Surgery is the main treatment of esophageal cancer. However, as an invasive approach, surgery is often accompanied by a variety of complications such as delayed gastrointestinal emptying; the latter mainly includes functional dyspepsia such as bloating, belching, nausea, and vomiting (6-8). The delayed gastrointestinal emptying may be explained by the following reasons (6-8): (i) During the esophageal cancer surgery, removal of the tumor will inevitably cause the injury or disconnection of the vagas nerve; once the stomach loses normal regulations from the vagus nerve, ectopic pacemaker can occur and cause tachygastria, resulting in retroperistalsis and finally causing ‘stomach paralysis’ or gastric stagnation. (ii) Surgery can activate the inhibitory sympathetic reflex system through a variety of pathways; the activated sympathetic nerve fibers can suppress the gastric motility by inhibiting the excitatory neurons in the gastrointestinal plexus; meanwhile, the catecholamines released from its endings can directly bind to the receptors a and b on the gastric smooth muscle cells and thus inhibit the contraction of smooth muscle cells. (iii) After the stomach moves into the thoracic cavity, its anatomical structure and physiological function changes, and the positive pressure inside the stomach and the negative pressure in the thoracic cavity form differential pressure. (iv) The gastrointestinal peptide hormones change after surgery. (v) the use of narcotic drugs during surgery may also influence the gastrointestinal function. And, (vi) esophageal cancer patients are often elderly with diabetes, thyroid dysfunction, and other diseases, which also increase the incidence of delayed gastrointestinal emptying after surgery.

The clinical symptoms are usually mild in most patients and can spontaneously resolve within 3-5 days. However, in some patients they can last 2-3 weeks or longer, and gastroparesis may occur in severe cases (about 3%). The early recovery of gastrointestinal function not only promotes the postoperative rehabilitation, shortens hospital stay, and reduces the financial burden of patients, but also helps to improve the food situation, reduce clinical symptoms, and improve patients' quality of life. Therefore, how to promote recovery of gastrointestinal function after surgery for esophageal cancer has became a hot research topic.

The current management for the recovery of gastrointestinal function after surgery for esophageal cancer, mainly based on modern Western medicine (6-8), includes: routine postoperative indwelling stomach tube; continuous gastrointestinal decompression; fasting; postoperative nutritional support; supplementation of sufficient calories, protein, vitamins and trace elements; infusion of whole blood, plasma, or albumin to correct the negative nitrogen balance, when appropriate; gastric lavage with a warm saltwater solution; and, use of prokinetic agents. However, even after the above treatment, there is still a high percentage of patients may experience delated gastrointestinal emptying or even gastroparesis. Furthermore, the conventional Western medicine-based therapies are often blamed for their high costs, frequent complications, and limited effectiveness. Therefore, the role of TCM in promoting the recovery of gastrointestinal function after surgery for esophageal cancer has increasingly been studied by Chinese researchers. Most TCM-based preparations have mild side effects and low costs. More importantly, TCM-based therapies (including traditional Chinese medicine, acupuncture, and physiotherapy) have been found to be effective in promoting the recovery of gastrointestinal function in both animal experiments and clinical studies. However, most currently available studies are based on personal experiences with small sample size, and few randomized controlled studies on the clinical application of TCM in this aspect have been published.

The current management for the recovery of gastrointestinal function after surgery for esophageal cancer is mainly based on modern Western medicine (6-8). However, even after the above treatment, there is still a high percentage of patients may experience delated gastrointestinal emptying or even gastroparesis, which severely impacted the postoperative rehabilitation, increases pain, and reduces quality of life. Furthermore, the conventional Western medicine-based therapies are often blamed for their high costs, frequent complications, and limited effectiveness. Therefore, the role of TCM in promoting the recovery of gastrointestinal function after surgery for esophageal cancer has increasingly been studied by Chinese researchers.

Most TCM-based preparations have mild side effects and low costs. More importantly, TCM-based therapies (including traditional Chinese medicine, acupuncture, and physiotherapy) have been found to be effective in promoting the recovery of gastrointestinal function in both animal experiments and clinical studies (9-12). Treatment using TCM enema or injection of drug(s) into acupoint Zusanli has shown satisfactory efficacies in adjusting gastrointestinal function and/or promoting the recovery of gastrointestinal function after surgery. According to TCM theories, the esophageal cancer is caused by the deficient and weak "Healthy Qi" and the disordered "Zang" and "Fu" organs. As stated by the Huangdi Neijing (“Yellow Emperor's Inner Canon”, circa 2000 BC, an ancient Chinese medical text), "When there is sufficient healthy Qi inside, the pathogenic Qi have no way to invade the healthy body", and, "the pathogenic Qi invades into the body where the healthy Qi must be deficient". The esophageal cancer occurs and develops at the esophagus, which is covered by the gastric Qi.

Patients with esophageal cancer tend to be deficient in both Qi and blood, and therefore the treatment must be focused in "strengthening the spleen and stomach and nourishing the Qi and body fluid". In the TCM preparation, codonopsis, Yunnan poria, Atractylodes macrocephala, and liquorice root, which are also the components of the famous "Decoction of Four Noble Drugs", are used for "strenthening the spleen and nourishing the Qi", which is further enhanced by the usage of a relatively large number of Radix astragali preparata. White peony root is used for “nourishing the blood and harmonizing the nutrients and defense system"; furthermore, it can enhance the prepared rhizome of rehmannia in "benefiting Yin and blood". The dried tangerine peel, pinellia, and villous amonmum fruit are effective in "benefiting Qi and harmonizing the stomach" or, "promoting Qi and warming the spleen and stomach". The bergamot is beneficial for "promoting qi circulation to relieve pain". The jujube can benefit the spleen and stomach and nourish the blood. The Gallus gallus domesticus can invigorating spleen to promote digestion. The whole preparation is effective for "strengthening the spleen and stomach and nourishing Qi and body fluid", particularly for patients who have just received a major surgery.

Also as shown in our current study, the time required for the first audible bowel sounds and bowel sound recovery were significantly shorter in TCM group than in control group. Meanwhile, the time to first flatus and time to first stool were also significantly earlier in TCM group. The abdominal symptoms showed no significant differences between these two groups. These results indicate that the application of the TCD preparation in our study can promote postoperative recovery of gastrointestinal function without causing more abdominal symptoms. Our findings are consistent with domestic and foreign literature (7-14). Meanwhile, this study showed no increase of TCM-related side effects in the TCM group, indicating that this TCM preparation is safe in promoting the postoperative recovery of gastrointestinal function (Figure 1).

Literatures have shown that there are various approaches for the administration of TCM preparations: oral administration, enema, injection into into acupoint Zusanli, infusion via gastric tube, and others (8-12,14). According to our experiences, infusion of TCM preparation via the enteral feeding tube may be superior because it has advantages including mild pain, fast enteral absorption, and rapid onset; meanwhile, it meets the requirement that the patient needs to be fasted after surgery for esophageal cancer.