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Advances in Radiotherapy
& Nuclear Medicine SRS after WBRT

were differences in survival based on primary tumor, and choice compared to repeat WBRT, since it is logistically
Caballero et al. reported that breast cancer patients had a easier to implement salvage SRS, which also less likely to
survival of 11.2 months versus 5.5 months of survival in induce toxicity as compared to repeat WBRT.
SCLC patients. 11 Another important finding that we should highlight
The other radiation option for failure after WBRT is from this study is the poor outcome for SCLC patients
to repeat WBRT. Sadikov et al. reported that 72 patients with multiple metastases. Overall, patients with SCLC had
having undergone repeat radiation treatment had a poor treatment outcome. SCLC is a potential predicator for
median survival of 4.1 months. In the same vein, Wong both worse CNS control and worse overall survival. In this
10
et al. reported a nearly identical median survival, i.e., study, none of the recruited SCLC patients having three
4 months, from an analysis involving 86 patients. While or more metastases did not have subsequent CNS failure.
2
survival for patients who had undergone repeat WBRT was Our data also underline the need to exercise caution in
shorter than those treated with SRS, this difference may be treating relapsed SCLC with multiple brain metastases and
secondary to bias in patient selection. to evaluate alternative treatment options such as systemic
There are several other limitations in this study, as well therapy, observation, and best supportive care. 14,15
as other relevant studies. While data for some variables 5. Conclusion
were prospectively collected, data for certain variables were
retrospectively collected. Furthermore, given the nature Salvage SRS after WBRT is a safe and effective treatment
of the illness, many patients were lost to follow-up. In approach for the majority of patients, irrespective of the
addition, some essential information, such as information time interval from WBRT. A subset of SCLC patients with
on chemotherapy, immunotherapy and targeted therapy, multiple brain metastases had an overall bad treatment
reasons for WBRT, and degree of extra-cranial disease, that outcome, and thus, alternative treatment options for this
are very instrumental to this analysis were not recorded. subset should be explored.
Determining local failure versus radiation necrosis is a
very challenging endeavor, and although some patients had Acknowledgments
been biopsied, such determination was often made based None.
on dynamic MRI imaging and tumor board discussion.
Funding
The findings from this study contribute significantly
to our understanding about the efficacy of this treatment None.
approach. First, the lack of correlation of the time from
WBRT failure with poor SRS outcome, even when the Conflict of interest
patients had CNS failure within 60 days of WBRT, The authors declare that they have no competing interests.
underscores the potential of salvage SRS treatment
regardless of time of failure after WBRT. Second, we also Author contributions
detected a difference in survival after SRS based on the Conceptualization: Gregory J. Kubicek, Howard Warren
number of treated brain metastases. As expected, patients Goldman
with fewer brain metastases had better survival compared Formal analysis: Badal Juneja
to patients with multiple brain metastases treated with Investigation: Natasha Mathur
salvage SRS (Figure 1). Importantly, we did not observe Methodology: Gregory J. Kubicek
an increase in distant brain failure related to the number Writing – original draft: Natasha Mathur
of treated brain metastases; this finding is expected since Writing – review & editing: Badal Juneja, Alan Turtz,
patients with multiple treated brain metastases typically Howard Warren Goldman, Qianyi Xu, Dave Mulvihill,
have reduced survival and thus shortened time for distant Gregory J. Kubicek
brain failure to develop and manifest. We found that
patients with multiple metastases had survival outcomes Ethics approval and consent to participate
comparable to those treated with repeat WBRT. In this
study, the median survival for patients with multiple This study is approved by IRB, Cooper Medical School
metastases was 5 months, slightly higher than the median of Rowan University (Approval no. EX1092). Per IRB
survival of 4 months in patients undergoing repeat WBRT individual patient consent was waived.
reported in other studies. Despite the overall poor Consent for publication
2,10
survival outcomes for multiple brain metastases after
WBRT failure, salvage SRS stands as a better and preferred Informed consent was waived by the IRB.

Volume 2 Issue 1 (2024) 4 https://doi.org/10.36922/arnm.2231