A woman adult with a bald head is holding a pink cancer awareness ribbon, symbolizing support for a cause
Women diagnosed with early breast cancer face a slightly elevated long-term risk of developing a second primary cancer compared to the general population, according to a new study published by The BMJ today. The research, which analyzed data from the National Cancer Registration and Analysis Service for England, found that the risk is only 2-3% higher, offering reassurance to survivors who may fear a significantly greater threat.
The study focused on 476,373 women diagnosed with early invasive breast cancer in England between 1993 and 2016, aged 20 to 75, who underwent surgery. Over a follow-up period extending up to 20 years, 64,747 of these women developed a second primary cancer. However, the absolute excess risks compared to the general population were minimal.
Understanding the Risks
By the two-decade mark, 13.6% of the women had developed a non-breast cancer, such as womb, lung, or bowel cancer, which is 2.1% more than expected in the general population. Additionally, 5.6% developed contralateral breast cancer, occurring on the opposite side of the body, which is 3.1% more than expected.
The study also revealed age-related variations in risk. For instance, a woman diagnosed with breast cancer at age 60 has a 17% risk of developing a new non-breast cancer and a 5% risk of contralateral breast cancer by age 80. In contrast, a woman of the same age in the general population faces a 15% and 3% risk, respectively. For a woman diagnosed at 40, the 20-year risk is 6% for both types of second cancers, compared to 4% and 2% in the general population.
Impact of Treatment on Second Cancer Risks
The type of adjuvant treatment received after surgery also influences the risk of developing a second cancer. Radiotherapy was linked to higher rates of contralateral breast and lung cancers, while endocrine therapy was associated with uterine cancer but reduced contralateral breast cancer risk. Chemotherapy was linked to an increased risk of acute leukemia.
Researchers estimate that around 7% of excess second cancers may be attributed to adjuvant therapies, but emphasize that the benefits of these treatments generally outweigh the risks.
Despite these findings, the authors caution that some data may be incomplete due to limitations in cancer registry records. They also lacked information on factors like family history, genetic predisposition, and lifestyle choices such as smoking.
Implications for Patients and Clinical Practice
This comprehensive study provides valuable insights for breast cancer survivors and their healthcare providers. The findings can inform clinical practice and policy, potentially guiding future research on cancer risk assessment. The results are particularly significant given the historical inconsistency in risk estimates from previous studies.
In a linked opinion article, patients expressed relief at the study’s findings, noting the difficulty in obtaining detailed information on the risks of second cancers post-breast cancer. They highlighted the importance of having this information readily available, as it aids in planning for the future.
“Information on risks should be readily available. It helps us to plan our lives and think ahead to the future,” patients concluded.
Overall, the study underscores that the benefits of treatments in preventing breast cancer recurrence far outweigh the potential downsides of developing a second cancer. This information should be communicated to patients during discussions about adjuvant therapies, ensuring they are well-informed about their treatment options.
