Identification and Management of Progressive Enhancement After Radiation Therapy for Brain Metastases: Results from a Neurosurgical Survey

Growth dynamics of brain metastases differentiate radiation necrosis from recurrence

Background

Radiation necrosis (RN) is a frequent adverse event after fractionated stereotactic radiotherapy (FSRT) or single-session stereotactic radiosurgery (SRS) treatment of brain metastases (BMs). It is difficult to distinguish RN from progressive disease (PD) due to their similarities in the magnetic resonance images. Previous theoretical studies have hypothesized that RN could have faster, although transient, growth dynamics after FSRT/SRS, but no study has proven that hypothesis using patient data. Thus, we hypothesized that lesion size time dynamics obtained from growth laws fitted with data from sequential volumetric measurements on magnetic resonance images may help in discriminating recurrent BMs from RN events.

Methods

A total of 101 BMs from different institutions, growing after FSRT/SRS (60 PDs and 41 RNs) in 86 patients, displaying growth for at least 3 consecutive MRI follow-ups were selected for the study from a database of 1031 BMs. The 3 parameters of the Von Bertalanffy growth law were determined for each BM and used to discriminate statistically PDs from RNs.

Results

Growth exponents in patients with RNs were found to be substantially larger than those of PD, due to the faster, although transient, dynamics of inflammatory processes. Statistically significant differences (P < .001) were found between both groups. The receiver operating characteristic curve (AUC = 0.76) supported the ability of the growth law exponent to classify the events.

Conclusions

Growth law exponents obtained from sequential longitudinal magnetic resonance images after FSRT/SRS can be used as a complementary tool in the differential diagnosis between RN and PD.

Response and safety of whole-brain radiotherapy plus temozolomide for patients with brain metastases of non-small-cell lung cancer: A meta-analysis

Objective

The aim of the present work was to investigate the response and safety of whole‐brain radiotherapy (WBRT) plus temozolomide (TMZ) for patients with brain metastases of non‐small‐cell lung cancer (NSCLC).

Methods

The electronic databases of Pubmed, EMbase, Cochrane, Wangfang, china national knowledge infrastructure (CNKI), and Google scholar were systematically searched to identify the prospective randomized trials relevant to WBRT plus TMZ for patients with brain metastases of NSCLC. The data associated with treatment response and toxicity were extracted from original included studies. The relative risk (RR) for treatment response and toxicity between WBRT+TMZ and WBRT alone was pooled by fixed or random effect model. Publication bias was investigated by Begg's funnel plot and Egger's line regression test.

Results

Twenty‐five clinical trials fulfilled the inclusion criteria and were included in the meta‐analysis. The pooled results showed WBRT+TMZ can significant improve the objective response rate (ORR) compared with WBRT alone (RR = 1.43, 95% confidence interval [CI] 1.32–1.55, p < 0.05) under a fixed effect model. WBRT+TMZ significantly increased the III–IV hematological toxicity compared to WBRT alone (RR = 1.66, 95% CI 1.12–2.54, p < 0.05) in the fixed effect model. Grade III–IV gastrointestinal toxicity was increased in WBRT+TMZ compared to WBRT alone (RR = 1.72, 95% CI 1.29–2.30, p < 0.05). Begg's funnel plot and Egger's line regression test indicated publication bias.

Conclusion

Based on the present work, WBRT+TMZ can improve the ORR for brain metastases of NSCLC, but the risk of treatment‐associated grade III/IV hematological toxicity and gastrointestinal toxicity were also increased compared to WBRT alone.