Find out all the latest headlines from the 11th European Breast Cancer Conference taking place in Barcelona, Spain (21–23rd March).
- Risk of a second breast cancer can be better quantified in women carrying a BRCA mutation
- Women with DCIS at lowest risk of recurrence if post-menopausal or have estrogen receptor positive cancer
- Screening helped reduce the average size of breast tumors decreased but size is now increasing again
Risk of a second breast cancer can be better quantified in women carrying a BRCA mutation
The risk of a second breast cancer in patients with high-risk BRCA gene mutations can be more precisely predicted by testing for several other genetic variants, each of which are known to have a small impact on breast cancer risk.
Technology already exists to test for genetic ‘low risk variants’ that each play a small role in breast cancer risk. The novel research conducted by the Netherlands Cancer Institute (Amsterdam) demonstrates that this technology can also be used for BRCA mutation carriers who have already had one cancer to better predict their risk of developing a tumour in the other breast.
The researchers studied a group of approximately 6000 breast cancer patients who had a mutation in the BRCA1 gene and around 4000 who had a mutation in BRCA2.
They used existing technology to examine the low risk variants that each woman carried. The effects of all these variants can be put together to give each individual a combined estimate termed a polygenic risk score.
The results revealed that these polygenic risk scores can predict the risk of a second breast cancer in BRCA breast cancer survivors. The difference in the risk of a second breast cancer between different polygenic risk scores can be up to 10% in the 10 years following a first diagnosis.
“These polygenic risk scores were originally developed to try to better predict the risk of developing a first breast cancer. Our research suggests that they can also be used to help patients who have survived their first breast cancer to better understand their level of risk for a second breast cancer. We hope these findings will add to the existing knowledge about predicting risk for a second breast cancer in these survivors,” explained Alexandra van den Broek (Netherlands Cancer Institute) who presented the research.
Women with DCIS at lowest risk of recurrence if post-menopausal or have estrogen receptor positive cancer
Patients with DCIS are less likely to suffer a recurrence if they are post-menopausal or if their tumor is estrogen receptor positive, researchers report.
This novel study demonstrates that treatment including removal of the cancer followed by radiotherapy to the affected breast leads to very low rates of recurrence. Researchers believe the study also offers clues as to which patients need more aggressive treatments and which could safely have fewer treatments.
“We wanted to look in detail at women treated for DCIS to see if there are any clues about who is most at risk of a recurrence, and to understand the risks and benefits of different treatments,” explained lead researcher Icro Meattini (University Hospital of Florence, Italy).
The researchers studied 1072 DCIS patients treated at nine hospitals in Italy from 1997–2012. All had received the recommended treatment of breast conserving surgery followed by radiotherapy. Researchers compared the rate of recurrence five years and ten years after diagnosis, as well as survival rates.
Overall, they discovered that patients had a 3.4% risk of a recurrence after 5 years and a 7.6% risk after 10 years. They also found that patients’ chances of dying from breast cancer were 0.7% after 5 years and 0.9% after 10 years.
They found that patients who were post-menopausal when they were diagnosed were less likely to suffer a recurrence compared to pre-menopausal patients. Recurrence was also less common among patients with estrogen receptor positive cancers. Being post-menopausal and having estrogen receptor positive DCIS halved the risk of a local recurrence.
On the other hand, patients with a final surgical margin of less than a millimeter had a three times higher risk of recurrence. This means that when the cancer was surgically removed, the surgeon was unable to remove a wide margin of non-cancerous tissue around the tumor.
“The results of this study should offer all DCIS patients reassurance that the risk of their cancer returning is very low, if they are treated with breast conserving surgery followed by radiotherapy.” Meattini added.
Screening helped reduce the average size of breast tumors decreased but size is now increasing again
Researchers from Weston General Hospital (Bristol, UK) have highlighted that although the average size of breast cancers at diagnosis decreased dramatically in the 1980s and 1990s following the introduction of screening, there is now a slight increase in the average size of breast tumors since 2001. The researchers suggest that perhaps this is a result of a decrease in the number of women going for attending their screening in the same period.
This study involved 386,454 women in the US who were diagnosed with breast cancer from 1983–2014. The results show that average tumor size has decreased by 23% over the 32 year period but the trend was not consistent over the years and varied according the women’s ages.
When breast screening was introduced in the early 1980s the average size of breast cancers dropped sharply. In women aged between 70 and 74, there was a decline in the average size of tumors of 27% but in women aged 85 and older, the decline was only 10%. Average tumor size in these older women, who are less likely to be screened, remains the highest.
From 2001 to 2014, researchers discovered an unexpected rise in average tumor size of between 3% (in the 75–79 age group) and 13% (in women aged 50–54 years).
“The recent increase in the average size of tumors may reflect a decline in rates of screening. If this is followed by deterioration in breast cancer mortality rates it would strengthen the argument for screening programs to continue. On the other hand, if declining screening rates are not followed by a rise in breast cancer death rates, it probably signals that advances in treatment are the main reason for the improvement in breast cancer mortality,” author Manon Jenkins from Weston General Hospital, commented.