The Histo Pathology Report

Planning of Adjuvant Treatment

How is the stage decided
from the Histo Pathology Report?

The one report which determines everything! The single most important document in the journey of breast cancer - The Histo Pathology Report. After surgery, the tumour and the nodes which were removed, are sent for examination to the pathology lab (People commonly refer to this as 'biopsy') and the report which the lab prepares after studying the tumour and the lymph nodes is called the Histo Pathology Report. This report determines the Final Stage of cancer for the patient. And according to this stage, and all the features written in the report, the decisions on further treatment - Chemotherapy, Radiation Therapy, Targeted Therapy, Hormonal (Endocrine) therapy, are taken.

How does a Pathologist write the histopathology report?

The 'specimen' of surgery (all that was removed in surgery - the breast or the tumour, along with the nodes) reaches the pathologist in a preservative solution. The Pathologist performs the assessment in three steps:

1. Gross Examination: The Pathologist first examines the specimen with 'naked eyes'. He notes the 'size' of the tumour, checks if there is a single tumour or multiple tumours, whether tumour is close to the skin / nipple / base etc. He will slice the breast tissue in detail to check for smaller tumours and other nearby breast tissue. He then checks the arm pit tissue, finds out all the lymph nodes from the fat, and see how those nodes are looking - how many nodes are there, are they looking enlarged in size, are they stuck to each other? etc.
2. Microscopic Examination: The Pathologist prepares 'slides' from all the above tissues - the tumour, the nodes, the normal breast tissue and then studies those slides under microscope. Under microscope, one can see 'typical' cancer cells. The Pathologist examines all the slides in detail. We will definitely see cancer cells in the slides from tumour. In the slides from nodes, if we see those same cancer cells, it means the cells had 'travelled' from tumour in the breast to that lymph node in the arm pit. The more the number of nodes which show cancer cells, the higher the stage.
3. Immuno Histochemistry and other special tests: Breast cancer is of several different types. And each type has its own treatment protocols and also has similar outcomes within a type. So, for further planning, we need to know the type of Breast Cancer. This is known by certain tests called Immuno Histo Chemistry (IHC)

So finally, we get to know a lot of details about the tumour, the surrounding breast, whether the tumour was actively spreading or not, the nodes and other information and from that, we finally denote which stage it is. The staging is laid down by AJCC (American Joint Committee on Cancer) along with UICC (Union Internationale Contre Cancer), the latest is the 8th Edition. A good explanation about staging is given on the - Website.
It would be too vast and distracting to write in detail about the stage determination here. So I have focussed only on explanation of certain important points in the report. Please leave the staging part for your Oncologist. When it comes to 'pathologic' staging, we focus on three things in the report, each of which is discussed below:

The Tumour: This is denoted by 'T'.
The Lymph Nodes: This is denoted by 'N'.
The Type of Cancer: This is determined by IHC.

After reading the report, we assign a number (1 to 4) to 'T' and one number (1 to 3) to 'N' - for example, T2N1, or maybe T3N0, which will gives us the final pathological stage. This is only for a rough understanding. A request to please do not try to stage the report on your known, as the latest staging according to AJCC 8th Ed. is very complex, and I have not added all the points needed for staging here since discussing all that is beyond the scope here.

The Tumour

The 'tumour' is in the breast tissue. The cancer started here. The Medical term for cancer in breast cells is 'carcinoma'. Following are some of the points which the report will mention about the tumour:

'Type' of tumour: Infiltrating Duct Carcinoma (originates in the milk 'ducts') Or Infitrating Lobular Carcinoma (originates in the 'lobules' or glands, which produce milk. Sometimes, the whole tumour may contain a 'pre cancerous' stage called 'DCIS' and there is no 'infiltrative' component.
Grade of tumour: This can be Grade 1, Grade 2 or Grade 3. Grade 1 is a slow growing tumour, grade 2 is medium, and grade 3 is a faster growing tumour. Most tumours, especially in the young, are usually grade 3.
Single or Multiple:In most patients, there will be 'one' tumour only. But in quite a few, the cancer is 'multi centric' meaning, there is 'more than one' tumour in the breast. A 'multicentric' tumour means that, even though we may see a few tumours, there could be more which are so small that they cannot be seen.
Skin and Base: Was the tumour involving the skin above it? If yes, it is considered as advanced. Was the tumour involving the 'base'? The 'base' is that part of breast, which lies on the chest wall.. If the base is involved, ideally, it will be noted by surgeon during surgery and he will remove some muscle below the breast in the area of tumour to make sure nothing is left behind.
Surrounding Breast: Were the surrounding breast cells normal or not; was there any focus of some pre cancerous stage in rest of the breast. This pre cancerous stage is called as 'DCIS - Ductal Carcinoma in situ'
Signs of a spreading tumour: There are 'lymphatic channels' all over the breast going into the armpit. If the pathologist can see some cancer cells in these channels, it means, those cells had disconnected from tumour and were on their way to reach the lymph nodes. These are called as 'Lympho Vascular Emboli (LVE)'. There are 'tiny' nerve twigs as well, in the breast tissue, to carry the sensation. Cancer cells can travel 'along' these nerves. If the Pathologist can see cells along these nerves, it is called as 'Peri Neural Invasion (PNI)'. A positive LVE or PNI tells us that the cancer cells have started their travel and we must take it seriously.
Margins (in BCS): In a Breast conservative surgery, we remove only the tumour, with a 'cuff' of normal tissue of 1 cm all around. When we send the specimen of the tumour, we label it in six directions - Up, Down, Left, Right, Front, Behind. The pathologsit checks all these 'six' margins to make sure they are free. If one of the margin is 'positive' it means, some cells could be left behind and need to be 'revised'

So what information do we gain from studying the tumour?

The tumour characteristics in the pathology report help us to understand whether this is a 'small silent' cancer or is it 'larger' and 'angry' and 'spreading'. The standard classification for tumour is as follows:
T0: No gross tumour identified
T1: Tumour less than 2 cm in greatest dimension
T2: Tumour between 2 to 5 cm in greatest dimension
T3: Tumour more than 5 cm in greatest dimension
T4: Tumour of any size, directly involving the skin

Tumour in pathology report
Nodes in pathology report

The Nodes

The number of nodes involved by a cancer has a direct effect on the outcome of cancer. The more the nodes positive, the higher the stage. In a Pathology report, some of the points about the lymph nodes are as following:

Number of Positive Nodes: Most of us will have anything between 7 or 8 to 25 or 30 nodes (or even more). The Pathologist studies these nodes, and under the microscope, tries to see how many of these nodes contained the same cancer cells which were there in the primary tumour in the breast. The following classification is followed
N0: No positive nodes
N1: 1, 2 or 3 positive nodes
N2: 4 to 9 positive nodes
N3: 10 or more positive nodes

Peri Nodal Extension (PNE): In the nodes which are positive, the Pathologist also tries to see if the cancer had started coming 'out' of the nodes.

IHC (Immuno Histo Chemistry)

Breast cancer, commonly, is of four different types (Actually it's five, but one category is complex, so we will keep it to four for this discussion). And this type is decided by a combination of results of three factors:

Estrogen and Progesterone Receptor( ER / PR): Estrogen is a 'hormone' found in body, much more in females, less in males. It has lots of beenficial effects in the female body. It can cause breast cells to multiply. When ER / PR are positive, it means, there are 'sockets' in the tumour, into which, if Estrogen 'plugs in', it will cause the tumour cells to multiply. We have variety of drugs to block these receptors. It is called' Hormonal Therapy' since it blocks 'Hormonal Receptors'.
CerbB2 (HER2neu): This is a 'gene'. In about 15 percent of breast cancer patients, there is 'mutation' in this gene, and this faulty gene plays a role in the development of cancer. We have a drug which acts on this gene called as 'Trastuzumab'. It is called 'Targeted Therapy', as it 'targets' a specific gene involved in causing cancer.

Depending on combination of positive and negative of above two, we can divide breast cancer in broadly four categories:
ER PR Positive CerbB2 Negative: This is labelled as 'Hormone Receptor Positive Breast Cancer'. Usually tends to be slow growing, but some of them can grow fast as well. Hormone Therapy will work here, Trastuzumab won't.
ER PR Positive CerbB2 Positive: This is labelled as 'Triple Positive Breast Cancer', as all three tests are positive. Here, both Hormone Therapy and Trastuzumab will work
ER PR Negative CerbB2 Positive: This is labelled as 'HER2 Positive Breast Cancer'. Hormone therapy won't work as hormone receptors are negative, but Trastuzumab will work.
ER PR Negative CerbB2 Negative: This is labelled as 'Triple Negative Breast Cancer (TNBC)'. Most TNBCs tend to be very aggressive cancers (most but not all), and many of them tend to be 'familial' as well.

The type of cancer does not affect the 'stage' of breast cancer, but it plays an important role in deciding the treatment and selecting drugs for chemotherapy. For example, consider a tumour 2.5 cm in size (T2) and all nodes negative (N0); this will be T2N0 - stage 2A
If ER PR Positive and HER2 Negative - may not need chemotherapy
If Triple Negative - will definitely need chemotherapy
So two tumours of same stage, depending on the type, may or may not need chemotherapy.

Immuno Histo Chemistry in pathology report

Our Approach at this Step

It is very crucial that the patient and her relatives understand what is written in the Histopathology Report, and how am I making decisions based on it. It usually takes about 15 minutes of time, together with the patient, to go through the report, line by line, and explaining to the patient, what each line means. I have a simplified version of staging in my Consulting Room. I do not calculate the stage myself. I hand out the simplified staging chart to the patient, make her read those few points on 'T' and 'N' and then make her go through her own pathology report and stage her cancer. That way, the patient understands much better. Once the staging is done, and we now know, which type of cancer it is, comes the step of decision making. I strongly believe in a 'Multi Disciplinary Team' approach. I organize a meeting with my colleague Medical Oncologist and I try to attend it as well, so we both jointly explain to the patient.

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Journey of BC: Diagnosis

1. I feel a lump! - The first visit to doctor
2. Is it really cancer? - Confirmatory tests
3. What is the stage? - Staging and fitness tests
4. Will it be surgery first? or chemo first? - Treatment planning and sequence

Journey of BC: Surgery

5. Should I conserve or remove breast? - Choice of Surgeries for breast cancer
6. How long will be the surgery? - Admission and Surgery
7. Care after surgery - Precautions and guidelines
8. What next? - The Pathology Report - You are presently on this page

Journey of BC: Further Treatment

9. How many chemo cycles? - Chemotherapy Consultation
10. Is a PORT necessary? - ChemoPORT insertion
11. Will I be normal during chemo? - The Chemotherapy time
12. Is Radiation painful? - Radiation Therapy
13. Yes!! I did it! - Treatment is over
14. How frequently do I meet doc? - Follow up guidelines

Other Topics

Risk Factors - The Risk Factors for Breast Cancer
Symptoms of Breast Cancer - Know the Symptoms of Breast Cancer
Early Detection of Breast Cancer - The Guidelines

Neo Adjuvant Chemotherapy (NACT) - For LABC
Sentinel Node Biopsy - How is it done?
Targeted Therapy - Trastuzumab
Hormone Therapy - Who gets it?