TISSUE COLLECTION
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Tissue biopsy processing for analysis is evolving, with a trend away from the once-common formalin-fixed paraffin embedded (FFPE) preservation of biopsy tissue for future analysis to flash-freezing freshly harvested samples in liquid nitrogen and storage at –80˚C. Biopsy tissue samples should not exceed 0.5-cm dimensions, and regardless of whether preservatives are used, both preservation and freezing must occur rapidly.1
“Paraffin-embedded tissue seems to be of lesser quality, particularly where extraction of DNA and/or RNA is concerned, requiring a level of skill on the part of the lab personnel that is rare,” Kaufman explains. Fine-needle collection of tumor tissue and cells is also common.1
The timing of postcollection processing for preservation is key, and all equipment must be ready before collection begins.1 When collecting samples from resected surgical specimens, the time from when blood flow to the tissue is clamped off to the time of flash freezing or immersion in formalin should be minimal.1 Frequently, particularly when a patient is participating in a clinical trial, tissue sample preparation may need to follow precisely specified procedures for specific biomarker analyses.
“I don’t believe that any of the collection and processing techniques are particularly difficult,” Kaufman says. “The challenge is doing it all within the protocol-specified time frames, which are all different. It’s more and more common that these details are so specific that they cannot be written into the protocol. A lab manual is then required.”
For example, collecting tissue during a colonoscopy or bronchoscopy is a matter of being in the room, explaining to the clinician performing the procedure as to what to collect and from where, then accepting the tissue sample provided.
“If there are eight pieces of tissues, they’ll likely come in rapid-fire succession,” Kaufman explains. “Some will have to be put into cryo-vials and immediately placed into liquid nitrogen. Some will be put into a container with formalin. For the latter, the protocol will specify how long the tissue has to be in formalin before it’s embedded in paraffin.”
If paraffin blocks cannot be used, then slides are made from the paraffin block. “The nurse will have to navigate the institutional policies, arrange for paraffin embedding, and arrange for cutting slides, usually in a histology lab.”
All cancer clinics should have written standard operating practices (SOPs) for these procedures. Even in clinics that do not participate in clinical trials, blood and tissue samples need to be collected for assays and gene sequencing that will likely guide the course of treatment for many patients with cancer, explained Kaufman.
THE FUTURE
With the increasing emphasis on biomarkers in treatment planning and monitoring and as biospecimen collection become more voluminous, many cancer centers may consider employing biospecimen resource managers. To date, many institutions tend to expect its oncology nurses to take on that role or have assigned others to become specialists/managers for biospecimen collecting.
“However, there’s more involved than just assigning a person to manage the biospecimens,” Kaufman cautions. Quite a bit of infrastructure is also required, including laboratory facilities, freezers, storage—and policy for accessing clinical archives for research, the approvals required, and biospecimens and biosafety review committees.
Understanding cancer at the molecular-genetic level will lead to detailed diagnoses and precise treatment planning, Kaufman and coauthors predict.1 “Among the emerging responsibilities of the oncology nurse is helping patients to take control of their disease and treatment.”
