Preservation of quality of life by preradiotherapy stereotactic radiosurgery for unresectable glioblastoma multiforme

The role of radiation therapy in treatment of adults with newly diagnosed glioblastoma multiforme: a systematic review and evidence-based clinical practice guideline update

TARGET POPULATION

These recommendations apply to adult patients diagnosed with newly diagnosed glioblastoma. QUESTION 1 : In adult patients (aged 65 and under) with newly diagnosed glioblastoma, is the addition of radiation therapy (RT) more beneficial than management without RT in improving survival?

RECOMMENDATIONS

Level I: Radiation therapy (RT) is recommended for the treatment of newly diagnosed malignant glioblastoma in adults. QUESTION 2 : In adult patients (aged 65 and under) with newly diagnosed glioblastoma, is the RT regimen of 60 Gy given in 2 Gy daily fractions more beneficial than alternative regimens in providing survival benefit while minimizing toxicity?

RECOMMENDATIONS

Level I: Treatment schemes should include dosage of up to 60 Gy given in 2 Gy daily fractions that includes the enhancing area. QUESTION 3 : In adult patients (aged 65 and under) with newly diagnosed glioblastoma, is a tailored target volume superior to regional RT for reduction of radiation-induced toxicity while maintaining efficacy?

RECOMMENDATION

Level II: It is recommended that radiation therapy planning include 1-2 cm margin around the radiographically T1 weighted contrast-enhancing tumor volume or the T2 weighted abnormality on MRI. Level III: Recalculation of the radiation volume during RT treatment may be necessary to reduce the radiated volume of normal brain since the volume of surgical defect will change during the long period of RT. QUESTION 4 : In adult patients (aged 65 and under) with newly diagnosed glioblastoma, does the addition of RT of the subventricular zone to standard tumor volume treatment improve tumor control and overall survival?

RECOMMENDATION

No recommendation can be formulated as there is contradictory evidence in favor of and against intentional radiation of the subventricular zone (SVZ) QUESTION 5 : In elderly (age > 65 years) and/or frail patients with newly diagnosed glioblastoma, does the addition of RT to surgical intervention improve disease control and overall survival?

RECOMMENDATION

Level I: Radiation therapy is recommended for treatment of elderly and frail patients with newly diagnosed glioblastoma to improve overall survival. QUESTION 6 : In elderly (age > 65 years) and/or frail patients with newly diagnosed glioblastoma, does modification of RT dose and fractionation scheme from standard regimens decrease toxicity and improve disease control and survival?

RECOMMENDATION

Level II: Short RT treatment schemes are recommended in frail and elderly patients as compared to conventional 60 Gy given in 2 daily fractions because overall survival is not different while RT risk profile is better for the short RT scheme. Level II: The 40.05 Gy dose given in 15 fractions or 25 Gy dose given in 5 fractions or 34 Gy dose given in 10 fractions should be considered as appropriate doses for Short RT treatments in elderly and/or frail patients. QUESTION 7 : In adult patients with newly diagnosed glioblastoma is there advantage to delaying the initiation of RT instead of starting it 2 weeks after surgical intervention in decreasing radiation-induced toxicity and improving disease control and survival?

RECOMMENDATION

Level III: It is suggested that RT for patients with newly diagnosed GBM starts within 6 weeks of surgical intervention as compared to later times. There is insufficient evidence to recommend the optimal specific post-operative day within the 6 weeks interval to start RT for adult patients with newly diagnosed glioblastoma that have undergone surgical resection. QUESTION 8 : In adult patients with newly diagnosed supratentorial glioblastoma is Image-Modulated RT (IMRT) or similar techniques as effective as standard regional RT in providing tumor control and improve survival?

RECOMMENDATION

Level III: There is no evidence that IMRT is a better RT delivering modality when compared to conventional RT in improving overall survival in adult patients with newly diagnosed glioblastoma. Hence, IMRT should not be preferred over the Conventional RT delivery modality. QUESTION 9 : In adult patients with newly diagnosed glioblastoma does the use of radiosensitizers with RT improve the efficacy of RT as determined by disease control and overall survival?

RECOMMENDATION

Level III: Iododeoxyuridine is not recommended to be used as radiosensitizer during RT treatment for patients with newly diagnosed GBM QUESTION 10 : In adult patients with newly diagnosed glioblastoma is the use of Ultrafractionated RT superior to standard fractionation regimens in improving disease control and survival?

RECOMMENDATION

There is insufficient evidence to formulate a recommendation regarding the use of ultrafractionated RT schemes and patient population that could benefit from it. QUESTION 11 : In patients with poor prognosis with newly diagnosed glioblastoma is hypofractionated RT indicated instead of a standard fractionation regimen as measured by extent of toxicity, disease control and survival?

RECOMMENDATION

Level I: Hypofractionated RT schemes may be used for patients with poor prognosis and limited survival without compromising response. There is insufficient evidence in the literature for us to be able to recommend the optimal hypofractionated RT scheme that will confer longest overall survival and/or confer the same overall survival with less toxicities and shorter treatment time. QUESTION 12 : In adult patients with newly diagnosed glioblastoma is the addition of brachytherapy to standard fractionated RT indicated to improve disease control and survival?

RECOMMENDATION

Level I: Brachytherapy as a boost to external beam RT has not been shown to be beneficial and is not recommended in the routine management of patients with newly diagnosed GBM. QUESTION 13 : In elderly patients (> 65 year old) with newly diagnosed glioblastoma under what circumstances is accelerated hyperfractionated RT indicated instead of a standard fractionation regimen as measured by extent of toxicity, disease control and survival?

RECOMMENDATION

Level III: Accelerated Hyperfractionated RT with a total RT dose of 45 Gy or 48 Gy has been shown to shorten the treatment time without detriment in survival when compared to conventional external beam RT and should be considered as an option for treatment of elderly patients with newly diagnosed GBM. QUESTION 14 : In adult patients with newly diagnosed glioblastoma is the addition of Stereotactic Radiosurgery (SRS) boost to conventional standard fractionated RT indicated to improve disease control and survival?

RECOMMENDATION

Level I: Stereotactic Radiosurgery boost to external beam RT has not been shown to be beneficial and is not recommended in patients undergoing routine management of newly diagnosed malignant glioma.

Phase I Trial of Radiosurgery Dose Escalation Plus Bevacizumab in Patients With Recurrent/Progressive Glioblastoma

BACKGROUND

The effectiveness of stereotactic radiosurgery (SRS) for recurrent glioblastoma (rGBM) remains uncertain. SRS has been associated with a high risk of radionecrosis in gliomas.

OBJECTIVE

To determine the safety of dose escalation of single-fraction radiosurgery for rGBM in the setting of bevacizumab therapy.

METHODS

We conducted a prospective trial to determine the safety and synergistic benefit of higher doses of SRS administered with bevacizumab for rGBM. A single dose of bevacizumab was given prior to SRS and continued until progression. Dose-limiting toxicity was evaluated in successive cohorts of 3 patients.

RESULTS

Seven males and 2 females entered the study. The maximum linear diameter of the enhancing tumor was 2.58 cm (2.04-3.09). Prescription dose was escalated from 18 to 22 Gy. The radiosurgery target was chosen before the first dose of bevacizumab, about 1 wk prior to SRS treatment. Pre-SRS bevacizumab treatment was associated with a reduction of the mean volume of the enhancing lesion from 4.7 to 2.86 cm3 on the day of SRS (P = .103). No patient developed an acute side effect related to SRS treatment. The combination of SRS and bevacizumab resulted in a partial response in 3 patients and stable disease in 6 patients. Median progression-free and overall survival were 7.5 and 13 mo, respectively.

CONCLUSION

A single dose of bevacizumab prior to SRS permitted safe prescription dose escalation up to 22 Gy for rGBM. Further evaluation of the efficacy of SRS for rGBM should be performed in the setting of bevacizumab treatment.

Indications and Efficacy of Gamma Knife Stereotactic Radiosurgery for Recurrent Glioblastoma: 2 Decades of Institutional Experience

BACKGROUND

The role of stereotactic radiosurgery (SRS) for recurrent glioblastoma and the radionecrosis risk in this setting remain unclear.

OBJECTIVE

To perform a large retrospective study to help inform proper indications, efficacy, and anticipated complications of SRS for recurrent glioblastoma.

METHODS

We retrospectively analyzed patients who underwent Gamma Knife SRS between 1991 and 2013. We used the partitioning deletion/substitution/addition algorithm to identify potential predictor covariate cut points and Kaplan-Meier and proportional hazards modeling to identify factors associated with post-SRS and postdiagnosis survival.

RESULTS

One hundred seventy-four glioblastoma patients (median age, 54.1 years) underwent SRS a median of 8.7 months after initial diagnosis. Seventy-five percent had 1 treatment target (range, 1-6), and median target volume and prescriptions were 7.0 cm 3 (range, 0.3-39.0 cm 3 ) and 16.0 Gy (range, 10-22 Gy), respectively. Median overall survival was 10.6 months after SRS and 19.1 months after diagnosis. Kaplan-Meier and multivariable modeling revealed that younger age at SRS, higher prescription dose, and longer interval between original surgery and SRS are significantly associated with improved post-SRS survival. Forty-six patients (26%) underwent salvage craniotomy after SRS, with 63% showing radionecrosis or mixed tumor/necrosis vs 35% showing purely recurrent tumor. The necrosis/mixed group had lower mean isodose prescription compared with the tumor group (16.2 vs 17.8 Gy; P = .003) and larger mean treatment volume (10.0 vs 5.4 cm 3 ; P = .009).

CONCLUSION

Gamma Knife may benefit a subset of focally recurrent patients, particularly those who are younger with smaller recurrences. Higher prescriptions are associated with improved post-SRS survival and do not seem to have greater risk of symptomatic treatment effect.