Abstract
In 2007, an article entitled “How Technology Is Reshaping the Practice of Nongynecologic Cytology: Frontiers of Cytology Symposium” [Bibbo: Acta Cytol 2007;51:123-152] was published. The moderator and editor was Marluce Bibbo, previous Editor-in-Chief of Acta Cytologica, and 17 participants from countries throughout the world were asked to answer how new technologies were being applied in their respective laboratories and whether future advances and challenges can be predicted. Ten years later, two previous participants in this Golden Anniversary Cytology Symposium were asked by Kari Syrjänen, current Editor-in-Chief of Acta Cytologica, to make a reappraisal of the 2007 predictions.
It is a great privilege for us to write the commentary on this article, published 10 years ago for the Golden Anniversary of Acta Cytologica, and of which we were coauthors [1]. Having a visionary idea, Dr. Marluce Bibbo, Editor-in-Chief of the journal at that time, invited 17 cytopathologists and cytotechnologists, from 12 countries and representing 4 continents, to discuss how new technology is being applied and what advances and challenges we are predicting for the future. Ten years on, and to celebrate 60 Years of Acta Cytologica, Dr. Kari Syrjänen, the current Editor-in-Chief, presented us with the challenge of describing the impact of this article in the development of our specialty as well as in the increase of knowledge at a conceptual level [2].
There were several ways to present this discussion, but we decided to do it according to the different questions originally formulated in the article, and to then verify if the expectations and projections made at that time are still of interest, have changed, or are no longer in place. We also comment on some of the new developments in the technology and the biomarkers that were not predicted at that time but are now implemented in most pathology laboratories.
1. The Role of Morphology. For several decades, cytopathologists have practiced diagnostic cytopathology of nongynecologic specimens based on morphologic features. Do you think morphologic features will still play an important role 10 years from now?
All the participants predicted that morphology would still play an important role 10 years later. They were, indeed, completely right. In 2017, morphology still is the cornerstone for diagnosis in cytopathology and, even with the huge advances in molecular genetics in the last decade, the success of these latter techniques depends on a good qualitative and quantitative evaluation of the cytologic material [3].
2. The Role of Imaging Techniques. Fine-needle aspiration (FNA) under the guidance of several imaging techniques has become an indispensable component of the workup of many lesions. The issues discussed under this topic were: Who performs FNA? What is the role of core biopsy? Can the imaging techniques replace cytology in the diagnosis?
Practice in this field is consolidated after 10 years. Guided FNA is usually performed by radiologists, and interventional radiology has grown exponentially during the last decade. Pathologists, clinicians, and surgeons still perform aspirations, mainly with the use of ultrasound guidance. One field that has expanded significantly is the cytomorphology of endobronchial ultrasound (EBUS)-guided FNA that allows for material to be obtained from the lung and mediastinal lymph nodes for the diagnosis and staging of lung (and other) cancer. This creates new opportunities for cytology, especially with the practice of rapid on-site evaluation (ROSE) to verify the quality of the material, thereby facilitating the collection of proper material for ancillary techniques. The role of core-biopsy is still the same in breast, prostate, liver, and soft-tissue tumors, among others. In many situations, this methodology complements FNA. As was predicted at the time, no imaging technique is able to replace morphological diagnosis in 2017.
3. The Role of Immunocytochemistry. Immunocytochemistry (ICC) has become an important adjunct for cytological diagnosis; however, the use of different preparations and fixation were a problem for standardization. Questions about the current and future roles of this technique and the challenges were discussed.
All the authors agreed that the major challenge would be to standardize ICC within and across laboratories. Despite efforts being made and collaborative studies [4] as well as significant improvements in the technique with automation and better quality control, we still do not have universal standardization for the application of ICC techniques in cytological material. This is understandable, particularly because when we deal with such material we talk about a series of different types of preparations: smears fixed in alcohol, air-dried smears, liquid-based cytology, cell blocks, etc. Since most laboratories perform the technique of immunodetection in paraffin-embedded blocks like 10 years ago, ICC is usually carried out from cell block material. Most of the diagnostic and prognostic applications of ICC described in the article are still being used [1]. However, it is interesting to note that one of the markers that is extremely useful today for the subtyping of non-small-cell lung cancer, i.e., p40 [5], was not described at that time. Some of the panelists predicted that ICC would be important to guide targeted therapies, but noone predicted the screening role of ICC for molecular techniques, e.g., in the use of ALK and ROS-1 antibodies in order to select cases for searching translocations in these genes [6].
4. The Role of Clinical Cytogenetics. Clinical applications of fluorescence in situ hybridization (FISH) have been growing in the last decade.
Although some authors predicted the expansion of the use of FISH in this last decade, its use in cytology is, in fact, practically the same as 10 years ago. Indications for using the UroVysion kit in urinary cytology are still under debate [7] as well as its role in the diagnosis of effusions or pancreaticobiliary cytology. Like 10 years ago, it is still used for the detection of translocations in sarcomas and lymphomas, but is limited to some specialized centers. Interestingly, one of the most common uses of FISH in cytological labs nowadays, i.e., the search for ALK translocations in lung cancer, was not predicted at that time [1,6]. However, the prediction that FISH analysis would be fully automatized, with specialized fluorescence microscopes and multiple filters for multiprobe FISH becoming the norm, was not accurate, as it is not in regular use in nonhematological solid tumors.
5. The Role of Molecular Techniques. A variety of molecular assays for the detection of gene mutations, amplifications, and DNA instability have demonstrated clinical utility in cytology. The main topics discussed were the applications of these techniques, the question if target therapies boost the use of molecular techniques in cytology, and the prediction of advances and challenges in their implementation.
Curiously, one technique that is changing the paradigm of molecular genetics, i.e., next-generation sequencing, was not mentioned, and this is revolutionizing cancer genomics [10]. High-quality reference genome sequences provide us with the prospect of studying genetic variations on an unprecedented scale. Genes, genomic regions, and whole genomes can be resequenced and aligned to appropriate references, and genetic peculiarity between tumors and individuals can be detected. We can investigate cancer in terms of specific events, i.e., somatic base-pair deletions and mutations, balanced and unbalanced rearrangements, and copy number changes, and we can discern cancer-specific genomic regions, genes, or exomes. Similar technology extends to RNA. We can explore the expression of genomic mutations, gene fusion events, posttranslational edits and alternative and novel splice events. This technology is rapidly replacing the classical use of polymerase chain reaction (PCR) or Sanger sequencing to detect alterations in individual genes. Ten years ago, the use of molecular techniques to detect mutations in EGFR in lung cancer, KRAS in colon cancer, and cKIT in GISTs was just starting. Genomic panels that allow the study of multiple genes at same time, with just 10 ng of DNA, are perfect for cytology as only a small amount of material is available. As predicted by the authors in the original article, targeted therapy boosted by the use of molecular techniques in cytology and lung cytology is the best example. In almost half of lung cancers, the only material available for molecular studies that guide therapy is cytologic material. This changed the paradigm of using materials such as small biopsies and cytology samples managed for diagnostic purposes, while maximizing the amount of tissue available for molecular studies [11] for theragnostic applications. Another methodology implemented in recent years which was not predicted in the article was HPV detection in head and neck cancers that has now become a routine in many centers [12].
One of the most important discussions still deserving to be reflected upon today concerns the challenges for the implementation of molecular techniques in the routine of pathology labs. We would like to quote several sentences from the article [1] on matters that are still under discussion at present:
“It is important that we cytologists take an active role in the adoption and application of molecular techniques, since we are able to interpret the results in the light of cytomorphology. If we do not act, others will take over.”
“The advance of molecular techniques poses two challenges for the cytology laboratory: deciding when to adopt a new test and deciding who should perform and interpret it.”
“The cytology laboratory will likely find itself squeezed between rising expectations for advances in molecular medicine and the limitation imposed by good evidence-based practice and funding.”
Ten years on, cytopathologists and pathologists, in general, still do not play an active role in the adoption and application of molecular techniques. There is no doubt that many things have changed, and there are more pathologists involved in molecular pathology. However, there is a gap between the fast speed of implementation of these techniques and the relatively slow engagement of the pathologists. In some laboratories, it is possible to see pathologists working actively together with molecular biologists and scientists, deciding with them which new tests to implement and signing out the respective reports. Many tests used today are based on large and solid clinical trials and molecular tumor boards are a reality in some centers. Funding is still a problem, but since many tests are tailored to specific treatments, in many cases it is possible to demonstrate the financial advantages to implement certain tests.
Let's remember some other quotes:
“Because therapies are now being directed toward individual molecular targets, the big challenge for the use of cytologic technology is a need for increased standardization of preanalytical and analytical methods.”
We raised the concerns with preanalytical issues some years ago, but this is still a problem in pathology in general, and specifically in cytology [13]. However, with the adoption of sophisticated technologies, this problem is increasingly being addressed and nowadays, more and more cytopathologists and cytotechnologists are becoming aware about the needs of a proper collection and preservation of the material as well as the need for the standardization of techniques [3,14].
“In the future, most if not all tumor diagnoses will consist of a morphologic type with molecular subclassification.”
This prediction is a reality in the clinical practice of some tumors. Breast cancer, lung cancer, central nervous system tumors, and lymphomas, besides the morphological classification, need a molecular classification obtained directly by molecular methods or by the use of surrogate ICC markers. This is fundamental for the correct management of these neoplasms and, in the near future, it will expand to other types of tumors.
“More organized and systematic molecular biology training is required in both undergraduate and postgraduate pathology education.”
Seven years ago, 3 years after the publication of this discussion, one of us wrote an editorial in Acta Cytologica [15], calling the attention for the need of a better training of all cytologists with the aim of understanding the main principles and applications of molecular diagnosis. This is progressing, but too slowly. In some countries, molecular pathology is part of the training in pathology. In Portugal, all residents have an obligatory rotation in molecular pathology: the period is short (2 months during the 5 years of training), but it is a beginning. In France, it is possible to obtain an academic diploma of molecular pathology (2 years), in place since 2011. Given the tremendous importance of the integration of molecular techniques in the specialty of pathology, we hope that the knowledge of pathologists in general, and cytopathologists in particular, will increase deeper and faster in the next few years.
As we wrote at the beginning of this commentary, it was a great pleasure for us to have the opportunity to revise the original article, and we hope that this review is pleasant reading. After 10 years, we can conclude, exactly as Dr. Bibbo concluded the original discussion [1]:
“Since molecular biology results are meaningful only when interpreted with proper morphologic correlation, it is important to standardize molecular techniques and organize education in molecular biology for pathologists.”
Disclosure Statement
The authors have no conflicts of interest to declare.
