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Open Access Research article

Primary tumor regression speed after radiotherapy and its prognostic significance in nasopharyngeal carcinoma: a retrospective study

Ning Zhang1, Shao-Bo Liang12, Yan-Ming Deng3, Rui-Liang Lu4, Hai-Yang Chen2, Hai Zhao4, Zhi-Qian Lv1, Shao-Qiang Liang1, Lin Yang2, Dong-Sheng Liu5 and Yong Chen2*

Author Affiliations

1 Radiotherapy Department of Nasopharyngeal Carcinoma, Cancer Center, The First People’s Hospital of Foshan, 81 Lingnan Street North, Foshan, People’s Republic of China

2 Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou 510060, People’s Republic of China

3 Chemotherapy Department of Head & Neck & Chest Carcinoma, Cancer Center, The First People’s Hospital of Foshan, 81 Lingnan Street North, Foshan, People’s Republic of China

4 Department of Imaging Diagnosis, The First People’s Hospital of Foshan, 81 Lingnan Street North, Foshan, People’s Republic of China

5 Department of Medical Statistics, The First People’s Hospital of Foshan, 81 Lingnan Street North, Foshan, People’s Republic of China

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BMC Cancer 2014, 14:136  doi:10.1186/1471-2407-14-136

Published: 27 February 2014

Abstract

Background

To observe the primary tumor (PT) regression speed after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) and evaluate its prognostic significance.

Methods

One 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.

Results

Of 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).

Conclusions

PT 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.

Keywords:
Nasopharyngeal carcinoma; Radiotherapy; Tumor regression; Survival