Prevalence and alternative explanations influence cancer diagnosis: An experimental study with physicians.

Abstract

Objective: Cancer causes death to millions of people worldwide. Early detection of cancer in primary care may enhance patients' chances of survival. However, physicians often miss early cancers, which tend to present with undifferentiated symptoms. Within a theoretical framework of the hypothesis generation (HyGene) model, together with psychological literature, we studied how 2 factors-cancer prevalence and an alternative explanation for the patient's symptoms-impede early cancer detection, as well as prompt patient management. Method: Three hundred family physicians diagnosed and managed 2 patient cases, where cancer was a possible diagnosis (one colorectal cancer, the other lung cancer). We employed a 2 (cancer prevalence: low vs. high) ϫ 2 (alternative explanation: present vs. absent) between-subjects design. Cancer prevalence was manipulated by changing either patient age or sex; the alternative explanation for the symptoms was manipulated by adding or removing a relevant clinical history. Each patient consulted twice. Results: In a series of random-intercept logistic models, both higher prevalence (OR ϭ 1.92, 95% confidence interval [CI 1.27, 2.92]) and absence of an alternative explanation (OR ϭ 1.70, 95% CI [1.11, 2.59]) increased the likelihood of a cancer diagnosis, which, in turn, increased the likelihood of prompt referral (OR ϭ 22.84, 95% CI [16.14, 32.32]). Conclusions: These findings confirm the probabilistic nature of the diagnosis generation process and validate the application of the HyGene model to early cancer detection. Increasing the salience of cancer-such as listing cancer as a diagnostic possibility-during the initial hypothesis generation phase may improve early cancer detection.

Expectations for antibiotics increase their prescribing: Causal evidence about localized impact.

“…The years of experience since the certification ranged from 0 to 40 years (M = 10.5, SD = 9.2 years). Upon completion of a 20-minute questionnaire administered online, comprising hypothetical patient vignettes -the vignette presented here and some other unrelated vignettes concerning cancer detection presented elsewhere (Sirota, Kostopoulou, Round, & Samaranayaka, 2016) -participants received a £20…”

“…After providing informed consent, participants diagnosed and managed five hypothetical patients (see details in Sirota et al, 2016). One of them, a 15-year-old competitive swimmer called Sarah, presented with symptoms of acute otitis media (see the vignette in the Appendix).…”

Do patients’ faces influence General Practitioners’ cancer suspicions? A test of automatic processing of sociodemographic information

“…Increasing age is a powerful risk factor for cancer [ 19 ]. That patients’ age influences GPs cancer suspicion has been reported before in studies in which patient’s age has been manipulated in written vignettes [ 6 – 9 , 28 ]. While these studies demonstrate that a reasoned, reflective choice is influenced by information about demographic characteristics, our study demonstrates that cancer suspicion may be generated earlier in the consultation process when the only information available is derived from appearance before eliciting verbal information.…”

Ability of verbal autopsy data to detect deaths due to uncontrolled hyperglycaemia: testing existing methods and development and validation of a novel weighted score

“…It is also interesting that there were differences between physicians in ascribing uncontrolled hyperglycaemia as a cause of death. These differences are likely to result from different exposure to disease prevalence and be influenced by the reason for examining the data; it would be expected that physicians who were used to dealing with a condition and who were specifically looking for that condition would find a greater prevalence of that condition 32–34. However, that there was reasonable agreement between the investigator physician (AW) and the algorithm with the Karonga site physician diagnoses is reassuring.…”