With the increasing age of the population and availability of diagnostic tools, neurosurgeons are faced with an increasing number of brain tumors in old people. The incidence of brain tumors (whether primary or secondary) increases with the advancement of age. Although there is appreciable and ongoing improvement in the knowledge and techniques in cranial surgery, neuro-anesthesia, and perioperative intensive care, nevertheless, increasing age deserves special care due to the frailty of patients and the higher incidence of associated diseases that might increase the risk of morbidity and mortality [1,2,3].
This is a single institution retrospective analysis of the postoperative outcome (30 days) in relation to preoperative risk factors (KPS and associated diseases) and postoperative risk factors (extent of resection, tumor pathology, KPS, and complications) in elderly patients who underwent cranial surgery for brain tumors in the absence of advanced intraoperative equipment.
Our institution is a tertiary referral center serving a district of more than 3 million mostly rural people. It is a dedicated neurosurgical unit, started work since 2014.
All patients underwent microsurgical removal of their brain tumors aiming at total excision whenever possible without affecting surrounding neural structures. This was in the absence of advanced equipment like intraoperative neuromonitoring, navigation, and ICP monitoring in the ICU.
The definition of elderly is not uniform in the literature, starting from 60 years old to 80 in some literatures [1, 4,5,6]. We stick to the WHO definition of the elderly as those who are 65 years and older [7, 8].
Elderly patients have poor fitness, take medications for chronic diseases, and liable to depression when diagnosed to have brain tumors. There is a debate whether advanced age is to be considered a poor risk factor by itself even in other subspecialties [1, 3, 5, 9, 10]. Some studies denied the effect of age on the outcome of brain tumor surgery [3, 4, 11,12,13]. Others favored avoiding surgery above the age of 70 .
Several studies showed that the preoperative functional status has a significant impact on the outcome more than the effect of age [3, 13, 14]. The cutoff value of KPS is 70 or 80 in some literature below which there will be significant poor outcomes after surgery [14, 15].
On the contrary, there was no significant correlation between preoperative KPS and the outcome. While there was a clinical improvement in postoperative KPS, this was not true statistically, possibly because of the small number of patients included.
In this study, not all the cases were elective; some of our patients were admitted on an emergency basis due to intracranial pressure rise from the mass effect of the tumor or the associated edema. Surgery was carried out to decrease the ICP and obtain pathology. We think this is an important point as many literatures that discussed the subject of cranial surgery in the elderly included only elective cases and came to conclude the safety of surgery in selected elective cases [5, 15]. Other studies that involved emergency cases found increased poor outcomes within these cases .
The associated medical comorbidity is reported in several studies to be associated with poor outcomes [3, 13, 14]. Although 16 of our patients (51.6%) had preoperative medical problems, this was not associated statistically with postoperative mortality. The severity of those problems was not studied, and this could explain the negative relationship.
Meningioma grade I then GBM accounted for most of the lesions like the publications, although GBM is more common in this age group in the literature [1, 16]. This is possible because of the limited number of patients in this series. To a lesser extent, there were fewer cases of atypical meningioma, anaplastic astrocytoma, grade II glioma, and metastasis.
The incidence of GBM is increasing as age advances, and the overall survival is short, and it is even shorter in the elderly. The relative risk is 3–4 times in old patients compared to the young [6, 17, 18]. We are not discussing here the adjuvant therapy, but the short-term outcome of surgery which is considered the first line of treatment for accessible lesions causing neurological deficit [6, 16].
The incidence of meningioma rises after the age of 65 also, and most of the cases are grade I [15, 19]. Surgery is considered safe even in very old cases more than 80 years old, so the long preoperative performance is good .
We tried to get out of the maximum tumor volume without jeopardizing tumor tissue as all the lesions had a significant size and/or edema causing compression on the surroundings. Gross total resection was achieved in most of the cases. This was proved by intraoperative microscopic total excision in conjunction with postoperative radiology. This agrees with studies that favor maximum tumor resection as this is in favor with better survival and lower risk for mortality and morbidity [21,22,23,24,25,26,27].
There was a significant correlation between GBM and mortality within 1 month. The mortality rate was higher than the reported in the literature. We think this is because not all cases were elective and so the lower preoperative KPS of GBM patients (mean around 50).
Not all risk factors were covered in this study. The severity of the concomitant morbidity also was not detailed, although there was no relationship with mortality. The retrospective nature and the limited number of patients also limited the assessment of a larger number of variables. The inclusion of emergency cases prevented the comparison with other studies focusing on elective cases and resulted in a higher number of mortality compared to the literature.