Predictors of outcomes in patients with gastric cancer treated with contemporary multimodality strategies-a single institution experience.

BACKGROUND

While gastric cancer is a leading cause of cancer-related mortality in Eastern Europe and Asia, it is less common in the United States. Recommendations regarding optimal treatment of non-metastatic gastric cancer with regard to type and extent of surgery, choice and sequence of chemotherapeutic agents, and use of radiation therapy vary somewhat depending on geographic location. There is paucity in the literature for direct comparison of various practices. To determine how variability in treatment practices affects patient outcomes, we conducted a retrospective study in patients with gastric cancer who had multimodality treatment for non-metastatic gastric cancer.

METHODS

We gathered clinical data (patient demographics, pathology reports, type of surgical intervention, chemotherapy, and radiation therapy) for patients diagnosed with gastric adenocarcinoma who underwent gastrectomy at five sites from 2010-2017 using Electronic Health Records and California Cancer Registry databases. Medical chart reviews were conducted to validate patient outcomes. We performed multivariate Cox regression analyses to determine predictors for cancer recurrence and survival. We also performed logistic regression analyses to determine predictors of positive resection margins and hospitalization.

RESULTS

One hundred and sixteen patients met eligibility criteria to be included. Mean age was 65.7±11.6 years. About 65.5% were male. The most common ethnicities were Asian (44.0%) and Caucasian (37.9%). About 58.6% of the patients had localized disease (defined as pT1-3, pN0) and the remaining 41.4% had loco-regional disease (i.e., pT4 or pN+). About 41.4% of the tumors were diffuse, 27.6% intestinal, 12.0% mixed, and 19.0% unknown histology. Surgery included laparoscopic (94.8%) and open gastrectomy (5.2%). Chemotherapy and radiation therapy were given in 51.7% and 19.0% of the patients, respectively. After a median follow-up time of 19 months after gastrectomy, 16.4% of patients had recurrence and 19.8% had died. Patients who had loco-regional tumors were more likely to have recurrence and death than those who had localized tumors (hazard ratios =7.0, P=0.0228 for recurrence and hazard ratios =3.3, P=0.0160 for death). Positive resection margins were seen in 9% of the patients and were associated with diffuse histology (odds ratio =6.6, P=0.0207). Hospitalization within six months of gastrectomy was seen in 22% of the patients. Peri-operative chemotherapy was the only significant predictor for re-hospitalization (odds ratio =3.5, P=0.0415).

CONCLUSIONS

In this contemporary cohort of patients with localized gastric cancer, only the pathological stage was significantly associated with survival while positive resection margins were associated with diffuse histology. Closer monitoring of patients undergoing perioperative chemotherapy within 6 months of surgery is warranted based on our observation of higher rate of re-hospitalization.