Impact of adjuvant radiochemotherapy on free flap volume in head and neck reconstruction: A systematic review and meta-analysis

Background: Limited data exist regarding the effect of adjuvant radiochemotherapy on free flap volume in head and neck reconstruction. However, an adequate free flap volume is an important predictor of functional and patient-reported outcomes in head and neck reconstruction. Methods: A systematic review of Medline, Embase, and the Cochrane Central Register of Controlled Trials was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. A total of 6710 abstracts were screened, and 36 full-text papers were reviewed. Nineteen studies met the inclusion criteria and were used to extract data for this analysis. Results: A meta-analysis of 14 two-arm studies comparing the impact of adjuvant radiotherapy versus no adjuvant radiotherapy was performed. The main analysis revealed that 6 months postoperatively, irradiated flaps showed a significant reduction of volume (average, 9.4%) compared to nonirradiated flaps. The average interpolated pooled flap volumes 6 months postoperatively were 76.4% in irradiated flaps and 81.8% in nonirradiated flaps. After a median postoperative follow-up of 12 months, the total flap volume was 62.6% for irradiated flaps and 76% for nonirradiated flaps. Four studies reported that chemotherapy had no significant impact on free flap volume. Conclusions: Compared to nonirradiated flaps, irradiated flaps were significantly reduced in volume (range, 5% to 15.5%). Clinicians should take this into account when planning the surgical reconstruction of head and neck defects. Conducting large-scale prospective studies with standardized protocols and well-defined follow-up measurements could contribute to defining the ideal, personalized free flap volume for optimal function and patient-reported outcomes.