Patient attitudes regarding the influence of diet on cancer development and treatment.
Authors: Barber Sean , Duggan Diarmuid , Murphy Jake , Markey Geraldine , O'Connor Derbrenn , Galiauskas Raimundas , Khan Hadia , Ahmed Gul , O'Mahony Deirdre , Murphy Conleth G. 
Published: June 2022

e24088 Background: Up to one third of cancers in high-income populations can be attributed to lifestyle factors (nutrition & physical activity). Data on dietary beliefs in Irish patients with cancer are lacking. This study aims to evaluate how patients with cancer conceptualize the effect of diet on their disease and treatment & determine if attitudes vary according to age, gender, education, disease type, treatment type & treatment intent. Methods: This is a questionnaire-based study, carried out in an Irish oncology unit over a 3-week period in April 2021. Patients with an active cancer diagnosis attending the oncology day ward were invited to participate. We adapted a previously used questionnaire following expert review. A combination of yes/no and Likert scale responses were used: Have you changed your diet since you received your diagnosis? (Yes/no). To what degree do you think that...(Likert): Diet may contribute to the condition that you are being treated for?. Your diet after diagnosis helps your sense of health and wellness?. Diet can help relieve side effects of treatment?. Diet helps in preventing cancer recurrence?. Demographic and treatment data were recorded from patient charts. Responses were compared across demographic variables including gender, age, highest education level, primary cancer location/type and treatment intent using Chi-squared/Fishers exact test. A P-value of < 0.05 was considered significant. Results: 130 patients were invited to take part & 113 responded (response rate 87%). 80% reported changing their diet since diagnosis, with no significant difference according to demographic variables. Most (68%) patients expressed a belief that diet played some role in their cancer development although only 15% believed that diet contributed ‘a lot’. Most patients (83%) believed that diet after a cancer diagnosis has an impact on their sense of health and well-being, and 32% expressed a strong belief in this regard (Likert scale 4, ‘a lot’). 75% believed that diet has some impact on managing treatment side effects. 81% believed that diet has some impact on cancer recurrence, and 30% believed it has a major impact (Likert scale 4). On multivariate analysis we found stronger beliefs in the impact of diet on cancer development (p = 0.049) and recurrence risk (p = 0.05) among men than women, and stronger belief in the impact of diet on recurrence risk among patients receiving treatment with curative versus palliative intent (p = 0.045). Conclusions: Most patients reported changing their diet following their cancer diagnosis, and most patients felt that diet had some impact on all of the areas studied including cancer development, health and well-being, managing side effects and cancer recurrence. Men expressed stronger beliefs than women in the impact of diet on cancer development and recurrence risk, and patients being treated with curative intent also expressed stronger beliefs in the impact of diet on cancer recurrence.