|‘It is negative. All margins are clear.’ These were the very words the surgeon wanted to hear.
‘Thank you,’ he said. ‘Please let me know when the final report is ready.’
This was the exchange between myself and a surgeon whose patient was still under anaesthesia. Now, knowing that the entire tumor had been removed, the surgeon was going to close the patient.
This is how a frozen section works. The surgeon removes a piece of tissue (biopsy specimen) and sends it to the pathologist. The pathologist quite literally freezes the tissue, then cuts thin slices (sections) of the specimen which are put on a slide and stained. Once the slide is ready, the pathologist examines the tissue under the microscope to render a diagnosis. The surgeon’s next move, whether to continue removing more tissue or stop and close the patient, depends entirely on the frozen section diagnosis.
The pathologist’s job during a frozen section is rife with stress. While routine processing of a biopsy specimen is performed overnight, a frozen section specimen is proceseed within minutes. The pathology lab can perform a large number of special stains to assist in making the right diagnosis, but these are of no use during a frozen section – there simply isn’t enough time! The whole process is a race against the clock. In most cases a diagnosis has to be given within 20 minutes of receiving the specimen. That is an incredibly small amount of time, but that is all that the pathologist can get, for while he does his thing, the patient is in the hands of the anaesthetist, who keeps the patient ‘under’ just in case more surgery needs to be performed.
|While a frozen section is not needed for most surgeries, it is very useful when the surgeon is operating to remove a tumor. Using frozen section, the pathologist can inform the surgeon if the entire tumor has been removed, or if there is tumor present at the margins. In the latter case, the surgeon can remove more tisse from the site in question during the same surgical procedure, saving the patient time, money, and most importatly, the risk of complications that comes with any surgicalprocedure.
The idea of a frozen section technique was first introduced more than a hundred years ago in the United States. Needless to say the technique has evolved greatly, with many advances coming in the last two decades. My father’s generation of pathologists used to freeze intra-operative specimens in deep freezers, and then cut sections using Treet platinum blades. Today we use solid steel bars and −26 degree chambers which can freeze the specimen in 45 seconds, and then use a precision microtome that can cut sections as thin as 3 micrometers.
Frozen Section slide: This lymph node shows metastatic carcinoma.
|All these techniques however don’t make one oune of a difference when you are the pathologist, the slide is under your microscope, and the surgery team is anxious to hear from you. The pressure is immense. It is the ultimate exercise in focus and discipline. Is is benign or malignant? Is the margin clear or not? Is it in situ or invasive? These are serious questions, and the answers are not always simple, especially when the clock is ticking and the phone keeps ringing. It is a lonely moment. There usually isn’t enough time to seek a second opinion. What happens to the patient next depends entirely on what you say.
Of course, nothing beats the feeling you get either, knowing that in this moment, by doing the very best you can do, you are making a real and positive impact in the life of your patient.
And that is why I became a doctor.