Breast Self-Exam, Mammogram Best for Finding Invasive Breast Cancer After DCIS
Published on January 16, 2024
If a woman is diagnosed with invasive breast cancer after finishing treatment for DCIS, she’s more likely to have the cancer found on a mammogram or find the cancer herself during a breast self-exam than to have it found by a healthcare provider during a breast physical exam, according to a study.
The research was published online on Dec. 28, 2023, by JNCCN, the official journal of the National Comprehensive Cancer Network.
DCIS and invasive breast cancer risk
DCIS is non-invasive breast cancer that hasn’t spread outside the milk ducts where it started. DCIS isn’t life-threatening, but it does increase the risk of developing invasive breast cancer later in life. About 20% of women with a history of DCIS develop another tumor in the same breast, and about half of these tumors are invasive breast cancer. Women with a history of DCIS also have a higher risk of developing invasive cancer in the opposite breast.
Why do the study?
After a DCIS diagnosis, National Comprehensive Cancer Network (NCCN) guidelines recommend a breast physical exam every six to 12 months for five years and then every year after that, as well as a mammogram every year. There is no recommendation for breast self-exam after DCIS. But these guidelines are based on expert opinion, not research, and some studies suggest that breast physical exams only find about 15% of DCIS recurrences or invasive cancers.
The researchers did this study to better understand how invasive breast cancer is found in women with a history of DCIS.
About the study
The study included 1,550 women who were diagnosed and received treatment for DCIS through Kaiser Permanente Northern California between January 2008 and January 2011. More than 60% of the women had at least 10 years of follow-up.
Among the women:
72% were between the ages of 50 and 75
56.4% were white
18.4% were Asian or Pacific Islander
11.8% were Hispanic
7.8% were Black
Most – 98.4% – of the initial cases of DCIS were found by a screening or diagnostic mammogram, and 81.5% of the DCIS tumors were hormone receptor-positive.
DCIS treatments included lumpectomy, mastectomy, sentinel node biopsy, radiation, and hormonal therapy:
75% of the women had lumpectomy with or without sentinel node biopsy
21.1% of the women had single mastectomy with or without sentinel node biopsy
3.9% of the women had double mastectomy with or without sentinel node biopsy
28.3% of the women took hormonal therapy after surgery
44.4% of the women received radiation therapy after surgery
In years 1 through 6 after receiving DCIS treatment, 92.5% of the women had four or more mammograms.
During follow-up, 179 second breast cancers were diagnosed. Black women were twice as likely to develop a second cancer compared to women of other races and ethnicities. But because the number of Black women in the study was very small, it’s hard to accurately interpret these results.
Of these 179 second cancers:
110 (61.5%) were invasive breast cancer
65 (36.3%) were DCIS
4 (2.2%) were Paget disease of the breast
77 (43%) were in the same breast
98 (54.8%) were in the opposite breast
4 (2.2%) were in a part of the body away from the breast, called distant recurrence or metastatic breast cancer
Overall, 74% of the second breast cancers were found by mammogram and 20% were found by the women themselves. Only 2.2% of the second cancers were found by a doctor during a breast physical exam. The other 4% were found by accident during imaging tests or procedures that weren’t related to breast cancer.
“I was not surprised that mammography found most of the second cancers,” first author Bethany Waites, MD, said in a statement. “However, I was surprised that so few of the second cancers were detected on physical exam performed by a healthcare provider. I think our finding that a significant portion of cancers were patient-detected can empower patients and highlights the importance of breast self-awareness.”
What this means for you
If you have a history of DCIS, this study highlights the importance of regular mammograms and breast self-exams.
While experts agree that mammograms are an important tool for detecting breast cancer, there has been debate about how valuable breast self-exam is. This is because studies have suggested that breast self-exam doesn’t affect breast cancer survival rates. So most medical organizations don’t recommend regular breast self-exams.
But it’s important to know that most of these studies included women with an average risk of breast cancer. Anyone who’s been diagnosed with DCIS has a higher-than-average risk of breast cancer, which may change how useful a self-exam can be. Breast self-exam is an easy, no-cost way to become familiar with your breasts so you can tell your doctor about any changes you notice as soon as they happen.
The Breastcancer.org page on breast self-exam offers step-by-step instructions on how to do one.