Sylvester Comprehensive Cancer Center

University of Miami Pathologist Revolutionizes Cancer Tissue Pathology

03.15.2004

The Department of Pathology at the University of Miami School of Medicine has created a revolutionary new way to test tissue samples so that patients learn the results of cancer biopsies and other surgery in just one hour instead of the next day.

The University of Miami, Jackson Memorial Hospital and UM/Sylvester Comprehensive Cancer Center are the only institutions in the world offering this patented technique. Pathology chairman Azorides Morales, M.D., devised a way to use microwave radiation to accelerate dehydration, a key step in tissue processing.

Not only will patients have their results much faster, but physicians can begin treatment even sooner. “This impacts not just our local patient population but the whole world,” said Gary Margules, Sc.D., director for Technology Transfer at the UM School of Medicine. “Imagine coming to the hospital and knowing your diagnosis and having a treatment plan before you go home,” said Margules. “No more restlessness or losing sleep to uncertainty.”

The Department of Pathology’s fully-automated technique uses low-wattage microwave radiation to agitate and dehydrate the tissue samples. “Rapid tissue processing is both continuous and rapid,” said Morales, who holds numerous patents on this process, alone and jointly with Ervin Essenfeld, M.D., and his son Harold Essenfeld, M.D. UM holds multiple U.S. and foreign patents on this method of microwave processing of pathology tissue, the RTP instrument, and the reagent chemicals used in the process. The automated process has been licensed to Sakura Finetek USA, Inc., which will manufacture the instrument for distribution to other hospitals.

A one-year blind study comparing conventional and rapid tissue processing showed comparable quality. “From the perspective of a technician, the RTP is actually much, much better,” said Carmen Duboue, a histopathology technician in the Department of Pathology. At UM, up to 40 samples can be processed at once and each system can process up to 500 samples each day, with samples presented to pathologists throughout the day for examination. In the past, a pathologist reviewed a large volume of tissue samples all at once on the following day.

Traditional cancer tissue pathology requires a 14-step process involving heating, multiple vacuum chambers, and agitation to dehydrate the sample and impregnate it with paraffin. The wax is necessary to allow tissue to be sliced in four micron sections – about one-fifth the thickness of a sheet of paper. The current process takes 12 hours and must be done in order, without interruption, for each tissue sample. “You must add alcohol to dehydrate the sample, then you must extract the alcohol to add paraffin,” said Morales. “The process has not changed significantly in 50 years.” The new UM process is only four steps.

Rather than heating the tissue, microwaves rapidly agitate the water inside at a molecular level, making moisture much easier to extract. Dehydration is much faster and is achieved much more uniformly throughout the sample, with less risk of tissue degradation from repeated heating and hours of exposure to reagent chemicals. The process uses customized cylinder-shaped microwaves which expose tissue to a much more uniform energy field than a kitchen microwave oven.

Unlike conventional pathology, the next tissue sample can be inserted for processing as soon as the preceding sample clears the first step – about 17 minutes. Each sample is done in 67 minutes. “We tell breast biopsy patients they can wait in the lobby for results,” said Duboue. Other patients may also learn results while they’re still in the recovery room after surgery.

The United States leads the world in attaining one-day biopsy results, with nearly eight in ten pathology reports being available the day after biopsy surgery. But at UM, two-thirds of tissue pathology reports are now available on the same day as the biopsy. Only hematopathology (blood) and neurological pathology samples are not yet processed in RTP. Processing is so efficient that a courier now circulates through the surgical areas at UM collecting biopsy and other tissue samples, delivering them to pathology for rapid processing and analysis throughout the day.

Rapid tissue processing also uses fewer reagent chemicals and far less toxic reagents than the conventional process. In the past, tissue in surgery immediately went into a solution of formalin, a known toxin and environmental hazard in use since 1893. By replacing toxins like formalin and xylene in the pathology process, RTP will reduce environmental exposure and potentially provide a healthier work environment for histopathologists. Formalin also destroys RNA in tissue, while the new reagents do not. That allows new molecular assays never before possible in tissue pathology. The results with the new reagents are equal to or better than conventional tissue processing and up to 1,200 tissue samples can be processed before reagents must be changed. Formalin also destroys RNA in tissue — the new reagents don’t. So for the first time ever, pathologists can use molecular assays for diagnosis.

Because the system is automated and attended to by a technician, this method may also reduce the risk of medical error with samples left processing overnight. An LCD screen indicates how many “blocks” or samples are inside, what stage they’re in, and how much time is left, accurate to the second. “If we have to re-run a sample because the results weren’t clear we can even do that on the same day, with better quality,” said Duboue. Because the results are available so quickly, the new technology also fosters better collaboration between pathologists and surgeons. “Close interaction and personal exchange between the two specialties provides especially precise samples and faster results to the patient,” said Morales.

The latest of several studies on this process will be published in the American Journal of Clinical Pathology on March 15 with the latest RTP system arriving at UM/Sylvester the same month. The next innovation will be to digitize microscopic images. “That will make it much easier to share and collaborate on tissue pathology, making mobile systems possible,” said Morales.

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