Why Do Some Women with Breast Cancer Have Both Breasts Removed Despite No Survival Benefit?

Zehra received a phone call. She had turned 60 that day, but this was not a message of celebration.

Her doctor’s office was calling with the results of her routine screening mammogram. Zehra was told that the screening had found something in her left breast and that she needed to return for further tests.

“I had a feeling deep down that it was definitely cancer,” Zehra said.

And she was right.

On a Monday evening, approximately 2 weeks after the biopsy, Zehra received a call from her doctor confirming cancer in her left breast. She saw her breast surgeon the next day.

Surgery would be the first step — she knew the process and treatment options well after her older sister’s breast cancer surgery 13 years earlier.

Her surgeon said that mastectomy was the best approach, but the decision to remove one or both breasts was hers.

No Additional Survival Benefit

A breast cancer diagnosis is a turning point in any woman’s life. Decisions made during this process are based not only on medical outcomes but also on emotional and cosmetic concerns. In recent years, many women have chosen bilateral mastectomy (surgical removal of both breasts) despite cancer being diagnosed in only one breast. What drives this decision? Why do many women opt for double mastectomy even when scientific evidence does not support it?

The main aim of breast cancer surgery is to remove cancerous tissue and improve survival. However, recent research shows that when breast cancer is diagnosed in only one breast, bilateral mastectomy offers no advantage in extending life.

A recent study published on 15 July 2024 in JAMA Oncology reported the latest findings: among patients with cancer in one breast, survival did not differ between lumpectomy (removal of only the cancerous area), unilateral mastectomy (removal of only the affected breast), and bilateral mastectomy. After 20 years of follow-up, breast cancer mortality was 16.7% in patients who underwent bilateral mastectomy and 16.3% in those who underwent unilateral mastectomy.

These data clearly show that double mastectomy does not improve overall survival in breast cancer patients. Yet many women still choose this more aggressive surgery. Why?

Zehra also knew that bilateral mastectomy would not prevent the cancer from returning; she understood that adjuvant chemotherapy and hormonal therapy offered her the best chance.

Nevertheless, like her older sister, Zehra decided to have both breasts completely removed through bilateral mastectomy.

“Once the decision was made, I never questioned it again,” she said.

Choosing Double Mastectomy Is Common

Zehra is not alone. Many women choose to have both breasts removed despite having cancer in only one.

Double mastectomy rates among women diagnosed with breast cancer began rising in the late 1990s and remained high in the late 2010s, despite research showing that more extensive surgery did not improve survival.

What explains this apparent contradiction?

The decision between unilateral and bilateral mastectomy is more complicated than simply assessing survival statistics.

Despite the survival data, bilateral mastectomy may give some women a greater sense of security. Others face the physical, psychological, and financial burden of continued screening and potential biopsies. Some choose removal of both breasts for cosmetic symmetry.

1. A Sense of Security and Cosmetic Concerns

Many women feel safer choosing bilateral mastectomy. Although cancer is present in only one breast and the risk of developing it in the other is low (between 0.1% and 0.6% annually), double mastectomy almost completely eliminates that risk.

According to the JAMA Oncology study, the risk of developing cancer in the other breast within 20 years was only 0.7% after bilateral mastectomy, compared with 6.1% after unilateral mastectomy and 7.8% after lumpectomy. However, reducing this already low risk does not affect overall survival. Thus, even without extending life, double mastectomy may give patients psychological reassurance.

Cosmetic concerns also play an important role. Women concerned about symmetry, in particular, may seek a more symmetrical appearance by removing both breasts. This can also affect confidence and body image.

2. The Pressure of the Screening Burden

Another important reason for choosing double mastectomy is the desire to escape the physical, emotional, and financial burden of continued screening and biopsies. Women with breast cancer commonly undergo regular mammography, ultrasound, and MRI. Screening may be even more frequent for women with dense breast tissue.

For some women, this process causes substantial anxiety. Waiting for screening results can bring the fear that something may be wrong every time. This is a major reason some patients choose more radical surgery. For example, Zeynep, who underwent double mastectomy, said she made the decision because of “screening anxiety.” For many patients, avoiding this emotional burden may make the surgical risks worth taking.

3. Overestimating the Benefits

One reason average-risk patients choose double mastectomy despite having cancer in only one breast is that they overestimate the risk of cancer developing in the other.

For many oncologists and breast surgeons planning treatment for patients with early-stage breast cancer, this is the issue they spend the most time discussing during those consultations.

Removing both breasts together is a larger operation and carries risks; some data suggest that bilateral mastectomies increase adverse event rates.

Nevertheless, the evidence is mixed, and other studies have found no significant difference in complication rates. Ultimately, breast reconstruction surgery more markedly increases complication risks.

Another patient, Ayşe, is 65 and underwent double mastectomy approximately 2 years ago. Her first cancer was ductal carcinoma in situ (DCIS). The new cancer, however, was invasive — conventional breast cancer.

Unilateral mastectomy could have been an option, but she said, “After years of [benign] things showing up on scans and needing biopsies, I decided I did not want that anymore. I was tired,” she said.

4. Other Important Factors

For Meltem, cost was an important factor. At 42, she underwent surgery for DCIS and stage 1 invasive ductal carcinoma. She initially chose unilateral mastectomy but is considering having her other breast removed.

Dense breast tissue had prevented her cancer from being detected on routine screening; it was diagnosed only when she felt a lump.

It May Genuinely Benefit High-Risk Groups

For women with BRCA1 and BRCA2 gene mutations, double mastectomy may significantly reduce the risk of cancer developing in the other breast. Women carrying BRCA mutations have an approximately 30-40% risk of cancer in the other breast over 10 years. For this high-risk group, bilateral mastectomy may be a more scientifically meaningful option. The American Society of Breast Surgeons also recommends that these patients consider double mastectomy.

Conclusion: A Personal Decision Following Accurate, Adequate Information

The decision to undergo double mastectomy cannot be explained by medical data alone. It involves many factors, such as feeling safer, escaping the burden of screening, and cosmetic concerns. Whatever the circumstances, physicians must carefully inform patients and guide them while taking their personal preferences into account.

Every patient has different needs and expectations. Some women feel safer with double mastectomy, while unilateral surgery may be enough for others. What matters is managing this process individually for each patient.

Having comprehensive information about surgical options for breast cancer and making a decision that considers the patient’s emotional, physical, and cosmetic needs is one of the most important stages of treatment.