The purpose of this study is to report the treatment effects of Korean medicine for patients with lateral epicondylitis. This study was done on 12 cases of patients with lateral epicondylitis who visited in Korean Medicine Clinic of Ganghwa-gun Public Health Care Center. We used muscle contraction/relaxation strengthen technique, Instrument assisted soft tissue mobilization (IASTM), acupuncture on patients and mesured numerical rating scale (NRS), pain disability index (PDI), and grip strength test to evaluate treatment effects. Among twelve patients, eleven cases showed decreasing in NRS and all cases showed decreasing in PDI. Ten cases showed increasing in grip strength test. Korean medical treatments including muscle contraction/relaxation strengthen technique and IASTM are thought to be one of the effective treatment for patients with lateral epicondylitis.

501 Background: Although colorectal cancer (CRC) with microsatellite instability (MSI) has a more favorable prognosis than microsatellite stable (MSS) CRC, patterns of recurrence has not been precisely investigated. We aim to explore patterns of recurrence and prognosis of CRC with MSI-H (high-frequency MSI) in comparison to MSI-L (low-frequency of MSI)/MSS. Methods: Patients with stage I-III colorectal cancer who received complete surgical resection were included using retrospective cohort of Yonsei Cancer Center. Patients were categorized to MSI status (MSI-H vs. MSS-L/MSS). Patterns of recurrence, disease free survival (DFS) and overall survival (time from diagnosis to death as OS1 and time from recurrence to death as OS2) between two groups were compared. Results: A total of 2944 patients were evaluated. Of all, 263 patients (8.9%) has MSI-H tumor. Patients with MSI-L/MSS tumor experienced more systemic recurrence events than patients with MSI-H tumor (13.1% vs. 4.6%). In patients who experienced recurrence, MSI-H tumor has tendency toward young age, proximal location and poorly differentiated histology. MSI-H tumor is more likely to recur as peritoneal metastasis (33.3% vs. 8.0%, p-value 0.002) and lymph node metastasis (25.0% vs. 7.7%, p-value 0.033). In contrast, MSI-L/MSS tumor is more likely to recur as lung metastasis (37.1% vs. 0.0%, p-value 0,008). There was no difference in DFS [hazard ratio (HR) = 0.753, p-value 0.241] and OS1 [HR = 1.486, p-value 0.203]. However, OS2 was marginally inferior in MSI-H tumor [HR = 1.779, p-value 0.064]. Conclusions: Patterns of recurrence in MSI-H CRC is different from that of MSI-L/MSS and modification of surveillance strategy in MSI-H CRC should be considered. In addition, prognosis of recurred MSI-H CRC is not superior than MSI-L/MSS and prognostic value of MSI in this circumstance should be evaluated using larger sample size.

760 Background: Clinical benefit of adjuvant chemotherapy (AC) is still controversial in locally advanced rectal cancer (LARC) after neoadjuvant chemoradiation therapy (CRT) followed by total mesorectal excision (TME). We aim to explore the role of adjuvant chemotherapy with fluoropyrimidine for ypT0-3N0 patients. Methods: Patients with ypT0-3N0 rectal cancer after neoadjuvant CRT and TME were included using retrospective cohort of Yonsei Cancer Center. Patients were categorized according to receipt of adjuvant chemotherapy (AC vs. no AC). Disease free survival (DFS) and overall survival (OS) between treatment groups were compared using all patients’ cohort (APC) and propensity score-matched patients’ cohort (PSMPC). Results: total of 339 patients were evaluated. Of all, 87 patients (25.7%) did not receive AC. There was no difference in DFS between two groups [hazard ratio (HR) = 1.079, p-value = 0.782 in APC; HR = 1.22, p-value in PSMPC]. Also there was no difference in OS between two groups (HR = 1.140, p-value 0.717 in APC; HR = 1.366, p-value 0.472 in PSMPC). Advanced T stage and positive resection margin were associated with inferior DFS and OS by multivariate analysis. In subgroup analysis by baseline characteristics, we could not find any group with benefit of adjuvant chemotherapy. Conclusions: AC did not improve DFS and OS of patients with ypT0-3N0 rectal cancer after neoadjuvant CRT followed by TME. The role of AC in LARC with ypT0-3N0 after preoperative CRT should be evaluated in prospective randomized trials with larger sample size.

Background: Although early stage colorectal cancer (CRC) with microsatellite instability (MSI) phenotype has a more favorable prognosis, impact on outcome of MSI status in metastatic CRC (mCRC) is rarely known. We aim to explore patterns of metastatic spread and prognosis of CRC with MSI-H (high-level MSI) in comparison to MSI-L (low-level of MSI)/MSS. Methods: Patients with mCRC who underwent testing for MSI were identified using retrospective cohort of Yonsei Cancer Center. Patients were categorized to MSI status (MSI-H vs. MSS-L/MSS). Patterns of metastatic spread, surgical resection after recurrence and outcome between two groups were compared. Results: A total of 944 patients were evaluated. Of all, 34 patients (3.6%) had MSI-H tumors. A distinct pattenrs of metastatic spread was observed in MSI-H tumors, namely higher rates of peritoneal metastasis (41% vs 10%, P < 0.001), intraabdominal lymph node metastasis (14.7% vs 4.8%, P = 0.011), and lower rates of lung metastasis (8.8% vs 24.6%, P = 0.034), liver metastasis (20.6% vs 53.6%, P < 0.001). Patients with MSI-H tumors were less likely to receive metastectomy (24.8% vs 55.9%, P < 0.001). Median overall survival was inferior in MSI-H tumor compared with MSI-L/MSS tumor (16.3 months vs 38.1 months, P = 0.005). Conclusions: Different patterns of metastatic spread and receipt of surgical resection in MSI-H mCRC is demonstrated in this study. In addition, MSI-H phenotype is associated with poorer survival in mCRC on the contrary to early stage disease. Future studies focusing on deeper understanding of tumor biology and therapeutic response in this rare disease entity are warranted. Citation Format: Jee Hung KIM, Chang-gon Kim, Joong Bae Ahn, MinKyu Jung, Seung Hoon Beom, Joo Hoon Kim, Soo Jin Heo, Sang Joon Shin. Microsatellite instability in metastatic colorectal cancer (mCRC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 808.