Connect
MJA

Stereotactic radiosurgery for managing brain metastases in Victoria, 2012–2017

Wee Loon Ong, Therese Ming Jung Kang, Gishan Ratnayake, Morikatsu Wada, Jeremy Ruben, Sashendra Senthi, Roger L Milne, Jeremy L Millar and Farshad Foroudi
Med J Aust 2020; 212 (11): 526-527. || doi: 10.5694/mja2.50573
Published online: 20 April 2020

The conventional treatment for brain metastases is whole brain radiotherapy (WBRT).1 But there has been a gradual move to managing limited brain metastases with stereotactic radiosurgery (SRS),2 and delaying or avoiding WBRT because of its effects on cognition and quality of life. Data on contemporary SRS practice for managing brain metastases in Australia are, however, very limited.3

We performed a population‐based linkage study, analysing data from the Victorian Cancer Registry and the Victorian Radiotherapy Minimum Data Set (VRMDS). We included all patients with solid tumours (ICD‐10 codes C00–C80), but excluding primary central nervous systems malignancies (ICD‐10 codes C69–72), who received brain radiotherapy in Victoria between 1 January 2012 and 31 December 2017.

The primary outcome was the proportion of patients treated with SRS. Although SRS refers to large single fraction radiotherapy, patients treated with fractionated “stereotactic radiotherapy” were also classified as receiving SRS. In addition, because of potential coding inconsistencies, patients who had no more than four fractions of radiotherapy and were treated with “volumetric modulated arc therapy” or “intensity modulated radiation therapy” were also classified as receiving SRS. Differences in factors of interest by SRS use were assessed in Pearson χ2 (categorical variables) and Student t or Mann–Whitney U tests (continuous variables). Temporal changes were assessed with the Cochran–Armitage test for trend. Factors associated with SRS use were assessed by logistic regression, with year as an ordinal categorical variable; variables for which P < 0.10 in univariate analyses were included in the multivariate model. The study was approved by the Austin Health Human Research Ethics Committee (reference, LNR/18/Austin/34).

A total of 3961 patients who received radiotherapy for brain metastases were included, of whom 1116 (28%) received SRS. The proportion of patients receiving SRS increased from 27% (105 of 388) in 2012 to 35% (287 of 821) in 2017 (for trend: P < 0.001). The mean age of patients who received SRS (63.5 years; standard deviation [SD], 12.5 years) was lower than for those who did not (65.2 years; SD, 12.5 years). Factors that influenced SRS use included socio‐economic status, primary cancer type (about half the patients with melanoma received SRS, and about one‐quarter of patients with other cancer types), treatment institution type (public institutions, 31%; private institutions, 24%), and location (metropolitan centres, 34%; regional centres, 5%). Remoteness of patients’ area of residence was not a significant factor. In multivariate analyses, age, primary cancer type, treatment centre type, and location were significant factors for SRS use (Box).

While the VRMDS captures all radiotherapy delivered in Victoria, it does not include data on patients’ performance status, numbers of brain metastases, the extent of extracranial disease, and other factors that would allow evaluation of the appropriateness of SRS for individual patients. Another limitation is potential misclassification of radiotherapy classified as “SRS”, as the VRMDS did not include data on radiotherapy dose.

As evidence supporting the use of SRS for managing brain metastases grows, we would expect SRS rates to rise.6,7 While SRS was less frequently used in regional centres, patients living in regional areas were as likely to receive SRS as patients living in metropolitan areas. It is nevertheless important to ensure easy and convenient access to SRS services for all cancer patients in Victoria.

Box – Baseline characteristics of 3961 patients who received radiotherapy for brain metastases, Victoria, 2012–2017

 

Stereotactic radiosurgery


Multivariable analysis: odds ratio (95%CI)

P

Received

Not received


Number of patients

1116 (28%)

2845 (72%)

 

 

Age at first treatment for brain metastases (years)

 

 

 

 < 55

266 (33%)

543 (67%)

1

 

 55–59

157 (32%)

331 (68%)

1.11 (0.86–1.44)

0.42

 60–64

161 (28%)

419 (72%)

0.89 (0.69–1.14)

0.35

 65–69

177 (26%)

502 (74%)

0.85 (0.67–1.08)

0.19

 70–74

153 (25%)

448 (75%)

0.88 (0.68–1.14)

0.33

 75 or more

202 (25%)

602 (75%)

0.78 (0.62–0.99)

0.045

 Mean (SD)

63.5 (12.5)

65.2 (12.5)

Sex

 

 

 

 

 Men

528 (28%)

1373 (72%)

 Women

588 (29%)

1472 (71%)

Primary cancer type

 

 

 

 

 Lung

419 (24%)

1344 (76%)

1

 

 Breast

203 (28%)

512 (72%)

1.24 (1.00–1.53)

0.05

 Melanoma

252 (47%)

277 (52%)

2.89 (2.32–3.59)

< 0.001

 Gastrointestinal

93 (28%)

235 (72%)

1.37 (1.03–1.80)

0.028

 Genitourinary

73 (28%)

189 (72%)

1.33 (0.97–1.80)

0.07

 Other

76 (21%)

288 (79%)

0.80 (0.60–1.06)

0.12

Socio‐economic status (quintile)

 

 

 

 

 1st (most disadvantaged)

188 (24%)

612 (77%)

1

 

 2nd

189 (27%)

501 (73%)

1.12 (0.87–1.44)

0.39

 3rd

202 (26%)

572 (74%)

1.02 (0.79–1.30)

0.90

 4th

220 (26%)

618 (74%)

0.90 (0.70–1.14)

0.38

 5th (least disadvantaged)

317 (37%)

542 (63%)

1.19 (0.94–1.50)

0.14

Remoteness classification5

 

 

 

 

 Major city

780 (29%)

1949 (71%)

 Inner regional

261 (26%)

732 (73%)

 Outer regional/remote/very remote

75 (31%)

164 (69%)

Treatment institution type

 

 

 

 

 Public

744 (31%)

1656 (69%)

1

 

 Private

372 (24%)

1189 (76%)

0.10 (0.07–0.14)

< 0.001

Treatment institution location

 

 

 

 

 Metropolitan

1071 (34%)

2071 (66%)

1

 

 Regional

45 (5%)

774 (95%)

0.58 (0.49–0.68)

< 0.001

Year of first brain metastasis treatment

 

 

 

 2012

105 (27%)

283 (73%)

1

 

 2013

111 (25%)

342 (76%)

1.01 (0.72–1.41)

0.95

 2014

147 (25%)

439 (75%)

0.86 (0.63–1.18)

0.35

 2015

207 (25%)

633 (75%)

0.79 (0.59–1.06)

0.12

 2016

259 (30%)

614 (70%)

1.10 (0.83–1.47)

0.50

 2017

287 (35%)

534 (65%)

1.41 (1.06–1.88)

0.017


CI = confidence interval; SD = standard deviation. * Index of Relative Socio‐Economic Disadvantage.4

Received 8 September 2019, accepted 19 November 2019

  • Wee Loon Ong1,2
  • Therese Ming Jung Kang3
  • Gishan Ratnayake3
  • Morikatsu Wada1
  • Jeremy Ruben3,4
  • Sashendra Senthi3,4
  • Roger L Milne5,6
  • Jeremy L Millar3,4
  • Farshad Foroudi1

  • 1 Olivia Newton‐John Cancer Centre at Austin Health, Melbourne, VIC
  • 2 University of Cambridge, Cambridge, United Kingdom
  • 3 Alfred Health, Melbourne, VIC
  • 4 Central Clinical School, Monash University, Melbourne, VIC
  • 5 Cancer Council Victoria, Melbourne, VIC
  • 6 Centre for Epidemiology and Biostatistics, University of Melbourne, Melbourne, VIC

Correspondence: weeloonong@cantab.net

Acknowledgements: 

Wee Loon Ong received funding from Avant (Doctors in Training Research Scholarship) for part of this investigation. We acknowledge the Victorian Government Department of Health and Human Services (DHHS) Centre for Victorian Data Linkage for performing data linkages and providing access to the dataset.

Competing interests:

No relevant disclosures.

  • 1. Tsao MN, Xu W, Wong RK, et al. Whole brain radiotherapy for the treatment of newly diagnosed multiple brain metastases. Cochrane Database Syst Rev 2018; CD003869.
  • 2. Sahgal A, Ruschin M, Ma L, et al. Stereotactic radiosurgery alone for multiple brain metastases? A review of clinical and technical issues. Neuro Oncol 2017; 19 (Suppl 2): ii2–ii15.
  • 3. Ong WL, Wada M, Ruben J, et al. Contemporary practice patterns of stereotactic radiosurgery for brain metastasis: a review of published Australian literature. J Med Imaging Radiat Oncol 2019; 63: 711–720.
  • 4. Australian Bureau of Statistics. 2033.0.55.001. Census of Population and Housing: Socio‐Economic Indexes for Areas (SEIFA), Australia, 2016: IRSD. Updated Mar 2018. https://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/2033.0.55.001~2016~Main%20Features~IRSD~19 (viewed Jan 2020).
  • 5. Australian Bureau of Statistics. Australian Statistical Geography Standard. (ASGS). Updated July 2018. https://www.abs.gov.au/websi​tedbs/​D3310​114.nsf/home/Austr​alian​+Stati​stica​l+Geogr​aphy+Stand​ard+(ASGS) (viewed Jan 2020).
  • 6. Kann BH, Park HS, Johnson SB, et al. Radiosurgery for brain metastases: changing practice patterns and disparities in the United States. J Natl Compr Canc Netw 2017; 15: 1494–1502.
  • 7. Halasz LM, Weeks JC, Neville BA, et al. Use of stereotactic radiosurgery for brain metastases from non‐small cell lung cancer in the United States. Int J Radiat Oncol Biol Phys 2013; 85: e109–e116.

Author

remove_circle_outline Delete Author
add_circle_outline Add Author

Comment
Do you have any competing interests to declare? *

I/we agree to assign copyright to the Medical Journal of Australia and agree to the Conditions of publication *
I/we agree to the Terms of use of the Medical Journal of Australia *
Email me when people comment on this article

Online responses are no longer available. Please refer to our instructions for authors page for more information.