Original Article Clinical and dosimetric analyses of acute xerostomia for hypopharynx and larynx carcinoma treated by rotational IMRT

* Equal contributors. Received August 30, 2015; Accepted October 27, 2015; Epub February 15, 2016; Published February 29, 2016 Abstract: Objective: To evaluate acute xerostomia in the concurrent chemoradiotherapy of locally advanced squa- mous cell carcinoma of the hypopharynx and larynx (LA-SCCH/L) realized with Helical tomotherapy (HT) and Rapi- dArc (RA). Methods: Between August 2008 and December 2014, 80 patients with LA-SCCH/L were treated by HT or RA, and combined with concurrent cisplatin-based chemotherapy. The prescription dose was 69~70 Gy to pGTVnx and pGTVnd, 60 Gy to PTV1 and 54 Gy to PTV2, in 30~33 fractions; respectively. The endpoint was ≥ grade 2 (G2) acute xerostomia. The clinical and dosimetric factors were analyzed. Results: Patients treated with HT had lower incidence of G2 xerostomia than RA (P = 0.025). Through the limit of parotid Dmean, other parotid parameters were not correlated to the xerostomia. Multivariate analyses showed that ICT was independently associated G2 xerosto- mia (P = 0.003). Both of HT and RA had good protection in parotid gland. However, RA had lower parotid Dmean than HT. Conclusions: In the treatment of LA-SCCH/L, HT and RA are effective in protecting the parotid, without significant difference in acute xerostomia. ICT is the predictor of xerostomia.