The diagnosis and treatment of cancer are extremely stressful and life-altering experiences that can challenge an individual’s conscious and unconscious coping ability. Perry, Metzger, and Sigal (2015) studied the unconscious coping strategies (i.e., defense mechanisms) in a recently recovered group of breast cancer survivors (N = 76) and found that they exhibited lower levels of defensive functioning than community controls (N = 157). This study extended Perry’s findings by comparing his groups with an active cancer treatment group (N = 50). The active cancer treatment group was undergoing radiation therapy for a variety of cancers at an outpatient oncology clinic. Cancer patients completed a brief psychodynamic relationship episode interview—the early memory interview. Narratives were reliably coded using the Defense Mechanism Rating Scale (DMRS; Perry, 1990). The study found that individuals in the active cancer group had lower (i.e., less mature/more pathological) overall defensive functioning scores than breast cancer survivors and community controls. These findings support the theoretically driven hypothesis that individuals experiencing extreme stress are likely to use more pathological/immature defenses than those experiencing less severe forms of the same stressor, as well as those without the stressor. (PsycINFO Database Record (c) 2019 APA, all rights reserved)