Single fraction prophylactic cranial irradiation for small cell carcinoma of the lung

Is Gamma Knife surgery, omitting adjunct whole brain radiation treatment, feasible for patients with 20 or more brain metastases?

Background

The importance of the number of brain metastases (BM) when deciding between whole brain radiation treatment (WBRT) and radiosurgery is controversial. We hypothesized that the number of BM is of limited importance when deciding radiation strategy, and offered Gamma Knife surgery (GKS) also for selected patients with 20 or more BM.

Methods

The outcome following single session GKS for 75 consecutive patients harboring 20 or more (20+) BM was analyzed. Data was collected both retro- and prospectively.

Results

The median survival time was 9 months. Two grade 3 complications occurred, 1 resolved and 1 did not. Sex and clinical condition at the time of GKS (ECOG value) were the only parameters significantly related to survival time. Eighteen patients developed leptomeningeal dissemination with or without distant recurrences (DR), and another 32 patients developed DR a total of 73 times. DR was managed with GKS 24 times, with WBRT 3 times and with systemic treatment or best supportive care 46 times. The median time to developing DR was unrelated to the number of BM, but significantly longer for patients older than 65 years, as well as for patients with NSCLC.

Conclusions

GKS is a reasonable treatment option for selected patients with 20 or more BM. It is better to decide the optimal management of post-GKS intracranial disease progression once it occurs rather than trying to prevent it by using adjunct WBRT.

Risk Factors for Brain Metastases in Patients With Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

The use of prophylactic cranial irradiation (PCI) for small cell lung cancer (SCLC) patients is controversial. Risk factors for brain metastasis (BM) development are largely lacking, hampering personalized treatment strategies. This study aimed to identify the possible risk factors for BM in SCLC.We systematically searched the Pubmed database (1 January 1995 to 18 January 2021) according to the PRISMA guidelines. Eligibility criteria: studies reporting detailed BM data with an adequate sample size (randomized clinical trials [RCTs]: N ≥50; non-RCTs: N ≥100) in patients with SCLC. We summarized the reported risk factors and performed meta-analysis to estimate the pooled hazard ratios (HR) if enough qualified data (i.e., two or more studies; the same study type; the same analysis method; and HRs retrievable) were available. In total, 61/536 records were eligible (18 RCTs and 39 non-RCTs comprising 13,188 patients), in which 57 factors were reported. Ten factors qualified BM data for meta-analysis: Limited stage disease (LD) (HR = 0.34, 95% CI: 0.17–0.67; P = 0.002) and older age (≥65) (HR = 0.70, 95% CI: 0.54–0.92; P = 0.01) were associated with less BM; A higher T stage (≥T3) (HR = 1.72, 95% CI: 1.16–2.56; P = 0.007) was a significant risk factor for BM. Male sex (HR = 1.24, 95% CI: 0.99–1.54; P = 0.06) tended to be a risk factor, and better PS (0–1) (HR = 0.66, 95% CI: 0.42–1.02; P = 0.06) tended to have less BM. Smoking, thoracic radiotherapy dose were not significant (P >0.05). PCI significantly decreased BM (P <0.001), but did not improve OS in ED-SCLC (P = 0.81). A higher PCI dose did not improve OS (P = 0.11). The impact on BM was conflicting between Cox regression data (HR = 0.59, 95% CI: 0.26–1.31; P = 0.20) and competing risk regression data (HR = 0.74, 95% CI: 0.55–0.99; P = 0.04). Compared to M0–M1a, M1b was a risk factor for OS (P = 0.01) in ED-SCLC, but not for BM (P = 0.19). As regular brain imaging is rarely performed, high-quality data is lacking. Other factors such as N-stage and blood biomarkers had no qualified data to perform meta-analysis. In conclusion, younger age, higher T stage, and ED are risk factors for BM, suggesting that PCI should be especially discussed in such cases. Individual patient data (IPD) meta-analysis and well-designed RCTs are needed to better identify more risk factors and further confirm our findings. Systematic Review Registration:https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021228391, identifier CRD42021228391.

The role of prophylactic cranial irradiation for patients with small-cell lung cancer

Small-cell lung cancer (SCLC) has a particular propensity to metastasize to the brain, affecting ~10% of SCLC patients at diagnosis, but may occur in more than 50% of 2-year survivors. Most cytotoxic drugs have limited ability to cross the blood-brain barrier, and the effectiveness of chemotherapy for brain metastasis is limited. Therefore, prophylactic cranial irradiation (PCI) has been proposed to treat SCLC. A meta-analysis revealed that PCI significantly decreased the risk of brain metastasis and increased the 3-year survival rate; it has been established as a standard therapy for limited-disease SCLC. However, certain aspects of PCI remain unclarified, including the roles in resected SCLC and extensive-disease SCLC, and its neurotoxicities. In addition, information on PCI has been obtained from old clinical trials without the use of new imaging devices, such as magnetic resonance imaging. Evidence from advanced imaging techniques is needed in this era.

Treatment of high numbers of brain metastases with Gamma Knife radiosurgery: a review

Effectiveness of stereotactic radiosurgery (SRS) has been shown in patients with one to four brain metastases. Work has been done to evaluate the role of SRS alone treatment without whole-brain radiation therapy in patients with more than four metastases. A recent multiinstitutional JLGK 0901 prospective study revealed the class-2 evidence that SRS without whole-brain radiation therapy is an effective treatment for patients up to 10 metastatic lesions. Several retrospective studies exist to show the efficacy and safety of SRS for patients with even more than 10 lesions. However, patient selection is very critical for SRS alone treatment. The PubMed database was searched using combinations of search terms and synonyms for multiple brain metastases, Gamma Knife and SRS published between January 1, 2005 and January 1, 2015 in order to address the effectiveness of Gamma Knife for patients with multiple brain metastases. Good performance status, controlled primary disease, total treated tumor volume of 15 cm(3) or less have been found to be significant predictors for survival among patients with two or more brain lesions. The data suggest that SRS can be used and whole brain radiation therapy can be withheld in selected patients with multiple lesions to avoid acute or chronic adverse effects, especially neurocognitive decline, without causing survival disadvantage. In this review, we assessed the evidence for SRS treatment of patients with multiple brain metastases.

Selecting patients with extensive-stage small cell lung cancer for prophylactic cranial irradiation by predicting brain metastases

INTRODUCTION

Prophylactic cranial irradiation has recently been reported to improve overall survival and quality of life in patients with extensive-stage small cell lung cancer. The generalizability of this treatment to an unselected population with extensive-stage small cell lung cancer is not clear, as the incidence of brain metastases is variably reported in the literature, ranging from 25 to 60%.

METHODS

We completed a retrospective review of 130 consecutive patients with extensive-stage small cell lung cancer seen in consultation between January 1, 2004, and December 31, 2006. Our primary objective was to determine the incidence of brain metastases and to establish significant factors that were predictive of developing brain metastases, using both univariate and multivariate regression analysis.

RESULTS

The median patient age was 68.0 years, and the median survival time was 25.6 weeks. The majority of patients (84.9%) received systemic therapy. Twenty-nine patients (22.3%) presented with brain metastases while an additional 21 patients (20.8%) developed brain metastases over their lifetime. Response to chemotherapy was a predictor of brain metastases using univariate (odds ratio [OR] 5.28, p = 0.03) and multivariate analysis (OR 5.49, p = 0.04). Weight loss more than 5 kg predicted for freedom from the development of brain metastases using univariate (OR 0.20, p = 0.01) and multivariate analysis (OR 0.69, p = 0.03).

CONCLUSIONS

20.8% of patients developed brain metastases after their initial presentation. This incidence is lower than that previously reported and may suggest that prophylactic cranial irradiation should be targeted to patients at highest risk. Response to chemotherapy and less than 5 kg baseline weight loss were independent predictors of future brain metastases.

Assessing perfusion changes during whole brain irradiation for patients with cerebral metastases

PURPOSE

To assess perfusion changes within brain and correlate these with clinical symptoms during whole brain radiotherapy (WBRT) for cerebral metastases.

MATERIALS AND METHODS

Fourteen patients with cerebral metastases underwent dynamic CT perfusion scans during palliative whole brain irradiation. Perfusion scans were performed on Day 1 prior to initial radiotherapy treatment, then on Day 2, and on Day 5 immediately after completion of radiotherapy. Measurements of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and capillary surface area permeability product (PS) were performed for each perfusion scan, and daily symptom assessment was taken prior to initial perfusion scan and thereafter prior to each daily radiation treatment.

RESULTS

Utilizing Day 1 as baseline, a 19% increase (P = 0.033) was noted in PS at Day 2, (median 1.47 ml/100 g/min), which returned to Day 1 range at Day 5 (median 1.31 ml/100 g/min). When symptoms were correlated with perfusion parameters, a statistically significant association between change in MTT with change in headache scores was observed, baseline to Day 2 (P = 0.019), and a trend between change in nausea scores with change in CBV (P = 0.059) as well as change in MTT (P = 0.098), baseline to Day 5.

CONCLUSION

This study has demonstrated the feasibility of a non-invasive technique to assess changes occurring within the human brain during a course of radiation treatment. Dynamic perfusion tomography provides insight into the pathophysiological processes taking place and allows correlation with patient symptomatology.

Gamma Knife radiosurgery for numerous brain metastases: is this a safe treatment?

PURPOSE

Gamma Knife (GK) radiosurgery has recently been employed in patients with numerous brain metastases (METs), even those with 10 or more lesions. However, cumulative irradiation doses to the whole brain (WB), with such treatment, have not been determined.

METHODS AND MATERIALS

Since the GammaPlan ver. 5.10 (ver. 5.31 is presently available, Leksell GammaPlan) became available in November 1998, 92 GK procedures have been performed for 80 patients with 10 or more brain METs at our facility. The median lesion number was 17 (range: 10-43) and the median cumulative volume of all tumors was 8.02 cc (range: 0.46-81.41 cc). The median selected dose at the lesion periphery was 20 Gy (range: 12-25 Gy). Based on these treatment protocols, the cumulative irradiation dose was computed.

RESULTS

The median cumulative irradiation dose to the WB was 4.71 (range: 2.16-8.51) Gy. The median brain volumes receiving >2 Gy, >5 Gy, >10 Gy, >15 Gy, and >20 Gy were 1105 (range 410-1501) cc, 309 (46-1247) cc, 64 (13-282) cc, 24 (2-77) cc, and 8 (0-40) cc, respectively.

CONCLUSION

The cumulative WB irradiation doses for patients with numerous radiosurgical targets were not considered to exceed the threshold level of normal brain necrosis.

Ultrarapid high-dose course of prophylactic cranial irradiation in small-cell lung cancer: evaluation of late neurologic morbidity in 16 long-term survivors

Despite the reduction in the incidence of brain metastases following prophylactic cranial irradiation (PCI) in patients with small-cell lung cancer (SCLC), the use of this modality is still controversial due to the lack of improvement in survival and the appearance of neurotoxicity in long-term survivors. Moreover, the optimum dose, fraction size, and timing are not known. From 1980 to 1988, 70 patients with limited stage SCLC underwent PCI after or during multimodality treatment of their primary tumor. Most of these patients (75.7%) received an unconventional ultrarapid high-dose course of 17 Gy in two fractions over 3 days. Long-term (range 60-138 months) survivors (n = 16) were invited to have a complete neurological evaluation including computed cranial tomography (CCT), 99mTc-HMPAO single photon emission computerized tomography (SPECT) scan, electroencephalography (EEG), magnetic resonance imaging (MRI), and neuropsychometry. Delayed neurologic complications or psychometric impairment was observed in 46% of patients. One or more abnormalities were detected by CCT in all patients, and the presence of neurologic complications seemed to correlate with periventricular and subcortical white matter changes. A strong correlation was found between CCT and SPECT periventricular white matter changes. Although the incidence of late neurologic toxicity following this rapid course of irradiation was high, clinical findings were less severe than expected, and all the patients were capable of self-care.