Highly-conformal intensity-modulated radiotherapy reduced toxicity without jeopardizing outcome in patients with paranasal sinus cancer treated by surgery and radiotherapy or (chemo)radiation

Objectives: To report oncologic outcomes of patients with paranasal sinus cancer (PNSC) treated by surgery and radiotherapy or (chemo)radiation and to investigate the impact of improving the radiation technique on outcomes and toxicity. Materials and Methods: Between 1999 and 2010, 82 consecutive patients with PNSC were treated by surgery and radiotherapy or by definitive (chemo)radiation. Three-dimensional conformal (3DCRT) or highly-conformal intensity-modulated RT (IMRT) was used. Endpoints were local control (LC), regional control (RC), disease-free (DFS), cause-specific (CSS), and overall survival (OS), late toxicity, and quality-of-life (QoL). Results: After median follow-up of 51 months, the 5-year actuarial rates of LC, RC, DFS, CSS, and OS were 74%, 94%, 56%, 64%, and 54%, respectively. Grade ≥2 late toxicity at 5-years was 28%. High T-stage and perineural invasion were significantly associated with poor LC and RT-technique with late toxicity. Late toxicity was significantly lowered using IMRT, compared to 3DCRT (17% vs. 52%, p < 0.0001). Visual preservation were significantly improved using IMRT (88% and 65%, respectively, p = 0.01). LC-rate was also improved by IMRT (80% vs. 64%, respectively, p = 0.2). QoL-scores deteriorated during and shortly after treatment but returned in almost all scales to baseline levels within 3-12 months. Conclusions: Surgery and radiotherapy or definitive (chemo)radiation resulted in good LC rates but with high rate of late side-effects. However, late toxicity and permanent visual impairment were significantly decreased by using highly-conformal IMRT without jeopardizing outcome. The improvements in the therapeutic ratio achieved by using IMRT would allow dose escalation of RT to further improve outcomes.

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