6^th edition 2002 UICC (01.01.2003)

(Aids & Proposals)

THE TNM FORMULA

• y Classification during or after multimodality therapy
• r Classification for recurrent tumor
• c Pretreatment clinical classification
• p Classification by the pathologist

T

• is = in situ carcinoma
• 1-4= extent only of the invasive component with invasion of a named anatomical structure and/or measured in metric units
• (m) and/or (4)= multiple primary tumors and/or the number of different primary tumors.
  (In the liver and thyroid gland the multiplicity is considered in the pT1-4 categories!)
• X= extent of primary tumor cannot be assessed

N

• 0= no regional lymph node metastasis (minimal number of nodes for pN0 see table)
• 1-3=presence of lymph node metastasis with description of number, localization, size, and perinodal invasion
• mi= only micrometastasis present (2 mmor less)
• sn= sentinel lymph node = first lymph node that takes up lymph from primary tumor.
  - x(sn) sentinel LN cannot be assessed.
  - 0 = no LN metastasis
  - 1 = LN metastasis
• i, mol= isolated tumor cells. ( ITC ) = tumor cells < 2 mm found by specific histochemical methods.
  - N0= no metastasis, no examination for proof of ITC
  - N0(i-)= no metastasis, no morphological proof of ITC
  - N0(i+)= no metastasis, morphological proof of ITC
  - N0(mol-)= no metastasis, no not-morphological proof of ITC
  - N0(mol+)= no metastasis, not-morphological proof of ITC
  
• (3/17)= number of lymph nodes involved/number of lymph nodes examined (optional)
• X= presence or absence of lymph node metastases cannot be assessed

M

• 0= no distant metastasis
• 1= distant metastasis present
• (mi)= microscopical metastasis; 2 mm or less
• i, mol= isolated tumor cells. ( ITC ) = tumor cells < 2 mm found by specific histochemical methods.
  - M0= no metastasis, no examination for proof of ITC
  - M0(i-)= no metastasis, no morphological proof of ITC
  - M0(i+)= no metastasis, morphological proof of ITC
  - M0(mol-)= no metastasis, no not-morphological proof of ITC
  - M0(mol+)= no metastasis, not-morphological proof of ITC
  
• X= distant metastases cannot be assessed

V

• 0= no venous invasion
• 1= microscopic venous invasion present
• 2=macroscopic venous invasion

L

• 0=no lymph vessel invasion
• 1= lymph vessel invasion present. Consider only proven lymphatic vessels lined with endothelium

G

Histological grade of malignancy according to WHO:

• 1= well differentiated
• 2= moderately differentiated
• 3= poorly differentiated
• 4= undifferentiated (small cell carcinoma of any site,
  undifferentiated carcinoma where provided, large cell carcinoma of the lung,
  Ewing sarcoma, rhabdomyosarcoma of soft tissue)

R

• 0 = no residual tumor
• 1 = residual tumor demonstrated microscopically (also positive cytology on lavage before the beginning of the surgical procedure on the tumor)
• 2 = macroscopic residual tumor (local or distant! e.g. non resectable liver metatasis of a locally completely
  resectable primary tumor), if possible microscopic confirmation

Minimal number of lymph nodes that should be found by the pathologists in a surgical specimen of different cancer sites

Head and neck (excl. thyroid gland)	10
Thyroid gland	6
Esophagus	6
Stomach	15
Small bowel	6
Colorectum	12
Anal canal	6
Liver, gall bladder, extrahepatic bile ducts	3
Pancreas, ampulla	10
Lung, pleura	6
Soft tissue, bones	6
Skin	6
Breast (level I nodes)	6
Vulva, vagina (lower third)	6
Vagina (upper part), cervix, corpus uteri, ovary	10
Penis	6
Prostate gland, testis, kidney, kidney pelvis, ureter, urinary bladder, urethra	8
Ophtalmic tumors	6
Pediatric tumors	3

Preparation of Lymph Nodes for pN Classification

General Considerations

1. A minimal number of regional lymph nodes should be found to state the pN0 category (s table)
2. The highest possible pN category can be sometimes diagnosed by examination of one or
   a limited number of lymph nodes. In this situation the examination of further lymph nodes is not needed.

Methodical considerations

1. In our experience the most simple and best method is the preparation of lymph
   nodes after overnight or longer fixation in formaldehyde. A careful palpation of the fatty
   tissue and slicing will result an appropiate number of nodes. All suspected nodules
   must be embedded and cut (10-30% of these nodules will be than small vessel convolutes).

   "Evidence of a good nodal dissection is the finding of nodules
   of lymphoid tissue in the 1- to 3-mm range, with a sprinkling
   of pieces of fibrofatty tissue and small vessels in cross section.
   Conversely, inadequate sampling is characterized by the finding of
   only a few nodes measuring 1 cm or more." KJ Lewin, RH Riddell
   WM Weinstein Gastrointestinal Pathology and its Clinical
   Implications. Igaku-Shoin, New York Tokyo 1992

2. We embed lymph node groups (max. 5-6 nodes/capsula). Large nodes may be embedded in several capsulas.

3. Step sections are a very useful method to find small nodes in the embedded tissue.

4. In large bowel and stomach specimens the lymph nodes are localized around the blood vessels. The slicing up of the vessels will help to find and localize the nodes

   

   Rectum specimen with opened a. mesenterica inf.
   and a. rectalis sup.

5. In several lymph nodes regions the preparation is difficult because lymph nodes contain fibrous or fatty tissue. Inflammations may lead to fixation of the nodes and the preparation of a single node is difficult or impossible.
   This applies to the following regions:
   inguinal,iliacal, obturator, all retroperitoneal nodes, nodes around the genitourinary tract,mediastinal, hilus of the lung.

6. The so called clearing techniques are time consuming and hazardous; we find an equivalent number of nodes (e.g. ca 30 nodes/gastrectomy; 20 nodes/Whipple specimen; 25 nodes/rectum specimen) after formaldehyde fixation and careful preparation.

7. The preparation of nodes needs some time and patience (25-40 min/large gastrointestinal specimen) Consider: the surgeon needs more time for preparation and a useful pathological diagnosis!