Erin, APRN on Instagram: "Iron deficiency is one of the most overlooked warning signs I see in oncology. At the time of diagnosis, roughly 30–50% of people with colon cancer are anemic, and iron deficiency is the most common cause. Even more concerning: many patients are iron deficient before hemoglobin ever drops, which means the signal is often missed. Colon tumors can bleed slowly over time. Not enough to notice. Enough to quietly drain iron stores. What I see clinically: • ferritin labeled “