Posted 05.18.2017 | by AMRA

Being diagnosed and treated for cancer can be highly stressful, and prolonged stress often alters the body’s normal stress response. For example, the amount of cortisol (a stress hormone) secreted by the adrenal gland typically varies over the course of the day, peaking upon morning awakening and gradually diminishing throughout the day. Prolonged stress blunts this biological response so that the difference between morning and afternoon cortisol levels is much smaller.

Cancer survivors often show this kind of blunted cortisol response—reduced daily variation and reduced reactivity to stress. This blunting of stress reactivity is associated with greater disease progression and shorter survival times for many types of cancers. It’s possible that somehow preventing this blunting may improve patient outcomes. Prior research shows that mindfulness-based interventions (MBIs) can limit cortisol blunting across the day in breast and prostate cancer patients.

Black et al. [Cancer] conducted a randomized, controlled test of whether a brief mindfulness activity could reduce the blunting of acute cortisol reactivity in colorectal cancer patients undergoing chemotherapy infusion.

The researchers randomly assigned 57 adults with colorectal cancer (average age = 54 years; 51% Male; 66% non-Hispanic, 33% Hispanic/Latino) who were undergoing chemotherapy infusion to one of three conditions: 1) a standard chemotherapy control group, 2) a chemotherapy + cancer education attention control group, and 3) a mindfulness meditation + cancer education group.

Saliva samples (to assess cortisol levels) were drawn four times during the hour-long chemotherapy infusion: at the start of infusion and at three 20-minute intervals thereafter. The patients also completed self-report measures of stress, anxiety, depression, and fatigue during the past week, as well as general levels of mindfulness (using a short form of the Mindfulness Attention Awareness Scale) after the saliva collections.

The patients in the attention control group read a cancer education module during the first 20 minutes of their hour-long infusion, then rested for the remaining 40 minutes. The patients in the mindfulness group viewed a guided mindfulness meditation video during the first 12 minutes of their infusion, rested for the next 8 minutes, then read the 20-minute cancer education module, and finally rested for the last 20 minutes.

The mindfulness video utilized the body scan, a meditation that emphasizes non-judgmental attention to physical sensations occurring in various areas of the body. After ascertaining that there were no significant differences between the two control groups, the data from the control groups were combined for statistical analysis.

The mindfulness group showed a significantly greater cortisol response (a greater cortisol increase from baseline) than the combined control groups. At 20 minutes into the infusion, 69% of the mindfulness group showed increased cortisol levels, whereas only 34% of the controls did.

Mindfulness for all three groups combined showed a significant negative correlation with self-report measures of fatigue (r = -.46) and depression, stress, and anxiety (r = -.54), but cortisol levels did not correlate with the self-report measures, and there was no difference in the mental state ratings between groups.

This study demonstrates that the body scan can effectively increase cortisol reactivity during the acute stress of chemotherapy infusion. This is important because it represents a brief intervention that can be easily integrated into cancer care that might possibly prevent or reduce the negative cancer outcomes associated with long-term stress response blunting.

The lack of correlation between cortisol levels and self-report measures is unsurprising given that the self-report measures assessed the patients’ mental states over an extended period of time, and not just their acute mental states during the infusion. While it’s possible that the mindfulness intervention successfully reversed cancer-induced stress-response blunting during the infusion, the study cannot definitely prove this due to the absence of pre-intervention measures of cortisol response.

Reference:

Black, D. S., Peng, C., Sleight, A. G., Nguyen, N., Lenz, H. J., Figueiredo, J. C. (2017). Mindfulness practice reduces cortisol blunting during chemotherapy: A randomized controlled study of colorectal cancer patients. Cancer.

[Link to abstract]