Editing Lung nodules (section)

== Specific guidance ==

* Size-based
** Nodules >3cm should be treated as bronchogenic carcinoma until proven otherwise
** Nodules <=8mm without documented growth are often followed with serial CT
** Nodules <=5mm have a malignancy rate of 1%, whereas those >2cm have a rate of up to 82%
* Growth-based
** Volume doubling in <20 days is considered indicative of infectious or inflammatory processes
** Volume doubling between 20 and 400 days is suspicious for malignancy
** Stability over >400 days implies benign process (granuloma or hamartoma), and nodules stable over 2 years are considered clinically benign (beware that some adenocarcinomas can be very slow-growing - be more careful with subsolid lesions)
** Malignant nodules can decrease in size due to necrosis/fibrosis, however all malignant lesions will grow over a long enough time period
* Indeterminate lung nodules >1cm should be assessed with FDG-PET/CT
** Likelihood of malignancy increases as SUV-max increases
** Small lesions <1cm are challenging to pick up on PET
* Solid lesions stable for 2 years and subsolid lesions stable for 5 years are likely to be benign, and can be signed off on
* Recent pneumonia - repeat the scan in 4-6 weeks, provided no other concerning features
* Lots of systemic features but small nodule - suspect metastases or lymphoma
* Multiple nodules - consider metastatic disease, reaction to chemotherapy, secondary infection in immunosuppressed patients, other inflammatory process - if no concerning features, may be appropriate for repeat scan in 3-6 months