Breast cancer affects approximately 1 in 11 women in their lifetime (to age 99) in Singapore with 1,850 women diagnosed with breast cancer, and over 400 die from the disease each year. These figures will continue to increase with our existing risk factors, compounded by our ageing population. Survivorship has improved over the years with majority diagnosed with early breast cancer (EBC). This has led to a remodelling of the approach and management beyond just surviving from this disease, with new techniques and treatments emerging to improve the quality of life.

MAMMOGRAPHY BENEFITS AND RISKS – WHAT YOU NEED TO KNOW

Mammograms do not prevent breast cancer, but they can save lives by finding breast cancer as early as possible. Finding breast cancers early allow more women being treated for breast cancer to keep their breasts as small cancers can be treated with breast-conserving surgery without resorting to mastectomies.

However, mammograms are not perfect. Normal breast tissue can hide a breast cancer; this is called a false negative. Mammography can also identify an abnormality that looks like a cancer, but turns out to be normal; this ’false alarm‘ is called a false positive. A false positive means more tests and follow-up visits, which adds to the anxiety of being diagnosed with breast cancer.

Hence, the roles of our healthcare professionals goes beyond recommending the screening mammograms at the primary care level, and include understanding and discussion of the benefits and the risks. Concerted efforts of education on awareness, breast self-examination and regular routine breast examinations by an experienced primary healthcare professional can allow cancers to be detected earlier. Occasionally, other forms of breast imaging, such as breast ultrasound, tomosynthesis (3-D mammograms) or MRI, may be added in the assessment.

Some statistics
The incidence of breast cancer tripled from 23.8 per 100,000 person-years in 1975 to 1979 to 64.6 per 100,000 person-years in 2010 to 2014. It is the most common cancer among women in Singapore, with 9,284 women diagnosed with breast cancer between the years 2010 to 2014.

In the past decade, early breast cancer accounted for more than 70% of those diagnosed, with 33.3% in stage I and 38.1% in stage II in 2010 to 2014. Majority in this period were aged 45 to 64. Chinese women have a significantly higher risk of developing breast cancer in comparison to Malays and Indians, but they have improved survival.

Over the years, the overall age-standardised 5-year observed survival improved from 40.3% in 1973 to 1877 to 70.5% in 2010 to 2014. The age-standardised observed survival in 2010 to 2014 was 90% for overall stage I, 80.1% for stage II; 72.7% for Chinese and 53.8% for Malays.

Singapore Cancer Registry, Interim Annual Registry Report, Trends in Cancer Incidence Singapore, 2010-2014 National Registry of Diseases Office, Singapore

Breast Self-Examination and Mammogram Recommendations

BREASTSCREEN SINGAPORE

BreastScreen Singapore (BSS) is our national breast cancer screening programme set up in 2002 under the Health Promotion Board (HPB) to raise public awareness, encourage early detection of breast cancer, and reduce its mortality. It enables early breast cancers to be detected before symptoms appear.

However, many myths about BSS still exist and they contribute to the low response to breast screening.

Myths About Breast Cancer Screening and BSS

Myth 1 Breast cancer screening mammogram can only be done in hospitals.

Fact: Breast cancer screening mammograms can be done at the Polyclinics under BSS. BSS Hotlines to help women book appointments for screening mammograms without needing a doctor’s consult:

Myth 2 Doctors in the Polyclinics reading the mammograms are junior doctors with limited experience.

Fact: Doctors in BSS are specialist consultant radiologists, surgeons and pathologists treating patients with breast cancer in their affiliated institutions. Mammograms are read by 2 independent radiologists (double reading) with a 3rd reader for discordant cases. There is a Quality Assurance framework with regular audits, quality improvement measures, and multidisciplinary management to maintain a high standard of care.

Myth 3 Screening mammogram is expensive and not subsidised.

Fact: The cost of a mammogram is $100. HPB subsidises the cost of the mammogram under HPB’s Screen for Life programme, after which women pay the rest:

*Aged 50 or above, screening mammogram is Medisave-claimable

Myth 4 The BSS process is slow and results in delay of treatment.

Fact: Women with symptoms are encouraged to see a doctor for early attention. BSS is recommended for well women with no symptoms and appointments can be made via the Hotline. After the mammograms are done on the screening date, the results letter is received within 3 to 4 weeks; there is no medical report or X-ray films provided as the reading results are recorded in the BSS system.

• If the results are normal, monthly breast self-examination and regular screening once every two years is recommended.
• If the results are abnormal or show changes, the notification result letters with instructions to book an appointment at the recommended hospital assessment centre will be sent instead. Further evaluations such as additional mammograms, ultrasounds, tomosynthesis (3-D mammography), including most of the needle biopsies, may be performed on the assessment day. This one-stop service negates the initial time required for assessment and notification for assessment.

Myth 5 BSS cannot do mammograms in women with breast implants.
Fact: Women with breast implants can still have mammograms done under BSS, but in the Assessment Centres as more specialised techniques (pinch view mammography) are required for all implants.

Myth 6 Radiation from mammograms can cause cancer.

Fact: Radiation exposure from mammograms is low, equivalent to 6 months of background radiation exposure from daily living. The risk of harm is low, and the benefits outweigh the risk of having a cancer undetected and allowed to progress till symptoms appear when the cancer is more advanced.

Myth 7 Mammograms can detect all cancers.
Fact: No screening test is perfect, including the mammogram. Age and breast density can be masked by the breast tissue on a mammogram. Technical difficulties including discomfort in some women with small and dense breasts may limit the ability to obtain good mammograms to allow examination of all the breast tissue, hence screening mammograms are less effective in younger women because they tend to have denser breasts.

Accessibility of BreastScreen Singapore Services

MULTIDISCIPLINARY TREATMENT OF EARLY BREAST CANCER

The success of treatment stems from the multi-prong approach to this disease, with improved treatment options over the decades. Our multidisciplinary approach with Breast Tumour Board discussions and decisions also maintains a consistent high level of care throughout our institutions in SingHealth.

SURGERY FOR BREAST CANCER

In EBC, surgery remains the cornerstone for treatment, occasionally, the only treatment needed, e.g. when DCIS is treated with mastectomy. More often, combination therapy, with the other modes of treatment after surgery as adjuvant therapy would be recommended. Surgery for breast cancer is viewed in two parts: the breast and the axilla, as axillary clearance is no longer a routine procedure for all breast cancers.

1. Sentinel lymph node biopsy (SLNB) is a standard of care for clinically early breast cancer. A blue dye or a radioactive isotope is injected around the cancer site or at the nipple prior to surgery to locate the SLN. If metastasis is detected in the SLN, axillary clearance with removal of the axillary lymph nodes will be performed immediately; otherwise, no further axillary surgery is needed.

The final histology will be reviewed about one week after surgery and in up to 5% of cases, the final assessment of the SLN may be different from the initial frozen section result and a second operation may be recommended.

2. Breast surgery involves either a breast-conservation surgery (lumpectomy or wide excision) or a mastectomy.

Breast-Conserving Surgery (BCS) involves removal of the breast cancer and a rim of normal surrounding breast tissue. The breast will remain; a scar and some changes in shape and size of the breast are expected. Patients can go home on the same day or the next day. A small tumour can be removed without noticeable deformities, but larger tumours to breast size and tumours in some locations result in more deformities.

Oncoplastic Breast-Conserving Surgery (OBCS) involves a range and combination of techniques we now provide to allow women to keep their breasts and avoid the disfiguring deformities that can arise. OBCS will be discussed in a later article.

Mastectomy is still the more common procedure amongst Singaporeans, with simple mastectomy the most performed surgery. However, the options and results of mastectomy with breast reconstructions have improved such that skin and nipple-sparing mastectomy with immediate breast reconstruction has become more common.

Flap reconstructions using skin, fat and sometimes muscle take about 6 to 8 hours and require a hospital stay between 1 to 2 weeks. Donor site for the flaps may be from the:

• Back (latissimus dorsi)
• Abdomen
• TRAM (transverse rectus abdominis myocutaneous) flap
• DIEP (deep inferior epigastric perforator) flap, taking skin and fat only
• Buttock
• Thigh

Breast silicone implants may be used and the operation takes about 4 to 5 hours, and the hospital stay is 2 to 5 days. It can be a 1-stage procedure when the permanent implant is inserted at the time of mastectomy; or a 2-stage procedure when a temporary expander is placed at the time of mastectomy and gradually expanded to stretch the skin. The expander will be exchanged for a permanent implant at a later surgery.

ADJUVANT THERAPY FOR BREAST CANCER

After surgery, most patients will require further (adjuvant) therapy. This usually depends on the size of the tumour, the lymph node status and the tumour characteristics e.g. hormone receptor status and HER2 status. These adjuvant therapies include chemotherapy, targeted therapy, radiotherapy and hormonal therapy.

1. Radiotherapy helps to decrease recurrence of the disease and usually takes place over a course of 4 to 6 weeks as external beam radiotherapy. If BCS is done, radiotherapy is recommended.

In some women with early breast cancer, a single dose of radiotherapy, known as Intraoperative Radiotherapy (IORT), may be given during the time of breast-conserving surgery (BCS). (IORT will be discussed in the following article).

2. Chemotherapy aims to decrease recurrence of the breast cancer in distant organs. It is usually administered over a course of 3 to 6 months.

Elderly patients, e.g. over 70 years old or those with multiple co-morbidities, would need additional considerations in view of the risks of complications.

In some women with large tumours, chemotherapy may be offered prior to surgery in order to shrink or downsize the tumour (neoadjuvant chemotherapy). In some cases, the chemotherapy may shrink the tumour enough so that a wide excision or lumpectomy can be safely done.

3. Hormone Therapy like Tamoxifen and Aromatase Inhibitors is recommended for women with cancers that have oestrogen or progesterone receptors. Hormonal therapy is usually taken for 5 to 10 years.

4. Targeted Therapy is recommended for women with cancer that have HER2/Neu receptor using Trastuzumab and Pertuzumab. Side effects are usually mild but cardio-toxicity must be considered.

ROLE OF GPs IN SHARED PATIENT CARE

GPs play an important role in the shared care of the patient in the following areas:

• Patient awareness and education: breast self-examination, recommend BSS mammograms
• Routine clinical examination
• Management of benign breast conditions
• Refer suspicious findings found in mammograms or ultrasound done outside BSS to specialists

WHEN TO REFER TO A SPECIALIST

GPs can call for appointments through the GP Appointment Hotlines at:
63214402 (SGH)
64368288 (NCCS)
62944050 (KKH)

Dr Benita Tan is a Senior Consultant General Surgeon sub-specialising in breast surgery. Her clinical practice is largely on breast diseases, both benign and malignant. Experienced in a wide range of breast procedures, she performs breast biopsies including vacuum assisted biopsies (VAB) and breast cancer surgeries, from breastconserving cancer surgery to mastectomies including skin-sparing surgery for breast reconstruction.

She enjoys teaching and shares her clinical experiences with students from the NUS Yong Loo Lin School of Medicine, Duke-NUS Medical School, SingHealth residents in General Surgery and Family Medicine programmes, as well as trainees in the Resident Nursing programme.

Active in research, she attained her Doctor of Philosophy at Saw Swee Hock School of Public Health, National University of Singapore. She has published in peer-reviewed journals and is a strong believer of collaborative efforts, with local and international research partners.