Abstract
BACKGROUND: The decision to transfer postoperative oral cancer patients to the intensive care unit (ICU) lacks standardized criteria and remains contentious. This study aimed to determine whether ICU transfer independently prolongs hospital length of stay (LOS) and identify the primary determinants of LOS in these patients. METHODS: A retrospective single-center cohort study was conducted in 674 patients who underwent oral cancer surgery. Patients were categorized into the ICU and general ward groups. Data on demographics (age, sex, BMI, smoking, drinking, and betel chewing), comorbidities (hypertension, diabetes and other chronic diseases), intraoperative factors (tracheotomy, duration of operation, lymph node dissection, flap transplantation, and blood transfusion), and clinical scoring systems (SOFA, APACHE-II, CAPRINI and NRS 2002), were all analysed. Linear regression analyses were performed to identify independent determinants of LOS. RESULTS: Patients in the ICU group were older and had higher rates of hypertension and diabetes (p < 0.05). Between-group comparisons exhibited a higher incidence of intraoperative blood transfusion in the ICU group (p = 0.001), whereas flap transplantation rate was lower (p < 0.001). Comparisons of postoperative clinical scores showed that the ICU group had significantly higher scores of SOFA (p < 0.001), APACHE-II (p < 0.05), and CAPRINI (p < 0.05). Additionally, patients with a SOFA score > 2 or an APACHE-II score ≥ 15 accounted for a higher proportion in this group. Subsequent analysis revealed that there was a longer unadjusted LOS in the ICU group (p < 0.001). However, ICU transfer was not an independent predictor of LOS after adjustment for confounders (p > 0.05). Independent determinants of prolonged LOS included tracheotomy (p < 0.001), intraoperative blood transfusion (p < 0.001), and bilateral lymph node dissection (p < 0.001). Age-stratified analyses indicated that ICU admission independently prolonged LOS in older adults (≥ 65 years, p < 0.05), but not in younger adults (< 65 years, p > 0.05). CONCLUSION: ICU transfer is not an independent determinant of the overall LOS of postoperative oral cancer patients, instead, surgical complexity and lymph node dissection play a more critical role. In older adults, ICU transfer represents a key modifiable factor associated with prolonged LOS. These findings support a risk-stratified and age-based triage protocol to optimize ICU utilization and improve healthcare efficacy. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12903-026-07997-1.