Breast Cancer I - Screening

Screening means checking for cancer in people who have no symptoms.

It’s important because screening can help doctors find and treat cancer early, before it becomes serious enough to cause noticeable effects.

Early detection almost always makes cancer easier to treat, makes cancer treatments more effective, or allows for the use of treatments that are less invasive. In many cases, early detection helps to increase the likelihood of overall survival.

At the same time, screening can act as a double-edged sword. Some screening tests have associated risks which could cause pain, bleeding, or other health problems. They can sometimes have false-positive, or false-negative results - meaning that screening tests aren’t always 100% accurate.

Further, screening can sometimes lead to over-diagnosis, which means that a person actually is found to have cancer, but it may not have harmed the person in their lifetime. When such cancer is treated, it is referred to as over-treatment.

As with any complex medical subject, it can be helpful for people to discuss the potential harm and benefits of different cancer screening tests with their doctors. Best practices and standards of care exist for a reason, and what’s more, they are constantly evolving.

One of the best things you can do is to educate yourself enough to have an informed conversation with your medical team and ensure that you’re following the best practices available.

So, let’s get started!

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Breast Tumors - Benign or Cancerous?

Cancer begins to form when cells become damaged, develop mutations, and begin to replicate uncontrollably.

Normally, damaged cells undergo a death process and are replaced by new healthy cells. However, cells can develop mutations which affect certain genes that allow them to replicate indefinitely. This may lead to the eventual formation of a tumor.

As cancerous cells continue to replicate, they can develop even more mutations which may make it easier for them to avoid destruction by the immune system, and allow them to invade other tissues in the body (metastasize). 

An important fact to realize is that breast tumors can either be benign or cancerous.

Many women develop benign tumors of the breast, meaning that these damaged cells have begun to replicate, but they are slow-growing, resemble the original cell, and do not have the ability to invade surrounding tissue. These tumors are classified as non-cancerous.

Cancerous tumors, on the other hand, are the opposite - they do not resemble the original cell, they are fast-growing and they can invade and metastasize into other tissues.

Before we get any further, let’s ask what seems like a basic question: What makes breast cancer so dangerous?

The danger associated with breast cancer comes from the fact that cancer cells can metastasize to other areas of the body and disrupt normal function in these areas.

Breast cancer can metastasize to almost any organ system, however, it most commonly metastasizes to the lungs, liver, bones, and, less commonly, to the brain. If left untreated, primary breast cancer lesions can also spread to the skin, invade the chest wall, and surrounding lymph nodes.

As it grows, the tumor mass impairs the normal physiological function of the organ it has invaded which can eventually lead to death.

That’s why screening is so important. Earlier detection of tumors and cancers is often critical and is one factor in determining how effective treatments are in eliminating cancer, and minimizing how invasive treatments may need to be.

Types of Breast Cancer

Let’s learn a little more about breast anatomy to understand where and how doctors screen for cancer. The breast has five main components:

  • Lobules which consist of glands that produce milk,

  • Ducts which transport milk to the nipple,

  • The nipple, the raised region of tissue on the surface of the breast through which milk leaves the breast,

  • The areola, a pigmented area on the breast surrounding the nipple,

  • and the fibrous, and fatty connective tissue that holds them all together.

There are several different types of breast cancer, each differentiated by the tissue in which the tumor initially formed. The most common types of cancer occur in the ducts and lobules of the breast. 

Common types of breast cancer:

  • Carcinoma in situ (CIS):  This condition is considered a pre-cancerous lesion or non-invasive stage 0 cancer. DCIS occurs when abnormal epithelial cells in the milk ducts replicate and line the duct. However, these cells have not invaded into surrounding tissue. In situ means “in place” which indicates that these cells stay in their place. The same can occur in breast lobules, known as lobular carcinoma in situ (LCIS), though this is much less common than DCIS.

  • Invasive ductal carcinoma: This is the most common type of breast cancer and accounts for 70-80% of all invasive lesions of the breast. This cancer begins in the milk ducts (hence ductal) but has invaded into the surrounding tissues.   

  • Invasive lobular carcinoma: This form of cancer constitutes 8% of all breast cancers. It occurs in the milk lobules of the breast and is typically more slow-growing than invasive ductal carcinoma. 

  • Inflammatory breast cancer:  Inflammatory breast cancer is a rapidly growing, rare, and aggressive form of breast cancer. It presents with pain and/ or a rapidly growing breast lump. Typically the skin of the breast may look like it has a rash, and may be warm, thickened, and itchy. The breast may also look swollen as inflammatory breast cancer usually involves the lymph nodes and, in many instances, has metastasized to other locations. Furthermore, the nipple may look abnormal and be retracted, crusted or flattened. 

  • Paget’s disease of the nipple:  Presents as an ulceration or eczema-like rash on the nipple. 

Symptoms & Warning Signs

Primary breast cancer:  

The majority of localized breast tumors are found either via a screening mammogram, clinical breast exam, or a self-breast exam before any other noticeable effects are apparent.

These breast masses commonly present as a firm, immobile lesions with irregular borders, and may be tender to the touch.

A more locally advanced disease may present with noticeable symptomatology such as swollen lymph nodes in the axilla, as well as skin changes such as redness, skin thickening, dimpling of the skin, nipple changes, and nipple discharge.

While other things such as trauma to the breast, dense breast tissue, and benign masses may also present as masses in the breast, it’s important to follow up with your doctor if you find anything suspicious during a regular self-exam, who may recommend imaging to check it out.

If cancer is identified, your doctor will implement further tests as a part of diagnosis and staging.

We’ll discuss these steps in our next blog post, but for now, we’ll just say that diagnosis and staging help your doctor outline and recommend the best steps to take next, as well as to help you to make informed decisions about your care.

Recurrence of primary breast cancer and/or metastatic disease:  

Similar to primary breast cancer, local recurrence of breast cancer may present with a firm, immobile mass.

There may also be axillary adenopathy, skin, and nipple changes.

If cancer has metastasized to a different area of the body, symptoms may depend on which organ system is affected. Common areas that breast cancer may metastasize to are:

  • Bone:  Metastasis to bone can present as bone tenderness or bone pain to the area of metastasis. If the damage to the bone is extensive then patients may present with fracture or low blood counts due to marrow involvement.

  • Lung:  Lung metastases may present as a sharp (known as pleuritic) chest pain, cough, or trouble breathing. 

  • Liver:  Liver metastases may present as pain in the upper right quadrant of the abdomen, a feeling of fullness in the same area, loss of appetite, and weight loss. 

  • Brain:  Brain metastases most commonly present with headaches, vision changes, loss of motor or sensory function, bowel or bladder dysfunction, seizures, changes in mental status, nausea and vomiting.

It’s important to involve your doctor if you begin having any of the symptoms above. He or she may order specific tests that will allow them to either confirm or rule out cancer as the cause behind that pain.


Breast Cancer Risk Factors

Research into the risk factors that may promote the development of breast cancer has discovered that there are A LOT of factors that influence the development of breast cancer. Some of these, such as obesity and smoking, are modifiable. Others…such as being female, and age of menarche, aren’t.

The key thing is to focus on what you can control, and recognize the things you can’t.

Modifying the factors that are changeable may help lower your overall risk of developing breast cancer and recognizing the factors that you can’t change can help you make sure your screening is as effective as it can be in your personalized case.

Factors that have been found to increase the risk of developing breast cancer include:

  • Age: Age is one of the largest factors in the development of any type of cancer. As people age, it isn’t uncommon to accumulate genetic mutations which increase the probability of developing cancer. 

  • Gender: Breast cancer is predominantly a female disease. Although men can develop breast cancer, women are 100-times more likely to develop breast cancer than men (1).

  • Race: Caucasian women have the highest rate of breast cancer. However, African American women are more commonly diagnosed with advanced disease and have higher mortality rates from breast cancer (2). It is estimated that factors ranging from BMI and lifestyle to socioeconomic status play a role in this discrepancy. 

  • Genetics:  Inherited genetic mutations account for only 5-6% of all breast cancers. However, having one of these mutations can significantly increase your risk of developing cancer. If you have a family history of breast cancer, we recommended that you receive genetic counseling.

    Common mutations that increase the risk of developing breast cancer include BRCA1, BRCA2, TP53, PTEN, CHEK2, CDH1, STK11, and various mismatch repair genes. 

  • Dense breast tissue:  While there has recently been debate over this in the scientific community, it is still commonly believed that having dense breast tissue increases your risk of developing breast cancer (6).

  • Radiation exposure:  Women who have had exposure to ionizing radiation in proximity to their chest wall at a young age are at increased risk of developing breast cancer. 

  • Prior breast cancer or ductal carcinoma in situ (DCIS):  Women who have a history of ductal carcinoma in situ or have a past diagnosis of breast cancer are at higher risk of developing breast cancer.

  • Hormone levels:  Higher levels of circulating estrogens have been associated with increased rates of breast cancer (7). This has been found to be the case in both premenopausal and postmenopausal women.

    While less conclusive, there is a link between elevated testosterone levels and an increased risk of developing breast cancer.

  • Insulin and IGF-1:  Both insulin and insulin-like growth factor 1 (IGF-1) are anabolic hormones that promote growth. Cancer cells can use these hormones to increase their growth. It has been found that women with elevated levels of Insulin and IGF-1 have an increased risk of developing breast cancer (9-10).

  • Hormone replacement therapy:  There is a moderately increased risk of developing breast cancer with the use of hormone replacement therapy (11-12). The type of hormones used, and duration of use are important factors in this. It has also been found that this risk decreases within two years of stopping the use of these (12). 

  • Birth control:  It has been found that women who use birth control have a slightly increased risk of developing breast cancer compared with women who have never used it (13). This risk stays elevated for up to 5 years after stopping but then begins to decrease.

  • Age of menarche:  It has been found that the age at which women have their first menses can influence their risk of developing breast cancer. Women who experience their first period at age 15 years old or older have a decreased risk of breast cancer (15). One study found that for every 2-year delay in menses there was a 10% reduction in breast cancer development (15). 

  • Age of menopause:  It has been found that undergoing menopause at a later age increases the risk of breast cancer. Women who undergo menopause after 55 years old have an increased risk of developing breast cancer (14-15).

  • Age of first child and number of children:  It has been found that women who do not have children are at an increased risk of developing breast cancer (16-18). Furthermore, women who have children later in life have a higher risk of developing breast cancer than those who have children at a younger age (17). Research suggests that there is a decreased risk of breast cancer with increasing numbers of pregnancies (16-17).

  • Breastfeeding: Women who breastfeed have a decreased risk of developing breast cancer. Studies have found that for every 12 months of breastfeeding a woman undergoes she has a 4.3% reduction in the relative risk of developing breast cancer (16, 19,20).

  • Alcohol use:  It has been well established that alcohol consumption is a risk factor for developing breast cancer. Research has found that women who have 2-3 drinks/ day have a 20% higher risk of developing breast cancer (21). Another study found that just one drink a day increase breast cancer risk by 5% in premenopausal women and 9% in postmenopausal women (22).

  • Tobacco use:  While results are not conclusive there is an association between smoking and developing breast cancer (25).

  • Disrupted circadian rhythm: It has been found that less than 6 hours of sleep per night increases the risk of breast cancer recurrence (23). Lack of sleep has also been associated with the development of more aggressive forms of breast cancer (23). Women who work night shifts are 30% more likely to develop breast cancer (24).

  • Stress: Both acute and chronic stress can impair the immune system, increase inflammation and affect the way our genes are expressed. All these factors can increase the risk of cancer development and recurrence. It has been found that early childhood stressors, such as the death of a parent, as well as adult stressors such as divorce, can increase the risk of developing breast cancer (26-29).

  • Obesity: It is estimated that people who are obese have a 1.6 times higher risk of developing cancer (3). There are multiple proposed mechanisms for this such as impaired immune function, increased inflammation and hormonal dysregulation (3). 

    • Post-menopausal: It has been found that women who are post-menopausal and obese have a higher risk of developing breast cancer. One reason for this is that increased fat stores increase the levels of circulating estrogen in the bloodstream leading to tumor growth (4). 

    • Pre-menopausal: Surprisingly it has been found that pre-menopausal women who are obese have a 46% less chance of developing breast cancer. The reason for this is currently unknown (5) '

    • Visceral fat: Having elevated levels of visceral fat increases the risk of developing breast cancer (32). To understand the role that visceral fat plays in cancer development read our blog post here (link).

  • Diet:  Research indicates that diet may play a large role in decreasing the risk of developing breast cancer. This may be mediated through multiple mechanisms such as its impact on BMI and visceral fat, inflammation and immune function. No study has been conclusive on what macronutrients (carbs, protein, fat) or diet are the most beneficial to decrease the risk of developing breast cancer. We recommend consuming an anti-inflammatory, plant-based, whole foods diet that is micronutrient dense. 

  • Exercise:  It has been found that 30 minutes of exercise/ day 5 days/ week reduces breast cancer risk anywhere from 10-20% (30). One study found that regular physical activity reduces breast cancer mortality and recurrence by 40% (31). 

  • Exposure to endocrine disruptors:  There is currently no conclusive evidence that chemicals in our environment cause breast cancer. What we do know is that many different chemicals disrupt normal hormone production and can cause health problems. Many of these chemicals are similar in structure to estrogen and can bind to the estrogen receptor activating it. We recommend trying to avoid exposure to these endocrine disrupting chemicals as much as possible. This entails carefully choosing what cookware, water bottles, cleaning products, herbicides, pesticides, cosmetics and sunscreen you use. 

Imaging Modalities


Mammography:  A screening mammogram is the recommended imaging modality for detecting breast cancer. It is the only screening modality that has been shown to reduce breast cancer mortality. However, it may miss up to 20% of breast cancers and in some instances may need to be supplemented with other imaging modalities.  

Ultrasound:  Ultrasounds are becoming a popular screening modality for many women as it does not use radiation. Its use is indicated as an adjunct therapy in women with dense breasts or in women whose axilla needs to be viewed. It is also recommended as a follow-up exam if an abnormality is seen on a mammogram. 

MRI:  Breast MRIs are an emerging imaging modality that is becoming more popular. Currently, they are not recommended in average-risk women. However, in high-risk individuals, such as those with a BRCA mutation, they are recommended in conjunction with mammography. Breast MRIs are better at detecting breast tumors compared with mammography, however, they have also been found to result in more false positives. This is why breast MRIs are recommended only in conjunction with mammograms. 

Thermography:  Other imaging modalities look at the anatomy of the breast whereas thermography looks at the physiology of the breast. Thermography uses an infrared camera to map heat changes in the breast. These heat changes can signify increased blood flow to an area which may be a sign of tumor formation. Thermography is not recommended as a stand-alone imaging modality and should only be used as an adjunct to mammography. 

Common Screening Practices Broken Up by Risk Group

Most women are considered to be in the average risk group. 

However, women who have a personal history and/or family history of breast, ovarian, or peritoneal cancer and/or a genetic predisposition to breast cancer and/or received radiotherapy to the chest between age 10 and age 30 are considered moderate to high-risk individuals for developing breast cancer.

The following screening practices are broken down by both ages, as well as risk groups. Common screening techniques may be adapted or used more frequently depending on your individual, physician assessed, risk factors.

Average risk individuals

Under age 40: Mammography is not recommended before the age of 40. It is recommended that women perform regular self-breast exams and receiving annual clinical breast exams. 

Age 40-49: In this age range shared decision making is encouraged. The topic of screening should be discussed as well as the pros and cons of screening. Pros of early screening include finding early-stage breast cancers and peace of mind for the patient. Negatives of early screening include false positives, over-diagnosis, and over-treatment. For women who decide to undergo early screening, it is recommended that they receive a mammogram every 2 years. Additionally, women should routinely administer self-breast exams and have an annual clinical breast exam. 

Age 50-74: In this age group mammography is recommended every 1-2 years or more frequently if a finding needs to be followed up on. Additionally, women should routinely administer self-breast exams and have an annual clinical breast exam.

Age 75+: Biennial screening is recommended in this age group if the individual is expected to live more than 10 years past their current age. Shared decision making should be employed in older individuals and the pros and cons discussed. Women should still undergo self-breast exams and have an annual clinical breast exam at this age.

mammography recommendations.png

Screening in Moderate Risk Individuals 
Women with a first-degree relative diagnosed with breast cancer, but with no genetic mutations fall into this category. The recommendations for breast screening for moderate risk individuals is the same as for average-risk individuals.

However, if the family member was diagnosed with pre-menopausal breast cancer you may want to begin being screened in your 40’s.  Furthermore, supplemental imaging such as ultrasound and MRI may be indicated, but only after discussing the pros and cons with your physician. 

Screening in High-Risk Individuals
For individuals who are at high risk for developing breast cancer, again, a woman who has a personal history and/or family history of breast, ovarian, or peritoneal cancer and/or a genetic predisposition to breast cancer and/or received radiotherapy to the chest between age 10 and age 30, it is recommended that they receive both annual mammography and breast MRI.

It is generally recommended that these exams are staggered so that one occurs at least every 6 months. Screening is recommended to commence 10 years before your youngest family member with breast cancer was diagnosed, but not occur any sooner than age 30. 

Screening - What’s The Bottom Line?

Summing things up, what can we say about breast cancer screening?

  • Screening means that you and your doctor are looking for the presence of cancer cells and/ or tumors, even though there isn’t any present symptomatology.

  • For self-breast exams, it’s important that you are familiar with your own anatomy and know how to recognize when something is unusual. There are a lot of reasons that breast tissue may feel different over time, but it’s never a bad idea to bring up anything suspicious to your doctor.

  • Remember that breast cancer doesn’t usually cause any outright symptoms before it’s large enough, or begun to spread to impact other areas of the body. Again, if something seems unusual with your body, bring it up with your doctor.

  • Familiarize yourself with your risk factors.

    If you can reduce your risk by improving your diet, exercise, or other modifiable choices, do it! It never hurts to make choices that will have a positive effect on your health overall, just remember that any change needs to be implemented responsibly. If you’re uncertain how to make these changes, consult with your physician first.

    Secondly, there are several risk factors that you can’t change. Even the most health-conscious person can develop cancer because it’s in their genes, or they are otherwise predisposed. Recognize whether you have those factors and let that serve to guide you on how diligently you follow your doctor’s recommendations about screening. Your medical plan, including screening, should be highly personalized to you and your situation.

  • Lastly, whether you’re in a high-risk or a low-risk category, get screened! Your doctor can make all the recommendations that he or she wants, but it’s up to you to make it happen. Remember, when it comes to breast cancer, it’s always better to know for sure.

Now that we’ve discussed screening, it’s time we move on to the next reasonable step. Our next blog post for this awareness month is going to cover diagnosis and staging. Follow us on Facebook, or add our blog to your RSS reader (just click the link for RSS in the footer of this page) to make sure you don’t miss it!

Written by Adam Kozin. ND.

Written by Adam Kozin. ND.

(Our blog isn't designed to provide specific medical advice or replace a medical professional.  If you have any specific questions about your health, how to make changes responsibly, or would like to set up an appointment with our clinic, head to our Contact Us page and let us know)!



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