I usually don’t write about new technology until its actually available in the marketplace. However, photoacoustic microscopy is likely to be available in the near future and has a potential benefit that’s important enough to be worth knowing.
One of the classic problems with cancer is that the surgeon can’t see which cells are cancerous. That means, when they do surgery to remove cancer, they may not get all of the cancerous cells on the first try.
The surgical response has been to talk extra tissue around the margins of the tumor to try to ensure getting all of the cells. As I like to tell people, if that involves taking a little extra skin tissue, that’s probably OK. A little extra brain tissue, maybe not so much.
The inability to visualize which cells are cancerous helps to make treatment of certain cancers particularly difficult. Obvious examples are brain, prostate and pancreatic cancer. Biopsies depend on sampling tissue, and it’s possible for samples to miss cancer cells. However, complete removal of an organ can be problematic as well.
There are various research projects to try to develop tools to eliminate this problem.
- Immunotherapy involves using a virus to identify and mark cancer cells, enabling the body’s immune system to eliminate the cells without surgery. The problem is that it can have side effects, including attacking cells you want to keep (heart tissue, liver, etc.). Duke University has been one of the leaders in this field for brain tumors. MD Anderson Cancer Center has been a leader in other cancer forms (pancreatic, prostate).
- Coloring cancer cells to make them more readily visible. There was a recent clinical trial at UPenn on this method.
- Photoacoustic microscopy.
This last procedure has been under development at the Optical Imaging Lab (formerly based at Washington University, St. Louis; as of the first of this year, at Caltech) for breast cancer surgery.
- Cancer tissue has a larger nuclei than normal breast tissue
- Cancer tissue is packed more tightly than normal breast tissue
- Using sound to cause tissue to vibrate, the surgeon can see which cells have with characteristics while surgery is in progress. This improves the odds that he will remove all malignant tissue while minimizing removal of good tissue, and reduces the need for follow-on surgeries.
That’s particularly important for “breast-conservation” or lumpectomy procedures. It may have value with other cancer forms.
Because photoacoustic microscopy is an imaging procedure, approval by the FDA is expected to be faster than for pharmaceuticals or surgical procedures that actually contact the body. Thus, this is a method that could be available for use relatively soon.
- Lihong V. Wang et al. Fast Label-free Multi-layered Histology-like Imaging of Human Breast Cancer by Photoacoustic Microscopy. Science Advances, May 2017 DOI: 10.1126/sciadv.1602168
- California Institute of Technology. “Cutting down on cancer surgeries: New microscopy technique could reduce repeat surgeries for breast cancer patients.” ScienceDaily. ScienceDaily, 17 May 2017. <www.sciencedaily.com/releases/2017/05/170517154728.htm>.