Treatment strategies for gastric cancer abdominal free cancer cells The distant metastasis of gastric cancer mainly consists of 3 routes: hematogenous metastasis, lymphatic metastasis and abdominal dissemination metastasis. Abdominal free cancer cells are a form of abdominal metastasis of gastric cancer, which is currently considered as a special type of advanced gastric cancer. Its special feature is that there are no metastases visible to the naked eye in the abdominal cavity, so without cytological examination of abdominal lavage fluid, it is easy to miss the diagnosis. In this article, we will discuss the prognosis, evaluation and treatment strategy of gastric cancer with free cancer cells in the abdominal cavity. I. Prognosis The prognosis of patients with abdominal disseminated metastasis of gastric cancer is extremely poor. According to statistics, the median overall survival of patients with abdominal carcinoma metastasis is only 3-6 months, while the long-term survival of patients with positive abdominal free cancer cells is also poor, with a 5-year survival rate of 0%-18% after surgery and a median OS of 10-15 months, and most patients will have abdominal tumor recurrence within 2 years. II. Assessment Currently, the assessment of abdominal free cancer cells in gastric cancer is mainly performed by staging laparoscopy and cytology. In the comprehensive treatment of resectable progressive gastric cancer, the current standard treatment model is preoperative neoadjuvant therapy + radical surgery + postoperative adjuvant therapy. In this process, the evaluation of abdominal free cancer cells can be performed before the start of treatment or before surgical resection, but its specific indications are not yet clear. In different studies, the most important risk factors for positive abdominal free cancer cells include the T-stage and N-stage of the patient’s tumor. Do patients with negative abdominal cytology prior to initial treatment need to undergo another abdominal cytology evaluation when they undergo surgery after preoperative neoadjuvant therapy? In order to answer this question, it is first necessary to identify how many of the patients with a negative initial evaluation will become positive for abdominal free cancer cells after preoperative neoadjuvant therapy. The percentage of patients with negative to positive abdominal free cancer cells varies from 0.6% to 24% in different studies, but the chemotherapy regimen, number of chemotherapy cycles, and patient enrollment criteria vary widely among studies, and the small number of cases enrolled in each study does not allow for the identification of risk factors associated with the conversion of negative to positive abdominal free cancer cells, which still needs to be confirmed in large prospective studies. This needs to be confirmed in large prospective studies. Nevertheless, different studies have confirmed the poor prognosis of patients with negative to positive free abdominal cancer cells. Currently, there are three main treatment modalities for abdominal free cancer cells: preoperative neoadjuvant chemotherapy followed by primary surgery, postoperative adjuvant chemotherapy, and treatment of the abdominal cavity. In the mode of preoperative neoadjuvant chemotherapy followed by primary surgery, the following issues should be considered: 1. how long is it appropriate for patients to receive chemotherapy before secondary staging; 2. whether patients should receive abdominal cytological evaluation again at secondary staging. Overall, positive abdominal free cancer cells in gastric cancer patients is a special kind of distant metastasis. The application of diagnostic laparoscopy and laparoscopic cytologic evaluation in clinical practice is still seriously inadequate, resulting in misdiagnosis and misdiagnosis of a large number of patients, and the best treatment strategy for this group of patients still needs to be explored in numerous clinical trials.