Prevention & Risk

Alcohol causes at least seven cancers and there is no safe threshold. Price, availability and cancer warning labels are the tools that work; most people still do not know alcohol causes cancer.

Daily low-dose aspirin lowers bowel cancer risk in people with Lynch syndrome and appears to cut recurrence in bowel cancers with a particular mutation. In healthy older people it caused more harm than good.

People with severe obesity who have weight-loss surgery develop about a third fewer cancers over the following decade, especially womb and other hormone-related cancers, than similar people who do not.

Cancer interception vaccines immunise people who do not yet have cancer but carry a high inherited risk, such as Lynch syndrome carriers, against the antigens their future tumour is predicted to express, so memory T cells remove transformed cells early. Because healthy people accept risk for a probabilistic benefit, the safety bar is far higher and trials take years.

The public systems that count every cancer diagnosis and death in a country, which tell us whether incidence and survival are improving.

Drugs or surgery for people at high inherited risk, before any cancer appears.

Coffee does not cause cancer: IARC downgraded it in 2016, and cohort studies link two to three cups a day with lower rates of liver and womb cancer. Drinks of any kind served above 65 C are classed as a probable cause of oesophageal cancer, so the temperature, not the coffee, is the risk.

Structured exercise during and after treatment, which the CHALLENGE trial showed improves survival in colon cancer.

A test of the DNA you were born with, to find inherited risk genes such as BRCA or Lynch syndrome.

Seventy percent of cancer deaths occur in low- and middle-income countries, where radiotherapy machines, pathologists, essential medicines and palliative care are scarce. Global oncology works on affordable, adapted care and the systems to deliver it.

GLP-1 agonists, the new weight-loss injections, lower weight by 15-20%. Early observational data suggest fewer obesity-related cancers in people who take them, but no trial has yet tested cancer as an outcome.

Drinking green tea is safe and pleasant, but a Cochrane review found no consistent evidence that it prevents cancer, and concentrated green tea extract capsules have caused liver injury and can interfere with some drugs.

Vaccines that prevent the viral infections behind cervical, throat, anal, and liver cancers. The most effective anti-cancer intervention ever created.

Diets built around vegetables, wholegrains, legumes, nuts, fish and olive oil, with little red or processed meat, are linked with lower cancer risk and better survival after diagnosis. The evidence is strong for the pattern, weak for any single food.

A trained health worker looking inside the mouth with a light can find mouth cancer early; in India this cut deaths by a third among people who use tobacco or alcohol.

A score built from hundreds of common gene variants that says whether your inherited risk of a cancer is higher or lower than average, now being tested as a way to decide who is screened and how often.

Processed meat (bacon, ham, sausages) is classed by IARC as a definite cause of bowel cancer and red meat as a probable one, with about 18% higher risk per 50 g of processed meat a day. One person's extra lifetime risk is a few percentage points, but 5 to 10% of bowel cancers in high-income countries are attributed to it.

Removing the fallopian tubes, where most ovarian cancer starts, during other pelvic surgery or in women at inherited risk.

Checking the whole skin for suspicious moles finds melanomas earlier, but no trial has yet shown that screening everyone saves lives, so most countries target people at high risk.

Stopping smoking after a cancer diagnosis improves survival, reduces treatment complications and second cancers, and is the single most effective supportive intervention that oncology services still routinely fail to deliver.

For years women with breast cancer were told to avoid soy because it contains plant oestrogens. Large studies show moderate soy food intake is safe and may slightly reduce recurrence, including on tamoxifen.

Testing cheap old drugs, aspirin, metformin, statins, beta-blockers, as cancer treatments, because they are safe, available and sometimes work.

Destroying precancerous cervical cells with a heated or frozen probe in under a minute, the tool that makes screen-and-treat possible where there are no surgeons.

Time-restricted eating means eating within a window of 8-12 hours a day and fasting overnight. It improves blood sugar and weight a little; whether it changes cancer risk or recurrence is unknown.

Giving the innate immune system a memory, so monocytes and NK cells respond harder the next time they meet a tumour.

Diets high in industrially processed foods and sugary drinks are linked with more cancer, mainly through obesity but perhaps also through additives and packaging chemicals. Sugar itself does not 'feed' a tumour in the way social media claims.

A nurse paints the cervix with household-strength vinegar and looks with a torch: precancer turns white within a minute and can be frozen or heat-treated at the same visit, which is how cervical cancer deaths were cut by a third in Indian villages without a laboratory.

The largest trial of vitamin D and fish-oil pills found they did not prevent cancer. A possible reduction in cancer deaths, and hints of benefit after a digestive cancer diagnosis, keep the question alive.