Timing of radiotherapy in head and neck free flap reconstruction--a study of postoperative complications.

The local treatment protocol of preoperative radiotherapy in head and neck cancer treatment at the Karolinska University Hospital has resulted in a unique cohort of preoperatively high dose-irradiated patients. In total 216 consecutive patients were reviewed, of whom 221 free flaps, for head and neck cancer reconstruction, were operated between 1984 and 2002. In 194 cases radiotherapy was administered preoperatively and 27 operations were performed without prior radiation. The radiation dose was 64 Gy in 147 cases, 54 Gy or less in 45 cases and uncertain in two cases. In order to study whether the time elapsed between the end of radiotherapy and surgery had any significance regarding postoperative events, the cohort was subsequently divided into three groups: patients operated on within 4 weeks (n=27), between 4 and 6 weeks (n=88) and more than 6 weeks (n=78) after the last radiotherapy session. Postoperative complications were analysed in relation to preoperative dose and timing of radiotherapy. Preoperative radiotherapy was related to an increased risk of free flap necrosis as 22 complete and eight partial flap necroses occurred in the group that had received preoperative radiotherapy and none were observed in the non-irradiated group (P<0.05). Furthermore, a linear trend of increased flap loss (P<0.001), infections (P<0.001) and delayed wound healing (P<0.001) was seen when time increased between the last radiotherapy session and surgery. The largest increase in all complication rates was seen when more than 6 weeks elapsed between last radiotherapy session and surgery. Postoperative complications were independent of the radiation dose given. Our data show an increased morbidity in free flap surgery in the head and neck region after preoperative radiotherapy. Furthermore, time elapsed between the last radiotherapy session and surgery is associated with the risk of developing postoperative complications. We strongly suggest that free flap reconstruction should be performed within 6 weeks of the last radiotherapy session.