Optimal dose and volume for postoperative radiotherapy in brain oligometastases from lung cancer: a retrospective study

Abstract

PurposeTo evaluate intracranial control after surgical resection according to the adjuvant treatment received in order to assess the optimal radiotherapy (RT) dose and volume.Materials and MethodsBetween 2003 and 2015, a total of 53 patients with brain oligometastases from non-small cell lung cancer (NSCLC) underwent metastasectomy. The patients were divided into three groups according to the adjuvant treatment received: whole brain radiotherapy (WBRT) ± boost (WBRT ± boost group, n = 26), local RT/Gamma Knife surgery (local RT group, n = 14), and the observation group (n = 13). The most commonly used dose schedule was WBRT (25 Gy in 10 fractions, equivalent dose in 2 Gy fractions [EQD2] 26.04 Gy) with tumor bed boost (15 Gy in 5 fractions, EQD2 16.25 Gy).ResultsThe WBRT ± boost group showed the lowest 1-year intracranial recurrence rate of 30.4%, followed by the local RT and observation groups, at 66.7%, and 76.9%, respectively (p = 0.006). In the WBRT ± boost group, there was no significant increase in the 1-year new site recurrence rate of patients receiving a lower dose of WBRT (EQD2) <27 Gy compared to that in patients receiving a higher WBRT dose (p = 0.553). The 1-year initial tumor site recurrence rate was lower in patients receiving tumor bed dose (EQD2) of ≥42.3 Gy compared to those receiving <42.3 Gy, although the difference was not significant (p = 0.347).conclusionsAdding WBRT after resection of brain oligometastases from NSCLC seems to enhance intracranial control. Furthermore, combining lower-dose WBRT with a tumor bed boost may be an attractive option.

Boost Irradiation Integrated to Whole Brain Radiotherapy in the Management of Brain Metastases

“…They rather suggest considering the use of selective neuroprotective agent (memantine) and hippocampus-sparing WBRT technique [36,37]. Chung et al [15]. applied a lower WBRT dose with a boost to the tumour bed after metastasectomy, since WBRT neurotoxicity is associated with the total dose and fractionation [38].…”

“…However, as for the OS, neither the treatment with SRS nor with SIB did result in any statistically significant difference, the SIB was associated with reduced intracranial impairment, likely due to the WBRT component of the treatment (HR 0.36, p < 0.001). Similarly for single and oligometastatic brain spread, several randomised clinical studies have proven the better outcome in terms of local and intracranial disease control with combined treatment approaches, such as surgery +WBRT, SRS + WBRT, or SIB; but in the majority of the cases these encouraging results could not be transformed into significantly improved survival [13,15,28,[42][43][44].…”

“…The ASCO recommendation in 2014 did not include the routine addition of WBRT to SRS for limited brain metastases, based on meta-analysis of published clinical research [12,13]. However, it could be substantially criticised and several arguments (including survival benefit, notable increase of intracerebral impairments, and more serious neurocognitive decline due to metastatic progression in the brain) support the further application of combined approaches including the WBRT [14,15].…”

Current surgical management of extrapulmonary oligometastatic non-small cell lung carcinoma

“…Postoperative radiotherapy prevented brain recurrence at the site of the original metastasis and at other sites in the brain (p ˂ 0.001) [39]. Similarly, Chung et al also advised WBRT after resection of brain oligometastasis due to NSCLC [40]. According to Chung et al WBRT seems to enhance intracranial control [40].…”

“…Similarly, Chung et al also advised WBRT after resection of brain oligometastasis due to NSCLC [40]. According to Chung et al WBRT seems to enhance intracranial control [40]. However, according to the series of Abacioglu et al, opposite to this option, an addition of WBRT did not have any effect on overall survival [35].…”