Judging a Fish by Its Ability to Climb a Tree? A Call for Novel Endpoints in the Appraisal of Ablative Local Treatments of Oligometastatic Cancer

Abstract

This commentary addresses the need for novel endpoints in clinical research to assess the added value of local treatment of metastases in oligometastatic patients and in patients experiencing limited metastatic progression during systemic therapy (oligoprogressive). Novel metrics are proposed for future implementation in clinical trials.

Figures

Figure 1

Natural history of oligometastatic disease considering integration of ablative local treatments (ALT). (A): Multimodal management of primary tumor (P). (B): Oligometastatic relapse consisting of a viable metastasis (black dot) treated with surgical or radiation ALT. (C): Stable remission of the ALT‐treated metastasis (white dot) and second course of ALT to novel active metastases (black dot). (D): Stable remission of the ALT‐treated metastases and onset of 3 metastases not amenable to ALT to all disease sites (black dots), resulting in first‐line systemic therapy initiation. (E): Polymetastatic conversion, requiring second‐line systemic therapy. (F): Oligoprogression consisting of 3 oligoprogressive metastases (black dots) treated with ALT and stable remaining disease (grey dots), resulting in second‐line systemic therapy continuation. (G): Polymetastatic progression (black dots) under second‐line systemic therapy, not amenable to ALTs and initiation of third‐line systemic therapy. (H): Death.Abbreviations: ALT‐DFS, ablative local treatments‐disease‐free survival; DFS, disease‐free survival; OS, overall survival; PFS, progression‐free survival; PFS‐1, progression‐free survival with first line systemic therapy; PFS‐2, progression‐free survival with second line systemic therapy; SA‐PFS, systemic therapy plus‐adjusted progression‐free survival; WSPFS, widespread progression‐free survival.