Background Stereotactic radiosurgery (SRS) has emerged as an important modality for the treatment of intracranial metastases. There are currently few established guidelines delineating indications for SRS use and fewer still regarding plan evaluation in the treatment of multiple brain metastases. Methods An 18 question electronic survey was distributed to radiation oncologists at National Cancer Institute (NCI) designated cancer centers in the USA (60). Centers without radiation oncologists were excluded. Physicians who indicated that they do not prescribe SRS were excluded from the remaining survey questions. Sign test and Chi-square test were used to determine if responses differed significantly from random distribution. Results One hundred sixteen of the 697 radiation oncologists surveyed completed the questionnaire, representing 51 institutions. Sixty-two percent reported treating patients with brain metastases using SRS. Radiation oncologists prescribing SRS most commonly treat CNS (66.2%) and lung (49.3%) malignancies. SRS was used more frequently for < 10 brain metastases (73.7%; p < 0.0001) and whole brain radiation therapy (WBRT) for > 10 brain metastases (82.5%; p < 0.0001). The maximum number of lesions physicians were willing to treat with SRS without WBRT was 1–4 (40.4%) and 5–10 (42.4%) (p < 0.0001 compared to 11–15, 16–20 and no limit). The most important criteria for choosing SRS or WBRT were number of lesions (p < 0.0001) and performance status (p = 0.016). The most common margin for SRS was 0 mm (49.1%; p = 0.0021). The most common dose constraints other than critical structure was conformity index (84.2%) and brain V12 (61.4%). The LINAC was the most common treatment modality (54.4%) and mono-isocenter technique for multiple brain metastases was commonly used (43.9%; p = 0.23). Most departments do not have a policy for brain metastases treatment (64.9%; p = 0.024). Conclusions This is one of the first national surveys assessing the use of SRS for brain metastases in clinical practice. These data highlight some clinical considerations for physicians treating brain metastases with SRS.
In a genomic analysis of prostatectomy specimens, metabolic gene expression, but not BMI, was associated with PCa metastases. Cancer 2017;123:2240-2247. © 2017 American Cancer Society.
It has been recently reported that a single nucleotide polymorphism (SNP) signature composed of ERCC1/2 genes (ERCC1:rs11615 and ERCC2:rs238406) was predictive of radiosensitivity in stage-III non-small cell lung cancer (NSCLC). That is, at relatively low radiation doses (<70 Gy), patients with a radiosensitive genotype would have better treatment outcome than those with a radioresistant genotype. On the other hand, at relatively high doses (>80 Gy), these radiosensitive patients would have worse treatment outcome due to overdose-related adverse effects. Patients with stereotactic body radiation therapy (SBRT) usually receive very high dose (>80 Gy equivalently). This study aimed to test if the radiosensitive patients predicted by the SNP signature would indeed have a poorer overall survival after SBRT. Materials/Methods: A total of 26 stage I-II NSCLC patients who enrolled in an IRB proved biomarker protocol and underwent SBRT treatment were included in this study. Four different dose regimens, with the minimum equivalent biological dose at 2 Gy/fraction being 83 Gy, were used. The SNPs of ERCC1: rs11615 and ERCC2:rs238406 were genotyped for each patient. Minimum follow-up time was 22 months. Results: The ERCC2 SNP had a <70% call rate for these patients so that it was excluded for the analysis. The ERCC1 SNP had a 100% call rate. Seven patients had the radio-resistant genotype, and 19 had the radiosensitive genotype. The patients with the radio-resistant genotype showed statistically significant better overall survival than the patients with radiosensitive genotype (P < 0.05). Only 1 radio-resistant patient died after 28 months from a surgical procedure to remove a new colon cancer, and all others were alive at the last follow-up date, with minimum follow-up of 27 months. On the other hand, the radiosensitive patients had a medium survival of 23 months, with a 10/19 death rate. The causes of death were distance metastasis (2), cardiac events (2) and unknown (6). For the 6 patients died with unknown cause, one had grade 3 acute lung toxicity, three had grade 2-3 late lung toxicity. There was no significant difference of gender, age, stage, and radiation regimens between the 2 genotype groups. However, there were 3 out of 7 African-Americans in the radio-resistant group, but only 1 out of 19 in the radiosensitive group, consistent with the reports that the African-Americans have much higher frequency in the genotype corresponding to radio-resistant for this SNP. Conclusion: Although limited number of patients, this study supported the previous finding that the SNP ERCC1:rs11615 can serve as a radiosensitivity marker. The radiosensitive patients showed poorer overall survival than the radio-resistant patients after high dose SBRT treatment, possibly due to too-high radiation dose to the normal tissue, suggesting that dose de-escalation may improve survival for the radiosensitive patients in SBRT.
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