Viable tumor in postchemoradiation neck dissection specimens as an indicator of poor outcome.

Management of the neck in patients treated with primary chemoradiation for cancer of the laryngopharynx with a clinically positive neck remains an area of controversy. The neck may be managed in 1 of 3 ways: by observation, by planned neck dissection, or by salvage neck dissection. Observation of the neck can be done in patients who have a complete or near-complete response to treatment and have a negative positron emission tomography (PET) scan result. Evidence for this approach comes from recent studies that have reported low regional recurrence rates.1–6 Planned neck dissection was carried out in the past in patients with N2 and N3 neck disease irrespective of the response to chemoradiation. The neck dissection was carried out 6 weeks after completion of chemoradiation; this approach had the advantage of carrying out the neck dissection before the onset of fibrosis, thereby making the neck dissection technically similar in complexity to a nonchemoradiation neck dissection. Evidence for a policy of planned neck dissection comes from studies that have shown the presence of tumor in neck dissection specimens in patients who have complete or near-complete radiologic and clinical response in the neck.4,7–10 Before the introduction of fluorodeoxyglucose–positron emission tomography (FDG-PET) scanning, planned neck dissection was a common method for managing the neck after chemoradiation. Some groups still practice this policy because of limitations or unavailability of PET. However, in general, most centers now reserve neck dissection for salvage for residual or recurrent neck disease. Salvage neck dissection is normally carried out if there is clinical or radiologic evidence of neck disease after completion of chemoradiation. Before 2005, our policy was to assess response by clinical examination and CT imaging at 6 to 12 weeks after completion of chemoradiation. However, since 2005, we have been using 18FDG-PET for the assessment of tumor response. The 18FDG-PET is usually carried out at 12 weeks after completion of chemoradiation to minimize any false-positive results from residual inflammation from chemoradiation. Salvage neck dissection in patients who have neck disease as detected by PET is therefore carried out 12 weeks after chemoradiation. This has the disadvantage of making the operation technically more difficult because of the onset of fibrosis. As a consequence, some have advocated the use of selective and superselective salvage neck dissections in these patients.11–14 Clearly there is evidence in the literature to support the practice of planned, as well as salvage neck dissection. However, there is little in the literature that describes what the impact of viable tumor in such neck dissection specimen has on prognosis. In this study, we have examined our own experience of patients undergoing comprehensive neck dissection either as a planned procedure or salvage procedure in the time period before our routine use of PET. The objective was to determine whether viable tumor had a negative impact on prognosis, even after removal of residual tumor by neck dissection.