Retrospective analysis of the impact of HPV status and smoking on mucositis in patients with oropharyngeal squamous cell carcinoma treated with concurrent chemotherapy and radiotherapy.

OBJECTIVES: The standard concurrent radiotherapy and chemotherapy regimens for patients with oropharyngeal cancer are highly toxic. Human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) has recently emerged as a distinct biological and clinical entity with improved response to treatment and prognosis. A tailored therapeutic approach is needed to optimize patient care. The aim of our study was to investigate the impact of HPV and smoking status on early toxicities (primarily mucositis) associated with concurrent chemotherapy and radiotherapy in patients with OPSCC. MATERIALS AND METHODS: We retrospectively evaluated 72 consecutive patients with OPSCC and known HPV status treated with concurrent radiotherapy and chemotherapy at our institution. Treatment-related toxicities were stratified by smoking and HPV status and compared using univariate and multivariate logistic regression. RESULTS: HPV-positive patients had a 6.86-fold increase in the risk of having severe, grade 3-4 mucositis. This effect was preserved after adjusting for patient smoking status, nodal stage, radiotherapy technique and radiotherapy maximum dose. Additionally, HPV status had significant effect on the objective weight loss during treatment and at three months after treatment. Consistently, non-smokers had a significant 2.70-fold increase in the risk of developing severe mucositis. CONCLUSION: Risk factors for OPSCC modify the incidence of treatment-related early toxicities, with HPV-positive and non-smoking status correlating with increased risk of high grade mucositis and associated outcomes. Retrospective single-institution studies need to be interpreted cautiously. However, this finding is important to consider when designing therapeutic strategies for HPV-positive patients and merits further investigation in prospective clinical trials.

Chiral symmetry breaking in crystallization: the role of convection

Chiral symmetry breaking in stirred crystallization of sodium chlorate ( NaClO3) occurs via the production of secondary crystals from a single "mother crystal." Martin, Tharrington, and Wu [Phys. Rev. Lett. 77, 2826 (1996)] investigated this phenomenon and concluded that it was mechanical crushing of a crystal by the stir bar, not convection, that produces secondary crystals from a single crystal. Here we report the generation of secondary crystals of sodium chlorate when a saturated solution of sodium chlorate is simply made to flow over a sodium bromate ( NaBrO3) crystal. This clearly shows that fluid flows alone can generate and disperse secondary nuclei.