Cancer patients are often given the choice of delaying or avoiding treatment as one of their options. However, there is not much information guiding lung cancer patients and their clinicians regarding this approach. Active surveillance is a way of either delaying or avoiding treatment and its possible side effects through carefully watching for changes in the tumor and considering treatment if there is progression. The purpose of this research study is to evaluate active surveillance and ways to better understand if and when to treat patients with stage IA lung cancer.

The University of Vermont Medical Center is looking at determining if active surveillance is a viable option for low risk lung cancer patients. Currently, the National Cancer Care Network (NCCN) guidelines recommends considering stereotactic ablative radiotherapy (SABR) for patients not well enough for surgery, which is generally well tolerated, but it's also been shown to cause significant worsening of shortness of breath, fatigue, chest pain, and in extreme cases, death. Investigators are using this pilot study as a means to determine outcomes for patients who choose an active surveillance approach. This information could change future conversations between doctor and patient regarding treatment options, giving patients the choice to choose radiation therapy or to delay treatment by taking an active surveillance approach.

Investigators have published outcomes for 12 elderly patients with stage IA lung cancer who had chosen the active surveillance approach, reserving radiation therapy for when rapid tumor growth was determined (PMID 30648024). The clinical outcomes were similar to those expected if treatment had been provided, and at two years from the time the tumor was found almost half the patients were able to avoid getting radiation.

By deciding to participate in this study, patients are agreeing to postpone their treatment for an active surveillance approach while continuing with a computed tomography (CT) scan regimen to follow tumor growth. Once their tumor size is determined there are parameters in place to decide when patients should consider radiation. These parameters are based on speed of tumor growth over time and tumor size.

Main Cohort Inclusion Criteria:

• Patient at UVMCC.
• Has pathologically proven recent diagnosis (≤180 days) of solitary or multifocal Stage T1a/b/c, N0, M0 [AJCC Staging, 8th Ed.] non-small cell lung cancer [NSCLC] or carcinoid tumors.
• History & physical ≤90 days prior to enrollment.
• Tumors may have a solid component of any magnitude ≤3 cm.
• Age ≥65 years old.
• Charlson Comorbidity Index [CCI] ≥6 within 90 days prior to enrollment.
• Zubrod performance status of 0-3 within 90 days prior to enrollment.
• Deemed unresectable or "medically inoperable" due to medical co-morbidities. Otherwise operable patients who decline surgery are considered inoperable.
• Eligible to receive treatment via SABR at the discretion of the treating oncologist.
• CT scan of the chest (contrast preferred) ≤90 days of enrollment with slice thickness ≤3 mm.
• Whole body PET scan ≤90 days prior to enrollment. [Preferably before biopsy performed]

Correlative Science Only Cohort Inclusion Criteria:

• Patient at UVMCC.
• Patients who have been followed via active surveillance > 180 days already may enroll in the correlative science only cohort for the purpose of blood draws only, regardless of reason active surveillance was chosen.
• Pathologically proven diagnosis (>180 days prior to enrollment) of solitary or multifocal Stage T1a/b/c, N0, M0 [AJCC Staging, 8th Ed.] non-small cell lung cancer [NSCLC] or carcinoid tumors.
• History & physical ≤90 days prior to enrollment.
• Any age.
• Any Charlson Comorbidity Index [CCI].
• Zubrod performance status of 0-3 within 90 days prior to enrollment.
• Can be medically operable or inoperable with any medical co-morbidities.
• CT scan of the chest (contrast preferred) ≤90 days around (before or after) enrollment with slice thickness ≤3 mm. [Frequency as deemed appropriate by managing oncologist].
• Whole body PET/CT scan [Not required pre-enrollment, and frequency as deemed appropriate by managing oncologist].

Exclusion Criteria (both cohorts):

• Prior radiation treatment of the study NSCLC.
• Prior receipt of any systemic treatment for the study NSCLC.