Radiation CT Scans for Lung Cancer – Navid Zanooz, MD


The use of imaging plays a critical roll in
the detection, diagnosis and staging of lung cancer. We spoke to Dr. Navid Zanooz at Desert
Comprehensive Cancer Center at Desert Regional Medical Center. Dr. Zanooz talks about CT
Scan vs. X-ray. A low dose CT Scan is able to detech much
more malignant nodules compared to a chest X-ray. In fact there was a large trial nationalwide:
one group was receiving annual chest X-rays for 3 years, the other group low dose CT Scan
for 3 years and the results of that trial showed that the group that received CT Scan
had 20% less death rate compared to the group that received chest X-ray. Who would be a
candidate for lung cancer screening. Smoking is responsible for at least 90% of the lung
cancer cases. Two groups of individuals are considered high risk for lung cancer. The
first group is people who are between ages of 55 and 74 and have had at least 30 pack
years of smoking or ex smokers who have quit in the last 15 years and the second group
are individuals who are at least 50 years old with more than 20 pack year smoking and
one additional risk factor. By additional risk factor I mean, either occupational exposure
radon exposure, having another malignancy in the past where which they were treated
like lymphoma or head and neck cancer that they received radiation therapy for and having
positive family history of lung cancer or history prior underlying diseases in the lung
such as pulmonary fibrosis or COPD. We ask Dr. Zanooz to explain the CT Scan procedure.
The procedure is non invasive, completely non invasive. So patient go check in, they
wait for a few minutes then the technologists will put them on a table and the scan takes
a couple of minutes at most. Thoracic Oncologists, a thoracic surgeon, a pulmonologist and a
radiologist will sit together and discuss the finding based on the appearance and size
of the nodules. If there is any nodule, based on that they decide whether the patient needs
to have a follow-up CT scan at what interval or have a procedure like biopsy. If there
is no nodule detected, we repeat the CT Scan every year for at least 3 years. When we do
a CT Scan of the chest in addition to the lung fields we see the heart, there were cases
that the patient had coronary calicifications which are not visible on chest X-ray but they
are detectable on CT Scan and based on those the patient was referred to a cardiologist
and got treated for that. So CT Scan lowered all caused mortality rate by 7% compared to
chest X-ray.