Source: www.medscape.com
Author: Roxanne Nelson

Intensity-modulated radiotherapy (IMRT) might be a better treatment option for patients with squamous cell carcinoma of the head and neck. Compared with conventional radiation therapy, IMRT significantly decreases the incidence of xerostomia and improves quality of life, according to a study published online January 13 in the Lancet Oncology.

British researchers report that at 12 months, grade 2 or higher xerostomia was significantly lower with IMRT than with conventional radiotherapy (38% vs 74%; P = .0027). At 2 years, the incidence of grade 2 or higher xerostomia continued to be significantly less common with IMRT than with standard radiotherapy; 9 patients (29%) reported xerostomia in the IMRT group, compared with 20 (83%) in the conventional therapy group.

The authors note that there were no significant differences in locoregional control or overall survival between the 2 patient groups.

Lead author Christopher M. Nutting, MD, FRCR, consultant and honorary senior lecturer in clinical oncology at the Royal Marsden Hospital and Institute of Cancer Research, London, United Kingdom, and colleagues note that their results “strongly support a role for IMRT in squamous cell carcinoma of the head and neck.”

Spares the Parotid Gland, Similar Outcomes
Head and neck oncology expert Ted Teknos, MD, agrees. “One of the advantages of IMRT is that you can deliver radiation very accurately and you can spare normal structures to a much higher degree than conventional radiation therapy,” said Dr. Teknos, director of the Division of Head and Neck Surgery at Ohio State University Medical School in Columbus.

“With IMRT, you can typically spare the opposite parotid gland, so that patients can have better salivary flow posttreatment,” said Dr. Teknos, who was approached by Medscape Medical News for independent comment. “Dry mouth is difficult to live with, and really affects quality of life.”

IMRT is commonly used. In fact, any facility that has the equipment will attempt to do parotid-sparing radiotherapy, he explained. It is the standard of care at his own institution, he said, adding that “it is the standard at many centers. The problem is that you need the technology to do IMRT. A lot of smaller medical centers may not have IMRT at their disposal. It is important for patients to ask the radiation oncologist if they have IMRT capability.”

Another important point is that IMRT is most effective in reducing xerostomia if the cancer is unilateral. “It is difficult to spare the parotid on both sides if there’s a midline lesion or the tumor originates in the nasopharynx,” Dr. Teknos explained.

The use of IMRT produces cancer outcomes similar to those observed with conventional radiation therapy. “That was seen in this paper and has been confirmed in many other studies,” he said. “There isn’t a trade-off in survival, but using IMRT can give a marked improvement in salivary flow and quality of life.”

Fewer Report Xerostomia
In this study, Dr. Nutting and coauthors evaluated the hypothesis that parotid-sparing IMRT will reduce the incidence of severe xerostomia. They randomized 94 patients with histologically confirmed pharyngeal squamous cell carcinoma (T1 to T4, N0 to N3, M0) from 6 British radiotherapy centers to treatment with either IMRT or conventional radiotherapy (47 in each treatment group).

In both study groups, the primary tumor and involved lymph nodes were treated with 65 Gy in 30 daily fractions, 5 days a week. Among postoperative patients, 60 Gy in 30 fractions was given unless there was macroscopic residual disease. Measurements of salivary flow were conducted prior to radiotherapy, at week 4 of treatment, and at 2 weeks and 3, 6, 12, 18, and 24 months after radiotherapy.

The median follow-up was 44 months (interquartile range, 30·0 to 59·7); 6 patients in each group died within 12 months.

At each time point from 3 to 24 months, the authors note that a smaller proportion of patients receiving IMRT than conventional radiotherapy reported grade 2 or higher subjective xerostomia. The proportion of patients reporting grade 2 or higher xerostomia at the 12 month time point did not differ by tumor site, radiotherapy indication, disease stage, or use of neoadjuvant chemotherapy.

At both 12 and 24 months, there were significant benefits in the recovery of saliva secretion with IMRT, compared with conventional radiotherapy. At 12 months, there was unstimulated saliva flow from the contralateral parotid gland in 47% of patients in the IMRT group, compared with none in the conventional radiotherapy group (P < .0001). Results were similar at 24 months (44% vs 0%; P < .0068).

There were also clinically significant improvements in dry-mouth-specific and global quality-of-life scores among patients who received IMRT.

At 24 months, there were no significant differences observed in nonxerostomia late toxicities. Fatigue was the only recorded acute adverse event of grade 2 or higher that differed between the 2 groups, and was more prevalent in the IMRT group (74% vs 41%; P = .0015).

Source: Lancet Oncol. Published online January 13, 2011.
Note: The study was funded by Cancer Research UK. The authors have disclosed no relevant financial relationships.