|Year : 2019 | Volume
| Issue : 3 | Page : 271-273
8th edition AJCC and imaging TNM: Time to break-in and assert in the staging process!
Tanvi Vaidya, Subhash Desai, Abhishek Mahajan
Department of Radiodiagnosis and Imaging, Tata Memorial Hospital, Mumbai, Maharashtra, India
|Date of Web Publication||19-Jul-2019|
Department of Radiodiagnosis and Imaging, Tata Memorial Hospital, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
The current practice of oncology focuses not only on early diagnosis, staging, and treatment of cancer but also defies the concept of “One size fits all.” This paradigm shift of the 8th edition American Joint Committee on Cancer (AJCC) manual to a “personalized medicine” approach sets the stage for introducing Imaging TNM (iTNM). The iTNM would provide physicians with a clear assessment of the disease extent derived exclusively from a combination of anatomical and functional imaging modalities and simplify decision-making in practice. Introduction of iTNM will complement the existing cTNM and pTNM and help to guide a personalized approach to patient management.
Keywords: American Joint Committee on Cancer, imaging, personalized medicine, precision medicine, staging, TNM
|How to cite this article:|
Vaidya T, Desai S, Mahajan A. 8th edition AJCC and imaging TNM: Time to break-in and assert in the staging process!. Indian J Cancer 2019;56:271-3
| » Introduction|| |
Imaging is a pillar that bears the onus of every aspect in cancer management; be it diagnosis, treatment, surveillance, staging, or follow-up. From simply being an anatomical mapper, it has come of age to become the means to assess the physiological and morphological features as well. Newer innovations are emerging in functional imaging tools, and the fusion of various imaging techniques makes it possible to study biological interactions at molecular levels and assess early response to therapeutic drug regimes, thereby ensuring optimal treatment to that individual. The future of cancer management lies in early tumor diagnosis, proper staging, and individually tailored treatments, a concept designated as “Personalized Medicine,” which essentially implies delivering the right treatment to the right patient at the right time. In the era of personalized medicine, the “One size fits all” approach no longer holds true, and the current practice of oncology involves an individualized cancer diagnosis, prognostication, and subsequent management on a case to case basis. This being the theme of the upcoming 8th edition of AJCC cancer manual emphasizing a “personalized” approach to cancer staging, sets the stage for the much-awaited imaging tumor node metastasis (iTNM).
Do we need iTNM?
The TNM classification of cancer was compiled by Dr. Pierre Denoix in the 1940's, and the first handbook on TNM classification was published in 1968. So far, it includes the final clinical stage “cTNM” according to all the available pre-treatment data and the pathologic stage designated as “pTNM” that reflects the tumor stage after evaluation of the surgical tumor specimen. These two stages together assign the final stage of the disease in that individual, which forms the basis of treatment and prognosis.
Over the years, with an improved understanding of cancer, its pathophysiology and variable clinical outcomes, significant changes have been made to the staging approach in the latest edition of the AJCC manual, such as including a site-based staging system that incorporates established clinical and non-imaging parameters within it. Imaging is an important aspect of the staging guidelines in the 8th edition, and, in most sections, the discussion on imaging is more detailed than in previous editions. The latest 8th edition of the AJCC cancer manual includes site-specific sections for the first time that describe the appropriate imaging tests for evaluating the tumor stage TNM along with the chronology in which the imaging tests are to be performed, and the specific T, N, and M information that can be extracted from all the imaging tests performed., Understanding of tumor biology and pathogenesis is also shifting the TNM staging systems focus from a population-based one to an individualized one. One such example is the incorporation of the presence or absence of human papillomavirus (HPV) and extra-nodal extension (ENE) in head and neck cancers.,
HPV–positive cancers tend to occur at a younger age and are associated with a more favorable prognosis as compared to HPV-negative cancers. These observations have led researchers to investigate as to whether these cancers differ in their imaging characteristics on baseline scans. Cantrell et al. and Goldenberg et al. demonstrated that the identification of certain imaging features could facilitate this differentiation. For instance, cystic nodal metastases were commonly seen with HPV-positive tumors. HPV-positive primary tumors were also more likely to present as well-defined, enhancing masses as compared to HPV-negative tumors that were more likely to be ill-defined and infiltrative on imaging., Thus, the recognition of these imaging features could provide a better understanding of the etiopathogenesis and prognosis of the disease, which would, in turn, enable the clinician to create a treatment plan that is tailored to the individual patient. On similar lines, the identification of ENE on imaging or pathology assumes importance as investigators have demonstrated the negative prognostic role of ENE in head and neck cancers, which has been acknowledged by the AJCC staging system. Moreover, the presence of ENE also necessitates a more intensive treatment regimen owing to the aggressive molecular profile of the primary tumor.
Radiologists and nuclear medicine physicians, as part of the Editorial Board, have contributed to the relevant imaging section of the 8th edition of the AJCC/UICC cancer staging manual.
At present, imaging parameters have been combined with clinical examination for deciding the cTNM stage. We feel that with the above-mentioned recent advances and the work in progress in the field of “personalized cancer imaging,” AJCC should now include a dedicated iTNM classification; in which, the T, N, and M stages are assigned purely by imaging. The iTNM would provide treating physicians with a clear assessment of the disease extent derived exclusively from a combination of anatomical and functional imaging modalities and simplify decision-making in practice. Clinico-pathologic correlation of imaging findings can be also performed with greater ease by assigning the respective stage, thereby facilitating a precision approach to the disease. Moreover, any discrepancies in clinical, radiological, and pathological staging can be identified and addressed more effectively.
The construction of iTNM is possible by rigorous standardization of imaging protocols to avoid issues that may arise owing to inter/intra-observer variability and subjective interpretation. Moreover, variability in the use of different diagnostic imaging tools as per availability, expertise, cost-effectiveness, and patient acceptability should be kept in consideration during formulation of consensus guidelines for iTNM. These factors should be considered during formulation of consensus guidelines for iTNM, and most of them are already addressed in the national comprehensive cancer network guidelines.
Do radiologists have stage fear?
As things stand of now, hardly any radiologists incorporate cancer staging in their reports; radiology reports tend to be descriptive. There is a felt need for synoptic reporting that is targeted not only to the stage of the disease but also answering clinical questions (relevant positive and negative related findings) that may have bearing on the disease management. One such example is laryngeal cartilage invasion, which is the basis for deciding management of glottic cancers (Chemo-radiotherapy versus surgery). Lack of communication between the treating physician and radiologist is one major reason for the radiologist not to incorporate pertinent clinico-radiological findings in their routine radiology practice. Such is not the case in tertiary care centers, where multidisciplinary approach is a mandate. This is evidenced by the observation that a second opinion by an in-house expert radiologist has a significant impact on the management.
Bringing the radiologist on the stage!
Staging is the identification of the anatomical extent of the disease that determines the prognosis and the choice of therapy. Imaging methodologies provide this prior to initiation of therapy. Thus, it is more imperative now that every radiologist must put down detailed staging in their report to facilitate early diagnosis, provide prognosis, and ensure appropriate management. Incorporation of a synoptic radiology reporting style is the need of the hour and could be the first step toward providing clarity in the staging process., Studies have shown that structured reports pose better clarity and relevant content than the conventional ones and provide information pertinent to the staging process with greater accuracy. Structured reporting augments the ability of the radiologist to capture meaningful data and present it in a standardized manner, which in turn results in improved communication of imaging findings to the treating physician and ultimately enhances the quality of patient care., Thus, structured reporting of imaging procedures will have tremendous potential in offering personalized rather than population-based care. From the researcher's perspective, synoptic reports will also assist in optimum data compilation for research purposes and simplify data mining for the development of artificial intelligence technologies.
Teamwork- all for one, not one for all!
Considering the limitations faced by clinicians and radiologists, staging a patient's disease requires teamwork with the final detailed staging done by a multidisciplinary clinic. The AJCC 8th edition has recognized the critical role that imaging plays in the management of cancer patients. Hence, introduction of iTNM is the need of hour and will certainly complement the existing cTNM and pTNM leading to a personalized or precision approach in oncology. This would finally translate to better utilization of resources, reduced expenses, and ensure improved patient outcomes.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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