Nasopharyngeal carcinoma. Clinical presentation, diagnosis, treatment, and prognosis.

Serologic testing is a useful diagnostic aid for patients with NPC, particularly those in whom the tumors are small and submucosal (difficult to see or occult). If a metastatic tumor is found in the neck but its primary source is occult, positive titers provide reason for a detailed investigation of the nasopharynx, including a thorough examination with the patient under anesthesia and a random biopsy procedure. This approach can spare the patient a biopsy of neck nodes. Dickson compared two groups of patients with NPC metastatic lesions in the neck--the only difference between the groups was that the patients in one group had undergone a neck biopsy before radiation treatment--and found a somewhat poorer survival rate in the biopsied group. A large body of clinical evidence, histopathologic data, and, more recently, immunologic studies support the concept that carcinomas of the nasopharynx constitute two distinct diseases. Today, these are classified as WHO type 1 tumors (according to previous terminology, the "keratinizing, squamous cell carcinomas") and combined WHO type 2 and 3 tumors (the "combined grade 4 undifferentiated carcinomas," which are mostly the lymphoepitheliomas and transitional cell carcinomas in previous terminology). Clearly, the anti-EBV serologic findings separate the WHO type 1 tumors from the WHO type 2 and 3 tumors. The serologic findings in the former group are essentially the same as those in control groups, and the WHO type 1 tumors can be considered the "common garden variety" of squamous cell carcinomas found in other areas of the head and neck region. Furthermore, the WHO type 2 and 3 tumors occur at an earlier age; disease-free periods after treatment are longer; survival after treatment is better; and early and advanced neck metastasis is more common. In addition, primary WHO type 2 and 3 tumors in the nasopharynx are more often small, submucosal, and sometimes difficult to detect; indeed, they may be clinically occult. The tumors seem to be more radiation-sensitive than the WHO type 1 carcinomas, which are more likely to recur or persist in the nasopharynx after treatment.