The NCRA is conducting a series of webinars for the AJCC 8th edition. The first was presented on thyroid. The second on oropharyngeal cancers. Below is a synopsis of the presentations.
Thyroid chapters which are now Chapter 73, 74 and 75. Chapter 73 is the chapter for papillary, follicular, poorly differentiated, Hurthle Cell and Anaplastic Thyroid Carcinoma. Chapter 74 covers the medullary thyroid cancers, and Chapter 75 is the parathyroid staging schema.
- T category sizes remain the same
- T3 is no longer concerned with minimal extrathyroidal extension. The tumor must now be greater than 4cm or invade the strap muscle to qualify as a T3. This creates less confusion for pathologists and us hopefully!
- Level VI and VII (upper mediastinal) are N1a lymph nodes
- Age cut off is now 55 years old instead of 45 years old
Chapter 73 is the chapter of follicle cell origin, these are the majority of the thyroid cancers.
- Anaplastic Thyroid CA is still Stage 4 regardless of other factors; however, this is no longer T4. We will assign the T based on the size/extension. The stage group is still 4.
Chapter 74 is medullary thyroid cancer from the C – Cells
- When reviewing for tumor markers keep in mind that the blood draw will determine if the patient has the hereditary marker that may impact offspring/family. The tumor may express the marker, but it may not be hereditary or found in the blood draw.
- Medullary uses neuroendocrine markers
- No role for I-131 as the C cells do not metabolize iodine.
- T category is the same as chapter 73.
Chapter 75 – parathyroid new chapter
- Added to gain data on these cancers.
- Cells stain for neuroendocrine synaptophysin and chromogranin, etc.
- Produces PTH- parathyroid hormone that regulates calcium levels in the blood
- Tis – atypical parathyroid neoplasm of uncertain malignant potential. Based on the information, these will be rare, but reportable for 2018.
- No stage groupings for Chapter 75, only T, N, and M.
- Very rare cancer
- The major pitfall with AJCC 7th edition was that it combined HPV positive and HPV negative cancer together which skewed the data.
- HPV positive Oropharynx cancer has a 54% survival benefit compared to HPV negative.
- Major differences between HPV + and HPV – include risk factors, tumor size and histology.
- HPV + = lingual and palatine tonsils / basaloid, nonkeratinizing poorly diff
- HPV – = Non-oropharyngeal sites / Keratinizing, mod differentiated
- HPV positive have a better response to chemo and RT and prognosis.
- HPV mediated (p16+) Oropharynx Cancer is a completely new classification in AJCC 8th edition
- p16 is an antibody (protein) produced by HPV
- p16 testing for the biomarker is mandatory for oropharynx cancer and “should” be included in the pathology report
- Nodal staging has been divided into clinical and pathologic. Staging has been simplified.
- HPV+ (p16+)
- Clinical N1 is one or more ipsilateral nodes no larger than 6 cm and considered low risk
- Clinical N2 is contralateral or bilateral nodes no larger than 6 cm
- Clinical N3 is unchanged
- Pathologic N1 is mets in 4 or less
- Pathologic N2 is mets in more than 4 lns
- HPV – (p16-)
- N classification unchanged except for Extranodal Extension
- N3 divided into N3a and N3b
- Stage IV oropharynx HPV + (p16+) reserved for M1 only.
- Tumor Thickness Breslow depth – determines T stage. It is directly tied to 5 year survival. 8th edition tumor thickness differs from the 7th edition
- T1a <0.8mm non ulcerated
- T1b 0.8-1.0mm without ulceration, <0.8mm with ulceration
- Tumor Thickness now rounded to 0.1mm instead of 0.01mm – driven by inherent lack of precision in measuring melanomas
- Ulceration – important part of T stage a designation no ulceration, b designation ulceration present
- Mitotic Rate – no longer included in 8th edition staging; however still important prognostic factor
- Micromets now called clinically occult disease – definition seen only on microscopy (under a microscope)
- Macromets now called clinically detected disease – definition seen without the aid of a microscope, clinically detectable
- Lymphoscintigraphy important due to melanomas can drain to separate lymph node basins
- C category added to each N designation for presence of in-transit, satellite and/or microsatellite mets
- Satellite nodules are within 2cm of primary tumor, in transit mets are greater than 2cm from primary between the primary and nodal basin, distant subcutaneous mets do not fall into either of these categories
- Elevated LDH no longer categorized as M1c, now 0 or 1 designation to each M stage to reflect LDH level
- M1d for distant mets to CNS
- Addition of 3D – Patients who are T4bN3a/b/c and M0 (now have 4 pathologic stage 3 groups)
- Group 3A smaller, contains only T1a/b to T2a.
- Group 3B no longer contains T3b or T4