Risk Factors That Prolong Length of Stay After Oral Cancer Surgery

Post-operative Length of stay (LOS) is associated with increased complications, mortality, and delay in adjuvant therapies.  It also reflects upon patients’ co-morbidities, post-operative status, and stability of housing¹. The purpose of this study was to determine the independent association of pre/post-operative variables and LOS, through a retrospective cross sectional study.

An exempt classification was granted by participating hospitals’ institutional review boards, to perform a retrospective review of patient charts from July 2007 to January 2014.  Lip and oral cavity tumor sites were included, while patients with previous head and neck surgery, adjunctive therapy, or recurrence were excluded to reduce confounders.  The outcome variable, LOS, was defined as the time interval between the day of surgery until discharge or death.  The study predictor variables included patient age, gender, social history, cancer stage, co-morbidities, and presence of post-operative complications.  The Carlson comorbidity index was used to standardize and quantify comorbidities².  Data was collected as binary data, either present or not present, regardless of magnitude.  Patients were classified as either prolonged LOS or standard LOS.  Prolonged LOS was defined as greater than or equal to the 75th percentile for each index operation, for consistency with other studies³.  Data was analyzed with IBM® SPSS® statistical package to find the odds ratio and perform Fisher’s exact test to determine significance.  P values <0.05 were considered statistically significant.

This study consisted of 89 surgically treated patients.  The mean age was 63.6±13.3 years, with 63 males and 26 females.  Stratifying for stage, 4 patients had carcinoma in situ, 23 were stage I, 19 were stage II, 14 were stage III, and 29 were stage IV.  Pre-operative variables statistically significant for increase in risk of prolonged LOS were advanced age of 65+ years (OR=3.6; CI_95% 1.4-9.2)_, and an advanced stage of III-IV (OR=2.5; CI_95% 1.0-6.2).  Post-operative complications significant for increased risk of prolonged LOS were delirium (OR=8.7; CI_95% 1.7-45.0), cardiovascular complication (arrhythmia, myocardial infarction, cerebrovascular accident, deep vein thrombosis, and/or hypoxemia) (OR=5.7; CI_95% 1.0-31.4), systemic bacterial infection (pneumonia, septicemia) (OR=5.0; CI_95% 1.7-14.5), PEG tube placement (OR=2.7; CI_95% 1.0-7.0), and respiratory failure (OR=2.5; CI_95% 1.0-6.1).  Increase risk was seen with males, alcohol and tobacco users, a co-morbidity index ≥3, and poor wound healing, however, these results were not statistically significant. 

A positive association was found between both pre and post-operative variables and an increased risk for prolonged LOS in this study population. Although findings were statistically significant for our 89 patients, a multicenter study would be indicated to further assess risk to this patient population and possible solutions to lowering this complication.

References:

1. Lee MK, Nalliah RP, Kim MK, et al. Prevalence and impact of complications on outcomes in patients hospitalized for oral and oropharyngeal cancer treatment. Oral surg Oral Med Oral Pathol Oral Radiol Endod.. 2011. 112(5):581-591.
2. Carlson ME, Pompei P, Ales KL, et al.  A new method of classifying prognostic comorbidity in logitudinal studies:development and validation.  J Chronic Dis. 1987. 40(5):373-83.
3. Collins TC, Daley J, Henderson WH, et al.  Risk factors for prolonged length of stay after major elective surgery. Ann Surg. 1999.230(2):251-9.