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The
role of tumor size in the radiosurgical management of patients with ambiguous
brain metastases
Chang EL, Hassenbusch SJ 3rd, Shiu AS, Lang FF, Allen PK, Sawaya R, Maor MH
Division of Radiation Oncology, Brain Tumor Center, The
University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.
echang@mdanderson.org
Objective. To identify a size cutoff below which it is safe to observe
obscure brain lesions suspected of being metastases so that treatment of
nonmetastases can be avoided.
Methods.
Medical records from patients who underwent linear accelerator-based
radiosurgery from August 1991 to October 2001 were reviewed.
Inclusion criteria were defined as brain metastasis tumor volume less than 5
cm(3) (diameter, thick similar 2.1 cm) treated with a dose of 20 Gy or
more.
One hundred thirty-five patients had 153 evaluable brain metastases with
follow-up imaging that met inclusion criteria.
Median age was 54 years (range, 18-79 yr).
Lesion primaries were non-small-cell lung (n = 39), melanoma (n = 44), renal (n
= 37), breast (n = 18), colon (n = 3), sarcoma (n = 5), other (n = 5), and
unknown primary (n = 2).
Median tumor volume was 0.67 cm(3) (range, 0.06-4.58 cm(3)).
The minimum peripheral dose was 20 Gy (n = 132) or 21 to 24 Gy (n = 21).
At the time of analysis, the median follow-up for all patients was 10 months
(range, 0.2-99 mo).
Results.
The 1- and 2-year actuarial local control rates for all of the lesions were 69
and 46%, respectively.
For lesions of 1 cm (0.5 cm(3)) or less, the corresponding local control rates
were 86 and 78%, respectively, which was significantly higher than the
corresponding rates of 56 and 24%, respectively, for lesions larger than 1 cm
(0.5 cm(3)) (P = 0.0016).
Conclusion.
A convincing brain metastasis measuring less than 1 cm should be pursued
aggressively.
If the suspected brain metastasis is ambiguous, observation is proposed up to a
diameter of 1 cm.
This is the first study in the literature to identify a 1-cm cutoff for
radiosurgical control of small brain metastases, and validation by additional
studies is required.
PMID: 12925241 [PubMed - in process]
Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12925241&dopt=Abstract |
