When you have surgery to remove a cancerous tumor, you want your doctor to get every last bit of it.
To that end, surgeons have to remove a certain amount of healthy tissue around the tumor.
Researchers from The University of Texas at Austin recently announced the invention of a tool designed to make that job faster and easier.
The MasSpec Pen is a small, handheld instrument that can identify cancerous tissue in about 10 seconds.
The research is published in Science Translational Medicine.
Surgical “margins” — the rim of healthy tissue that’s removed along with the tumor — are important because cancer cells that get left behind can form new tumors.
Depending on the part of the body involved, removing healthy tissue can result in serious side effects.
Surgeons take great pains to get it right. This often means people spend more time under anesthesia.
The surgical oncologist’s challenge is to remove enough, but not too much, healthy tissue.
How the technology works
The MasSpec Pen is used in conjunction with a spectrometer, a foot pedal, and a computer screen.
During the operation, the surgeon must hold the pen to the tissue in question.
With the use of a foot pedal, the pen delivers a water droplet to the surface of the tissue, where it extracts biomolecules.
The spectrometer then analyzes the proteins, lipids, and metabolites to distinguish cancer cells from healthy tissue.
A few seconds later, the word “normal” or “cancer” will appear on the computer screen.
Researchers used the pen for ex vivo (outside the body) analysis of 253 human patient samples. These included normal and cancerous tissues from the breast, lung, thyroid, and ovary.
The pen was more than 96 percent accurate.
Researchers also tested the pen by performing surgery on mice with cancer. They said use of the pen caused no harm to tissue or additional stress to the animals.
For the surgical patient, it would be considered a low-impact procedure.
Researchers say the MasSpec Pen has potential as a clinical and intraoperative technology for ex vivo and in vivo (inside the body) cancer diagnosis.
It has yet to be tested during surgery on humans.
Determining surgical margins
Dr. Anton Bilchik is professor of surgery and chief of gastrointestinal research at John Wayne Cancer Institute at Providence Saint John’s Health Center in California.
Bilchik told Healthline that the evaluation of margins differs based on the type of cancer.
“For example, colon cancer can be easily seen by the surgeon. The procedure is well-established. Surgical margins can be determined by visualization. There’s no need to do a frozen section and there’s certainly no use for the MasSpec Pen in those kinds of surgeries,” he explained.
“In other cancers, such as pancreatic, stomach, or breast cancer, it’s more difficult for the surgeon to determine simply by looking at tissue itself,” he added.
That’s when a frozen section is generally used.
It can take up to half an hour or more to get results from a frozen section analysis. Meanwhile, the patient remains under anesthesia.
According to University of Texas researchers, interpretation can be difficult and unreliable 10 to 20 percent of the time.
Dr. Michele M. Carpenter is medical director of the Breast Program at The Center for Cancer Prevention and Treatment at St. Joseph Hospital in California.
The hospital was involved in the beta testing for a device called MarginProbe, which Carpenter is currently using in surgeries.
This device uses radio-frequency electrical fields to differentiate between cancerous and normal tissue in real time.
“We take the tumor out and check ex vivo,” Carpenter told Healthline. “The FDA does not authorize us to do it in vivo.”
If the MarginProbe determines there’s cancer on the surface of the tissue, additional tissue can be removed during the same surgery.
But MarginProbe is only approved for use in breast cancer.
Potential of the MasSpec Pen
Carpenter said there are a number of questions to be answered about the MasSpec Pen technology.
“You’re using the tip of a pen to look at a droplet. So, if you don’t apply this probe to every surface — technically speaking, can you be sure you’ve looked at every surface? It takes about 10 seconds, but when you look at the size of the pen, how many times do you have to use it? How long will that take?” she asked.
“You also have to design the study,” Carpenter added. “What type of cancer will you use it in? Will it be effective in some types of cancer but not in others?”
Carpenter doesn’t believe the MasSpec Pen will be in general use anytime soon.
“It’s wonderful and promising, but it’s bench research,” she explained. “They looked at tissue on the bench and it seemed to do a good job. Then they put it in a mouse model. Knowing the FDA, you are not going to see this used in a live person until you prove its safety and efficacy compared to standard protocols.”
“I think what is really important for people to understand is that scientific technology is growing by leaps and bounds,” added Carpenter. “But we have to be able to use it safely in real everyday experience so that it helps us and does not hurt the patient in the end. That’s the take home message. It’s not ready yet. They have to take a couple of steps before it will be ready for prime time,” she said.
Bilchik sees the potential of the pen for certain types of cancer, especially if it will reduce the time a person must be under anesthesia.
“But I don’t see it being necessary for many of the operations we do, when we can determine margins simply looking at the tumor at the time of surgery,” he said.
“The concept of the MasSpec Pen is really quite fascinating and very innovative based on the identification of a molecular fingerprint that really is the wave of the future. I’m sure if we can do a better job at time of surgery, in defining margins and essentially planning our operations based on accurate instrumentation, we’re likely to do operations that are in a patient’s best interest from both a safety and oncologic view as well,” explained Bilchik.
“On a cautionary note, we tend to get very excited about new technology. And it really needs to be more carefully evaluated against standard approaches before it can be widely embraced,” he said.