Prostate Cancer — NZ Condition Guide | KiwiMeds

What is Prostate Cancer?

Prostate cancer is the most common cancer in New Zealand men, with around 4,000 new cases diagnosed each year. It occurs when cells in the prostate gland grow abnormally. Prostate cancer varies enormously in its behaviour — many prostate cancers grow very slowly and may never cause problems, while others are more aggressive.

Overview

Early prostate cancer usually has no symptoms. Symptoms that can occur (often from prostate enlargement — not necessarily cancer) include difficulty urinating, frequent urination (especially at night), weak urine stream, blood in urine or semen, and pelvic discomfort. The PSA (prostate-specific antigen) blood test is used for prostate cancer screening, but it has limitations — it can be elevated due to non-cancerous conditions. NZ currently recommends informed decision-making about PSA testing rather than routine screening.

Treatment in New Zealand

Treatment for prostate cancer depends on the stage and grade (Gleason score). Options include active surveillance (monitoring without treatment for low-risk cancer), surgery (radical prostatectomy), radiation therapy, hormone therapy (androgen deprivation therapy — ADT), and for metastatic disease, chemotherapy and novel hormone agents. Pharmac funds a range of prostate cancer treatments including ADT and newer agents like enzalutamide and abiraterone for eligible patients.

NZ-Specific Information

Prostate Cancer Foundation NZ (prostate.org.nz) provides information and support. NZ does not have a national prostate cancer screening programme — PSA testing is an individual decision made with your GP. Māori men have lower prostate cancer incidence but higher mortality — access to timely diagnosis and treatment is an equity issue.

Frequently Asked Questions

Should I have a PSA test? This is a personal decision to make with your GP, weighing the benefits (early detection of significant cancer) against harms (anxiety, overdiagnosis of clinically insignificant cancers). What is active surveillance? Active surveillance means monitoring low-risk prostate cancer with regular PSA tests, biopsies, and scans — treating only if the cancer shows signs of progression.

Supplements That May Support Management

⚠️ Important: The supplements listed below have varying levels of clinical evidence. They are not a substitute for prescribed medications and should only be considered as adjunctive support under the guidance of a qualified healthcare professional. Always inform your GP or pharmacist before commencing any supplement, as interactions with prescribed medicines are possible.

• Lycopene — Lycopene, a carotenoid found predominantly in tomatoes, has demonstrated inverse associations with prostate cancer risk and progression in epidemiological studies. Supplementation at 15–30 mg/day (or dietary equivalents) may reduce PSA levels and prostate cancer progression risk.
• Vitamin D — Vitamin D deficiency is associated with more aggressive prostate cancer phenotypes. Supplementation is recommended where deficiency is confirmed, as vitamin D receptors in prostate tissue modulate cell differentiation and apoptosis.
• Pomegranate Extract — Pomegranate polyphenols (punicalagins, ellagic acid) have demonstrated anti-proliferative and pro-apoptotic effects on prostate cancer cells. A clinical trial demonstrated significant lengthening of PSA doubling time with 8 oz pomegranate juice daily.
• Selenium and Vitamin E — CAUTION — The SELECT trial demonstrated that selenium and vitamin E supplementation was not protective and high-dose vitamin E (400 IU/day) significantly increased prostate cancer risk. These supplements should be AVOIDED for prostate cancer prevention.
• Green Tea Catechins (EGCG) — Epigallocatechin gallate (EGCG) has demonstrated anti-proliferative effects on prostate cancer cells and reduced progression rates in men with high-grade prostatic intraepithelial neoplasia in a small randomised trial.

Relevant Vaccinations

Individuals living with prostate cancer may benefit from the following vaccinations. Please discuss your vaccination status with your GP or practice nurse, as eligibility and funding through the New Zealand National Immunisation Schedule may apply.

• Influenza (annual) — Recommended for all men with prostate cancer, particularly those on androgen deprivation therapy (ADT) which affects immune function.
• Pneumococcal — Recommended for those on immunosuppressive cancer treatments.
• COVID-19 — Men with prostate cancer, particularly on ADT or chemotherapy, have reduced immune function. Maintaining COVID-19 vaccination is strongly recommended.
• Shingles (Shingrix) — Recommended for men aged 50+ on immunosuppressive cancer therapies.

Dietary Guidance

Evidence-based dietary modifications play a meaningful role in the management of prostate cancer. The following foods are generally recommended as part of a balanced, condition-appropriate diet. A referral to a registered dietitian may be beneficial for personalised nutritional planning.

• Tomatoes and lycopene-rich foods (cooked tomatoes, watermelon, guava) — Cooked tomatoes provide the highest bioavailable lycopene. Meta-analyses support regular tomato consumption for reduced prostate cancer risk and slower progression.
• Cruciferous vegetables (broccoli, cauliflower, Brussels sprouts, cabbage) — Contain sulforaphane and indole-3-carbinol with demonstrated anti-cancer activity in prostate tissue, including enhanced carcinogen detoxification and pro-apoptotic signalling.
• Pomegranate juice or seeds — Evidence for slowing PSA rise in prostate cancer as noted above.
• Green tea (3–5 cups daily) — Provides EGCG catechins with anti-proliferative prostate cancer activity.
• Limit: dairy and saturated fat — High dairy and saturated fat intake is associated with increased prostate cancer progression risk in several large cohort studies. Moderate dairy intake and preference for plant proteins is advised.

Related Conditions & Medications

Related conditions: Erectile Dysfunction.