Fleur Huang MD, Presenter: Nothing to Disclose

Siavosh Vakilian MD, Abstract Co-Author: Nothing to Disclose

William Parker MSc, Abstract Co-Author: Nothing to Disclose

George Shenouda MD, PhD, Abstract Co-Author: Nothing to Disclose

Weight loss holds significant impact on the clinical outcome and quality of life of head and neck cancer patients. Treatment decisions are often guided by the magnitude of weight change. In radiotherapy-treated patients, re-planning is often mandated on this basis, and on the basis of clinical changes in neck separation. We sought to investigate, using daily MVCT imaging, the anatomical changes particular to this group.

We retrospectively reviewed the clinical data from all cases of nasopharyngeal cancer treated by helical tomotherapy at our institution, from March to September 2007. Both simulation kVCT and MVCT images of treated patients were extracted, and analyzed using the following measurement parameters: anterior-posterior (AP) separation, left-right separation, axial section area, and maximal skin-to-mask air gap. Four representative cuts-of-interest were chosen, based on bony landmark and measurement reproducibility, designated as base of skull, upper neck, mid neck, and lower neck. Measurements were undertaken on each selected axial cut using ImageJ (National Institutes of Health, Bethesda, USA) software.

We identified 6 patients, all with node-positive nasopharyngeal cancer. Each was planned to receive 69.96Gy in 33 fractions, concomitant with cisplatin-based chemotherapy. All received anticipatory nutritional guidance, in addition to prophylactic percutaneous gastrotomy tube (PEG) placement. The median percent weight lost during chemoradiotherapy was 12% (range 5.5-13.7). A median of 3 (range 2 to 4) re-scans were performed for each patient, and 2 to 4 plans were used for treatment. After a large drop initially, continued steady decline in weight was observed in 50%. Changes in separation were seen throughout treatment, and reflected in axial area measurements. However, there were more prominent declines in left-right than in AP dimensions. While skin-to-mask distances increased with weight loss, these did not always correlate with left-right and AP variations.

In this small series of PEG-bearing node-positive nasopharyngeal cancer patients, marked weight loss is observed during chemoradiotherapy, alongside changes in neck separation and mask fit. While all may be suitable to trigger a re-scan for re-planning purposes, the most appropriate parameter, and the threshold value, remains to be elucidated.

Huang, F, Vakilian, S, Parker, W, Shenouda, G, Anatomical Changes during Chemoradiotherapy for Nasopharyngeal Cancer: Considerations for Re-planning.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/7002320.html