This is an introduction to oncology for breast cancer physiotherapists developed by Siobhan O’ Reilly Bracken MISCP PT MPA MSc CLT as part of the course “Breast Cancer Rehabilitation for Physiotherapists ” – Updated Sept 20th 2016


Section 1. Oncology

What exactly is cancer?

“ Cancer is not a disease but a whole family of diseases. These diseases are linked at a fundamental biological level. They’re characterized by the proliferation of cells-occasionally cells that don’t know how to die, but certainly cells that don’t know how to stop dividing. That abnormal, uncontrollable growth of cells is a process that typically starts in a single cell and the cell multiplies over and over, and every generation produces a little evolutionary cycle such that you get more and more evolved cells. But although there’s a deep commonality between prostate cancer, breast cancer, leukemia, although they’re connected at the cellular level, every cancer has a different face “.

Siddhartha Mukherjee.

The Emperor of All Maladies, A Biography of Cancer, Winner of The Pulitzer Prize

Current trends in Breast Cancer in Ireland 1994-2013

According to the most recent trend reports published by the National Cancer Registry of Ireland,  1 in 10 women may develop breast cancer before the age of 75.

Breast cancer is the most common cancer with 2,883 cases diagnosed each year on average during 2011-2013. From 1994 to 2013 the Registry reports an increase of 1.5% in the numbers of women diagnosed with breast cancer but a decrease of 2% in the number of women dying from their disease. The 5 year survival rate in Ireland is now at 82%.

The trends for increasing survival are due in part to improvement in screening (increased public awareness and BreastCheck which was instituted in 2000) and improvements in treatment.

Treatment may be a combination of chemotherapy, surgery, radiotherapy, hormone therapy and/or immunotherapy.

85% of patients have surgery (and due to screening and early detection) there is a strong trend towards greater use of breast-conserving surgery (BCS) i.e. lumpectomy and radiotherapy. Compared with mastectomy (removal of the breast), lumpectomy allows faster recovery without the need for breast reconstruction. Lumpectomy now accounts for about two thirds of all surgical treatments for breast cancer.

The proportions of patients receiving radiotherapy have increased from 62% in 1999-2003 to 69% in 2009-2013, and hormone therapy from 49% to 55% over the same period.

HER2+ (positive) tumours are more aggressive (i.e. grow faster). Most breast cancers are now tested for HER2 status, and a high proportion of HER2+ cases received the monoclonal antibody trastuzumab (Herceptin), which reduces the risk of recurrence and death.  About 15% Irish cases diagnosed during 2011-2013 were HER2+ and, of these, 65% received trastuzumab (Herceptin).

The National Cancer Registry Ireland


Usually breast cancer is slow growing and can spread microscopically for many years before it is detected. When a suspicious abnormal lump or thickening is detected on mammogram either a fine needle aspiration or excisional biopsy will be performed to confirm the diagnosis and facilitate appropriate surgical planning.


The Pathologist reports the stage (or burden) of the disease to the medical oncologist, the breast and reconstruction surgeons and radiation oncologist to help determine the patient’s course of treatment. The stage is typically divided at diagnosis into early (stage 1 and 2), locally advanced (stage 3) or metastatic categories (stage 4).

Including stage 0 there are 5 stages of breast cancer. The stage is determined by the size of the tumor, how many lymph nodes are involved and whether or not there are metastatic lesions.

There are 2 formal staging systems used. The TNM staging system illustrates key pathology information where T = Tumor size, N = Number of positive lymph nodes, M = Metastasis.

Stage 0 is used to describe non-invasive breast cancers, such as DCIS (ductal carcinoma in situ). In stage 0, there is no evidence of cancer cells or non-cancerous abnormal cells breaking out of the part of the breast in which they started, or getting through to or invading neighboring normal tissue.

Stage 1 – T < 2cm; N = 0; M = 0

Stage 2 – T > 2cm but < 5cm; N = at least 1 node +ive; M = 0

Stage 3 – T > 5cm: N = some: M = 0 or T = some; N = high #;

M = 0;

Stage 4 – T = any size: N= any number; M = 1 metastatic disease is present in bone, liver, lung and/or in the brain.

Types of Breast Cancer

Non-invasive breast cancers

Examples of non-invasive cancers of the breast are Lobular and Ductal Carcinoma in Situ (LCIS and DCIS). LCIS is not believed to be a precursor of invasive disease whereas DCIS is an established precursor of invasive disease. DCIS is treated with BCS (breast conserving surgery “lumpectomy”) or mastectomy and radiotherapy to reduce the risk of recurrence.  Evaluation of the axilla may be but is generally not performed and 5 years of Tamoxifan may also be considered.

Invasive Breast Cancers

Lobular and Ductal carcinomas that have invaded the surrounding stroma and do have the capacity to metastasis – are referred to as invasive cancers. Approximately 75% of our patients are ductal carcinomas.

Less Common Breast Cancers

Paget’s disease of the nipple, inflammatory breast cancer, male breast cancer, invasive lobular carcinoma, medullary and tubular carcinomas and recurrent and metastatic breast cancer.

Key Breast Cancer Tests


A mammogram is a safe and generally accurate X-ray of the breast. Mammograms are the most useful test doctors have to screen, diagnose, evaluate, and monitor breast cancer. In the USA women at average risk of being diagnosed, screening mammograms begin at age 40. Higher risk women determine their screening schedule  in close consultation with their doctor.

Breast Ultrasound

Ultrasound is used to complement mammography to find out if an abnormality is solid (e.g. a tumor or fibroid) or fluid-filled (e.g. a cyst). In young women, mammograms alone can be difficult to interpret because their breasts tend to be dense and full of milk glands. Older women’s breasts tend to be more fatty and are easier to evaluate.

Genomic Tests

When there is a breast cancer diagnosis the Oncotype DX genomic test score is helpful with both prognosis (risk of recurrence) and predicting the benefits of having chemotherapy and radiation in both early stage breast cancer and in DCIS.

Oncoytpe Recurrence Scores For Early-Stage Estrogen Positive Breast Cancer

  • Scores lower than 18 = a low risk of recurrence + smaller benefit from chemotherapy
  • Scores of 18 up to and including 30 = an intermediate risk of recurrence + its unclear if the benefits outweigh the risks of chemotherapy side effects.
  • Scores greater than or equal to 31 = a high risk of recurrence + the benefits are greater than the risks of chemotherapy side effects.

The Oncotype DX scores for DCIS

Recurrence Score lower than 39 = low risk of DCIS recurrence + benefits are smaller than the risks of radition side effects.

Recurrence Score between 39 and 54 = an intermediate risk of DCIS recurrence + it’s not clear if the benefits outweigh the risks of radiation side effects.

Recurrence Score greater than 54 = a high risk of recurrence + , the benefits are greater than the risks of radiation side effects.

PET Scan.

Positron Emission Tomography, can detect areas of cancer by obtaining images of the cancer cells metabolizing radioactive sugar.

FISH Test and ImmunoHistoChemistry or IHC Test. 

These tests detect HER2 genes which stimulate the growth of breast cancer cells and will indicate if the breast cancer is “positive” or “negative” for HER2. Fish = Fluorescence In Situ Hybridization. HER2 is treated with Herceptin, Tykerb and Perjeta.


  1. CANCER REHABILITATION, Principals and Practice, Michael D Stubblefield and Michael W. O’Dell 2009 Pgs 181 – 193 Evaluation and treatment of breast cancer; Heather L. McArthur and Clifford A. Hudis,
  2. The Emperor of All Maladies, A Biography of Cancer, Siddhartha Mukherjee 2010, pgs 573 – end. Winner of the Pulitzer Prize. Ebook edition
  3. The National Cancer Registry of Ireland.
  4. – Oncotype DX testing
  5. The Irish cancer society
  7. Canadian Cancer Society
  8. American Cancer Society