Aspirin acts in esophageal cancer: a brief review
Improved survival in esophageal cancer patients with regular aspirin use have been reported. However, with conflicting experimental results existed, an explicit definition on the role of aspirin as an adjuvant chemotherapy of esophageal cancer remains unestablished. We have summarized the current epidemiologic trials evidence over antitumor effect of aspirin in esophageal cancer in the past decades, and most of the clinical data supports that long-term regular aspirin use could reduce the mortality and improve the survival in patients with esophageal cancer. Although most of the clinical trials of aspirin on esophageal cancer are designed focusing on the prediagnosed chemo-preventive role, other than the post-diagnosed therapeutic role, it has been suggested by some studies that aspirin use as an adjuvant treatment after the standard surgery in esophageal cancer may benefit more. In the meanwhile, post diagnosed aspirin use may lead to lower risk of hemorrhage and other side effects of NSAIDs. Potential involved molecular pathways in the antitumor activities of aspirin are under studied worldwide for years and the possible mechanisms so far are reviewed in this article as cyclooxygenase (COX)-dependent pathways and COX-independent pathways, involving anti-inflammatory activity, apoptosis, platelet deactivation, PIK3CA mutation specificity and heparanase-related microenvironment changes of tumor cells. NOSH-aspirin has been developed as a succedaneum of aspirin with a wider application ranges by reducing the risk of hemorrhage in aspirin users. Further clinical and basic studies are suggested focusing on whether regular aspirin use as an adjuvant treatment prolongs survival and prevents recurrence in patients with esophageal cancer.