Outcomes in patients with gastric cancer and positive peritoneal washings

Background The presence of positive cytological washings in the absence of overt peritoneal disease (P0C1) represents metastatic disease. Most centres advocate for neoadjuvant chemotherapy and full restaging including repeat laparoscopy and washings, with resection offered to those in whom restaging is negative. This approach was implemented at our institute in 2012 and when evaluated in 2015 was found to have very good results with 63% of patients resected and 90% 2-year survival. Since this time chemotherapy regimens have changed meaning this earlier approach requires additional scrutiny. Methods A retrospective review of a prospectively maintained database of all upper GI cancer patients treated at the Northern Oesophago-Gastric Unit (NOGU) was undertaken. All patients with adenocarcinoma of the stomach or gastroesophageal junction without metastases on imaging and who underwent staging laparoscopy between August 2012 and August 2022 were identified. Patients who had positive cytological washings without evidence of overt peritoneal disease were included in the analysis. Data were extracted including demographics, treatment data and oncological outcomes. Survival data were collected and patterns of recurrence determined. Results 630 patients underwent staging laparoscopy. Resectable P0C1 disease occurred in 55/630 (8.7%), and 48/55 commenced chemotherapy. Restaging occurred in 45/48 (93.8%) and 21/45 (46.7%) went on to have definitive surgery where 15/45 (33%) were resected. Recurrence occurred in 8/15 patients, 3 of which had peritoneal metastases. Median time to recurrence was 16 months (range: 6-34). A total of 9 patients died during follow up which occurred at a median of 14 months (range: 5 to 43). Overall median survival of the cohort was 28 months (range: 5 – 111), with survival of 60% and 25% at 2 and 5 years, respectively. Conclusions This study demonstrated 60% 2-year survival in patients treated with curative intent who initially had positive peritoneal cytology. We were not able to demonstrate a predominate pattern of peritoneal recurrence. Furthermore, 25% of patients survived for at least 5 years after surgery, indicating that this remains an acceptable approach to the management of P0C1 disease with current best practice chemotherapy regimens.