Introduction

Established risk factors for prostate cancer currently include: age, family history, ancestry, and genetics [1]. Modifiable risk factors include maintaining a healthy body weight, with the evidence for the role of diet in the etiology of prostate cancer still equivocal. According to the World Cancer Research Fund’s Continuous Update Project, the current level of evidence for diet is limited and suggestive only for a potentially increased risk of prostate cancer associated with a high intake of dairy and calcium foods, and low plasma levels of selenium and alpha tocopherol [1]. No other dietary factors are currently considered to have sufficient evidence to suggest either a protective or harmful influence on the development of prostate cancer, although there is emerging evidence to suggest that cholesterol which acts as a substrate for steroid hormone biosynthesis and lipid metabolism may have a role in prostate cancer cell growth, proliferation and progression [2, 3]. Dysregulation of lipid metabolism has been reported as a hallmark of prostate cancer progression with prostate cancer cells having an increased demand for de novo lipogenesis [2,3,4].

Here we report on a relatively young, active male who had no significant medical or family history of prostate cancer prior to diagnosis, only a history of dyslipidemia and his personalized dietary management using nutrigenomics, bloods, and dietary assessment.

Case report

A 57-year-old white Australian male was diagnosed with advanced prostate cancer (Gleason Score: 9) in early September 2020. He had played sport at an elite level for many years and was keeping highly active at the time of diagnosis but was seeking dietary advice to help optimize the effects of his medical treatment, which included one dose of radiation (177Lutetium-Prostate-Specific Membrane Antigen), and surgery six weeks later involving a radical prostatectomy with pelvic lymph node dissection.

At his initial dietary consultation his self-reported weight was 88 kg, height 183 cm (estimated BMI of 26 kg/m²) and waist circumference was 84 cm. Medical history prior to diagnosis included an egg allergy as a child, intermittent sinusitis, hemorrhoids, and surgeries for sports-related injuries. Family history included obesity, diabetes, breast cancer (mother) and dyslipidemia (father).

He reported having changed his diet from the typical Western dietary pattern to a vegan diet immediately post-diagnosis. Protein intake was approximately 12% of his total energy intake and was solely from plant sources. Thus, the quantity and quality of protein intake needed to be increased to promote enhanced recovery from his upcoming radiation and surgery. Total dietary fat intake was estimated at approximately 37% of total energy intake (goal < 30%), and he was deficient in several micronutrients: vitamins B2, B12, A, zinc, and selenium.

His previous blood results were reviewed and showed a history of dyslipidemia. Nutrigenomic tests were also undertaken via the SmartDNA Genomic Wellness Test (https://www.smartdna.com.au/). He was provided with an OC-100 (DNA Genotek) Saliva Test Kit and mass array analysis was conducted on more than 167 genetic variants or SNPs, although based on his bloods, the focus was on his genetic predisposition to lipid metabolism [5].

He was provided with an initial meal plan of a high plant-based diet (approximately 75% of intake) averaging 12,000 kJ per day. Protein intake was increased to around 20% of total energy intake from both suitable animal and plant sources to ensure that he met his iron, vitamin B12 and micronutrient requirements. Other dietary recommendations focused on reducing consumption of total and saturated fat, and refined sugars.

He kept regular food diaries and dietary consultations across all phases of his active treatment and successfully underwent radiation therapy and surgery without any clinically significant issues other than some temporary general fatigue and loss of fitness. Dietary adjustment based on his food diaries helped to alleviate these symptoms e.g., slight increase in low GI carbohydrate intake.

Table 1 presents the lowered lipid levels corresponding with his dietary modifications. Results from his targeted nutrigenomic tests in Table 2 indicate a genetic predisposition to dyslipidemia, which could be managed via his personalized diet (Table 1). Total cholesterol reduced from 6.2 mmol/L to 5.1 mmol, triglycerides from 2.4 mmol to 1.0 mmol/l and LDL cholesterol from 3.8 mmol to 3.4 mmol following his dietary intervention. PSA levels are also shown to drop to 0.1ug/L following radiation and surgery. At two years post treatment there was no detectable disease recurrence or plans for ADT.

Table 1 Blood results for the case.
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Table 2 Nutrigenomics test results for the case.
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Discussion

We report on a case who received personalized dietary recommendations alongside multidisciplinary prostate cancer management, and achieved improved lipid profiles, enhanced recovery to an excellent performance status, and undetectable cancer at conclusion of our surveillance.

To date, there are only limited studies reporting on potential dietary associations with prostate cancer risk. A large prospective cohort study (Health Professionals Follow-up Study) reported that men with low cholesterol levels had a lower risk of high-grade prostate cancer/advanced disease [6]. Other studies have reported that adherence to the Western dietary pattern and high consumption of saturated fats are associated with advanced disease and higher overall and cancer specific mortality [7, 8]. There is currently even less on diet and prostate cancer management in the scientific literature, outside of maintaining a healthy body weight, eating according to the general dietary guidelines, and maintaining adequate calcium intake and vitamin D status for men on ADT [9].

To our knowledge this is the first reported case where personalized dietary management using nutrigenomics has been incorporated into the multidisciplinary management of advanced prostate cancer. Some of the limitations of this case report include investigation of a small range of targeted nutrigenomic tests which do not identify other potential risk factors for advanced prostate cancer and this being a single case’s experience which may not necessarily be generalizable. However, this case study provides important initial insights into the potentially valuable role of personalized dietary management of advanced prostate cancer. Larger studies are needed to examine the role of lipids and cholesterol in this disease and its management.

Conclusion

Utilizing nutrigenomics, bloods and dietary data could be clinically beneficial in providing more precision-based dietary and overall management of prostate cancer patients resulting in better patient health outcomes.