[This is a reblog of a post on the #LCSM Chat website, shared with permission (it’s really easy to give myself permission to reblog something I wrote).]
The next #LCSM Chat will occur on December 19 at 5 PM Pacific Time (8 PM ET), and will be moderated by Janet Freeman-Daily. The theme will be “Lung Cancer Screening – The Good, The Bad and the Indolent.”
Discussion topics for #LCSM Chat:
T1: For patients who don’t fit “older heavy smoker” profile, should doctor order low-dose CT screening if patient requests it? #LCSM
T2: Some lung nodules are not cancer. When are you comfortable just watching a lung nodule instead of treating it? #LCSM
T3: A new blood test detects w/ 90% accuracy if lung nodule IS NOT cancer (but can’t tell for sure if it IS). Is this useful when combined with low-dose CT screening? #LCSM
The National Lung Screening Trial found 15% to 20% fewer lung cancer deaths among participants who were screened for lung cancer by low-dose helical CT scans compared to those screened by chest x-ray. Participants included 53,454 current or former heavy smokers ages 55 to 74 between 2002 and 2004.
From this statistic, it would seem obvious that lung cancer screening for older patients who are or were heavy smokers would be a slam dunk. However, the screening does raise some concerns. For instance, some studies show 20% to 60% of screening CT scans of current and former smokers show abnormalities, most of which are not lung cancer. Lung biopsies and surgery do carry risk, yet the uncertainty over having lung nodules might cause considerable anxiety for the patient. How do we determine whether or not to biopsy such abnormalities?
A biopsy of a nodule found by screening could determine if the nodule is cancerous. However, according to the NCI, studies indicate some small lung cancer tumors are indolent – that is, they so slow growing that they never become life threatening. This situation, called overdiagnosis, might cause some patients to be subjected to challenging and potentially damaging lung cancer treatment when they have no symptoms and an extremely low risk of death from lung cancer. Are the risks associated with biopsies and cancer treatment ALWAYS less than the risk of lung cancer death?
Another issue: this new CT screening is recommended only for patient who fit a specific profile (generally, current or former heavy smokers ages 55 to 79).Never smokers and some smokers and former smokers don’t fit this profile, but might have other risk factors for lung cancer. If a patient who doesn’t fit the recommended profile requests a low-dose helical CT scan, and agrees to pay for it, should their doctor agree to order the scan?
A new blood test announced in October (by Bioinformatics for Integrated Diagnostics and the Institute for Systems Biology) can determine if a detected lung nodule is NOT cancerous with 90% accuracy. However, it can’t reliably detect whether a nodule IS lung cancer. Used in combination with CT screening, this blood test might help determine whether a lung nodule warrants a biopsy. Do doctors and patients feel comfortable using a blood test that can say if the patient does NOT have lung cancer, but can’t say if the patient DOES have it?
For those who wish to do more reading
The National Lung Screening Trial: Results are in
Overdiagnosis in Low-Dose Computed Tomography Screening for Lung Cancer
Harmless lung cancer? Many tumors not lethal
Can Lung Cancer be Clinically Insignificant? The Case for “Overdiagnosis” and “Overtreatment” of Lung Cancer
Blood Test Distinguishes Early Lung Cancer From Benign Nodules
A blood-based proteomic classifier for the molecular characterization of pulmonary nodules.
Blood Test to Define Probability of Lung Nodule Being Cancer? Could Help, but Potential to Backfire