Author's Reply.

We would like to thank our colleagues for their interest in our manuscript and their question to clarify certain issues presented in that manuscript.[1]

To address the first question, the diagnosis of bone metastasis is done by imaging using bone scans or positron emission tomographic scan and sometimes with magnetic resonance imaging if the spine is involved or to delineate a vague nonspecific lesion. We do not use biopsy of bone lesions except in rare circumstances when there is a single metastatic lesion in the bone that is not characteristic of the primary disease. The other scenario to have a bone biopsy is when an orthopedic surgeon obtains tissue during an open fixation of a bone fracture.

The second question is whether including early-stage lung cancer patients is the correct methodology.

Our methodology and the study design were to include all lung cancer patient population, not just metastatic disease to make sure we assess the impact of bone disease on the whole population of lung cancer. We believed that this is a better denominator to get the complete picture for lung cancer population.

The liver and bone metastases are overwhelmingly multiple. We rarely have a patient with single bone metastatic lesion and single liver lesion at the same time. We do not have the number of liver lesions in our database which will require reviewing all the records again for a question that may not have major impact but can be considered in future studies.

At present, when we are encountering patients with oligometastatic disease including the bone or the liver, we are approaching these patients with radiosurgery; especially, in the setting of good disease control for tumor with actionable driver mutation.[23]