abbreviatioNs ARE = adverse radiation effect; AVM = arteriovenous malformation; CI = confidence interval; HR = hazard ratio; PACS = picture archiving and communication system; SRS = stereotactic radiosurgery; UCSF = University of California, San Francisco; WBRT = whole-brain radiation therapy. obJect The authors sought to determine the incidence, time course, and risk factors for overall adverse radiation effect (ARE) and symptomatic ARE after stereotactic radiosurgery (SRS) for brain metastases. methods All cases of brain metastases treated from 1998 through 2009 with Gamma Knife SRS at UCSF were considered. Cases with less than 3 months of follow-up imaging, a gap of more than 8 months in imaging during the 1st year, or inadequate imaging availability were excluded. Brain scans and pathology reports were reviewed to ensure consistent scoring of dates of ARE, treatment failure, or both; in case of uncertainty, the cause of lesion worsening was scored as indeterminate. Cumulative incidence of ARE and failure were estimated with the Kaplan-Meier method with censoring at last imaging. Univariate and multivariate Cox proportional hazards analyses were performed. results Among 435 patients and 2200 brain metastases evaluable, the median patient survival time was 17.4 months and the median lesion imaging follow-up was 9.9 months. Calculated on the basis of 2200 evaluable lesions, the rates of treatment failure, ARE, concurrent failure and ARE, and lesion worsening with indeterminate cause were 9.2%, 5.4%, 1.4%, and 4.1%, respectively. Among 118 cases of ARE, approximately 60% were symptomatic and 85% occurred 3-18 months after SRS (median 7.2 months). For 99 ARE cases managed without surgery or bevacizumab, the probabilities of improvement observed on imaging were 40%, 57%, and 76% at 6, 12, and 18 months after onset of ARE. The most important risk factors for ARE included prior SRS to the same lesion (with 20% 1-year risk of symptomatic ARE vs 3%, 4%, and 8% for no prior treatment, prior whole brain radiotherapy [WBRT], or concurrent WBRT) and any of these volume parameters: target, prescription isodose, 12-Gy, or 10-Gy volume. Excluding lesions treated with repeat SRS, the 1-year probabilities of ARE were < 1%, 1%, 3%, 10%, and 14% for maximum diameter 0.3-0.6 cm, 0.7-1.0 cm, 1.1-1.5 cm, 1.6-2.0 cm, and 2.1-5.1 cm, respectively. The 1-year probabilities of symptomatic ARE leveled off at 13%-14% for brain metastases maximum diameter > 2.1 cm, target volume > 1.2 cm 3 , prescription isodose volume > 1.8 cm 3 , 12-Gy volume > 3.3 cm 3 , and 10-Gy volume > 4.3 cm 3 , excluding lesions treated with repeat SRS. On both univariate and multivariate analysis, capecitabine, but not other systemic therapy within 1 month of SRS, appeared to increase ARE risk. For the multivariate analysis considering only metastases with target volume > 1.0 cm 3 , risk factors for ARE included prior SRS, kidney primary tumor, connective tissue disorder, and capecitabine. coNclusioNs Although incidence of ARE after SRS was low overall, risk inc...

The poor outcome seen in the particularly vulnerable elderly patient population highlights the need for clinical trials targeting the elderly in hopes of improving treatment strategies and survival.

Management of patients with glioblastoma (GBM) often includes radiation (RT) and temozolomide (TMZ). The association between severe treatment-related lymphopenia (TRL) after the standard chemoradiation and reduced survival has been reported in GBM patients with the median age of 57. Similar findings were described in patients with head and neck, non-small cell lung, and pancreatic cancers. This retrospective study is designed to evaluate whether elderly GBM patients (age ≥65) develop similar TRL after RT/TMZ and whether such TRL is associated with decreased survival. Serial total lymphocyte counts (TLC) were retrospectively reviewed in patients (age ≥65) with newly diagnosed GBM undergoing RT/ TMZ and associated with treatment outcomes. Seventy-two patients were eligible: median KPS 70, median age 71 years (range 65–86) with 56 % of patients >70 years, 53 % female, 31 % received RT ≤45 Gy. Baseline median TLC was 1100 cells/mm3 which fell by 41 % to 650 cells/ mm3 2 months after initiating RT/TMZ (p < 0.0001). Patients with TLC <500 cells/mm3 at 2 months had a shorter survival than those with higher TLCs with a median overall survival of 4.6 versus 11.6 months, respectively. Multivariate analysis revealed a significant association between TRL and survival (HR 2.76, 95 % CI 1.30–5.86, p = 0.008). Treatment-related lymphopenia is frequent, severe, and an independent predictor for survival in elderly patients with GBM. These findings add to the body of evidence that immunosuppression induced by chemoradiation is associated with inferior clinical outcomes. Prospective studies are needed to confirm these findings suggesting that immune preservation is important in this cancer.

No abstract