Differential Change in Size of Human Papillomavirus-Positive Cystic Versus Solid Squamous Cell Carcinoma Lymph Node Metastases in Response to Induction Chemotherapy.

Abstract

According to certain cancer treatment protocols, the response to induction chemotherapy of lymph node metastases based on radiographic measurements guides further management. The aim of this study is to verify the observation that cystic metastatic lymph nodes tend not to shrink as rapidly as solid metastatic lymph nodes in response to induction chemotherapy in patients with human papillomavirus-related oropharyngeal squamous cell carcinoma. The lymphadenopathy in a cohort of patients from a clinical trial with human papillomavirus-related oropharyngeal squamous cell carcinoma with both baseline and postinduction chemotherapy (carboplatin/paclitaxel/cetuximab) contrast-enhanced neck computed tomography was retrospectively reviewed. The appearance of the metastatic lymph nodes on computed tomography was characterized as cystic or solid. A cystic lymph node was defined as having a hypoattenuating component greater than 20% of the total volume. The rates of short-axis and volume changes of cystic and solid lymph nodes were compared using 1-tailed t test. A total of 46 patients were included in this study, comprising 39 solid and 45 cystic lymph nodes. The rate of short-axis decrease was significantly greater for solid (1.33% per day) than cystic (1.08% per day) lymph nodes (P = 0.036). Likewise, the rate of volume decrease was significantly greater for solid (2.13% per day) than cystic (1.87% per day) lymph nodes (P = 0.014). This study suggests that in patients with human papillomavirus-related oropharyngeal squamous cell carcinoma solid lymph node metastases generally decrease in size at a greater rate than cystic lymph nodes after induction chemotherapy.