Clinical Corner - July 2024

The Importance of Second Cancers

The importance of “sequence” and documentation of subsequent cancer continues to be an important aspect of cancer registry abstraction. A study from researchers at the University of Cambridge in England highlights this issue and reports that patients with breast cancer are more likely to develop a second cancer in their lifetime.

Previous studies suggested the risk of developing a non-breast second primary cancer was 24% for women and 27% for men. However, the recent study found the risk can be greater depending on the type of cancer. The study, published in April 2024, used the National Cancer Registration Dataset in the United Kingdom to analyze data from more than 580,000 women and more than 3,500 men who survived breast cancer and were diagnosed between 1995 and 2019.

Here are six findings:

  1. Women who survived breast cancer had double the risk of contralateral breast cancer as the general population, and they were at 87% greater risk of endometrial cancer, 58% higher risk of myeloid leukemia and 25% greater risk of ovarian cancer.
  2. Women diagnosed with breast cancer before age 50 were 86% more likely to develop a second primary cancer, whereas women diagnosed after age 50 had a 17% increased risk.
  3. Women from more socioeconomically disadvantaged backgrounds were at a 35% higher risk of second primary cancer compared to those from less deprived backgrounds. The difference was driven by non-breast cancer risks, particularly for lung, kidney, head and neck, bladder, esophageal and stomach cancers.
  4. Male breast cancer survivors were 55 times more likely to develop contralateral breast cancer compared to the general male population.
  5. Male breast cancer survivors were 58% more likely to develop prostate cancer.
  6. About 3 in every 100 men diagnosed with breast cancer at age 50 or older developed contralateral breast cancer during a 25-year period.

The documentation of subsequent cancers will be an even more critical issue in the future as the number of cancer survivors increases.