Stage 0 breast cancer, or ductal carcinoma in situ (DCIS) is the very first stage of breast cancer. At this point, the cancer cells have not started to spread. While stage 0 breast cancer is not life-threatening, it can develop into more advanced breast cancer. Therefore, it is essential to understand the symptoms of stage 0 breast cancer and get an early diagnosis. Not only is it important to start treatment at this stage, but it is also imperative that appropriate follow-ups are done even after the treatment begins. Routine mammograms and scans as well as self-checks for breast cancer are crucial for all women. Read on to know more about stage 0 breast cancer and how to get tested and treated.

What is stage 0 breast cancer?

The American Cancer Society (ACS) states that 20 percent of all breast cancers are stage 0 breast cancer. Stage 0 breast cancer, also known as ductal carcinoma in situ (DCIS), represents the earliest form of breast cancer. “It is characterised by the presence of abnormal cells inside the milk ducts of the breast, but these cells have not yet spread to surrounding breast tissue or other parts of the body,” says surgical oncologist Dr Garvit Chitkara.

Is stage 0 breast cancer life-threatening?

Since DCIS is non-invasive, it is not considered life-threatening on its own. However, without treatment, it has the potential to develop into invasive breast cancer, which can spread to other areas of the body and become more difficult to treat. Stage 0 is sometimes referred to as a ‘pre-cancerous’ condition because of its early stage, making it crucial to diagnose and treat promptly.

The Cancer Research UK relates to stage 0 breast cancer as being pre-invasive. It also clarifies that this is not the same as being diagnosed with invasive breast cancer. When someone is diagnosed with invasive breast cancer, the cancer cells in their body have broken out of the ducts, and have spread into the surrounding breast tissue.

Symptoms of Stage 0 breast cancer

Stage 0 breast cancer often does not cause any symptoms, which makes it difficult to detect without regular screening. “Most cases of DCIS are found during a routine mammogram, where the abnormal cells show up as microcalcifications or tiny deposits of calcium in the breast tissue,” explains Dr Chitkara.

Since the condition is non-invasive, it typically does not cause pain, noticeable lumps, or changes in the breast. In some rare cases, a woman might experience a lump in the breast or unusual nipple discharge, but these symptoms are not common for Stage 0 breast cancer, states the US’s National Breast Cancer Foundation.

Types of stage 0 breast cancer

There are two types of stage 0 breast cancer:

• Ductal carcinoma in situ (DCIS): Here, abnormal cells are found in the lining of the breast duct.
• Paget disease of the nipple: In this condition, the abnormal cells are found in the skin cells of the nipple and they may spread to the areola as well. These patients may also have DCIS or invasive breast cancer in the same breast, states the US National Cancer Institute.

Do you need to treat stage 0 breast cancer?

Yes, treatment is generally recommended for Stage 0 breast cancer to prevent it from progressing to invasive breast cancer. “The primary goal of treating DCIS is to eliminate the abnormal cells before they can spread,” says Dr Chitkara.

Treatment options include surgery, such as a lumpectomy, the removal of the abnormal tissue and a small margin of surrounding healthy tissue or mastectomy (removal of one or both breasts), depending on the extent and location of the DCIS.

Stage 0 breast cancer also needs to be treated urgently to avoid it from advancing. Image courtesy: Adobe Stock

Do you need radiation for stage 0 breast cancer?

In many cases, surgery is followed by radiation therapy to destroy any remaining cancer cells and reduce the risk of recurrence. However, the American Cancer Society states that many women don’t require radiation therapy after a mastectomy in the case of stage 0 breast cancer. However, although DCIS is not life-threatening, treatment is important because untreated DCIS can increase the risk of developing invasive breast cancer in the future.

Can you wait and watch if you have Stage 0 breast cancer?

No. A ‘wait and watch approach’ is generally not advisable for Stage 0 breast cancer, unlike some other low-risk conditions, explains Dr Chitkara. DCIS has the potential to progress into invasive breast cancer, which can spread to other parts of the body and become more challenging to treat. While the progression from DCIS to invasive cancer is not inevitable, the risk is significant enough that proactive treatment is usually recommended.

For some patients, with very low-risk DCIS, clinical trials or expert consultations might explore more conservative management options, but this is done under strict monitoring and is not the standard of care, explains Dr Chitkara.

Who is most at risk for stage 0 breast cancer?

Certain individuals are at a higher risk of developing Stage 0 breast cancer. The US NIH lists the following factors that might increase the risk of getting stage 0 breast cancer.

• Women with a strong family history of breast cancer, particularly those with close relatives who had breast cancer at a young age, are at increased risk. Genetic mutations, such as BRCA1 and BRCA2, also significantly elevate the risk of developing both DCIS and invasive breast cancer.
• Personal history of breast conditions like atypical hyperplasia
• Previous radiation therapy to the chest (especially during childhood or early adulthood).
• Early onset of menstruation or early menopause can increase the risk of breast cancer.
• Having a first pregnancy after the age of 30 years.
• Use of hormone replacement therapy after menopause.
• Lifestyle factors such as obesity, alcohol consumption, and lack of physical activity can contribute to an increased risk.

Follow up treatments, scans and mammograms are required after diagnosis of stage 0 breast cancer. Image courtesy: Adobe Stock

What are the follow-up treatments after stage 0 breast cancer?

After initial treatment for Stage 0 breast cancer, follow-up care is essential to monitor for any signs of recurrence or the development of new breast cancer. “This follow-up typically includes regular physical exams and imaging tests, such as mammograms, to detect any changes in the breast tissue,” says Dr Chitkara. Check out other breast cancer monitoring methods that you must know about.

For women, whose DCIS was hormone receptor-positive, hormone therapy, such as tamoxifen or aromatase inhibitors, may be prescribed for five to ten years to reduce the risk of recurrence. “The exact follow-up plan will depend on the specific treatment received, the characteristics of the DCIS, and individual risk factors,” says Dr Chitkara. The goal of follow-up care is to catch any potential issues early when they are most treatable and to provide ongoing support and guidance to maintain breast health.

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