Ive made poor decisions and had untreated gerd for years and ive had lots of alcohol and acidic foods. my throat feels damaged and although im only 21 im worried i could have done enough damage to have esophageal cancer. is it possible?

Whenever you ask the question "is it possibly", The answer is almost always "yes" (with a few exceptions). However, is it likely, by your age, probably not. However, Acid reflux over time could lead to problems like barrett's esophagus.. (predisposing to future cancer), also esophageal damage, aspiration, etc. Alcohol can add to it. You may want to speak with a GI doc, and possibly endoscopy.

It takes usually years to decades for cancers to develop in the context of poor lifestyle choices. It sounds like your lifestyle choices are creating health related anxiety, maybe the right time to revise them, not just to avoid life threatening conditions, but symptoms that will definitely affect quality of life. Talk to your doc about your worries.

If you alter your habit, cancer is not inevitable. You can reduce your risk of cancer by adopting healthy habits: Eat a mostly vegetarian diet, avoid alcohol, tobacco and street drugs, avoid excessive exposure to sun, maintain healthy weight, get HPV vaccine, exercise 30 minutes each day, drink enough water so your urine is mostly colorless. Wish you good health!