Second primary squamous cell carcinoma in patients with nasopharyngeal carcinoma after radiotherapy-Predictors and prognostic factors.

BACKGROUND

We investigated risk and prognostic factors for second primary squamous cell carcinoma (SCC) in patients with nasopharyngeal carcinoma (NPC) after radiotherapy (RT).

METHODS

A total of 49 021 patients with NPC were treated at Sun Yat-Sen Cancer Center between January 1970 and December 2009. The incidence and management of second primary SCCs were analyzed.

RESULTS

A total of 142 patients (0.29%) developed second primary SCC, with 78.2% in the upper aerodigestive tract. Older age, smoking, and chemotherapy were associated with an increased rate of second primary SCC. The 3, 5, and 10-year overall survival (OS) rates for second primary SCC were 47.18%, 31.69%, and 11.97%, respectively. Advanced age, family history of cancer, and treatment modality were independent prognostic factors for survival.

CONCLUSION

Second primary tumors rarely develop in patients with NPC treated with RT, but when this occurs, second primary SCC comprises a majority of these. Intensity-modulated RT may shorten the latency to second primary SCC. Surgery as the first-line treatment may improve survival and prognosis.