A Nomogram to Predict Locoregional Recurrence after Surgery and Postoperative Adjuvant Radiation Therapy for Primary Mucosal Melanoma of the Head and Neck

Abstract

To evaluate postoperative radiotherapy (PORT) on prognosis for patients with mucosal melanoma of the head and neck (MMHN) and create a specific nomogram to predict the probability of locoregional recurrence (LRR) of MMHN after surgery and PORT. We retrospectively reviewed 111 patients with non-metastatic MMHN who underwent definitive surgical treatment with PORT between January 2008 and December 2018. Clinical characteristics and blood test parameters were analyzed for relationships with treatment outcomes, and a nomogram was created to estimate the risk of LRR using R software. The median follow-up was 44.2 months (range, 5.9–111 months), and we identified 17 local recurrence (15.3%), 1 regional lymph node metastasis (0.9%), and 33 distant metastases (29.7%). Relative to later recurrence, early locoregional recurrence (<2 years after surgery and PORT) was associated with poorer overall survival (OS) (P = 0.001). The multivariate analysis revealed that independent risk factors for better locoregional recurrence-free survival (LRRFS) included age > 56 years, bilirubin (BIL) > 8.5 μmol/L, Mg2+ > 0.8 mmol/L, mean corpuscular hemoglobin (MCH) < 32.3 pg and mean platelet volume (MPV) <10.0 fL. These five factors were used for the nomogram which had a C-index of 0.884 for predicting LRR, and internal validation revealed a good discriminative ability. Early locoregional recurrence (<2 years) was associated with poor OS of MMHN after surgery and PORT. Our nomogram may be useful for predicting LRR of MMHN, and internal validation confirmed good discriminative ability.