Prognostic significance of keratinization in nasopharyngeal carcinoma.

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.