In Reply to Drs. Larson and Sahgal

Multi-institutional competing risks analysis of distant brain failure and salvage patterns after upfront radiosurgery without whole brain radiotherapy for brain metastasis

Background

In this study, we use a competing risks analysis to assess factors predictive of early-salvage whole brain radiotherapy (WBRT) and early death after upfront stereotactic radiosurgery (SRS) alone for brain metastases in an attempt to identify populations that benefit less from upfront SRS.

Patients and methods

Patients from eight academic centers were treated with SRS for brain metastasis. Competing risks analysis was carried out for distant brain failure (DBF) versus death prior to DBF as well as for salvage SRS versus salvage WBRT versus death prior to salvage. Linear regression was used to determine predictors of the number of brain metastases at initial DBF (nDBF).

Results

A total of 2657 patients were treated with upfront SRS alone. Multivariate analysis (MVA) identified an increased hazard of DBF associated with increasing number of brain metastases (P < 0.001), lowest SRS dose received (P < 0.001), and melanoma histology (P < 0.001), while there was a decreased hazard of DBF associated with increasing age (P < 0.001), KPS < 70 (P < 0.001), and progressive systemic disease (P = 0.004). MVA for first salvage SRS versus WBRT versus death prior to salvage revealed an increased hazard of first salvage WBRT seen with increasing number of brain metastases (P < 0.001) and a decreased hazard with widespread systemic disease (P = 0.002) and increasing age (P < 0.001). Variables associated with nDBF included age (P = 0.02), systemic disease status (P = 0.03), melanoma histology (P = 0.05), and initial number of brain metastases (P < 0.001).

Conclusions

Patients with a higher initial number of brain metastases were more likely to experience DBF, have a higher nDBF, and receive early-salvage WBRT, while patients who were older, had lower KPS, or had more systemic disease were more likely to experience death prior to DBF or salvage WBRT.

The Future Is Now-Prospective Study of Radiosurgery for More Than 4 Brain Metastases to Start in 2018!

Stereotactic radiosurgery (SRS) has replaced whole brain radiotherapy (WBRT) as standard therapy for most patients with four or fewer brain metastases due to improved cognitive outcomes and more favorable health related quality of life (QoL). Whether SRS or WBRT is the optimal radiation modality for patients with five to fifteen brain metastases remains an open question. Efforts are underway to develop prospective evidence to answer this question. One of the planned trials is a Canadian Cancer Trials Group (CCTG)-lead North American intergroup trial. In general cancer treatments must have two basic aims: prolonging and improving QoL. In this vein, the selection of overall survival and QoL metrics as outcomes appear obvious. Potential secondary outcomes are numerous: patient/disease related, treatment related, economic, translational, imaging, and dosimetric. In designing a trial, one must also ponder what is standard WBRT—specifically, whether it should be associated with memantine. With the rapid accrual of an intergroup trial of hippocampal-sparing WBRT, we may find that the standard WBRT regimen changes in the course of planned trials. As up-front radiosurgery is increasingly used for more than 4 brain metastases without high level evidence, we have a window of opportunity to develop high quality evidence which will help guide our future clinical and policy decisions.

Quality of life and efficacy of temozolomide combined with whole-brain radiotherapy in patients with brain metastases from non-small-cell lung cancer

The aim of the present study was to investigate the efficacy and life quality of temozolomide (TMZ) combined with whole-brain radiotherapy (WBRT) for patients with brain metastases (BM) from non-small-cell lung cancer (NSCLC). A total of 77 cases of patients with lung cancer and BM were selected and divided into two groups; the first group was administered WBRT with TMZ, and the second group was administered WBRT with placebo. The efficacy, overall survival (OS) and quality of life (QoL) were then compared between the two groups. There were no significant differences in toxicity between the two groups. However, the first group exhibited an advantage over the second group in terms of objective response and OS (P<0.5). Therefore, WBRT may improve the QoL of patients with BM. TMZ concomitantly with WBRT was well-tolerated and may be recommended for the treatment of BM from NSCLC.

Radiosurgery to the postoperative surgical cavity: who needs evidence?

There is a growing interest in adjuvant radiosurgery after resection of hematogenous brain metastases. This is exemplified by the approximately 1000 cases reported in mainly retrospective series. These cases fall into four paradigms: adjuvant radiosurgery as an alternative to whole-brain radiotherapy (WBRT), radiosurgery neoadjuvant to the surgical resection, radiosurgery as an intensification of adjuvant WBRT, and adjuvant radiosurgery for patients having failed prior WBRT. These procedures seem well tolerated, with an approximate 5% risk of radiation necrosis. Although crude local control rates for each strategy seem improved over surgery alone, multiple biases make comparisons with standard WBRT difficult without prospective data. Because evidence lags behind clinical practice, an upcoming intergroup trial will aim to clarify the value of the most common tumor bed radiosurgery strategy by randomizing oligometastatic patients between adjuvant WBRT and adjuvant radiosurgery.

Management of brain metastases

OPINION STATEMENT

As systemic cancer therapies have improved, the natural history and importance of treating brain metastases continues to evolve. Historically, most patients with brain metastases have been managed with whole brain radiation therapy (WBRT) with surgical resection or radiosurgery added for patients with single or few metastases. Because the potential late toxicity of WBRT is increasingly recognized when systemic tumor is more effectively controlled, there has been increased interest in the use of focal therapies such as radiosurgery with deferred WBRT even for patients with larger numbers of metastases. Although WBRT in combination with radiosurgery or surgical resection significantly reduces central nervous system recurrences at the treated site and elsewhere in the brain, it is not clear whether a patient's quality of life is more affected by tumor recurrence or by treatment with WBRT. In our practice, most patients with fewer than 7 to 10 tumors are treated with radiosurgery alone, with WBRT initially deferred because of concerns about its late toxicity. The ongoing technical improvements in radiosurgery have made this transition away from WBRT clinically feasible. This approach also allows patients to begin systemic therapy sooner, rather than waiting 2 to 4 weeks to complete WBRT. For patients with large or very symptomatic tumors, surgical resection is performed, followed by postoperative radiosurgery to the resection cavity, again initially deferring WBRT for many patients. This focal-only approach in the postoperative setting is associated with a higher rate of subdural dissemination and needs further prospective study, as some would argue that tumor progression is the major determinant of loss of function. Ultimately, better survival will require better systemic therapy that both controls extracranial disease and penetrates the brain to reduce intracranial recurrences. Unfortunately, many clinical trials of novel agents exclude patients with brain metastases.