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One hundred and forty-three patients (Group 1) with histologically proven nasopharyngeal-carcinoma (NPC) had bone scintigraphy with 99Tcm methylenediphosphonate (MDP) or dihydroxypropanediphosphonate (DPD) within 2 months of the initial diagnosis. A further 162 patients (Group 2) had bone scans during the course of follow-up if there were symptoms of bone pain or evidence of metastases at other sites. Twenty-three per cent (33/143) of the newly diagnosed NPC patients (Group 1) had evidence of bone metastases. Of these 143 patients, 101 were T0-T2, 16 were T3 and 25 were T4. Thirty-six patients had no neck nodes (NO), 44 were N1, 25 N2 and 38 N3. Of the 162 patients in Group 2, 96 (59%) had a positive bone scan. The commonest sites for bony metastases from NPC were the spine, ribs, pelvis and lower limbs in order of frequency. There is a highly significant association with the nodal stage but no association with the UICC T staging which is not adequate in nasopharyngeal carcinoma. In our part of the world, bone metastases from NPC are a common cause of an abnormal bone scan.

A total of 363 cases of nasopharyngeal carcinoma (NPC) in Singapore were classified into squamous cell carcinoma (SCC; 73 cases), non-keratinizing carcinoma (NKC; 178 cases) and undifferentiated carcinoma (UC; 172 cases). Possible biological differences between these histologic types and between tumors with and without lymphocytic infiltration were investigated by correlations with survival rates and with selected epidemiologic, immunovirologic, and immunogenetic data on the disease. The 5-year survival rates following radiotherapy were 25.3% for all cases and 58.8% for tumors restricted to the nasopharynx. The 5-year survival rate for SCC was poorer than for the combined NKC and UC groups (p less than 0.05). The 3-year survival rate was better for tumors with lymphocytic infiltration (p less than 0.05), but there were no differences in the 5-year survivals. The survival rates were better in females (p less than 0.01) and in the younger age groups (p less than 0.01). There were no significant correlations between histopathology of NPC and the distributions of cases by age, sex, HLA antigen profiles, or cell-mediated immune status. Squamous cell carcinoma was associated with lower levels of antibodies to the Epstein-Barr nuclear antigen (p less than 0.05), but there were no differences with respect to antibodies against other EBV related antigens. These findings support the view that SCC, NKC, and UC of the nasopharynx, as defined in the WHO classification, are variants of a fairly homogeneous group of neoplasms in the Singapore population.

Three hundred and fifty-two consecutive cases of nasopharyngeal carcinoma were analysed to determine the pattern of distant metastases. Diagnosis of distant metastases was made wholly on clinical signs and radiography. Ninety-nine patients developed distant metastases, an incidence rate of 28.1%. There did not appear to be any difference in "risk" by age or sex. The predilection of this cancer to develop skeletal metastases is further confirmed. Pulmonary and hepatic involvement were the next commonest. Both extent of primary tumour (T) and cervical lymph node status (N) exerted a significant influence on the probability of metastases developing. Thus significant differences in metastatic rate were observed between T0/T1, T2 and T3/T4 and N0, N1, N2 and N3 groups. 65.6% of metastatic cases had control of local disease (nasopharynx and cervical lymph nodes). When metastases are diagnosed the prognosis is gloomy with a median survival under four months and a fatality rate of 91% within a year of first metastasis.

Newly diagnosed NPC patients were found to have impaired general T-cell functions, as determined in vivo by the Mantoux test and in vitro by the PHA response assay. Treated remission patients were as hyporesponsiveness as newly diagnosed patients. PHA hyporesponsiveness was associated with the HLA profile of A2-B Sin 2 and with high antibody titres to EBV-related antigens, in particular to the early antigen. Impaired responses in the Mantoux or PHA tests were associated with poor survival. The impaired response could be partially or totally restored by in vitro treatment of the hyporesponsive lymphocytes with levamisole.

Antibody titres to EBV-associated antigens in Chinese NPC patients were analysed according to length of survival after diagnosis and to disease stage. Geometric mean titres of ADLC antibody were highest in the long-term survivors, whereas VCA, EA and EBNA antibody titres showed an inverse relationship to survival. High VCA, EA and EBNA titres were less frequent, and high ADLC titres were more frequent in long-term survivors than in intermediate or short-term survivors. The association of geometric mean titres of EBV antibodies with prognosis could not be entirely explained by stage of disease. A functional role for the ADLC antibody is suggested by the association of a high ADLC antibody titre with a good prognosis regardless of stage of disease.

Nasopharyngeal Carcinoma is one of the most prevalent malignancies treated by radiotherapy in Singapore. Planning of the radiation fields for this condition is difficult because of the proximity of anatomical structures that are vulnerable to irradiation, such as the eyes, brain stem and cervical cord. However, the treatment results have shown progressive improvement. The treatment technique currently used utilized cobalt as well as caesium teletherapy units. Of the 104 cases treated in 1970 using this technique, the overall absolute 5 years survival rate with no evidence of disease is 30.8%. For Stage I cases, the rate is 62.5%. The prognosis is significantly better for the female than the male and is also related to age.