Tumor Volume Reduction After Gemcitabine Plus Cisplatin Induction Chemotherapy in Locally Advanced Nasopharyngeal Cancer: Comparison with Paclitaxel and Cisplatin Regimens

Abstract

BACKGROUND Gemcitabine plus cisplatin (GP) is a novel regimen of induction chemotherapy (IC) for treating locoregional advanced nasopharyngeal cancer (NPC). This retrospective study aimed to compare the efficacy of GP and TP (paclitaxel plus cisplatin) regimens in tumor volume reduction after IC. MATERIAL AND METHODS Between January 2014 and July 2017, 44 patients with III-IVB stage NPC received GP IC followed by concurrent chemoradiotherapy. These patients were matched with 44 patients receiving TP IC according to clinical characteristics. The gross tumor volume of the primary site and positive lymph nodes were delineated by magnetic resonance imaging before and after IC, as well as the nasopharyngeal air cavities. The changes in tumor volume and nasopharyngeal air cavity after IC were calculated and compared between the 2 groups. Treatment toxicities and early survival outcomes were also reported. RESULTS There were no differences in the initial tumor volume and nasopharyngeal cavity between the 2 groups. The volume changes after IC for the primary site, lymph nodes, and nasopharyngeal cavity were 31.4 (range, -0.97-75.8), 4.68 (range, -7.08-22.06), and 2.62 (range, 0.1-7.63) mL for GP and 23.36 (range, -59.14-83.58), 4.7 (range, -11.21-48.61), and 1.47 (range, -2.47-6.17) mL for TP, respectively. All comparisons favored the GP regimen. The toxicities of the 2 regimens were comparable and no survival differences were observed at follow-up (median, 18.7 months). CONCLUSIONS Changes in the tumor volume and nasopharyngeal air cavity showed that the GP regimen was significantly more effective than the TP regimen in tumor burden reduction. However, whether the advantages of GP can translate into survival benefits requires further investigation.

Figure 1

Representative images of contouring tumor volume and nasopharyngeal air cavity according to computed tomography and magnetic resonance imaging fusion images: (A) GTVnx before induction chemotherapy (IC), (B) GTVnd before IC, (C) NC before IC, (D) GTVnx after IC, (E) GTVnd after IC, and (F) NC after IC. Note that all outlines are manually drawn. GTV – gross tumor volume; GTVnd – gross tumor volume of lymph node involved; NC – nasopharyngeal cavity.

Figure 2

Comparison of tumor volume and nasopharyngeal air cavity changes before and after induction chemotherapy. (A) Time interval between completion of 2^nd induction chemotherapy and post-chemotherapy magnetic resonance imaging (MRI). (B) Time interval between pre-chemotherapy and post-chemotherapy MRI. (C) Primary tumor volume before induction chemotherapy. (D) Nodal volume before induction chemotherapy. (E) Volume of nasopharyngeal air cavity. (F) Degree of regression (DRV) in primary tumor volume. (G) DRV in nodal volume. (H) Volume change in nasopharyngeal air cavity.

Figure 3

Kaplan-Meier survival curves. (A) Overall survival, (B) Disease-free survival, (C) Locoregional-free survival, and (D) Distant metastasis-free survival of patients with nasopharyngeal cancer in different groups.