Table 3 Highlighted gaps in the research field identified by the scoping review, with associated research initiatives

• Studies focused on patient-related outcomes, such as perceived quality of life indicators

• Substantial lack of prospective comparative trials

• Knowledge regarding the prognosis and survival of patients with MBD-E, especially in those who undergo a surgical intervention, including en bloc resection

• Knowledge regarding survival outcomes of MBD-E patients in the setting of new targeted biologic therapies

• Understanding of the health resource and economic implications of MBD-E and its surgical management

• Lack of evidence based multi-disciplinary clinical decision-making approaches and algorithms, as well as for surgical adjuncts such as radiotherapy

• Patient and family surveys, multi-disciplinary meetings and trial planning to assess identified knowledge gaps and patient-related outcomes

• Development and validation of a patient-related outcome measurement tool for MBD-E

• Further development of prospective, multi-centered registries for patients with MBD-E

• Further research into economic implications of MBD-E and associated surgical interventions

• Assessing the utility of en bloc resection vs. stabilization in oligometastatic disease [31]