Treatment of Incidentally Discovered Low-Grade Gliomas: “Watch-and-Wait” or Not?

The benefit of early surgery on overall survival in incidental low grade glioma patients: a multicenter study

BACKGROUND

The role of surgery for incidentally discovered diffuse low-grade gliomas (iLGGs) is debatable and poorly documented in current literature.

OBJECTIVE

The aim was to identify factors that influence survival for patients that underwent surgical resection of iLGGs in a large multicenter population.

METHODS

Clinical, radiological, and surgical data were retrospectively analyzed in 267 patients operated for iLGG from 4 neurosurgical Centers. Univariate and multivariate analyses were performed to identify predictors of overall survival (OS) and tumor recurrence (TR).

RESULTS

The OS rate was 92.41%. The 5- and 10-year estimated OS rates were 98.09% and 93.2% respectively. OS was significantly longer for patients with a lower preoperative tumor volume (p=0.001) and higher extent of resection (EOR) (p=0.037), regardless the WHO defined molecular class (p=0.2). In the final model, OS was influenced only by the preoperative tumor volume (p=0.006), while TR by early surgery (p=0.028). A negative association was found between preoperative tumor volumes and EOR (rs = -0.44, p<0.001).The median preoperative tumor volume was 15 cm 3. The median EOR was 95%. Total or supratotal resection of FLAIR abnormality was achieved in 61.62% of cases.Second surgery was performed in 26.22%. The median time between surgeries was 5.5 years. Histological evolution to high grade glioma was detected in 22.85% of cases (16/70). Permanent mild deficits were observed in 3.08% of cases.

CONCLUSIONS

This multicenter study confirms the results of previous studies investigating surgical management of iLGGs and thereby strengthens the evidence in favour of early surgery for these lesions.

Diffuse low grade glioma and pregnancy: Practical considerations and clinical tips

OBJECTIVE

The interaction between pregnancy and diffuse low-grade glioma (DLGG) is poorly investigated. The goal of this study was to provide further insights into the relationship between pregnancy and DLGG.

METHODS

A total of 12 patients were selected from a shared database of DLGGs, according to the following inclusion criteria: DLGG diagnosis in post-partum, DLGG recurrence after pregnancy in patients previously operated for DLGG. The extent of surgical resection (EOR) at first surgery were evaluated. All cases were assessed based on the 2016 WHO classification. The tumor growing patter, expresses by preoperative ΔT2T1 MRI index was evaluated.

RESULTS

In four cases newly diagnosed DLGG were detected patients in post-partum. Seven women, previously operated for DLGG, experienced pregnancy during the natural history of glioma, and were affected by tumor recurrence after pregnancy. One singular had an incidental LGG not surgically treated, who presented an important tumor growth after pregnancy. Radiological and surgical data were discussed according to literature.

CONCLUSIONS

Pregnancy does not seem to have an impact on the survival of women with DLGG. The potential role of pregnancy as risk factor in tumor recurrence is described, however, not proven. In this regard, the association between pregnancy and Tumor recurrence is extremely doubtful, and currently attributable to the simple coincidence. Further multicenter molecular investigations are required to better understand the mechanisms by which the pregnancy, in patients with a pervious surgery for DLGG, may influence tumor regrowth in comparison with the natural history of the disease.

Incidental Brain Tumors in the Pediatric Population: A Systematic Review and Reappraisal of Literature

OBJECTIVES

Management of incidental asymptomatic brain tumors in children is controversial due to lack of clear evidence-based guidelines. We present this systematic review in an attempt to highlight an optimal treatment paradigm.

METHODS

This systematic review was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Databases were searched up to August 2019 using the keywords "incidental," "brain tumor," and "pediatric." Our main focus was on brain lesions suspected for neoplasm, diagnosed incidentally on neuroimaging in an otherwise asymptomatic patient <18 years old. Cystic, vascular, and inflammatory brain lesions were excluded.

RESULTS

Fourteen studies comprising 308 patients were included. All cases were diagnosed using magnetic resonance imaging. The most common indications for imaging were headache (93; 30%) and trauma (72; 23%). Lesion distribution was supratentorial (179; 58%), infratentorial (121; 40%), and intraventricular (8; 3%). Of 308 cases, 243 (79%) were managed with neuroradiological surveillance and 57 (19%) by upfront surgical excision. Of those managed conservatively, 177 (73%) remained stable within a mean follow-up of 30 months, 54 (22%) progressed, and 12 (5%) spontaneously regressed. Meanwhile, upfront excision achieved complete remission in all 57 cases over a mean follow-up of 68.3 months.

CONCLUSION

A small body of evidence has emerged, highlighting the marked heterogeneity and contradictory results between the available studies, limiting our ability to draw solid conclusions. At this point, the decision between surgery and "watchful waiting" should be tailored on an individual patient basis depending on suspicion of malignancy, clinical or radiologic progression, and parental preference.

Incidental Low-Grade Gliomas: Single-Institution Management Based on Clinical, Surgical, and Molecular Data

BACKGROUND

Incidentally discovered diffuse low-grade gliomas (iLGG) are poorly documented in the literature. They are diagnosed by chance during radiological examinations.

OBJECTIVE

To review a cohort of patients with iLGG surgically treated in our institution, analyzing clinical, molecular, and surgical aspects.

METHODS

Clinical, radiological, and treatment data of iLGG were retrieved and compared with those of symptomatic diffuse LGGs (sLGG). Histological and molecular review was carried out as well. The extent of resection was evaluated on preoperative and postoperative T2-weighted magnetic resonance imaging.

RESULTS

Thirty-four iLGG cases were identified within a monoinstitutional cohort of 332 patients operated for low-grade gliomas from 2000 to 2017. Clinically, patients with iLGG had higher preoperative karnofsky performance scale (KPS) (P = .003), smaller tumor volume (P = .0001), lower frequency of eloquent areas involvement (P = .0001), and higher rate of complete resection (P = .0001) compared to those with sLGG. No differences in the molecular profile and O6-methylguanine-DNA-methyltransferase promoter methylation were detected between iLGG and sLGG. Importantly, patients with iLGG had longer overall survival than those with sLGG (P = .0001), even when a complete surgical resection was achieved (P = .001).

CONCLUSION

Although the therapeutic strategy of iLGG is still a matter of debate, our data support the safety and the effectiveness of early surgical resection. The favorable prognosis of iLGG may be due to the higher practicability of extensive resection, noneloquent tumor location, and smaller tumor volume.

Preoperative grading of supratentorial nonenhancing gliomas by high b-value diffusion-weighted 3 T magnetic resonance imaging

The purpose of this study was to determine the difference in discrimination between high- and low-grade supratentorial nonenhancing gliomas (HGGs and LGGs, respectively) when using apparent diffusion coefficient (ADC) values with high or standard b-value. Thirty-nine patients underwent conventional magnetic resonance imaging and diffusion-weighted imaging (DWI) with standard and high b-values (b = 1000 and 3000 s/mm², respectively). Minimum, maximum, and mean ADC values (ADC_MIN, ADC_MAX, and ADC_MEAN, respectively) were measured from ADC maps with both b-values. Receiver operating curve analysis was used to determine the cutoff ADC values for distinguishing between nonenhancing HGGs and LGGs. ADC_MIN, ADC_MAX, and ADC_MEAN values for the nonenhancing HGGs were lower than those for LGGs. These differences were much larger when a high b-value was used (all P < 0.0001) than when a standard b-value was used (P = 0.0001, <0.0001, and <0.0001, respectively). Discriminant analysis indicated that the greatest likelihood for discriminating HGGs and LGGs when ADC_MEAN was obtained with a high b-value, with cutoff value of 0.814 × 10^-3 mm²/s. ADC values obtained with a high b-value can be useful for grading and surgical management of nonenhancing HGGs and LGGs. The lowest degree of overlap was obtained when ADC_MEAN was determined with a b-value of 3000 s/mm².

Patients with incidental WHO grade II glioma frequently suffer from neuropsychological disturbances

BACKGROUND

Incidental WHO grade II gliomas (low-grade glioma, LGG) are increasingly diagnosed in patients undergoing MRI for many conditions. These patients are classically considered asymptomatic because they do not experience seizures. Although it was previously demonstrated that symptomatic LGG patients frequently have neurocognitive disorders, the literature does not provide data on the neuropsychological status of patients with incidental LGG (iLGG).

OBJECTIVE

Our aim is to investigate whether neurocognitive impairments exist in a homogeneous iLGG population.

METHODS

We conducted an analysis of pretreatment neuropsychological assessments of patients with iLGG (histologically proven) admitted to our center from 2007 to 2014. We also obtained data on subjective complaints, tumor size and location.

RESULTS

Our study focused on 15 iLGG patients. Two thirds reported subjective complaints, mainly tiredness (40 %) and attentional impairment (33 %). Neurocognitive functions were disturbed in 60 % of patients; 53 % had altered executive functions, 20 % had working memory impairment, and 6 % had attentional disturbances. Only one patient with normal preoperative neuropsychological assessment experienced a deficit at the 3-month postoperative examination.

CONCLUSIONS

For the first time to our knowledge, we suggest that numerous iLGG patients have neuropsychological impairments. Therefore, greater attention should be paid to objective neuropsychological assessment in iLGG because of the high prevalence of insidious cognitive deficits. Moreover, our original findings bring into question the traditional wait-and-see attitude in iLGG, mainly based on the erroneous dogma that these patients have no functional disturbances. Neuropsychological assessment is mandatory to select the best individualized therapeutic management with preservation of quality of life.