OBJECTIVE: We sought to assess the efficacy of different modalities in the detection of disease during the early posttreatment period of nasopharyngeal carcinoma (NPC). Study design and setting We prospectively evaluated 57 patients with NPC who were treated with radiation. A postnasal space (PNS) biopsy, an endoscopic examination, and computed tomography (CT) scans were performed 4 months after treatment. RESULTS: Four patients had evidence of disease in the PNS biopsy specimen. The sensitivity, specificity, and positive and negative predictive values of the endoscopic examination were 75%, 94.3%, 50%, and 98%, respectively, while those of the CT scan were 50%, 49.1%, 6.9%, and 92.9%, respectively. CONCLUSION: In the early postradiation period for patients with NPC, an endoscopic examination is a suitable surveillance modality, but routine CT scanning has no added clinical benefit. SIGNIFICANCE: When an endoscopic examination of the PNS yields normal results, a biopsy is not necessary because the likelihood of disease is low.