Purpose: To assess the tumor volume change after induction chemotherapy with docetaxel plus cisplatin (DP) in nasopharyngeal carcinoma (NPC).
Methods: A total of 259 non-metastatic NPC patients who received DP induction chemotherapy were retrospectively reviewed. Gross tumor volume of nasopharynx and lymph nodes (GTVnx and GTVnd) were contoured before and after chemotherapy. Univariate and multivariate analyses were performed to identify factors associated with tumor volume reduction.
Results: For GTVnx, the mean volume before and after chemotherapy were 43.2 cm3 vs 37.4 cm3 (p < 0.001) and the mean relative volume reduction was 12.7%. For GTVnd, the mean volume before and after chemotherapy were 24.6 cm3 vs 17.6 cm3 (p < 0.001) and the mean relative volume reduction was 13.9%. There was a positive linear correlation between the reduction of GTVnx and GTVnd (r = 0.351, p < 0.001). For GTVnx volume reduction, pretreatment GTVnx volume (≤ 20 cm3 vs > 20 cm3, OR = 4.644, p = 0.001) and chemotherapy cycle (2 cycles vs 3 cycles, OR = 2.418, p = 0.009) were independently associated factors. For GTVnd volume reduction, pretreatment GTVnd volume (≤ 8 cm3 vs > 8 cm3, OR = 7.472, p < 0.001) and chemotherapy cycle (2 cycles vs 3 cycles, OR = 2.621, p = 0.007) were independently associated factors.
Conclusion: DP induction chemotherapy reduces tumor volumes moderately in NPC. Larger pre-treatment tumor volumes and three cycles of chemotherapy are associated with higher likelihood of tumor volume reduction.
Keywords: Cisplatin; Docetaxel; Induction chemotherapy; Nasopharyngeal carcinoma; Tumor volume.