Risk factors for recurrence in each pattern after curative gastrectomy for pStage II/III gastric cancer: An exploratory analysis of a randomized controlled trial (JCOG1001).

4052 Background: Peritoneal, lymph node, and hematogenous recurrence are frequently observed as patterns of recurrence after surgery for gastric cancer. However, the clinicopathological characteristics associated with each recurrence have rarely been comprehensively reported in a multicenter study. Understanding the risk factors for each pattern of recurrence would be helpful for the early detection of recurrence and the initiation of optimal treatment. This study investigated the risk factors for the first recurrence in each pattern after curative gastrectomy, using data from a multicenter randomized controlled trial (JCOG1001) that was designed to investigate the efficacy of bursectomy. Methods: Patients of 20-80 years of age, with cT3(SS)-T4a(SE) gastric carcinoma according to the 14th Japanese Classification of Gastric Carcinoma, with an ECOG PS of 0-1, and a body mass index of < 30 kg/m2, and without bulky lymph nodes, Borrmann type 4 or large type 3 carcinoma were eligible for inclusion in JCOG1001. Of the 1204 patients who were enrolled in JCOG1001, 932 pStage II/III patients with a common histological type were included in this study. Risk factors for hematogenous, lymph node, and peritoneal patterns of recurrence were estimated by a multivariable Fine and Grey model considering death or site of recurrence other than the first site of recurrence as competing risks. Results: The overall rate of recurrence was 27.1%. Hematogenous recurrence was the most frequent pattern (12.3%), followed by peritoneal (11.2%) and lymph node (7.5%) recurrence. Differentiated type (HR, 1.818; 1.237-2.674; p = 0.0024), pT4 (in comparison to pT1-3, HR, 1.511; 95% CI, 1.011-2.257; p = 0.0440), and pN3 (in comparison to pN0-2, HR, 2.431; 95% CI, 1.635-3.616; p < 0.0001) were associated with an increased incidence of hematogenous recurrence. Conversely, more than D2 lymphadenectomy reduced this pattern of recurrence (in comparison to D1+or D2 lymphadenectomy, HR, 0.575; 95% CI, 0.364-0.907; p = 0.0174). Peritoneal recurrence was significantly associated with large (≥5 cm) tumor (HR, 1.649; 95% CI, 1.034-2.629; p = 0.0356), pT4 (in comparison to pT1-3, HR, 3.222; 95% CI, 2.086-4.976; p < 0.0001), pN3 (in comparison to pN0-2, HR, 1.865; 95% CI, 1.275-2.727; p = 0.0013), and undifferentiated type (HR, 2.674; 95% CI, 1.628-4.394; p = 0.0001). Extended lymph node metastasis (pN3) was the only risk factor (in comparison to pN0-2, HR, 8.030; 95% CI, 4.605-14.002; p < 0.0001) for lymph node recurrence. Conclusions: The risk factors for recurrence differed according to the patterns of recurrence. Vigilant follow-up with an understanding of patterns of recurrence is required, especially for high-risk patients.

Site of Recurrence and Survival After Surgery for Colorectal Peritoneal Metastasis

Background Multimodal treatment, including systemic treatment and surgery, improved the prognosis of peritoneal metastasis (PM). Despite all efforts, recurrence rates remain high, and little data are available about clinical behavior or molecular patterns of PM in comparison to hematogenous metastasis. Here, we aimed to analyze recurrence patterns after multimodal treatment for PM from colorectal cancer. Methods Patients with colorectal PM undergoing multimodal treatment including systemic chemotherapy and cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) between 2005 and 2017 at 4 centers were analyzed retrospectively. Results A total of 505 patients undergoing CRS/HIPEC were analyzed. Of the patients, 82.1% received preoperative chemotherapy. Median peritoneal cancer index was 6 (interquartile range = 3-11). Median disease-free and overall survival was 12 (95% confidence interval [CI] = 11 to 14) months and 51 (95% CI = 43 to 62) months, respectively. Disease recurred in 361 (71.5%) patients, presenting as isolated peritoneal recurrence in 24.6%, isolated hematogenous recurrence in 28.3%, and mixed recurrence in 13.9% of patients. Recurrence to the peritoneum was associated with an impaired time from recurrence to death of 21 (95% CI = 18 to 31) months for isolated peritoneal and 22 (95% CI = 16 to 30) months for mixed recurrence, compared with 43 (95% CI = 31 to &gt;121) months for hematogenous recurrence (hazard ratio [HR] = 1.79, 95% CI = 1.27 to 2.53; P = .001; and HR = 2.44, 95% CI = 1.61 to 3.79; P &lt; .001). On multiple logistic regression analysis, RAS mutational status (odds ratio [OR] = 2.42, 95% CI = 1.11 to 5.47; P = .03) and positive nodal stage of the primary (OR = 3.88, 95% CI = 1.40 to 11.86; P = .01) were identified as predictive factors for peritoneal recurrence. Conclusions This study highlights the heterogeneity of peritoneal metastasis in patients with colorectal cancer. Recurrent peritoneal metastasis after radical treatment represents a more aggressive subset of metastatic colorectal cancer.

The clinicopathological significance of SWI/SNF alterations in gastric cancer is associated with the molecular subtypes

The clinicopathological significance of altered SWI/SNF complex has not been well evaluated in gastric cancer (GC). We examined SMARCA2, SMARCA4, SMARCB1 and ARID1A expression by immunohistochemistry in 1224 surgically resected GCs with subtyping into Epstein-Barr virus (EBV), microsatellite instability (MSI) and non-EBV/MSI Lauren histotypes. SWI/SNF mutations were investigated using the GC dataset of the TCGA Pan-Cancer Atlas. Clinicopathological association was assessed by statistical analysis. There were 427 cases (35%) of SWI/SNF-attenuated GC, including 344 SMARCA2 (28%), 28 SMARCA4 (2%), 11 SMARCB1 (1%) and 197 ARID1A (16%) cases. Simultaneous alterations of multiple subunits were observed. Compared to SWI/SNF-retained cases, SWI/SNF-attenuated GC exhibited a significant predilection to older ages, EBV and MSI genotypes, higher lymphatic invasion and less hematogenous recurrence (P < 0.05). SWI/SNF attenuation was an independent risk factor for short overall survival (P = 0.001, hazard ratio 1.360, 95% confidence interval 1.138–1.625). The survival impact stemmed from SMARCA2-attenuated GCs in stage III and non-EBV/MSI diffuse/mixed subtypes (P = 0.019 and < 0.001, respectively). ARID1A-lost/heterogeneous GCs were more aggressive in the EBV genotype (P = 0.016). SMARCB1 or SMARCA4 loss was not restricted to rhabdoid/undifferentiated carcinoma. In the TCGA dataset, 223 of 434 GCs (52%) harbored deleterious SWI/SNF mutations, including ARID1A (27%), SMARCA2 (9%), ARID2 (9%), ARID1B (8%), PBRM1 (7%), and SMARCA4 (7%). SWI/SNF-mutated GCs displayed a favorable outcome owing to the high percentage with the MSI genotype. In conclusion, SWI/SNF-altered GCs are common and the clinicopathological significance is related to the genotype.

Characteristics of long-term survivors in stage III gastric cancer patients.

163 Background: Stage III gastric cancer patients had poor prognosis. This study aims to evaluate prognostic factor of stage III gastric cancer. Methods: We retrospectively studied 126 patients who were treated for stage III gastric cancer from Jan. 2007 to Dec. 2010 at Korea University Hospital and performed complete follow up for five years. Long-term survivor was defined more than five years survivor after gastrectomy. Results: Long-term survivor was 70 patients (55.6%). Tumor size, lymph node involvement, lymphatic invasion, venous invasion and neural invasion had prognostic significance on univariate analysis. But location of tumor, gross type, depth of invasion, TNM stage, combine resection, complication, histologic differentiation, type of operation and adjuvant treatment had no prognostic significance. The most common recurrence pattern was peritoneal recurrence (57.4%) according to analysis of recurrence pattern. The disease free survival according recurrence pattern was peritoneal recurrence (21.3 months), hematogenous recurrence (32.1 months), distant lymph node recurrence (12.0 months) and locoregional (12 months). The disease specific survival according recurrence pattern was peritoneal recurrence (9.2 months), hematogenous recurrence (11.3 months), distant lymph node recurrence (16.2 months) and locoregional (26.9 months). Conclusions: Lymph node involvement were the most significant prognostic factors on stage III gastric cancer after curative resection. Therefore, postoperative surveillance and adjuvant therapy were very carefully selected in stage III gastric cancer patient with extensive lymph node metastasis.