Stereotactic ablative body radiation for oligometastatic and oligoprogressive disease

Abstract

Stage IV non-small cell lung cancer (NSCLC) exists on a spectrum, with a subset of patients presenting with oligometastatic disease involving only a limited number of distant sites. For these patients, local consolidative therapy (LCT) has been demonstrated to improve outcomes through ablation or cytoreduction of metastatic disease, as shown in an increasing number of randomized controlled trials. In particular, stereotactic ablative body radiation (SABR) has emerged as a feasible treatment modality for elimination of oligometastatic sites. This focused review examines the underlying biologic mechanisms and clinical data in support of SABR in the setting of oligometastatic NSCLC. Following a comprehensive evaluation of the pertinent retrospective, prospective, and anticipated trials to date, we summarize the evidence regarding patient selection, treatment safety, and technical considerations to provide guidance of this approach for clinicians.

Keywords: Stereotactic ablative body radiation (SABR); consolidative radiation; lung cancer; non-small cell lung cancer (NSCLC); oligometastatic; oligoprogressive; stereotactic body radiation therapy (SBRT).

Figure 1

Example case report of the use of SABR in consolidative RT for oligometastatic NSCLC. (A) A 72-year-old male with T3N2M1b NSCLC presenting with 3-cm RUL lesion, 1.5-cm satellite RUL lesion, right hilar and lower paratracheal adenopathy, and solitary splenic lesion, biopsy-proven as oligometastasis. Following induction cisplatin/pemetrexed ×4 c; (B) he received concurrent chemo-RT to 66 Gy in 33 fxs to the thorax; (C) followed by SBRT to 50 Gy in 4 fxs to the spleen. NED for 30 months until progression and alive nearly 5 years post-RT. SABR, stereotactic ablative body radiation; NSCLC, non-small cell lung cancer; RUL, right upper lobe; SBRT, stereotactic body radiation therapy; NED, no evidence of disease.