantly higher for melanomas than for nevi.
Conclusions Melanomas are growing significantly faster than nevi of the same patient. The average horizontal growth rate of melanoma was 0.43 mm2 per month, which is lower than expected, and supports the hypothesis that the growth rate of melanoma is not linear.© 2010 Lippincott Williams & Wilkins, Inc.