Fatigue is extreme tiredness that doesn’t get better with rest. It may be an important symptom as cancer grows. But it may happen early in some cancers, like leukemia. Some colon or stomach cancers can cause blood loss that’s not obvious. This is another way cancer can cause fatigue.

At one point or another, we have all experienced fatigue. For most of us, it is temporary, usually caused by stress or being overworked.

For some people, however, fatigue can become persistent, occurring daily. When fatigue becomes frequent, it is natural to be concerned about what may be causing it.

While fatigue alone without other symptoms is uncommon in many cancers, for people with leukemias and lymphomas fatigue may well be the first symptom.