Prognostic Impact of Klintrup–Mäkinen (KM) Score in Gastric Cancer and Its Association with Pathological Parameters

<i>Background and Objectives:</i> Gastric cancer (GC) remains a significant global health challenge with a poor prognosis. This study aimed to evaluate the association between Klintrup-Mäkinen (KM) inflammatory infiltrate grading and clinicopathological features in gastric cancer patients, investigating its potential as a prognostic marker. <i>Material and Methods:</i> This retrospective study analyzed 133 gastric adenocarcinoma patients diagnosed between 2020 and 2021 at County Clinical Hospital in Târgu Mureș, Romania. Patients were divided into two groups based on KM grades: low (grades 0-1, <i>n</i> = 62) and high (grades 2-3, <i>n</i> = 71). Clinicopathological characteristics and survival outcomes were compared between the groups. <i>Results:</i> Demographic characteristics were similar between the groups. Patients with low KM grades demonstrated significantly more aggressive tumor features, including a higher prevalence of Borrmann classification types III-IV (75.8% vs. 54.9%, <i>p</i> = 0.01), poorly differentiated histology (74.1% vs. 33.8%, <i>p</i> < 0.0001), advanced T stage (93.5% vs. 80.2%, <i>p</i> = 0.04), and lymph node involvement (87% vs. 60.5%, <i>p</i> = 0.0008). This group also exhibited higher rates of lymphatic invasion (79% vs. 50.7%, <i>p</i> = 0.001), venous invasion (51.6% vs. 30.9%, <i>p</i> = 0.02), perineural invasion (50% vs. 22.5%, <i>p</i> = 0.001), and positive surgical margins (32.2% vs. 15.4%, <i>p</i> = 0.02). Survival analysis revealed a hazard ratio of 1.642 (95% CI: 1.02-2.62) for patients with low KM grades compared to those with high KM grades. <i>Conclusions:</i> Low KM grades are associated with more aggressive tumor characteristics and poorer prognosis in GC patients. The KM score may serve as a valuable, cost-effective histological marker for assessing tumor aggressiveness and could aid in risk stratification when applied to routine H&E-stained slides. While it does not replace immunohistochemical or molecular analyses, integrating the KM score into pathological assessment may enhance prognostic accuracy and support identifying patients who might benefit from immunotherapy.