Study examines relationship between life events and survival after diagnosis of melanoma

A study that is published in the last issue of Psychotherapy and Psychosomatics examines the relationship between life events and survival after diagnosis of melanoma, a life-threatening cancer of the skin. Negative, undesirable events are important for health outcomes. The psychobiological process in cancer is supposed to be mediated by personal (including coping), medical, social, and life stress variables, and result in quality of life and survival. The Authors of this study have previously examined the contribution of baseline psychosocial factors to survival in localized breast cancer and melanoma. Baseline life stressors were evaluated retrospectively over the course of 1 year and they did not predict survival. In this paper they investigated the effect of life events evaluated cumulatively over 4 years on survival of patients with localized melanoma.

The study sample comprises 59 newly diagnosed 28- to 70-year-old patients with Clark II–IV skin melanoma, as in the previous study. The patients completed several validated questionnaires 3–4 months after the diagnosis. Life events were evaluated with the Life Experience Survey and the measurement was repeated at 9, 15, 21, 27, and 39 months. Up to 27 months, the measurement took place within semi-structured interviews with probing by a psychologist (the first author), and at 3 years by a postal survey. In the follow-up, the events that had taken place since the previous measurement were recorded. The analyses indicated also an impact of the baseline life events on survival. However, the investigators still did not find any when baseline events were individually analyzed. When the cognitive avoidance/denial coping was in the model, a low impact of the baseline negative events (lower scores indicating less stress) predicted a longer survival in men (p=0.05). Also, the total number (negative + positive) of events predicted a shorter survival (p = 0.032) when tested simultaneously with all the variables of the earlier model. There were no time trends in the life stress summary variables over the follow-up time, nor did they differ by the Breslow classification.

Life events evaluated over the first 2 years did not predict survival. When the effects were analyzed over the 3- and 4-year periods, there still was no impact in the total sample. When the investigators added the denial coping in the models, both number and impact of the negative events evaluated over the 3- and 4-year periods predicted survival. In men, the effect was even stronger. The proportional hazard assumption was not violated, indicating that it holds for the chosen models. Analyzing only patients reporting negative events any effect for the negative impact scale was found (perceived impacts of the negative events). The positive event and loss event scales did not predict survival. When the cumulative event variables were tested in the previous model, the total number of events predicted survival (2 years p = 0.04; 4 years p = 0.05). In these models, all the previously identified psychosocial predictors remained statistically significant.

Negative life events predicted shorter survival when they were evaluated with a validated instrument and cumulatively during several years. The effects of the number scales and impact scales were similar. These findings clarify why the impact of life stressors on cancer survival has been unclear. The methodology for this research seems to be demanding. When measuring life events comprehensively and with subjective impact evaluation (negative vs. positive), the investigators found the effect. This required an expert interview and repeated measurement over several years. Also, the impact of other stress-mediating factors has to be taken into account, especially baseline denial/minimizing coping describing denying the cancer disease or its seriousness. The cumulative events showed an impact also within the previously identified model, which is in line with the theory on the psychobiological process in cancer. When survival was now followed for a longer period of time also the baseline stressors had an impact. This supports the idea that psychological stress has a slow but cumulative effect on cancer survival.