While it was previously thought that a subset of patients with limited metastatic disease could potentially achieve long-term survival, established approaches for treating patients with radiation therapy or surgery other than for palliative purposes were lacking prior to single-institutional data emerging over the past 10-15 years that suggest a survival benefit in selected patients when compared with historical controls treated with systemic therapy alone.
To confirm these data in a randomized manner, using progression-free survival as an endpoint, Daniel R. Gomez, MD, and colleagues designed a trial in which patients with oligometastatic lung cancer who did not progress after induction therapy were allocated to one of two treatment regimens in a 1:1 ratio: standard maintenance therapy/observation (MT/O) or aggressive radiation therapy/surgery, which the study team termed local consolidative therapy (LCT). “We tracked toxicity but our primary endpoint was progression free survival (PFS), with relevant secondary endpoints being overall survival and the time to development of new lesions,” explains Dr. Gomez, whose study results were published in the Journal of Clinical Oncology.
“Our study was closed early by our data safety monitoring board because we found a substantial benefit in PFS with LCT compared with standard care,” Dr. Gomez notes. Indeed, with an updated median follow-up of 38.8 months, the PFS benefit was 14.2 months, compared with 4.4 months with MT/O. The LCT group also experienced an overall survival benefit, with a median of 41.2 months, compared with 17.0 months in the MT/O group, as well as longer survival after progression (37.6 months vs 9.4 months). No additional grade 3 or greater toxicities were observed. Among patients in the MT/O group who experienced progression, nearly half received LCT to all lesions following progression and had a median overall survival of 17 months.
“I would view this data as provocative in demonstrating the benefit of LCT for patients with oligometastatic disease,” says Dr. Gomez. However, there are limitations that need to be taken into account when interpreting the data, primarily the small size of the trial, the heterogeneous population, and the fact that it was done in the pre-immunotherapy era. Future studies should attempt to expand on the existing data by addressing these constraints.”