Which clinical sign or symptom in a chronic drinker should prompt evaluation for alcohol-related esophageal or gastric damage?

Mild transient thirst that resolves with fluids and does not affect diet, as this is the most specific sign of esophageal cancer and requires immediate endoscopy.

Intermittent headaches relieved by alcohol because this pattern rules out any GI pathology and indicates no need for evaluation of the esophagus or stomach.

Slightly increased sweating during exercise only, since this is pathognomonic for alcohol-induced gastritis and always predicts malignant transformation within days.

Persistent heartburn, dysphagia (difficulty swallowing), odynophagia (pain with swallowing), unexplained weight loss, or persistent upper GI bleeding—these symptoms warrant endoscopic evaluation because they may reflect significant mucosal injury or cancer risk.