Patterns of response, recurrence and survival according to diagnosis in patients with brain metastases treated by Gamma Knife surgeryKeywords: brain metastasis, breast cancer, gamma knife, lung cancer, melanomaInteractive Manuscript
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What is the background behind your study?
It has been suggested sometimes that the response of brain metastasis to radiosurgery is relatively independent of diagnosis.
What is the purpose of your study?
This is not our experience and the objective of this study is to identify patterns of survival and failure of local control after radiosurgery that are diagnosis dependent.
Describe your patient group.
A prospective cohort analysis of 220 patients with 1391 brain metastasis treated by Gamma Knife 4C with 88% complete follow up to death or up to 6 years has been analyzed (CoE Class II).
Describe what you did.
All cases were treated according to RTOG 90-05 protocol. The diagnoses with a population adequate for independent analysis were non small cell lung carcinoma (NSCLC, n=94), breast carcinoma (n=49) and melanoma (n=17). Statistical analyses were Spearman Rank correlation and Kaplan Meier logrank/Cox proportional-hazards regression methods with survival and time to local progression as end points measured in months (mo).
Describe your main findings.
There is a significant difference between the 3 diagnoses in survival after radiosurgery (P=0.024). Median survival for Ca breast=13mo, for NSCLC=9mo and for melanoma=5mo. The overall survival at the mean of covariates for Ca breast is 6mo=80%, 1yr=55%, 2yr=35%; for NSCLC 6mo=70%, 1yr=45%, 2yr=20%; for melanoma 6mo=60%, 1yr=36%, 2yr=6%. The BSBM prognostic index is not relevant to survival in Ca breast (P=0.305) but is highly significant in NSCLC (P<0.0001) with median survivals for grade 3=14.5mo, 2=12mo, 1=6mo and 0=3mo. There is a trend to gender difference in survival in NSCLC (P=0.053) with median survival male=12mo and female=8mo. The multiplicity of metastases is not statistically significant for survival in any diagnosis but there is a trend for worse results in multiple melanoma (P=0.153) where the median survival for >3 metastases is only 3mo.The actuarial chance of local progression after radiosurgery varies with diagnosis and, at 6 months, was found to be 9.3% for NSCLC, 7.4% for Ca breast and 39.4% for melanoma. However at 1 year the figures were 20.2% for Ca lung, 36.7% for Ca breast and 63.7% for melanoma.
Describe the main limitation of this study.
This was a retrospective review.
Describe your main conclusion.
The prognostic indexes for patient selection will certainly need to be diagnosis related in the future.
Describe the importance of your findings and how they can be used by others.
The results above suggest there is a diagnosis related difference in sensitivity to radiosurgery.
It has been suggested sometimes that the response of brain metastasis to radiosurgery is relatively independent of diagnosis.
This is not our experience and the objective of this study is to identify patterns of survival and failure of local control after radiosurgery that are diagnosis dependent.
A prospective cohort analysis of 220 patients with 1391 brain metastasis treated by Gamma Knife 4C with 88% complete follow up to death or up to 6 years has been analyzed (CoE Class II).
All cases were treated according to RTOG 90-05 protocol. The diagnoses with a population adequate for independent analysis were non small cell lung carcinoma (NSCLC, n=94), breast carcinoma (n=49) and melanoma (n=17). Statistical analyses were Spearman Rank correlation and Kaplan Meier logrank/Cox proportional-hazards regression methods with survival and time to local progression as end points measured in months (mo).
There is a significant difference between the 3 diagnoses in survival after radiosurgery (P=0.024). Median survival for Ca breast=13mo, for NSCLC=9mo and for melanoma=5mo. The overall survival at the mean of covariates for Ca breast is 6mo=80%, 1yr=55%, 2yr=35%; for NSCLC 6mo=70%, 1yr=45%, 2yr=20%; for melanoma 6mo=60%, 1yr=36%, 2yr=6%. The BSBM prognostic index is not relevant to survival in Ca breast (P=0.305) but is highly significant in NSCLC (P<0.0001) with median survivals for grade 3=14.5mo, 2=12mo, 1=6mo and 0=3mo. There is a trend to gender difference in survival in NSCLC (P=0.053) with median survival male=12mo and female=8mo. The multiplicity of metastases is not statistically significant for survival in any diagnosis but there is a trend for worse results in multiple melanoma (P=0.153) where the median survival for >3 metastases is only 3mo.The actuarial chance of local progression after radiosurgery varies with diagnosis and, at 6 months, was found to be 9.3% for NSCLC, 7.4% for Ca breast and 39.4% for melanoma. However at 1 year the figures were 20.2% for Ca lung, 36.7% for Ca breast and 63.7% for melanoma.
This was a retrospective review.
The prognostic indexes for patient selection will certainly need to be diagnosis related in the future.
The results above suggest there is a diagnosis related difference in sensitivity to radiosurgery.
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