Abstract
BackgroundTo observe the primary tumor (PT) regression speed after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) and evaluate its prognostic significance.MethodsOne hundred and eighty-eight consecutive newly diagnosed NPC patients were reviewed retrospectively. All patients underwent magnetic resonance imaging and fiberscope examination of the nasopharynx before RT, during RT when the accumulated dose was 46–50 Gy, at the end of RT, and 3–4 months after RT.ResultsOf 188 patients, 40.4% had complete response of PT (CRPT), 44.7% had partial response of PT (PRPT), and 14.9% had stable disease of PT (SDPT) at the end of RT. The 5-year overall survival (OS) rates for patients with CRPT, PRPT, and SDPT at the end of RT were 84.0%, 70.7%, and 44.3%, respectively (P < 0.001, hazard ratio [HR] = 2.177, 95% confidence interval [CI] = 1.480-3.202). The 5-year failure-free survival (FFS) and distant metastasis-free survival (DMFS) rates also differed significantly (87.8% vs. 74.3% vs. 52.7%, P = 0.001, HR = 2.148, 95% CI, 1.384-3.333; 91.7% vs. 84.7% vs. 66.1%, P = 0.004, HR = 2.252, 95% CI = 1.296-3.912). The 5-year local relapse–free survival (LRFS) rates were not significantly different (95.8% vs. 86.0% vs. 81.8%, P = 0.137, HR = 1.975, 95% CI, 0.976-3.995). By multivariate analyses, the PT regression speed at the end of RT was the only independent prognostic factor of OS, FFS, and DMFS (P < 0.001, P = 0.001, and P = 0.004, respectively). The 5-year FFS rates for patients with CRPT during RT and CRPT only at the end of RT were 80.2% and 97.1%, respectively (P = 0.033). For patients with persistent PT at the end of RT, the 5-year LRFS rates of patients without and with boost irradiation were 87.1% and 84.6%, respectively (P = 0.812).ConclusionsPT regression speed at the end of RT was an independent prognostic factor of OS, FFS, and DMFS in NPC patients. Immediate strengthening treatment may be provided to patients with poor tumor regression at the end of RT.
Highlights
To observe the primary tumor (PT) regression speed after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) and evaluate its prognostic significance
The 5-year overall survival (OS) rates for patients with complete response of PT (CRPT), partial response of PT (PRPT), and stable disease of PT (SDPT) at the end of RT were 84.0%, 70.7%, and 44.3%, respectively (P < 0.001, hazard ratio [Hazard ratios (HR)] = 2.177, 95% confidence interval [CI] = 1.480-3.202)
The 5-year failure-free survival (FFS) and distant metastasis-free survival (DMFS) rates differed significantly (87.8% vs. 74.3% vs. 52.7%, P = 0.001, HR = 2.148, 95% CI, 1.384-3.333; 91.7% vs. 84.7% vs. 66.1%, P = 0.004, HR = 2.252, 95% CI = 1.296-3.912)
Summary
To observe the primary tumor (PT) regression speed after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) and evaluate its prognostic significance. The main prognostic factors of NPC widely used in clinical work include the staging system, tumor size, and plasma Epstein-Barr virus (EBV) DNA level [5,6,7,8,9,10,11,12]. Previous research has demonstrated that tumor sizes, including primary tumor (PT) volume and maximum PT diameter, could serve as important prognostic factors in NPC [7,8,9]. The plasma EBV DNA level is useful for predicting prognosis and evaluating treatment failure in NPC [11]. In patients with Stage I–II NPC, pretherapy plasma EBV DNA levels identified a high-risk group with a probability of distant failure similar to that of patients with advancedstage disease [12]
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