DNA content of nasopharyngeal carcinoma: An independent prognostic indicator

The purpose of this study was to examine whether tumor DNA content correlat ed with prognosis in nasopharyngeal carcinoma (NPC). DNA flow-cytometric an alysis in fresh specimens of nasopharyngeal biopsy from 123 patients with c linical suspicion of NPC was collected initially. Histopathologic study and successful flow-cytometric analysis had 28 lymphoid hyperplasias and 87 NP Cs. Seventeen NPC patients were treated elsewhere and were excluded. A tota l of 98 patients, including 28 lymphoid hyperplasias and 70 NPCs, formed th e materials of this study. There were 34 (49%) diploid and 36 (51%) aneuplo id in NPC patients. No lymphoid hyperplasias were aneuploid. The mean of S- phase fraction was higher in NPC than in lymphoid hyperplasia (P < .001), i ndicating higher cellular activity in NPC. DNA content failed to associate with age, gender, pathology, distant metastasis, and stage, indicating that DNA content was an independent prognostic indicator and possibly a clinica l parameter. The log rank test of overall survival curves was significant f or stage (P = .002) and DNA ploidy (P = .042); it was almost significant fo r S-phase fraction (P = .057). Because the follow-up duration was not long enough, univariate and multivariate analysis were not significant for stage , ploidy, and S-phase fraction, except for distant metastasis. It is also m ost likely colinearity of clinical stage and distant metastasis that explai ned why clinical stage could not show significance in prognosis. Interestin gly, the DNA content appeared to be a potential prognostic parameter in ove rall survival, although it was not statistically significant (P = .052). Ou r data suggested that NPC patients with aneuploid DNA and high S-phase frac tion tend to have poor prognosis and should be treated more aggressively, e ven in the early stage of the disease.