Margie Petersen Breast Center at Providence Saint John's Health

The Margie Petersen Breast Center at Providence Saint John’s Health Center provides a one-stop, comprehensive, multidisciplinary clinic for an array of supportive services to complement your breast health conditions.

Margie Petersen Breast Team
Breast Health

Breast Health

There are many reasons to come to the Margie Petersen Breast Center at Providence Saint John’s Health Center, but one of the best is that we have the ability to fully evaluate any breast problems in one day. Most breast lumps are not cancer, yet any breast related concerns can be frightening. We have radiologists on site Monday-Friday to review mammograms and ultrasounds. If a biopsy is needed, we facilitate that the same day or as soon as possible. Our team of breast specialists can then determine next steps quickly.

Most tests fall into one of the following categories:

  • Screening tests – such as yearly mammograms, are given routinely for women who appear to be healthy and are not suspected of having breast cancer. Their purpose is to find breast cancer early, before any symptoms can develop and the cancer may be easier to treat.
  • Diagnostic tests – performed if you have a breast abnormality or an abnormal screening test result. These tests are used to determine the type of abnormality found, and whether or not breast cancer is present. Diagnostic tests also are also used to gather more information if cancer is diagnosed, to guide decisions about treatment.

Scheduling a Mammogram or Ultrasound after a COVID vaccine

The Society of Breast Imaging recently reported that the COVID vaccine can cause temporary enlargement of the underarm (axillary) lymph nodes. This is a normal reaction to some vaccinations, however this can lead to unnecessary additional workup with ultrasound and or biopsies. It has been recommended to avoid breast imaging (mammograms/ultrasound MRI) immediately after a vaccine injection. In order to eliminate unnecessary workups, after receiving the vaccine, we will follow these guidelines when scheduling a mammogram or ultrasound:

Screening or Diagnostic Mammograms and Ultrasounds

In addition to the standard COVID screening questions we will also ask patients, “Have you had or will you be having a COVID vaccine?”

If the answer is “yes” we will schedule your breast screening appointment at least 1 day BEFORE the FIRST vaccine dose or at least 2 weeks AFTER the SECOND vaccine dose.

We hope this approach will avoid unnecessary tests for our patient who have normal reactive lymph nodes.

This only applies to patients who do not have breast symptoms and or concerns. For patient with a breast concern, we will schedule as normal, and our technologist will get your medical history.

Methods and Myths

Breast Cancer Screening Methods and Myths Webinar

Watch our breast cancer doctors at the Margie Petersen Breast Center at Providence Saint John’s, discuss the different types of breast cancer screening methods including, breast exams, mammography, ultrasounds, MRI, and biopsy, as well as share the facts for all the common breast cancer myths you’ve heard.

Risk Factors for Breast Cancer

Risk Factors for Breast Cancer

A risk factor is anything that may increase your chance of developing a disease. Many risk factors are things you can control, like smoking, but others may be genetic.

Knowing your risk factors for any disease can help guide you in taking appropriate actions to reduce your risk, including changing behaviors, and being clinically monitored for the disease.

  • Gender. Breast cancer occurs nearly 100 times more often in women than in men.
  • Race or ethnicity. It has been noted that white women develop breast cancer slightly more often than African-American women. However, African-American women tend to die of breast cancer more often. This may be due to the fact that African-American women often develop a more aggressive type of tumor. The risk for developing breast cancer and dying from it is lower in Hispanic, Native American, and Asian women.
  • Aging. Most breast cancer is diagnosed in women after age 55.
  • Previous radiation therapy to the chest during adolescence. Women who had radiation therapy to the chest for another type of cancer are at greater risk of developing breast cancer.
  • Family history. Having a close relative, such as a mother or sister, with breast cancer increases one’s risk of developing breast cancer.
  • Genetic factors. Only about 5-10% of all breast cancer is known to be associated with an inherited genetic mutation. The most common mutations are in BRCA1 and BRCA2. If someone inherits such a mutation, the risk of developing breast cancer is much higher than for the average man or woman.
  • Benign breast disease. Women with certain benign (not cancerous) breast conditions (such as atypical ductal or lobular hyperplasia, or lobular carcinoma in situ) have an increased risk of developing breast cancer.
  • Mammographically dense breast tissue. Breast tissue may look dense or fatty on a mammogram. Women with dense breast tissue are at slightly increased risk of developing breast cancer. Dense breast tissue also makes it more difficult to see changes on mammogram. Tomosynthesis makes this easier.
  • Diethylstilbestrol (DES) exposure. Women who took this drug while pregnant (to lower the chance of miscarriage), and their daughters born from that pregnancy, are at slightly higher risk.
  • Early menstrual periods. Women whose periods began early in life (before age 12) have a slightly higher risk of breast cancer.
  • Late menopause. Women are at a slightly higher risk if they began menopause later in life (after age 55).

View more risk factors at the American Cancer Society.

The Margie Petersen Breast Center Breast Team endorses the American Cancer Society recommendations for taking an active role in reducing your risk of developing breast cancer by:

  • Getting to and maintaining a healthy weight.
  • Staying physically active.
  • Limiting or eliminating alcohol from your diet.

Patients of the Margie Petersen Breast Center who are at high risk for breast cancer, and those who are diagnosed with breast cancer, are referred to the Willow Sage Wellness program nutritionist for a full body composition assessment and tailored nutritional coaching. Performance Physical Therapy also provides consultation on fitness and exercise.

Our calculator is intended only as a guideline. Please see your Providence Saint John’s Margie Petersen Breast Center surgeon or cancer genetics and genomics team to determine your risk of developing breast cancer.

Meet Our Breast Health Care Team

The Margie Petersen Breast Center at Providence Saint John’s Health Center brings you some of the finest breast health and cancer care in Southern California. 


The Breast Health Clinic can be reached at (310) 582-7209. If you have questions regarding a new symptom or want to make an appointment for evaluation please call and a staff member will assist with navigating you in the right direction.

Schedule an Appointment For more information