Caregiving takes a toll

Going through cancer diagnosis and treatment is scary. This is true for both patients and their loved ones.

Partners or spouses of breast cancer survivors, for example, report high rates of psychological distress, including a fear of cancer recurrence. This may be because intimate partners of breast cancer patients often assume the role of informal caregivers.

University of Delaware clinical psychologist Jean-Philippe Laurenceau, Unidel A. Gilchrist Sparks III Chair in the Social Sciences and professor in the Department of Psychological and Brain Sciences, has studied fear of cancer recurrence for more than a decade through a longitudinal study of couples coping with breast cancer. In this work, Laurenceau found that if a patient or their partner feels like they can't talk about their worries about the cancer with the other person, known as disclosure inhibition, they are more likely to have concerns about cancer recurrence and feel less intimacy.

Now, a new study in the Journal of Cancer Survivorship from Laurenceau and colleagues has shown that fear of cancer recurrence may be associated with cortisol levels of partners of breast cancer survivors. It's an important line of study, given that partners are known to have poorer physical health outcomes than the general population.

"Partners tend to have worse health outcomes long-term, including a higher risk of cardiovascular disease. This has been linked to caregiving, even informal caregiving with a partner. It's important to figure out what may be driving that," said Alyssa Fenech, the paper's lead author. Fenech is a fifth-year doctoral student studying clinical psychology at UD with a fellowship funded by the National Institutes of Health.

Co-authors on the paper from UD include Laurenceau and doctoral students Fenech, Michael Morreale and Hannah Brownlee. Additional co-authors include UD alumni Emily Soriano from Scripps Whittier Diabetes Institute and Arun Asok from Alien Therapeutics, Inc., as well as long-term collaborator Scott Siegel from Christiana Care Health System's Helen F. Graham Cancer Center and Research Institute.

The cost of caregiving

Cortisol is a hormone. Produced in the body's adrenal glands, cortisol helps the body regulate its response to stress. The hair on our bodies stores cortisol, providing an objective, long-term measure of chronic stress.

Fear of recurrence is a common stressor that patients and their significant others experience into long-term survivorship, following treatment for cancer. Notably, up to 48% of partners report clinically significant levels of fear that their loved one's cancer will come back or progress.

Laurenceau explained that as human beings, we use relationships as a way of regulating stress and coping with problems in our lives. This is called emotion co-regulation, a term that evolves from infant-caregiver relationships, where infants turn to their caregiver, seeking physical proximity and emotional connection to feel better when under stress. This has been one way of understanding the function of adult intimate relationships.

As a couple is adjusting to a new normal after the breast cancer patient's treatment is completed, feelings of uncertainty can persist.

"Part of finding a new equilibrium, both as individuals and as a couple, is figuring out how to talk about things that can feel scary and threatening," said Laurenceau. "When you feel like you can't talk about those concerns, it's associated with more fear of cancer occurrence, because you're not processing it together."

To determine whether fear of cancer recurrence could be reflected in greater physical stress in the partner, the research team measured cortisol levels in scalp hair samples taken at two time points: directly after cancer treatment ends, when fear of cancer occurrence typically begins, and six months later.

Laurenceau explained that hair cortisol reflects a measure of chronic stress over the previous three-to-four months. So, the first hair cortisol measurement reflected how the significant others were feeling during their loved one's treatment, or even potentially before diagnosis, when cancer wasn't even on the radar. The second hair sample measured the partner's cortisol level during the six months after treatment ended, while the patient and their partner were figuring out normal life again.

"We saw a rather strong correlation, reflecting that partners who had higher fear of cancer recurrence also showed greater increases in cortisol over that six-month period," said Laurenceau.

So, caregiving takes a physical toll - even when it's done out of love.

Tracking chronic stress

According to the research team, the study shines a light on the fact that without intervention, chronic fear of recurrence is associated with reduced quality of life among partners of cancer survivors. One implication of this finding is that patients who have gone through these treatments aren't the only ones who may benefit from extended support. And while many interventions exist to help patients cope with fear of cancer recurrence, there are often few resources for the partners.

The findings highlight the need for additional research on the relationship between these fears of recurrence and the physical health outcomes in partners of breast cancer survivors.

"There's something about that experience of your partner getting cancer, and going through it with them, that makes a partner more vulnerable to having their own health problems," Laurenceau said. "Our study points out that one possible mechanism could be the increase in cortisol."

Further study of cortisol as a mechanism in partner health outcomes could include looking at the degree to which fear of recurrence fluctuates over time, Fenech said, which could inform intervention development. For example, knowing whether partner cortisol levels increased or diminished at certain time points could provide health care professionals with information about whether interventions would be more helpful during a patient's treatment or after, when patients and partners are processing and adjusting to a new normal.