Is a 0.5 cm lung nodule in colon cancer pt regarded a small ? can it be ablated ?

Depends on what: the nodule is. If the nodule is a met from colon cancer, then ablating this apparent solitary nodule is not likely to affect the course of the disease. Calling is small or large is not relevant, the nature of the lesions needs to be ascertained.

Resected: It should be resected for pathology and if positive it will be stage 4 and treatment will be different.