Prognostic significance of keratinization in nasopharyngeal carcinoma

Abstract

Introduction: Keratinization may be a vulnerable aid in predicting response to therapy for nasopharyngeal carcinoma. Methods: The presence or absence of keratin in biopsy specimens was correlated with tumor behavior, locoregional control, patterns of failure, and survival of patients irradiated for nasopharyngeal carcinoma. Results: Patients with keratinizing squamous-cell cancers (World Health Organization [WHO] type 1) had a higher incidence (76%) of locally advanced tumors than those with nonkeratinizing (WHO type 2) and undifferentiated (WHO type 3) cancers (55%). The former group of patients had a lower incidence (29%) of lymph node metastases than the later group (70%). Primary tumor was controlled in 62% and neck nodes were controlled in 82% of all patients. Primary tumor control rates were 29% in patients with keratinizing squamous-cell cancers and 79% in those with nonkeratinizing and undifferentiated cancers ( P = .001). Nodal control rates were 76% for keratinizing squamous-cell cancer and 85% for nonkeratinizing and undifferentiated cancers ( P = .001). The incidence of distant metastases was 6% in patients with keratinizing squamous-cell cancer and 33% in those with nonkeratinizing and undifferentiated cancers ( P = .001). Patients with keratinizing squamous-cell cancers, even though they had a lower incidence of lymphatic and distant metastases, had a poorer survival rate because of a higher incidence of deaths from uncontrolled primary tumors and nodal metastases. The 5-year survival rates were 35% for all patients, 6% for those with keratinizing squamous-cell cancers, and 51% for nonkeratinizing and undifferentiated cancers respectively ( P = .001). Conclusion: Higher doses of external beam radiotherapy with or without brachytherapy boost may be needed to improve local control and survival of patients with keratinizing squamous-cell carcinoma of the nasopharynx, whereas an effective systemic therapy is needed for nonkeratinizing and undifferentiated cancers, which tend to metastasize.