The NSQIP database contains only patients who underwent surgery; therefore, we were not able to capture any patient who did not undergo surgery because of pre-existing risk factors, including advanced age, as has been reported in other surgical specialties.23 We cannot account for issues of surgeon and hospital volume, which are known to influence postoperative morbidity and mortality after craniotomy for brain tumor,24 because it is ACS policy to maintain confidentiality for data-reporting institutions.10 However, we did model for the presence or absence of resident participation in the OR, which is a surrogate for academic versus nonacademic hospitals and tends to correlate with hospital size and volume, and which was not identified as different between age groups (Table 1) nor related to any of our outcomes of interest (data not shown). In addition, the low levels of postoperative complications identified in our sample were similar to those at high-volume facilities.24 Third, NSQIP only provides the last set of laboratory results before surgery, within 90 days of surgery; and it does not include certain features (such as the presence of a neurologic deficit, rather than overall “functional status”) that may influence outcome, disposition, and survival. Fourth, we did not have data on the size, exact location, number, or type of primary lesions for patients who had metastasis (n = 380); whether patients received whole-brain radiotherapy before resection; or the extent of resection, all of which have been previously identified as affecting survival.2–5 However, postoperative complications and short-term mortality reportedly were similar between patients who underwent craniotomy for a single tumor resection versus multiple tumor resections4and, although it has been observed that the type of primary lesion affects overall survival,25 no study to date has demonstrated a difference in postoperative short-term outcomes. Fifth, because there are suboptimal data on preoperative and postoperative neurologic function, these results cannot be compared against studies that only assessed neurologic function as a postoperative complication.20,21 Finally, the surgical population captured by NSQIP may not be wholly representative of the US neurosurgical population, because self-selected institutions contribute patient data. However, the sex and race distributions in the NSQIP database are representative of the US population, and data are collected prospectively from a substantial number of various types of institutions, thus providing a large and diverse sample size.10 Additional benefits of the NSQIP database are that data are collected in a standardized manner at each site with strict variable definitions and annual quality checks10and the database has been validated for accuracy and reproducibility and achieves a >95% 30-day outcome follow-up rate across consecutive cycles.10,26
In conclusion, to our knowledge, this is the first prospective, multi-institutional study to assess the relation between age, other preoperative and perioperative risk factors, and short-term outcomes after craniotomy for definitive tumor resection in the elderly (aged ≥75 years) compared with younger adults. Advanced age (≥75 years) was not correlated with poorer short-term outcomes. Although a few studies have assessed the role of age on the short-term outcome of patients with a primary or metastatic tumors, these had numerous limitations.7,9,19–22 Because patients aged 75 years (and, in some cases, aged 65 years or ≥70 years) usually or frequently are excluded from most clinical trials,13–15 there is a paucity of data regarding the risk of definitive surgical resection and its correlation with short-term, perioperative outcomes in these patients. Contrary to common assumptions, our analysis of a large, prospective, multi-institutional database suggests that advanced age does not predispose individuals undergoing aggressive surgical therapy for primary or metastatic intracranial tumor to increased risk for operative or short-term postoperative morbidity or mortality.