Efficacy of salvage stereotactic radiotherapy (SRT) for locally recurrent brain metastases after initial SRT and characteristics of target population

Repeated Stereotactic Radiotherapy for Local Brain Metastases Failure or Distant Brain Recurrent: A Retrospective Study of 184 Patients

BACKGROUND

The main advantages of stereotactic radiotherapy (SRT) are to delay whole-brain radiotherapy (WBRT) and to deliver ablative doses. Despite this efficacy, the risk of distant brain metastases (BM) one year after SRT ranges from 26% to 77% and 20 to 40% of patients required salvage treatment. The role and consequences of reirradiation remain unclear, particularly in terms of survival. The objective was to study overall survival (OS) and neurological death-free survival (NDFS) and to specify the prognostic factors of long-term survival.

METHODS

we retrospectively reviewed the data of patients treated between 2010 and 2020 with at least two courses of SRT without previous WBRT.

RESULTS

In total, 184 patients were treated for 915 BMs with two-to-six SRT sessions. Additional SRT sessions were provided for local (5.6%) or distant (94.4%) BM recurrence. The median number of BMs treated per SRT was one with a median of four BMs in total. The mean time between the two SRT sessions was 8.9 months (95%CI 7.7-10.1) and there was no significant difference in the delay between the two sessions. The 6-, 12- and 24-month NDFS rates were 97%, 82% and 52%, respectively. The 6-, 12- and 24-month OS rates were 91%, 70% and 38%, respectively. OS was statistically related to the number of SRT sessions (HR = 0.48; p < 0.01), recursive partitioning analysis (HR = 1.84; p = 0.01), salvage WBRT (HR = 0.48; p = 0.01) and brain metastasis velocity (high: HR = 13.83; p < 0.01; intermediate: HR = 4.93; p < 0.01).

CONCLUSIONS

Lung cancer and melanoma were associated with a lower NDFS compared to breast cancer. A low KPS, a low number of SRT sessions, synchronous extracerebral metastases, synchronous BMs, extracerebral progression at SRT1, a high BMV grade, no WBRT and local recurrence were also associated with a lower NDFS. A high KPS at SRT1 and low BMV grade are prognostic factors for better OS, regardless of the number of BM recurrence events.

Re-irradiation in patients with progressive or recurrent brain metastases from extracranial solid tumors: A novel prognostic index

BACKGROUND

Most studies evaluating factors associated with the survival of patients with brain metastases (BM) have focused on patients with newly diagnosed BM. This study aimed to identify prognostic factors associated with survival after brain re-irradiation in order to develop a new prognostic index.

METHODS

This 5-year retrospective study included patients treated with repeat-radiotherapy for recurrent BM at the "Instituto Nacional de Cancerología" of Mexico between 2015 and 2019. Significant variables in the multivariate Cox regression analysis were used to create the brain re-irradiation index (BRI). Survival and group comparisons were performed using the Kaplan-Meier method and the log-rank test.

RESULTS

Fifty-seven patients receiving brain re-irradiation were identified. Most patients were women (75.4%) with a mean age at BM diagnosis of 51.4 years. Lung and breast cancer were the most prevalent neoplasms (43.9% each). Independent prognostic factors for shorter survival after re-irradiation were: Age >50 years (hazard ratio [HR]:2.5 [95% confidence interval [CI], 1.1-5.8]; p = 0.026), uncontrolled primary tumor (HR:5.5 [95% CI, 2.2-13.5]; p < 0.001), lesion size >20 mm (4.6 [95% CI, 1.7-12.2]; p = 0.002), and an interval <12 months between radiation treatments (HR:4.3 [95% CI, 1.7-10.6]; p = 0.001). Median survival (MS) after re-irradiation was 14.6 months (95% CI, 8.2-20.9).MS of patients stratified according to the BRI score was 17.38, 10.34, and 2.82 months, with significant differences between all groups.

CONCLUSIONS

The new BRI can be easily implemented for the prognostic classification of cancer patients with progressive or recurrent BM from extracranial solid tumors.

Salvage Surgery for Local Control of Brain Metastases After Previous Stereotactic Radiosurgery: A Single-Center Series

BACKGROUND

Although overall survival (OS) has improved in patients with brain metastases (BMs), control of recurrent BMs remains a therapeutic challenge. Salvage surgery may achieve acceptable control rates in the setting of progression after previous stereotactic radiosurgery (SRS), yet it remains a question how additional adjuvant therapies may affect outcomes and how patient selection for salvage surgery may be optimized.

METHODS

Patients receiving salvage surgery for BM progression after previous SRS were retrospectively reviewed from a single center. Outcomes of interest included local tumor progression, leptomeningeal dissemination, and OS. Cox proportional hazard models and nominal logistic regression were applied to determine factors associated with outcomes of interest.

RESULTS

A total of 43 patients with 50 BMs were included. After salvage surgery, local progression was observed for 17 BMs (34%), leptomeningeal dissemination was observed in 17 patients (39.5%), and censored median OS was 17.9 months. On multivariate analysis, use of brachytherapy was associated with improved local control (hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04-0.6; P = 0.008). For patients treated with SRS ≥4.5 months before salvage surgery, both brachytherapy (HR, 0.07; 95% CI, 0.01-0.39; P = 0.002) and postoperative adjuvant SRS (HR, 0.14; 95% CI, 0.02-1.00; P = 0.05) were associated with improved local control compared with no adjuvant radiation therapy. Presence of extracranial malignancy (HR, 6.70; 95% CI, 2.58-17.42; P < 0.0001) was associated with shorter survival. Graded prognostic assessment underestimated survival in 79.1% of patients, with a mean difference of 18.9 months between graded prognostic assessment-estimated and actual OS.

CONCLUSIONS

In properly selected patients, salvage surgery may be an appropriate therapy for BM progression after previous SRS. Adjuvant brachytherapy and repeat SRS can offer significant benefit for local control with salvage resection.