Journal Article Annotations
2017, 4th Quarter
Annotations by Elie Isenberg-Grzeda, MD, and Carlos Fernandez-Robles, MD
Type of study: Prospective cohort study
The finding: The authors tried to address the knowledge gap of why cancer patients are known to have cognitive dysfunction even prior to starting chemotherapy. They tested the possibility that PTSD may be a contributor to cancer-related cognitive impairment, by comparing cognitive performance among (a) breast cancer patients (stage 0-III) who received chemotherapy; (b) breast cancer patients who did not receive chemotherapy; and (c) healthy controls. They also used structured clinical interviews to measure the incidence of PTSD at various time points. They found that PTSD partially accounted for the greater degree of cognitive dysfunction noted among both cancer groups compared to healthy controls.
Strength and weaknesses: They had a relatively large sample size (n=150 cancer patients; n=56 controls), low attrition rates, the use of gold standard methods of neuropsychological testing, and the use of structured clinical interviews to diagnose PTSD. The main limitation is generalizability to other patient populations.
Relevance: Much attention has been paid to trying to elucidate the mechanism behind cognitive dysfunction among cancer patients even prior to starting treatment. Various mechanisms have been proposed, including the possibility that inflammatory processes caused by the tumor are responsible for early cognitive dysfunction seen prior to initiating treatment. The authors study PTSD and propose a possible link between cancer-related PTSD and cognitive dysfunction, which is becoming increasingly substantiated by their research. It thus behoves clinicians to evaluate for PTSD and treat as necessary among patients with cancer.
Type of study: Randomized controlled trial (RCT)
The finding: The authors studied the early (6-week) impact of Swedish massage versus (a) an active control (light touch) and (b) waitlist control on cancer-related fatigue among a sample of stage 0-III breast cancer survivors. They found that the treatment arm (Swedish massage) yielded clinically-significant improvements in cancer-related fatigue compared to both control groups.
Strength and weaknesses: The main limitations are the single-blind design (though the intervention prevents a double-blind design), small sample size (n=22 per group), and homogenous patient population (breast cancer survivors). The strength include the credibility, expectancy, and preference analysis that the authors conducted, as a way of ensuring that the results found were not attributable to differences in expectations between groups.
Relevance: Cancer-related fatigue can be a disabling outcome of cancer treatment, and one that affects survivors as well as their families. The mainstay of treatment has been pharmacologic (stimulants), albeit with limited efficacy. More recently, nonpharmacologic treatments have been proposed and studied, mostly in the realm of physical activity. This study reports on yet another nonpharmacologic treatment with efficacy in reducing cancer-related fatigue, which is a much needed addition to the literature and a welcomed addition to a relatively limited toolbox.
Type of study: A pooled, secondary analysis of two previous RCTs.
The finding: Among advanced cancer patients randomized to receive (a) palliative care intervention versus usual care, or (b) early palliative care versus delayed intervention, the authors found that early palliative care intervention prolonged survival the most among the subset of patients with clinically-relevant depressive symptoms.
Strength and weaknesses: This study was a reanalysis of two RCTs which had previously been conducted, which was both a strength and a weakness of the study. As a post hoc analysis, the authors were unable to control for possible confounding variables. As with all pooled analyses, the larger sample size also allowed for findings which may not have been possible with each of the two smaller studies.
Relevance: It is well understood that early palliative care intervention prolongs survival among patients with advanced cancer. It is also well known, from large meta-analyses, that depression seems to negatively impact survival among cancer patients. The authors aimed to study whether early palliative care interventions moderate the impact that depression has on survival, and they conclude that it may mediate this relationship by helping depressed cancer patients engage in health-promoting behaviors when they otherwise wouldn’t. The fact that depressed patients have a greater survival benefit from early palliative care compared to non-depressed patients may also guide the allocation of resources when early palliative care is being considered.