Evaluation of patterns of failure and subjective salivary function in patients treated with intensity modulated radiotherapy for head and neck squamous cell carcinoma

Abstract

Our aim was to correlate patterns of failure with target volume delineations in patients with head and neck squamous cell carcinoma (HNSCC) treated with intensity-modulated radiation therapy (IMRT) and to report subjective xerostomia outcomes after IMRT as compared with conventional radiation therapy (CRT). Between January 2000 and April 2005, 69 patients with newly diagnosed nonmetastatic HNSCC underwent curative parotid-sparing IMRT at Stanford University. Sites included were oropharynx (n = 39), oral cavity (n = 8), larynx (n = 8), hypopharynx (n = 8), and unknown primary (n = 6). Forty-six patients received definitive IMRT (66 Gy, 2.2 Gy/fraction), and 23 patients received postoperative IMRT (60.2 Gy, 2.15 Gy/fraction). Fifty-one patients also received concomitant chemotherapy. Posttreatment salivary gland function was evaluated by a validated xerostomia questionnaire in 29 IMRT and 75 matched CRT patients >6 months after completing radiation treatment. At a median follow-up of 25 months for living patients (range, 10-60), 7 locoregional failures were observed, 5 in the gross target or high-risk postoperative volume, 1 in the clinical target volume, and 1 at the junction of the IMRT and supraclavicular fields. The 2-year Kaplan-Meier estimates for locoregional control and overall survival were 92% and 74% for definitive IMRT and 87% and 87% for postoperative IMRT patients, respectively. The mean total xerostomia questionnaire score was significantly better for IMRT than for CRT patients (p = .006). The predominant pattern of failure in IMRT-treated patients is in the gross tumor volume. Parotid sparing with IMRT resulted in less subjective xerostomia and may improve quality of life in irradiated HNSCC patients.