Increased risk of cancer?

You may wonder what caused your cancer, or maybe you simply want to build your own cancer-free microenvironment. I have spent 25 years, day in, day out helping people with cancer; 25 years since my own daughter developed brain cancer, 25 years researching cancer. And that is after my Oxford University Biochemistry degree where I had the second best paper in the year (for viruses), beaten only by the best paper in the year - my own paper on cancer.

Rather than make this a boring paper on research and my views, I simply used IARC, the International Agency for Research on Cancer to tell me what their data says increases the risk of cancer. 

1. Tobacco smoking is the leading risk factor, accounting for 19% of all cancer cases and nearly 29% of cancer deaths. Secondary smoke is also a problem increasing risk by 20-30%. E cigarette aerosols - IARC classification Group 1 carcinogenic).
    

2. Excess body weight is the second largest modifiable risk, responsible for 7.8% of cases
    

3. Alcohol consumption  - 5.6% of cases.
    

4. Physical inactivity - lack of movement lowers blood oxygen and the immune system. It can raise insulin and oestrogen levels, and cause inflammation - all drivers of cancer. 
    

5. Poor diet - Some foods increase cancer risk -  for example,:processed and super processed meat (bacon, sausage, some hams, salami, hot dogs) – (IARC Group 1 carcinogenic); Red meat – (IARC Group 2A)  - linked to colorectal cancer; High-temperature or burnt foods e.g.: heterocyclic amines (HCAs), polycyclic aromatic hydrocarbons (PAHs), and acrylamide (Group 2A) from frying/baking;  Then there’s Aflatoxins – (IARC Group 1).  Mycotoxin on peanuts, maize, tree nuts.  
    

6. Sunburn - sunshine is good; it’s burning that’s bad.
    

7. Cancer-causing infections like HPV, EBV, Herpes simplex, Helicobacter pylori, and Hepatitis, which cause at least 10 per cent of global cancers.
    

8. Chronic inflammation - colitis and diverticulitis can lead to colorectal cancer; GERD can lead to oesophageal cancer; coeliac disease can lead to T-cell lymphoma and small bowel adenocarcinoma; cirrhosis can lead to liver cancer. There are more! Not least of all, a poor or damaged microbiome!
    

9. Common drugs and antibiotics; for example Methotrexate for Rheumatoid arthritis can lead to lymphoma; Proton Pump Inhibitors have been linked to increased risk of stomach cancer. Immunosuppressive drugs such as Ciclosporin – (IARC Group 1) post-transplant → lymphomas, skin cancers, Kaposi sarcoma; Tamoxifen (IARC Group 1) endometrial cancer.
    

10. Medical ionising radiation - (IARC Group 1) -.CT scans, diagnostic X-rays, prior radiation therapy is a major and often overlooked risk factor -individual  effects are small but accumulate.

11. Age is the most critical non-modifiable factor, as risk accumulates with cumulative exposure and declining cellular repair mechanisms. 
     

12. Air pollution - exposure to fine particulate matter (PM2.5), benzene, diesel fumes, radon, and nitrogen dioxide (NO2) are linked to lung cancer. PM2.5 raises the overall risk of developing cancer by 11%, with particularly sharp increases for liver cancer (32% higher incidence), colorectal cancer (18% higher odds), and breast cancer.
     

13. Genetic factors such as inherited mutations (e.g., BRCA1/2) or Lynch syndrome.
     

14. Occupational exposures to chemicals like asbestos, arsenic, dioxin and benzene also contribute significantly to cancer incidence. Wood dust and Vinyl Chloride are others. We have a separate page on this.
     

15. Forever Chemicals - Per- and polyfluoroalkyl substances (PFAS) are a large group of thousands of synthetic chemicals used since the 1940s. They are found in numerous consumer products including non-stick cookware, waterproof clothing, food packaging, and firefighting foams.  
     

    1. IARC classifies PFOA (Perfluorooctanoic acid) as carcinogenic to humans (Group 1). NCI research found people with the highest PFOA blood levels were more than twice as likely to develop kidney cancer.
        

    2. A 2025 study linked PFAS-contaminated drinking water to up to a 33% increase in certain cancers (oral cavity, brain, endocrine). A 2026 UC Irvine study linked early PFAS exposure to childhood leukemia.  
        

16. Herbicides -

    1. Lindane - (Group 1 – Carcinogenic to humans) In 2015, this was the first pesticide given Group 1 status in 30 years.  Based on sufficient evidence in humans specifically for non-Hodgkin lymphoma, in both occupational and non-occupational settings.  Strong evidence also exists that lindane causes immunosuppressive effects in humans.
        

    2. Glyphosate classified by IARC as Group 2A (probably carcinogenic to humans) for non-Hodgkin lymphoma. A 2025 international study reinforced this, linking glyphosate-based herbicides to multiple cancer types, particularly hematological malignancies.
        

    3. DDT -  (Group 2A – probably carcinogenic to humans) - associations found for non-Hodgkin lymphoma, testicular cancer, and liver cancer.
        

    4. Atrazine - (Group 2A) Atrazine is banned in the EU but remains the second most-used herbicide in the US on corn, sorghum, and sugarcane - findings include oxidative stress, inflammation, immunosuppression, and endocrine disruption.
        

17. Chemicals - 
     

    1. Mercury. IARC classifies methylmercury compounds as Group 2B (possibly carcinogenic).
        

    2. Arsenic and cadmium: (Group 1 carcinogens). Found as contaminants in lipsticks, hair dyes, and some skin-lightening products. Tobacco smoke can obtain high levels of cadmium. Arsenic is found in high levels in certain parts of the USA, India, China - it is also used in wood preservatives and sheep dipping.
        

18. Personal care products - A 2026 peer-reviewed study of 110+ products found unlabeled toxic chemicals in approximately 85 per cent of products, including products labeled "natural" or "eco."
     

    1. Benzene -  (Group 1 – Carcinogenic to humans). Of course it’s not intentionally added, but never-the-less it is found in aerosol deodorants, dry shampoos, sunscreens, and products with benzoyl peroxide (especially after heat exposure).  Linked to leukemia and blood cancers.  A 2022 public health study found it in 27% of products tested, some at ‘life-threatening levels’.
        

    2. Formaldehyde - (Group 1 – Carcinogenic to humans). The single most well-established cancer risk in personal care products; in hair relaxers, straighteners, nail products, shampoos, lotions, and even eyelash glue. 
        

    3. Ethylene Oxide (contaminant - Group 1 – Carcinogenic to humans). Used as a sterilising agent in manufacturing; found as a residual contaminant in cotton-based products, some makeup, and medical-grade personal care items.  Linked to lymphoma, leukemia, and breast cancer.
        

    4. PFOA (Group 1) and PFOS (Group 2B). Found in waterproof/make-up-resistant cosmetics, lipsticks, eyeliners, and some shampoos.  The 2026 study noted PFAS as one of the most commonly detected unlabeled toxic chemicals in personal care products, even in "natural" brands.
        

    5. Coal tar dyes - (Group 1 – Carcinogenic to humans). Found in dark hair dyes (black, dark brown).
        

    6. Talc - (Group 2A- probably Carcinogenic); Body powder, eye shadow, blush
        

    7. Dioxane - (Group 2B – Possibly carcinogenic). A byproduct of ethoxylated surfactants (common in shampoos, body washes, and lotions).  Found in PEG-containing products.
        

    8. Endocrine disrupters - Humans are exposed through air, water, diet, and skin contact, for example phthalates, bottle plasticisers, Bisphenol A, food packaging, chemical pollutants such as  PCBs, perfumes - Linked to breast, ovarian, endometrial, prostate cancers, hormone disorders, neurological issues, metabolic diseases like diabetes and obesity, and immune system dysfunction.
        

19. Disrupted sleep - Night shift work is Group 2A carcinogenic  - we have seen cases of breast cancer and prostate cancer associated with the disruption of melatonin production. A similar disruption can be caused by EMF’s and excessive blue light.
     

20. Hormone and reproductive factors  - Combined oral contraceptives – (IARC Group 1 - liver, cervical cancer); Postmenopausal oestrogen therapy e.g. HRT – (IARC Group 1 breast, endometrial); Nulliparity, late first pregnancy, no breastfeeding – increased breast cancer risk; Undescended testes (cryptorchidism) – ~2–5× testicular cancer risk.