The geography of clinical cancer research: analysis of abstracts presented at the American Society of Clinical Oncology Annual Meetings.

BACKGROUND: The American Society of Clinical Oncology Annual Meeting is the largest forum for presentation of clinical research in oncology. We quantified the contribution of countries and assessed correlates of their presence at such meetings. METHODS: After stratifying abstracts according to category of presentation (oral, poster, and 'publication only'), we took a random sample of 10% of the studies presented at years 2001-2003 and 2006-2008. We assigned abstract nationality using the affiliation of authors. For multinational studies, we developed an algorithm to assign nationality. RESULTS: Of the 22 045 eligible abstracts, 2206 were analyzed and represented 71 countries: 905 (41%) abstracts were from a single institution, 969 (44%) were multicenter, uninational studies, and 332 (15%) were multinational studies. United States nationality was assigned to 49% of all abstracts and the next 14 countries with a higher number of studies accounted for 41%. There was a statistically significant temporal trend in the proportion of multinational studies. Also, multinational studies and abstracts with United States nationality were more frequently presented in oral and poster fashion and had more frequent involvement of the pharmaceutical industry. CONCLUSION: This study provides a geographic overview of clinical cancer research and indicates that multinational collaboration is increasing.

Radiosurgery for brain metastases: who may not benefit?

PURPOSE: To select a group of patients with brain metastases for whom stereotactic radiosurgery (SRS) may not be beneficial. PATIENTS, MATERIALS, AND METHODS: Actuarial survival of 87 patients with brain metastases treated with SRS between July 1993 and May 1999 was retrospectively analyzed under stratification by the Score Index for Stereotactic Radiosurgery for Brain Metastases (SIR). To identify the group of patients most likely to survive less than 6 months after SRS, Cox model survival curves were calculated for all SIR values, and Kaplan-Meier survival curves were calculated for two SIR subsets (0-5 and 6-10) and were compared by log-rank test. RESULTS: Overall median survival after SRS was 6.88 months. The stratification of patients into two SIR subsets (0-5 and 6-10) sustained statistical significance regarding survival with p = 0.0001. The median survival time for the group of patients with SIR between 0 and 5 was 4.52 months (95% confidence interval of 2.82 to 5.84 months). Survival probability at 6 months for this group of patients with poor prognosis was 35.6%. CONCLUSION: Patients with brain metastases and SIR of 5 or lower have an expected median survival of less than 6 months after treatment with radiosurgery. Thus, radiosurgery may not be beneficial for this group of patients.

Radiosurgery for brain metastases: a score index for predicting prognosis.

PURPOSE: To analyze a prognostic score index for patients with brain metastases submitted to stereotactic radiosurgery (the Score Index for Radiosurgery in Brain Metastases [SIR]). METHODS AND MATERIALS: Actuarial survival of 65 brain metastases patients treated with radiosurgery between July 1993 and December 1997 was retrospectively analyzed. Prognostic factors included age, Karnofsky performance status (KPS), extracranial disease status, number of brain lesions, largest brain lesion volume, lesions site, and receiving or not whole brain irradiation. The SIR was obtained through summation of the previously noted first five prognostic factors. Kaplan-Meier actuarial survival curves for all prognostic factors, SIR, and recursive partitioning analysis (RPA) (RTOG prognostic score) were calculated. Survival curves of subsets were compared by log-rank test. Application of the Cox model was utilized to identify any correlation between prognostic factors, prognostic scores, and survival. RESULTS: Median overall survival from radiosurgery was 6.8 months. Utilizing univariate analysis, extracranial disease status, KPS, number of brain lesions, largest brain lesion volume, RPA, and SIR were significantly correlated with prognosis. Median survival for the RPA classes 1, 2, and 3 was 20.19 months, 7.75 months, and 3. 38 months respectively (p = 0.0131). Median survival for patients, grouped under SIR from 1 to 3, 4 to 7, and 8 to 10, was 2.91 months, 7.00 months, and 31.38 months respectively (p = 0.0001). Using the Cox model, extracranial disease status and KPS demonstrated significant correlation with prognosis (p = 0.0001 and 0.0004 respectively). Multivariate analysis also demonstrated significance for SIR and RPA when tested individually (p = 0.0001 and 0.0040 respectively). Applying the Cox Model to both SIR and RPA, only SIR reached independent significance (p = 0.0004). CONCLUSIONS: Systemic disease status, KPS, SIR, and RPA are reliable prognostic factors for patients with brain metastases submitted to radiosurgery. Applying SIR and RPA classifications to our patients' data, SIR demonstrated better accuracy in predicting prognosis. SIR should be further tested with larger patient accrual and for all patients with brain metastases subjected or not to stereotactic radiosurgery.