Impact of the time interval between surgery and postoperative radiation therapy on locoregional control in advanced head and neck cancer

Between January 1975 and December 1980, 111 patients with AJCC stages III and IV squamous cell carcinoma of the head and neck were treated with surgery followed by planned postoperative radiation therapy. A previous analysis of a subgroup of these patients showed that, when radiation was delayed more than 6 weeks from surgery, a higher incidence of regional failure occurred compared with the incidence observed when therapy began within a 6 week period. We have looked back at this group of patients plus others in an attempt to determine whether other factors played a role in the results obtained. In the current study, 50 patients had a delay of 6 weeks or more and, of these, 11 (22%) suffered a locoregional recurrence. However, 8 of these 11 patients received suboptimal radiation doses (less than 56 Gy) for permanent control of the disease. In fact, of 17 patients who received at least 60 Gy and had more than a 6 week delay, only 2 (12%) had locoregional failure. This was similar to the incidence of failure in the patients who received at least 60 Gy and who started radiation within the first 6 weeks from surgery (3/20 [15%]). The effect of delay was apparent only in those who received less than 60 Gy (27% vs. 7%, P less than 0.05). Therefore, we cannot validate the previous conclusion that a greater than 6 week delay in the delivery of postoperative radiation therapy in advanced head and neck cancers produces poorer results. The current analysis suggests that a prolonged delay in postoperative radiation therapy in itself does not have a negative impact on locoregional control as long as appropriate tumorcidal doses of more than 60 Gy are employed.