What is the most useful next investigation for assessing suitability for surgical resection in a patient with squamous cell lung carcinoma?

The most useful next investigation for assessing suitability for surgical resection in a patient with squamous cell lung carcinoma is a PET-CT scan. This imaging modality is particularly valuable for several reasons in the context of lung cancer evaluation.

Firstly, the PET-CT scan provides detailed information about the metabolic activity of the tumor and can help identify any distant metastases that may not be evident on traditional imaging. This is crucial for determining whether a patient is a suitable candidate for surgery, as the presence of metastases can significantly alter the management plan.

Secondly, a PET-CT scan can help in assessing the lymph nodes for involvement, which is critical in staging the disease. Accurate staging is essential for deciding on surgical resection versus other treatment options, such as chemotherapy or radiotherapy.

In contrast, while other investigations like bone scans can identify bone metastases, they do not provide comprehensive information about the thoracic structures involved with lung cancer. Cardiopulmonary exercise testing evaluates the functional capacity of the lungs and heart, which is important but does not give information about the extent of disease. A ventilation/perfusion isotope lung scan primarily assesses lung function rather than staging or metastasizing of lung cancer, making it less relevant for surgical planning.

Thus, the PET