Risk of leptomeningeal disease in patients treated with stereotactic radiosurgery targeting the postoperative resection cavity for brain metastases.
OBJECTIVE
We sought to determine the risk of leptomeningeal disease (LMD) in patients treated with stereotactic radiosurgery (SRS) targeting the postsurgical resection cavity of a brain metastasis, deferring whole-brain radiation therapy (WBRT) in all patients.


METHODS
We retrospectively reviewed 175 brain metastasis resection cavities in 165 patients treated from 1998 to 2011 with postoperative SRS. The cumulative incidence rates, with death as a competing risk, of LMD, local failure (LF), and distant brain parenchymal failure (DF) were estimated. Variables associated with LMD were evaluated, including LF, DF, posterior fossa location, resection type (en-bloc vs piecemeal or unknown), and histology (lung, colon, breast, melanoma, gynecologic, other).


RESULTS
With a median follow-up of 12 months (range, 1-157 months), median overall survival was 17 months. Twenty-one of 165 patients (13%) developed LMD at a median of 5 months (range, 2-33 months) following SRS. The 1-year cumulative incidence rates, with death as a competing risk, were 10% (95% confidence interval [CI], 6%-15%) for developing LF, 54% (95% CI, 46%-61%) for DF, and 11% (95% CI, 7%-17%) for LMD. On univariate analysis, only breast cancer histology (hazard ratio, 2.96) was associated with an increased risk of LMD. The 1-year cumulative incidence of LMD was 24% (95% CI, 9%-41%) for breast cancer compared to 9% (95% CI, 5%-14%) for non-breast histology (P=.004).


CONCLUSIONS
In patients treated with SRS targeting the postoperative cavity following resection, those with breast cancer histology were at higher risk of LMD. It is unknown whether the inclusion of whole-brain irradiation or novel strategies such as preresection SRS would improve this risk or if the rate of LMD is inherently higher with breast histology.
Department of Radiation Oncology, Acibadem University School of Medicine, Istanbul, Turkey.
Banu
B
Atalar
Leslie A
LA
Modlin
Clara Y H
CY
Choi
John R
JR
Adler
Iris C
IC
Gibbs
Steven D
SD
Chang
Griffith R
GR
Harsh
Gordon
G
Li
Seema
S
Nagpal
Alexandra
A
Hanlon
Scott G
SG
Soltys
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology; D003131:Combined Modality Therapy / Q000379:methods; D016001:Confidence Intervals; D016371:Cranial Irradiation / Q000009:adverse effects / Q000379:methods; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008577:Meningeal Neoplasms / Q000453:epidemiology / Q000209:etiology*; D008578:Meninges / Q000528:radiation effects; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D012306:Risk; D016879:Salvage Therapy / Q000379:methods; D055815:Young Adult