Patients with pharyngeal cancer had better salivary function, less xerostomia, and improved quality of life when treated with parotid-sparing intensity-modulated radiotherapy (IMRT) rather than conventional radiotherapy, according to a new study in Lancet Oncology (January 13, 2011).
In a randomized, controlled trial conducted between January 21, 2003, and December 7, 2007, a team of U.K. researchers compared conventional radiotherapy (control) with parotid-sparing IMRT. The trial's primary objective was to assess late side effects. The primary end point was the incidence of grade 2 or higher xerostomia at 12 months. Principal secondary end points included salivary flow after radiation therapy, acute and other late radiation effects, and quality of life.
The final analysis comprised 94 patients and a median follow-up of 44 months. At 12 months, 25 of 34 (74%) evaluable patients in the conventional radiotherapy arm had grade 2 or higher xerostomia compared with 15 of 39 (38%) patients allocated to IMRT (p = 0.0027). At 24 months, 20 of 24 patients in the conventional radiotherapy arm had grade 2 or higher xerostomia versus 9 of 31 in the IMRT arm (p < 0.0001).
At 12 months, 16 of 34 patients in the IMRT group had unstimulated saliva flow in the contralateral parotid gland by sialometry versus none of 25 patients who received conventional radiation therapy. After 24 months, 7 of 16 patients in the IMRT group had unstimulated salivary flow, whereas no patient in the control group had recovered spontaneous salivary flow. Significantly more patients in the IMRT group had stimulated salivary flow at 12 months (p < 0.0001) but not at 24 months.
IMRT was associated with almost a 50% reduction in xerostomia compared with conventional radiotherapy at one year, a difference that increased to 65% after two years, the researchers noted. Significantly more patients treated with IMRT had unstimulated contralateral salivary flow at 12 months (p < 0.001) and 24 months (p = 0.0068).
No patients in the IMRT group had recurrence in spared parotid tissue, and estimated two-year overall survival was similar in the two groups. Sparing the parotid glands with IMRT significantly reduces the incidence of xerostomia and leads to recovery of saliva secretion and improvements in associated quality of life, the researchers noted.
"Our trial has shown a clinically and statistically significant reduction in xerostomia, improved salivary flow, and improved quality of life, and thus strongly supports a role for IMRT in squamous cell carcinoma of the head and neck," they concluded.
Copyright © 2011 DrBicuspid.com
