Oropharyngeal Cancer Patients Report Benefit in Salivary Function With Reduction of Radiation Dose to Bilateral Submandibular Lymph Nodes
For head and neck cancer patients undergoing radiation therapy, a reduction in the amount of radiation treatment volume to the submandibular (level IB) lymph nodes resulted in better patient-reported salivary function, according to research presented today at the 2014 Multidisciplinary Head and Neck Cancer Symposium. The study results also found significant reductions in radiation dose to the salivary organs, and good local-regional control.
Study Details
Researchers evaluated 125 patients with node-positive oropharyngeal cancer who received chemoradiation at Memorial Sloan Kettering Cancer Center in New York between May 2010 and December 2011. The average patient age was 57.
Fifty-one percent of patients had base-of-tongue lesions, 41% had tonsil cancer, and 6% were classified as “other.” Seventy-four percent of patients had cancer classified as stage T1-2, and 26% had stage T3-4 tumors. All patients had cancer with lymph node involvement, with N1 in 16%, N2A in 8%, N2B in 48%, and N2C in 28%.
Patients were categorized into two groups: those with sparing of bilateral level IB nodes and those who underwent treatment without such sparing. A prospective questionnaire to assess late xerostomia was given to patients in both groups at each patient follow-up visit; clinical assessment (observer-rated) xerostomia scores were also recorded.
Improvement in Xerostomia Scores
The participants who received treatment involving sparing experienced significant improvement in patient-reported xerostomia summary scores (P = .021) and observer-rated xerostomia scores (P = .006) over the group in which there was no sparing. The 2-year local-regional control rate was 97.5% for the spared group and 93.8% for the treated group, indicating a low rate of cancer recurrence at the original tumor site.
Additionally, study results showed reductions in the mean radiation doses to the mouth and neck regions of patients in the spared group over the group with no sparing, including the ipsilateral submandibular gland (63.9 Gy vs 70.5 Gy, P < .001), the contralateral submandibular gland (45.0 Gy vs 56.2 Gy, P < .001), and the oral cavity (35.9 Gy vs 45.2 Gy, P < .001).
“Radiation therapy plays an important role in the treatment of head and neck cancers,” said lead author Moses Tam, BS, an MD candidate in his final year at New York University School of Medicine. “Poor salivary function is the most common side effect of radiation treatment to the head and neck region. Our data shows that it is safe to spare the tumor-free level IB lymph nodes in oropharyngeal cancer from radiation treatment. Sparing this lymph node level will reduce radiation dose to several nearby salivary organs and therefore cause less damage to a patient’s post-treatment salivary function.”
The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
