patients in Singapore revealed that almost half had suffered from cognitive decline at some point during treatment and up to one year post-treatment. Close to 30 per cent had reported some degree of cognitive impairment one year after undergoing
‘Almost 50 percent of breast cancer patients suffer from cognitive decline during chemotherapy and up to one year post-treatment; 30 percent continue to experience the condition a year after treatment.’
"Cognitive impairment among breast cancer survivors is an important issue now because early stage breast cancer is treatable. Knowing when patients experience these cognitive problems, and how long the symptoms persist, can aid the development of suitable screening and clinical management measures," said research team leader Associate Professor Alexandre Chan, who is from the Department of Pharmacy at NUS Faculty of Science.
Cognitive challenges affecting breast cancer patients
Breast cancer is the most prevalent cancer among Singaporean women. Between 2010 and 2014, more than 1,800 women in Singapore were diagnosed with the condition each year.
While current treatments convey excellent survival benefits - with more than 90 per cent of patients surviving beyond five years - many patients acquire cognitive toxicities known as chemobrain. These toxicities can dramatically affect patients' quality of life.
"Early treatment for breast cancer patients usually involves intensive therapy - this means that patients are exposed to high levels of chemotherapy drugs, and they are also at higher risk of long-term side effects. After treatment, we need to manage survivorship issues. However, the clinical presentation of cognitive toxicities remain poorly understood," explained Assoc Prof Chan.
To examine the impact of chemobrain on breast cancer patients, Assoc Prof Chan and his team studied patients with Stages I to III breast cancer. The patients were evaluated at four time points - prior to the start of chemotherapy; six weeks after chemotherapy started; 12 weeks after chemotherapy started; and approximately 15 months after the start of chemotherapy.
Both subjective and objective measures were used to assess cognitive decline. For the former, patients were asked whether they faced difficulty in areas such as concentration, memory, multitasking and verbal fluency, using a validated questionnaire. The patients were also evaluated on their attention, memory, mental processing speed and speed of response using a computer-based software.
The scientists found that almost half of the respondents suffered from some degree of cognitive impairment during treatment and up to one year post-treatment. About 30 per cent complained of cognitive impairment one year after chemotherapy. In addition, a year after undergoing chemotherapy, 15 per cent of the participants were objectively assessed to suffer from memory challenges, and close to 10 per cent experienced issues with response speed. These results were first reported in the journal Psychooncology
earlier this year.
Breast cancer survivor Ms Chan Yoke, who is a graphic designer, can attest to cognitive impairment as a result of chemotherapy. In 2015, Ms Chan went through 16 sessions of chemotherapy, along with radiotherapy, as part of her treatment for breast cancer. She said, "I became forgetful after chemotherapy started. I would walk from the kitchen to a room to get something, but once I reached the room, I would not able to recall what I wanted."
About three years after the start of her chemotherapy, Ms Chan still grapples with the after-effects of her cancer treatment. She shared that her memory did not go back to what it was like before she had cancer, and her thought processes are also slower than they were prior to the start of her chemotherapy treatment.
Early screening and intervention programs needed
The results of this study draw attention to the difficulties faced by breast cancer survivors after completion of active treatment, when they begin to resume their societal roles. The findings also highlight the importance of raising awareness about cognitive impairment among breast cancer patients, so that they can be better prepared for the changes they will experience during treatment and survivorship.
"A well-rounded holistic survivorship program will be very useful for cancer patients and survivors. More importantly, we should actively screen and manage patients at risk of cognitive impairment. This is extremely important as we are expecting to see an increasing number of cancer survivors in Singapore, and cognitive impairment can bring significant negative impact to survivors' quality of life," said Assoc Prof Chan.
Scientists from the National Cancer Centre Singapore and KK Women's and Children's Hospital also contributed to the study, which was conducted from 2011 to 2017.
Building on the knowledge gained from this study, Assoc Prof Chan and his team are studying the biomechanisms behind post-chemotherapy cognitive impairment. The scientists will also evaluate the effectiveness of various interventions for managing chemobrain symptoms.