Letter to the Editor. Laser ablation after stereotactic radiosurgery

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TO THE EDITOR: I read with great interest the article by Ahluwalia et al.1 (Ahluwalia M, Barnett GH, Deng D, et al: Laser ablation after stereotactic radiosurgery: a multicenter prospective study in patients with metastatic brain tumors and radiation necrosis. J Neurosurg [epub ahead of print May 4, 2018; DOI: 10.3171/2017.11.JNS171273]). Having treated post-stereotactic radiosurgery (SRS) brain metastases in multiple ways, including via laser interstitial thermal therapy (LITT), I am intrigued by the emerging data on the role of LITT in this patient population.2–5 I disagree with the authors’ conclusion that “LITT is a low-risk surgical procedure” that “should be considered in those who are surgically eligible.” The study does not present sufficient evidence to support the broad use of LITT over craniotomy for post-SRS brain metastases and demonstrates less efficacy than would be expected for treatment with craniotomy.

Thirty-seven percent of patients were lost to follow-up at 12 weeks and 62% of patients were lost to follow-up at 26 weeks. Given this amount of discontinuation in a study that started with 44 patients, it is challenging to draw any conclusions. That said, the patient population is relatively healthy for a cohort of individuals with brain metastases with a mean age of 58.5 years and exclusion criteria that included serious systemic medical illnesses and the need for ongoing anticoagulation or antiplatelet therapy. Within this group of favorable surgical candidates, 12% experienced an immediate neurological complication and 33% had surgery-related adverse effects. These complication rates are higher than what would be expected for similar patients undergoing craniotomy.7–9

A key differentiator between LITT and craniotomy is the degree of postoperative cerebral edema, and the subsequent requirement of corticosteroids, and this topic was not addressed in the article. Following intracranial laser ablation the lesion initially increases in size, and subsequent lesion size reduction occurs over the following 3–60 days.6 There is an inflammatory reaction in the perilesional normal brain and resultant cerebral edema that persists until the lesion abates. This results in a corticosteroid requirement often up to or longer than 1 month. This contrasts with a craniotomy for lesion resection that may cause increased cerebral edema from surgical manipulation for 24 hours and typically results in a rapid reduction in cerebral edema and the need for corticosteroids over 1 week. Of note, only 31% of patients were able to stop or reduce steroid usage at the 12-week follow-up, again a stark contrast to what would be expected following a craniotomy for lesion resection.

A clinical trial directly comparing LITT to craniotomy for post-SRS brain metastases would be incredibly useful. Although LITT has proven to be an exciting new neurosurgical tool, the current evidence, including this article, does not support its broad use when treating post-SRS brain metastases, and its role in this patient population may be limited to smaller, deep-seated lesions. The degree of cerebral edema created by LITT versus the reduction in cerebral edema following craniotomy is a key advantage of craniotomy for this pathology.

Disclosures

The author reports no conflict of interest.

References

  • 1

    Ahluwalia MBarnett GHDeng DTatter SBLaxton AWMohammadi AM: Laser ablation after stereotactic radiosurgery: a multicenter prospective study in patients with metastatic brain tumors and radiation necrosis. J Neurosurg [epub ahead of print May 4 2018. DOI: 10.3171/2017.11.JNS171273]

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  • 2

    Fabiano AJAlberico RA: Laser-interstitial thermal therapy for refractory cerebral edema from post-radiosurgery metastasis. World Neurosurg 81:652.e1652.e42013

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  • 3

    Fabiano AJQiu J: Delayed failure of laser-interstitial thermotherapy for postradiosurgery brain metastases. World Neurosurg 82:e559e5632014

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  • 4

    Fabiano AJQiu J: Post-stereotactic radiosurgery brain metastases: a review. J Neurosurg Sci 59:1571672015

  • 5

    Fanous AAFabiano AJ: Bevacizumab for the treatment of post-stereotactic radiosurgery adverse radiation effect. Surg Neurol Int 7:S542S5442016

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    • Search Google Scholar
    • Export Citation
  • 6

    Medvid RRuiz AKomotar RJJagid JRIvan MEQuencer RM: Current applications of MRI-guided laser interstitial thermal therapy in the treatment of brain neoplasms and epilepsy: a radiologic and neurosurgical overview. AJNR Am J Neuroradiol 36:199820062015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Patel AJSuki DHatiboglu MARao VYFox BDSawaya R: Impact of surgical methodology on the complication rate and functional outcome of patients with a single brain metastasis. J Neurosurg 122:113211432015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Sawaya R: Surgical treatment of brain metastases. Clin Neurosurg 45:41471999

  • 9

    Tan TCBlack PMLunsford LDBarnett GHGutin PHBruce JN: Image-guided craniotomy for cerebral metastases: techniques and outcomes. Neurosurgery 53:82902003

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    • Search Google Scholar
    • Export Citation
Keywords:

Response

Thank you to Dr. Fabiano for his letter about the Laser Ablation After Stereotactic Radiosurgery (LAASR) study.

While we agree that the rate of loss to follow-up was high in this study, similar findings have been noted in other trials in patients with brain metastases, which is a concern especially because neurocognition and quality of life is important in this patient population. In the landmark trial on the effect of SRS alone versus SRS with whole-brain radiation therapy (WBRT) on cognitive function in patients with 1–3 brain metastases, the primary endpoint was cognitive deterioration at 3 months.2 Only 79 of the 111 patients randomized to SRS alone and 72 of the 102 randomized to SRS plus WBRT completed the 3-month evaluation, indicating an approximately 30% drop-off at 12 weeks. The patients in the SRS versus SRS plus WBRT study were an upfront brain metastases population, and the patient population in the LAASR study are those in whom prior SRS failed; hence they were a sicker patient population by definition.

Similarly, the proposed comparison to the surgical literature provided is not appropriate because LITT is being used for metastases in which radiosurgery has failed and not as first-line treatment of patients with single intracranial lesions. What was noted in this study is important: sick patients, especially those with multiple brain metastases, have a hard time following up in the study scenario. There are no data in the literature to show rates of accrual and drop-out for craniotomy as studied in our trial. In addition, rates of surgery-related complications are also not comparable to the literature cited because the patient population studied in the LAASR trial is a group with dismal outcomes and who are intrinsically at high risk for complications even without surgery. The only comparative study available in the literature is a meta-analysis of LITT versus craniotomy for high-grade glioma by Barnett et al., and the rate of major complications for LITT was less than half the rate for craniotomy (5.7% vs 13.8%).1

What this effort emphasized is that patients who otherwise might not entertain surgery are willing to consider a minimally invasive surgical procedure. For the majority of these patients, especially those with radiation necrosis, an excellent outcome can be achieved. Evidence from the epilepsy literature shows clearly how much easier recovery from LITT is than recovery from a craniotomy.3 The patient populations that are agreeing to undergo LITT are therefore not likely to be the same as those agreeing to craniotomy. Although a randomized study is theoretically ideal to compare the two tools, in our experience there is a high likelihood that accrual to this study would be difficult given the perceived differences in the invasiveness of the procedures by the patient.

References

  • 1

    Barnett GHVoigt JDAlhuwalia MS: A systematic review and meta-analysis of studies examining the use of brain laser interstitial thermal therapy versus craniotomy for the treatment of high-grade tumors in or near areas of eloquence: an examination of the extent of resection and major complication rates associated with each type of surgery. Stereotact Funct Neurosurg 94:1641732016

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    • Search Google Scholar
    • Export Citation
  • 2

    Brown PDJaeckle KBallman KVFarace ECerhan JHAnderson SK: Effect of radiosurgery alone vs radiosurgery with whole brain radiation therapy on cognitive function in patients with 1 to 3 brain metastases: a randomized clinical trial. JAMA 316:4014092016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Hoppe CWitt JAHelmstaedter CGasser TVatter HElger CE: Laser interstitial thermotherapy (LiTT) in epilepsy surgery. Seizure 48:45522017

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Article Information

Contributor Notes

Correspondence Andrew J. Fabiano: andrew.fabiano@roswellpark.org.INCLUDE WHEN CITING Published online September 28, 2018; DOI: 10.3171/2018.7.JNS181847.Disclosures The author reports no conflict of interest.
Headings
References
  • 1

    Ahluwalia MBarnett GHDeng DTatter SBLaxton AWMohammadi AM: Laser ablation after stereotactic radiosurgery: a multicenter prospective study in patients with metastatic brain tumors and radiation necrosis. J Neurosurg [epub ahead of print May 4 2018. DOI: 10.3171/2017.11.JNS171273]

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Fabiano AJAlberico RA: Laser-interstitial thermal therapy for refractory cerebral edema from post-radiosurgery metastasis. World Neurosurg 81:652.e1652.e42013

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3

    Fabiano AJQiu J: Delayed failure of laser-interstitial thermotherapy for postradiosurgery brain metastases. World Neurosurg 82:e559e5632014

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4

    Fabiano AJQiu J: Post-stereotactic radiosurgery brain metastases: a review. J Neurosurg Sci 59:1571672015

  • 5

    Fanous AAFabiano AJ: Bevacizumab for the treatment of post-stereotactic radiosurgery adverse radiation effect. Surg Neurol Int 7:S542S5442016

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6

    Medvid RRuiz AKomotar RJJagid JRIvan MEQuencer RM: Current applications of MRI-guided laser interstitial thermal therapy in the treatment of brain neoplasms and epilepsy: a radiologic and neurosurgical overview. AJNR Am J Neuroradiol 36:199820062015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Patel AJSuki DHatiboglu MARao VYFox BDSawaya R: Impact of surgical methodology on the complication rate and functional outcome of patients with a single brain metastasis. J Neurosurg 122:113211432015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Sawaya R: Surgical treatment of brain metastases. Clin Neurosurg 45:41471999

  • 9

    Tan TCBlack PMLunsford LDBarnett GHGutin PHBruce JN: Image-guided craniotomy for cerebral metastases: techniques and outcomes. Neurosurgery 53:82902003

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 1

    Barnett GHVoigt JDAlhuwalia MS: A systematic review and meta-analysis of studies examining the use of brain laser interstitial thermal therapy versus craniotomy for the treatment of high-grade tumors in or near areas of eloquence: an examination of the extent of resection and major complication rates associated with each type of surgery. Stereotact Funct Neurosurg 94:1641732016

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Brown PDJaeckle KBallman KVFarace ECerhan JHAnderson SK: Effect of radiosurgery alone vs radiosurgery with whole brain radiation therapy on cognitive function in patients with 1 to 3 brain metastases: a randomized clinical trial. JAMA 316:4014092016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Hoppe CWitt JAHelmstaedter CGasser TVatter HElger CE: Laser interstitial thermotherapy (LiTT) in epilepsy surgery. Seizure 48:45522017

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