I am inquiring on behalf of my sister-in-law who was diagnosed with stage three colon and rectal cancer in July 2020. She is 53 years old and a former smoker. She underwent chemotherapy for six months, followed by six weeks of radiation, and in April 2020 she had surgery to remove the tumor in her sigmoid. At that time, 17 od her lymph nodes were removed and all were clear, so she was restaged to stage two.
In November 2020, two nodules were found, one on each lung, as well as a spot on her liver. The liver was further looked at and was determined not to be cancer and that is what she was told a couple weeks ago following a PET scan. However, in addition to those two nodules which she wa previously told were nothing, she now has new activity on the lung. Two spots (not the original nodules) lit up on the scan. The report said they were too small to biopsy, then they scheduled her for a biopsy, and now they're back to saying they're too small. So, she will have a repeat scan in eight weeks.
In the meantime, I am wondering what the likelihood of this not being cancer is. Generally I would think that yes, it's obviously metastasized, but does anyone know how often cancer metastasizes when it hasn't been in the lymph nodes? Also, given she is a former smoker (up until two years ago), is it at all likely that she has a second cancer, and not a metastasized cancer?
Mon, 11/22/2021 - 10:04
Hi and welcome to Grace. I'm sorry your sister-in-law is going through this it's so unsettling, to say the least. Cancer travels through the lymph system but also through blood vessels. Inflammation and infection light up a PET just like cancer does and looks the same on CT so it's impossible to tell without a biopsy. You can't biopsy a nodule in the lungs if it's too small especially in a difficult-to-reach place. So a watch and wait approach is the standard way to proceed and an 8 week rescan is appropriate.
We get small infections and inflammation that come and go in our lungs that would light up a PET all the time without ever knowing it happened, our immune system takes care of them without us ever feeling sick. If it grows to a size that can be biopsied and is found to be cancer the biopsy will be scrutinized to find out if it is a new cancer or from the colon. I don't know the odds of it being a new cancer but if so it would be treated as so and not as metastasized colon cancer.
This happens all the time to people post cancer treatment and scrutinizing every nodule. I hope your sister-in-law finds nothing in her followup.
All the best,