Is headaches caused by brain cancer constant or comes and goes? can it be cancer if headache is the only symptom?

Very Unlikely: 99% of the time, a headache (ha) isn't cancer. It's a stress ha, migraine, sinuses or other benign cause. We can't say for 100% its not tumor and few red flags may raise our concern. Realize that you might have few or all of these and not have cancer. Redflags -new or different ha -other accompanying symptoms -ha starts with waking up in am -ha getting worse -something isn't right -inner voice.

Depends: Consult your physician (or neurologist). May need imaging (ct or mri) based on clinical evaluation.

No Rules: I agree that headache is rarely because of a brain tumor. However, if you have a brain tumor , symptoms can be very mild or even nonexistent. Symptoms cause by a brain tumor could be any of the following: headache personality change dizziness blurred vision unsteadiness change in senses (smell, hearing, taste) weakness- especially if one sided or one limb phantom smells or sounds stroke-like.