We say "have cancer" (without a/an). When you talk about diseases, the indefinite article is generally unnecessary.
We say "have cancer" (without a). When you talk about diseases, the indefinite article is generally unnecessary.
Daniel has cancer.
Daniel has a cancer.
Most names of diseases are uncountable and don't take a/an.
Having cancer can be very challenging.
The tests suggest that Barbara has breast cancer.
Follow the same rule with the expressions "treat cancer", "cause cancer", "develop cancer", "prevent cancer", "diagnose cancer", etc.
Can you prevent cancer?
Immunotherapy is an encouraging new strategy to treat cancer.
Does lifestyle or behavior cause cancer?
However, you can use a possessive pronoun (my, your, his, her, our, your, their).
If your cancer metastasizes, you may notice symptoms in different parts of your body.
You can use the word cancer as an adjective (before a noun). In this situation, use the article a/an or another determiner (this, the, my, etc.) according to the usual rules.
Ask your doctor if your community has a cancer support group.
Being overweight or obese is a breast cancer risk factor.
Other names of diseases that do not take the article a/an can be found below: