"Just As I Expected": A Longitudinal Cohort Study of the Impact of Response Expectancies on Side Effect Experiences During Radiotherapy for Prostate Cancer

Men's perceptions and preferences regarding prostate cancer radiation therapy: A systematic scoping review

PURPOSE

To assess the literature on men's preferences and perceptions regarding prostate cancer radiation therapy.

METHODS

A scoping review was undertaken as per JBI guidelines. Searches were conducted in PubMed, CINAHL, Scopus and Science Direct with search terms including "prostate cancer," "radiotherapy," "radiation therapy," "radiation oncology," "patient preferences," "patient perceptions" and "patient experience." The resultant studies were mapped and grouped according to the emergent themes and pathway stages.

RESULTS

A total of 779 titles and abstracts were screened by two independent reviewers. Fifty-two full-text studies were reviewed, with 27 eligible for inclusion. There were 4 pre-treatment, 13 during treatment and 10 post-treatment studies covering broad themes of information needs (n = 3), preferences and decisions (n = 6), general experiences (n = 8), side effects (n = 6), and support (n = 4). There were a mix of methodologies, including 11 qualitative, 14 quantitative (including four preference studies), one mixed methods and one narrative review.

CONCLUSION

There were only four preference studies, with the remaining 23 reporting on perceptions. Overall, there is a paucity of literature regarding patient preferences and perceptions of prostate cancer radiation therapy, particularly when considering how many clinical and technical studies are published in the area. This highlights opportunities for future research.

Genetically modified bacteria for targeted phototherapy of tumor

Live attenuated bacteria have been used as target vehicles for genetic therapy of malignant carcinoma because they can be reprogrammed by following simple genetic rules and have the ability to target tumor hypoxic region. In this research, noninvasive Escherichia coli (E. Coli) is genetically modified through the plasmid transfection to afford E. Coli(p) with overexpressed human catalase for catalyzing H₂O₂ into O₂ in the tumor site. The produced O₂ is consequently converted to cytotoxic ¹O₂ under near-infrared (NIR) light irradiation for photodynamic therapy. Chlorin e6 (Ce6) is chosen as the photosensitizer for its excellent photodynamic ability, and polydopamine (pDA) is employed to encapsulate Ce6 for its good biosafety, photothermal ability, and adhesion capacity with bacteria. Dopamine polymerizes in the presence of Ce6 to form pDA/Ce6, and then E. Coli(p) is coated with pDA/Ce6 to afford the final E. Coli(p)/pDA/Ce6. The obtained system is intravenously administrated for selective accumulation and replication in the hypoxic tumor. NIR light irradiation is introduced to enable photothermal and O₂-enhanced photodynamic therapy. On account of complementary combination, the system exhibits efficient antitumor effect in vitro and in vivo. Thus, the integration of genetically modified bacteria with pDA/Ce6 presents a promising application potential for precise tumor inhibition.

Open- and Closed-Label Placebo and Nocebo Suggestions About a Sham Transdermal Patch

OBJECTIVE

Placebo effects may occur when it is known that an inert substance is given (i.e., open-label placebo). It is not yet clear whether these effects are similar to concealed (i.e., closed-label) placebo effects for itch or whether nocebo effects can be induced under open-label conditions.

METHODS

Healthy volunteers (n = 112) were randomized to an open-label (I) or closed-label (II) positive suggestions group, or an open-label (III) or closed-label (IV) negative suggestions group. Participants were told, as cover story, that a transdermal caffeine patch would be applied that positively influences cognitive abilities and, as a side effect, positively or negatively (depending on group allocation) influences itch. Participants in the open-label groups were given a rationale explaining placebo and nocebo effect mechanisms. Itch (the primary outcome) was induced at baseline and postsuggestions by histamine iontophoresis.

RESULTS

Analyses of variance revealed significantly lower itch in the positive compared with the negative suggestions groups for both open- and closed-label contexts (all, p ≤ .008, Cohen d ≥ 0.47). Self-rated skin response was less severe after positive versus negative suggestions (all, p ≤ .017, Cohen d ≥ 0.33), but no effects on physical skin response were found (all, p ≥ .23, Cohen d ≤ 0.30).

CONCLUSIONS

Itch can be reduced by positive compared with negative suggestions under both open- and closed-label conditions. These findings indicate that open-label suggestions may potentially be a tool to use placebo effects for self-reported outcomes in clinical practice, for example, by explaining the role of expectancy in treatment. It needs to be investigated further under which circumstances an open-label rationale may impact placebo and nocebo effects.Trial Registration:www.trialregister.nl; NTR7174.

'Measuring up': A comparison of two response expectancy assessment formats completed by men treated with radiotherapy for prostate cancer

OBJECTIVE

Response expectancies of cancer treatment toxicities are often, but not always, associated with subsequent experiences. A recent meta-analysis indicated that response expectancies, measured using different assessment formats, reveal different effect sizes, potentially explaining mixed outcomes. Utilizing a clinical sample, we compared 5-point assessments and visual analogue scales, as measures of response expectancies for the incidence and severity of subsequent toxicities.

METHODS

Four weeks pre-radiotherapy, 45 men with prostate cancer rated their response expectancies of the same 18 toxicities on 5-point assessments and visual analogue scales, presented in random order. Descriptors anchored each end of visual analogue scales and every point of 5-point assessments was labelled, including an 'unsure' midpoint. Toxicities were subsequently assessed 2-weeks into radiotherapy on 100-point visual analogue scales.

RESULTS

Across all toxicities, 17.5-62.8% of patients selected 'unsure' on 5-point assessments. No response expectancies were reported on 5-point assessments for 'blood in stools' or 'rectal urgency' yet 54.8%-64.3% of patients indicated response expectancies for these toxicities on visual analogue scales. Visual analogue scales and 5-point scales demonstrated small-to-moderate associations (r = 0.30-0.58) as measures of response expectancy incidence, but mostly large associations when visual analogue scales captured severity (r = 0.43-0.76). Response expectancies measured with visual analogue scales predicted more toxicities to a moderate degree or greater (68.8%) than 5-point assessments (37.5%).

CONCLUSION

This novel investigation demonstrated an 'unsure' midpoint is often selected, potentially reducing the sensitivity of 5-point assessments. Based on their associations, and outcomes, these assessment formats should be considered independent in response expectancy research of cancer treatment toxicities.