Application of Single-cell RNA Sequencing in Research on Tumor Immune Microenvironment / 中国医学科学院学报

Tumors are highly complex systems. Understanding the compositions and functions of the tumor immune microenvironment is a prerequisite for effective tumor immunotherapy. Single-cell RNA sequencing can detect the transcriptome of a cell at the resolution of single-cell level,describe its functional status,and thus deepen the understanding of the composition and function of different cell clusters in tumor immune microenvironment. This article reviews the application of single-cell RNA sequencing in research on tumor immune microenvironment.

Predictive Biomarkers of Immune-related Adverse Events Induced by Checkpoint Inhibitors in Malignancies / 中国医学科学院学报

While immune checkpoint inhibitors(ICIs)are effective and promising treatments for a variety of malignancies,they also have safety concerns,especially the immune-related adverse events(irAEs).Unlike the side effects of traditional chemotherapy and targeted therapy,irAEs are adverse events caused by immune activation after ICIs treatment and thus may involve almost every system of the body.Therefore,biomarkers for predicting irAEs after ICIs treatment are urgently needed.Here we review the currently available predictive biomarkers of irAEs.

Expression of α-smooth Muscle Actin in Advanced Colorectal Cancer Tissue and Its Significance in Chemotherapy Response Prediction and Prognosis / 中国医学科学院学报

Objective To investigate the expression of α-smooth muscle actin(α-SMA)in advanced colorectal cancer tissue and its association with chemotherapy response and prognosis.Methods The expression of α-SMA was detected by immunohistochemistry in tissues from 52 advanced colorectal cancer patients who received oxaliplatin plus 5-fluorouracil regimen as first-line chemotherapy. Its relationship with clinical characteristics,chemotherapy response,and survival were analyzed.Results Of these 52 patients,29(55.8%)were α-SMA overexpression,and the expression of α-SMA protein was not significantly associated with the age(χ =0.113,P=0.730),gender(χ =0.515,P=0.332),tumor location(χ =3.675,P=0.159),and tissue differentiation(χ =1.852,P=0.604). The chemotherapy resistance rate was 65.5%(19/29)in patients with high α-SMA expression,which was significantly higher than that (13.0%,3/23)in patients with low α-SMA expression(χ =14.470,P=0.000). Patients with high α-SMA expression exhibited a significantly shorter progression-free survival(PFS)compared with those with low α-SMA expression [(6.4±1.0)months vs.(16.0±3.5)months; χ=5.985,P=0.018]. Conclusion High α-SMA expression is associated with resistance to first-line chemotherapy and poor prognosis in advanced colorectal cancer patients.

Gut Microbiome Differences between Gastrointestinal Cancer Patients and Healthy People / 中国医学科学院学报

Objective To compare the differences in fecal flora among patients with esophageal cancer,gastric cancer,or colorectal cancer and between patients with gastrointestinal tumors and healthy people.Methods The 16S rRNA method was used to analyze the differences in fecal flora among 13 patients with esophageal squamous cell carcinoma,23 patients with gastric cancer,6 patients with colorectal cancer,and 49 healthy persons.Results Bifidobacterium,,and were less abundant in the fecal flora of cancer patients than in those of healthy controls(all <0.05).Some species of and were significantly reduced in the feces of patients with esophageal cancer or gastric cancer than in healthy people(<0.05),whereas others showed consistency with the intestinal cancer group.Anti-tumor treatment,antibiotics,and lactic acid could affect the fecal flora of cancer patients.Conclusion The gut microbiota compositions(mainly and )and some specific bacteria species in the feces of patients with esophageal cancer and gastric cancer are similar to those in the feces of patients with intestinal cancer,suggesting these bacteria may be involved in the development of upper gastrointestinal tumors.

Clinical Analysis of 25 Cases of Malignant Peritoneal Mesothelioma / 中国医学科学院学报

Objective To investigate the clinicopathological features,treatment,and prognosis of patients with malignant peritoneal mesothelioma(MPM). Methods Clinical data of 25 MPM patients admitted to Peking Union Medical College Hospital from 1993 to 2017 were retrospectively analyzed.Results The mean age of these 25 patients with pathologically confirmed MPM(epithelioid subtype) was 50 years.The tumors were diffuse in 24 patients(96%) and localized in 1 patient(4%).Cytoreductive surgery was performed in 6 patients(24%),intraperitoneal chemotherapy in 12 patients(48%),and systemic chemotherapy in 24 patients(96%).The median overall survival was 26 months,with 1-year survival rate of 74.2% and 5-year survival rate of 16.7%.Cytoreductive surgery or intraperitoneal chemotherapy combined with systemic chemotherapy showed a significant survival advantage over intraperitoneal or intravenous chemotherapy alone(P=0.046,P=0.005).Cytoreductive surgery(P=0.018) showed statistical significance by multivariate analysis as a predictive factor in survival(hazard rate=6.889;95%CI=1.386-34.247).Conclusions MPM has its diverse clinical manifestations.Patients after cytoreductive surgery have longer survival time.Chemotherapy drugs(except for pemetrexed) and targeted therapy may be promising treatments.Cytoreductive surgery is an independent prognostic factor.

Efficacy and Prognostic Factors of Cetuximab Therapy in Treating KRAS or All RAS Wild-type Metastatic Colorectal Cancer / 中国医学科学院学报

Objective To explore the efficacy and prognostic factors of cetuximab therapy for KRAS or all RAS wild-type(WT)metastatic colorectal cancer(mCRC).Methods We screened mCRC patients receiving at least two cycles of cetuximb and chemotherapy from those with KRAS WT(before November 2013)or all-RAS-WT(after November 2013)in the Department of Medical Oncology,Peking Union Medical College Hospital from November 2007 to December 2016. The relationship between the clinicopathological characteristics and the efficacy was retrospectively analyzed.Results A total of 60 patients were included. For the 34 patients receiving cetuximab as first-line treatment,the objective response rate(ORR)was 55.9%,and the progression-free survival and overall survival(OS)was 10 and 24 months,respectively. All-RAS-WT mCRC had significantly lower risk of progression than those with KRAS-only-WT(P=0.012),and left-sided colorectal cancer had higher ORR than right-sided colon cancer(62.1% vs. 0,P=0.033)during the first-line treatment. The median OS of the eight patients continuing cetuximab beyond first-line progression was 35.0(95%CI:23.6-46.4)months.Conclusions The efficacy of cetuximab for left-sided colorectal cancer was better than for right-sided colon cancer,and patients with all-RAS-WT have lower risk of progression than those with KRAS-only-WT. Patients benefiting from first-line cetuximab and continuing cetuximab beyond progression survive longer.

Efficacy of Gemcitabine and S-1 for Patients with Advanced Pancreatic Cancer / 中国医学科学院学报

Objective To explore the efficacy and toxicities of gemcitabine combined with S-1 in treating locally advanced and metastatic pancreatic ductal adenocarcinoma and prognostic factors. Methods We retrospectively analyzed the clinical data of patients with locally advanced and metastatic pancreatic cancer receiving gemcitabine and S-1 as first-line therapy in the Department of Medical Oncology,Peking Union Medical College Hospital from January 2014 to January 2017.Gemcitabine was administered at a dose of 1000 mg/mover 30 min-utes on days 1 and 8,and oral S-1 at a dose of 40-60 mg twice daily from days 1 to 14,repeated every 3 weeks.All patients received at least two cycles of chemotherapy. Results A total of 60 patients were included,13(22%) achieved partial remission,37(61%) had stable disease,and 10(17%) experienced progressive disease.The median progression-free survival was 7 months(95% CI=6-10 months) and the median overall survival was 12 months(95% CI=9-20 months).Both univariate and multivariate analyses of prognostic factors showed primary resection was significant in predicting shorter progression-free survival and lung metastasis was significant for shorter overall survival.The most common grade 3-4 toxicities were neutropenia(27%) and leukopenia(18%). Conclusion Gemcitabine combined with S-1 is an effective regimen with manageable toxicities in the treatment of advanced pancreatic cancer and can be used as first-line therapy.

Single Nucleotide Polymorphisms of Paclitaxel-induced Peripheral Sensory Neuropathy in Chinese Han Population / 中国医学科学院学报

Objective To study the single nucleotide polymorphisms (SNPs)that predict a patient's risk of grade 2-3 paclitaxel-induced peripheral sensory neuropathy (PSN) in Chinese Han populations.Methods Totally 216 patients received paclitaxel in Peking Union Medical College Hospital from May 2014 to December 2016 were enrolled.DNA was isolated from peripheral blood.Genotyping for eight candidate SNPs was performed on Sequenom-MassARRARYiPLEX platform.Patients were followed up and PSN was assessed by trained physicians according to National Cancer Institute-Common Terminology Criteria for Adverse Events v4.03.Results A total of 209 patients entered the final analysis.Among the candidate SNPs,only rs4141404:A>C(LIMK2) was significantly associated with grade 2/3 PSN (OR:4.32,95%CI:2.37-7.89,P<0.0001).In multivariate logistic regression analysis,both rs4141404:A>C(LIMK2) and history of receiving platinum compound (OR:2.70,95%CI:1.32-5.51,P=0.007) were associated with grade 2/3 PSN.Conclusion rs4141404:A>C(LIMK2) may be the markers of risk of grade 2/3 PSN.

KLF17 Expression in Colorectal Carcinoma and Its Clinical Significance / 中国医学科学院学报

<p><b>OBJECTIVE</b>To detect KLF17 expression in colorectal carcinoma (CRC) and to evaluate its effect on the prognosis of colorectal carcinoma.</p><p><b>METHODS</b>Immunohistochemistry was performed to detect the expression of KLF17 in CRC and matched pericarcinous tissue,and the relationship between KLF17 expression and disease-free survival (DFS) was analyzed.</p><p><b>RESULTS</b>Of 73 CRC patients, KLF17 expression was positive in 32 patients and negative in 41 patients. KLF17 expression rate was significantly lower in CRC tissue than in pericarcinous tissue (χ(2)=12.418, P=0.001). The DFS of KLF17-positive stage III colon cancer patients was (56.3±7.2) months (95% CI: 42-70 months), which was significantly longer than that [(32.3±5.5) months (95% CI: 22-43 months)] of KLF17-negative patients (P=0.039).</p><p><b>CONCLUSION</b>KLF17 expression decreases in CRC tissue, and a positivie KLF17 expression predicts a better prognosis in stage III CRC patients.</p>

Efficiency of Sunitinib in Chinese Patients with Advanced Progressive Pancreatic Neuroendocrine Tumor / 中国医学科学院学报

Objective To explore the efficiency of sunitinib in Chinese pancreatic neuroendocrine tumors (pNET) patients. Methods Advanced pNET patients who had accepted sunitinib treatment in the oncology department of PUMC Hospital from January 2009 to June 2015 after disease progression were enrolled in this study. Data collection included clinicopathological characteristics,medical therapies and outcomes. Results Eighteen pNET patients were collected. The overall response rate (ORR) was 27.7% and the disease control rate (DCR) was 83.3%. Nine patients received sunitinib as the first-line therapy and 9 as the second/post-second line. The median progression-free survival (mPFs)(12 month vs. 12 month;HR:0.92,95%CI:0.31-2.75,P=0.88),ORR (22.2% vs.33.3%;Χ(2)=0.055,P=0.98),and DCR (88.9% vs.77.8%;Χ(2)=0.4,P=0.98)showed no significant difference between first-line therapy and post-second line therapy. The mPFS of Ki-67≥10% and Ki-67<10% group patients was not significantly different (8 months vs. 13 months;HR:1.13,95% CI:0.34-3.77,P=0.845). The commonly reported adverse events included bone marrow suppression,diarrhea,roteinuria,hypertension,and rash. Conclusions First-line or second/post-second line sunitinib treatment has certain antitumor activity in Chinese patients with advanced pNET. The efficiency and commonly reported adverse events of Sunitinib are consistent with the known Western data.

Three-dimensional Pseudo-continuous Arterial Spin Label Non-contrast Enhanced Perfusion Imaging of Head and Neck Tumors with High-field MR System / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the feasibility of three-dimensional pseudo-continuous arterial spin label (3D pCASL) non-contrast enhanced perfusion imaging applied to head and neck tumors in high-field MR and detect the effects of different postlabeling delay (PLD) time on image quality and the reliability of repeated measurements of tumor blood flow (BF) in different 3D pCASL groups.</p><p><b>METHODS</b>In this prospective study,all the 25 patients received neck 3D pCASL non-contrast enhanced perfusion examinations in a 3.0 T MR system by using an 8-channel head and neck joint coil. Conventional T1-weighted (TIWI) and T2-weighted imaging (T2WI) were performed firstly. Finally,three 3D pCASL with different PLD time [ASL1(PLD1=1525 ms),ASL2 (PLD2=2025 ms), ASL3(PLD3=2525 ms)] were acquired. Patients' perfusion-weighted images acquired from different 3D pCASL sequences underwent the analysis of signal to noise ratio (SNR) and contrast noise ratio (CNR) for tumors. Two observers performed the qualitative assessments on spiral artifacts and vascular artifacts of perfusion-weighted images from different 3D pCASL sequences. Blood flow (BF) of tumors from different 3D pCASL sequences were measured by the two observers respectively for the first time and by observer 2 for the second time.</p><p><b>RESULTS</b>Seventeen enrolled patients (age:50.1 ± 12.7 years,M/F=10:7) with histopathologic.</p><p><b>RESULTS</b>underwent the evaluation of image quality and measurements of BF values. The SNRs and CNRs of ASL1,ASL2, and ASL3 showed a descending trendency. SNRs (P=0.011) and CNRs (P=0.009) of ASL1 were significant higher than those of ASL3. There was no significant difference of scores of spiral artifacts among the three ASL groups (P=0.932). The scores of vascular artifacts of ASL1,ASL2,and ASL3 showed a descending trendency,also. And scores of ASL1 was significant higher than that of ASL3(P=0.000). The intraclass correlation coefficient (ICC) of intre-and intraobserver were high (ICC>0.9). Although the BF values of ASL1,ASL2, and ASL3 showed an ascending trendency,there was no significant difference among the three groups (P=0.977).</p><p><b>CONCLUSIONS</b>The 3D pCASL no-contrast enhanced perfusion MR imaging can be used for head and neck tumor. The image quality of perfusion weighted images and reliability of BF measurements were satisfied. The 3D pCASL series with PLD of 1525 ms and 2025 ms have better image quality than PLD of 2525 ms. And BF values do not show significant statistic difference among the three groups. Therefore, 3D pCASL series with PLD of 1525 ms and 2025 ms are more suitable for the perfusion imaging of head and neck tumors</p>

Cancer biomarkers and personalized cancer medicine / 中国医学科学院学报

The development of cancer biomarkers has brought the treatment of cancer from the tumor type-based to molecular target-based,and the latter marks the introduction of personalized cancer medicine (PCM). However,each individual tumor has unique molecular information,and the real PCM should be focused on single individuals and their specific molecular identities.

Chemotherapy risk assessment for elderly patients / 中国医学科学院学报

The incidence of cancer increases with age and most elderly patients will choose chemotherapy, and the complications of cytotoxic chemotherapy will be more common in these patients. Therefore, it is particularly important to predict the chemotherapy toxicity for the elderly patients. This review article summarizes the recent chemotherapy risk assessment tools for the elderly patients.

Folfox4 regimen administered through combined hepatic arterial and systemic infusion for treatment of colorectal cancer with unresectable liver metastases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Hepatic arterial infusion chemotherapy for liver metastases is under evaluation because of the high target dose and low general toxicity. To investigate the efficacy and safety of a Folfox4 regimen administered through a combined hepatic arterial and systemic infusion for the first-line treatment of colorectal cancer (CRC) with unresectable liver metastases.</p><p><b>METHODS</b>Twenty-seven CRC patients with unresectable hepatic metastases and no prior chemotherapy were enrolled into the study. They received a Folfox4 regimen; 1st day: HAI of oxaliplatin 85 mg/m(2) and L-folinic acid 200 mg/m(2), followed by a bolus hepatic arterial injection of 5-fluorouracil 400 mg/m(2), then continuous HAI of 5-FU 600 mg/m(2); 2nd day: infusion of L-folinic acid 200 mg/m(2) i.v. followed by an intravenous bolus injection of 5-Fluorouracil 400 mg/m(2), then continuous infusion of 5-fluorouracil 600 mg/m(2) i.v. The patients received HAI during the odd cycles, and the intravenous administration of the same Folfox4 regimen during the even cycles.</p><p><b>RESULTS</b>A total of 236 treatment cycles were given with a median of 10 cycles. The therapy generated the following results after six treatment cycles: complete response (CR) 1/27 (3.7%), partial response (PR) 17/27 (63.0%), stable disease (SD) 6/27 (22.2%), and progress disease (PD) 3/27 (11.1%). Five patients had hepatectomy. The serum levels of both carcinoembryonic antigen (CEA) and CA19-9 were significantly reduced (P < 0.05). A median time to progression of 11 months and a median overall survival of 24 months were documented. The major adverse events included grade 1/2 nausea/vomiting, upper abdominal pain, peripheral neuropathy, and neutropenia/thrombocytopenia.</p><p><b>CONCLUSIONS</b>The Folfox4 regimen administered through combined hepatic arterial and systemic infusions is efficacious and safe for the treatment of CRC with unresectable liver metastases, and it facilitates the control of local lesions.</p>

Endostar combined with chemotherapy for treatment of metastatic colorectal and gastric cancer: a pilot study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Antiangiogenesis is a promising field of cancer therapy. Endostar, a novel recombinant human endostatin, is one of the few approved drugs acting as angiogenesis inhibitors of cancer in China. However, there are few clinical studies about Endostar in gastrointestinal cancer. This pilot study aimed to evaluate the efficacy and safety of the combination of Endostar and chemotherapy in patients with metastatic colorectal and gastric cancers.</p><p><b>METHODS</b>From March 2007 to October 2009, 23 patients were enrolled. Patients received Endostar intravenously at a dose of 15 mg daily from day 1 to 14 and day 1 to 7 when combined with 3- and 2-week chemotherapy regimens, respectively, which were determined according to patients' previous chemotherapy history. Treatment was repeated until disease progression, unacceptable toxicity or patients' refusal.</p><p><b>RESULTS</b>Seven, six and ten patients received Endostar as first-, second- and third-line therapy, respectively. A total of 75 cycles were administered. Twenty-one patients were assessable for responses. The overall response rate and disease control rate were 19.0% and 47.6%, respectively. All the four partial responses were among patients receiving Endostar as first-line therapy, whose response rate was 57.1%. The median time to progression and overall survival were 2.6 months (95%CI, 2.0 - 3.2 months) and 10.3 months (95%CI, 3.9 - 16.7 months), respectively. Toxicity was tolerable, with grade 3-4 toxicities observed for leucopenia (30.4%), neutropenia (34.8%), thrombocytopenia (17.4%) and anemia (13.0%). Three patients (13.0%) encountered transient sinus bradycardia with spontaneous remission.</p><p><b>CONCLUSION</b>Endostar combined with chemotherapy is well-tolerated in patients with metastatic colorectal and gastric cancers, and it is relatively effective as a first-line therapy.</p>

Biomarkers of antiangiogenic therapy / 中国医学科学院学报

Antiangiogenic therapy has entered clinical practice and shown good clinical benefits. However, no validated biomarker has been confirmed to be useful for screening patients who will respond to antiangiogenic therapy. Many systemic, circulating, tissue and imaging biomarkers are emerging and need to be prospectively validated.

Clinical significance of insulin-like growth factor-1 receptor in platinum-based chemotherapy for non-small cell lung cancer / 中国医学科学院学报

<p><b>UNLABELLED</b>OBJECTIVE; To explore the influence of the expression of insulin-like growth factor-1 receptor(IGF-1R)in end-stage non-small cell lung cancer.</p><p><b>METHOD</b>The expression of IGF-1R was detected in 39 paraffin-embedded chemotherapy-naive non-small cell lung cancer tumor samples with immunohistochemical method,and the relationship between the outcomes of platinum-based chemotherapy and IGF-1R expression was analyzed.</p><p><b>RESULTS</b>IGF-1R expression was detected in 21 cases (53.8%). The IGF-1R expression status shown no correlation with tumor pathological status,tumor differentiation status,history of smoking,as well as smoking index. Better outcomes of platinum-based chemotherapy were observed in patients with negative IGF-1R expression.</p><p><b>CONCLUSION</b>IGF-1R expression may be used to predict the effectiveness of the first-line platinum-based chemotherapy for end-stage non-small cell lung cancer.</p>

Clinical pathological characteristics and treatment patterns of breast cancer in elderly women / 中国医学科学院学报

<p><b>OBJECTIVE</b>To summarize the clinical pathological characteristics and treatment patterns of breast cancer in elderly women.</p><p><b>METHODS</b>A total of 87 patients (≥ 60 years) admitted to our hospital between January and December 2007 were included in this retrospective study. The patients were divided into 60-69-year group and ≥ 70-year group, and their clinical pathological data and treatment modes were summarized and compared.</p><p><b>RESULTS</b>The tumor size (T2-T3), number of involved axillary lymph nodes,and positive rates of estrogen/progesterone receptors,over-expression of epidermal growth factor receptor 2, and ≥ 2 complication were not significantly different between two groups (P > 0.05). The ≥ 70-year group tended to have similar p53 gene mutation and Ki-67 labeling index with the 60-69-year group, although the P values were close to 0.05 (P = 0.09, P = 0.08,respectively). In the ≥ 70-year group, 33.3% of patients underwent extended resection,while in the 60-69-year group, all patients received modified radical treatment (P < 0.005). The percentages of adjuvant chemotherapy were 25% and 56.9% in the ≥ 70-year group and the 60-69-year group (0.005). The percentages of adjuvant endocrine therapy applied after surgery were similar in 2 groups (77.8% and 68.6% separately, P=0.347). Binary logistic regression showed that age,number of involved axillary lymph nodes,and estrogen receptor-positive rate were independently associated with adjuvant chemotherapy,while the pathological tumor size and complication were irrelevant. The 2-year disease-free survival rates of 2 groups were not significantly different.</p><p><b>CONCLUSIONS</b>The clinical pathological characteristics of breast cancer were similar in elderly patients who are 60-69 years old or ≥ 70 years. In the treatment pattern,patients who are ≥ 70 years tend to receive endocrine therapy rather than adjuvant chemotherapy.</p>

Oxaliplatin plus capecitabine for advanced gastric cancer: report of 38 cases / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the efficacy and toxicity of the combination chemotherapy of oxaliplatin with capecitabine(XELOX)in patients with advanced gastric cancer.</p><p><b>METHODS</b>Thirty-eight advanced gastric cancer patients who received XELOX regimen during 2004-2009 were analyzed retrospectively. The combination chemotherapy included oxaliplatin as 2-hour infusion on day 1 and capecitabine po bid on days 1 to 14. Treatment was repeated every 3 weeks.</p><p><b>RESULTS</b>XELOX regime was applied as first-line therapy in 34 patients and as second-line therapy in 4 patients. After three cycles of chemotherapy, the outcomes in 32 patients who received XELOX as the first-line therapy included partial response (n = 8,25.0%), stable disease (n=14,43.8%), and progressive disease (n=10, 31.2%); no patient achieved complete response. The median time to progression and overall survival time were 7.0 months (95% CI: 4.5-9.5 months) and 12 months (95% CI: 9.8-14.2 months), respectively. One-year and two-year survival rates were 40.6% and 23.7%, respectively. Grade 3-4 toxicities including neutropenia (10.5%), thrombocytopenia (2.6%), nausea (7.9%), and vomiting (5.3%)were noted in a few patients.</p><p><b>CONCLUSION</b>XELOX regimen can be effectively and safely applied as first-line treatment for advanced gastric cancer patients.</p>

Clinical characteristics of gastric cancer in the elderly patients / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the clinical manifestations,treatment,and prognosis of gastric cancer in the elderly patients.</p><p><b>METHOD</b>A total of 252 patients with gastric cancer who admitted to the Oncology Department of Peking Union Medical College Hospital were divided into elderly group (≥ 65 years) and non-elderly group (< 65 years) and the clinical characteristics of these two groups were analyzed and compared.</p><p><b>RESULTS</b>The elderly accounted for 36.0% of all gastric cancer patients in our department. The proportion of male was significantly higher in elderly group than non-elderly group (male:female = 3.74:1, P=0.020). Abdominal satiety and pain were the most common symptoms,which were significantly lower in elderly group (43.3% vs. 61.7%, P=0.005). However,the frequency of weight loss was significantly higher in the elderly group (15.6% vs. 6.2%, P = 0.015). Significantly more elderly patients with gastric cancer were found the second tumors (12.2% vs. 2.5%, P=0.002). The most common tumor location was cardia (36.7%) in elderly group and antrum (34.6%) in non-elderly group. A small proportion (2.2%) of elderly patients had multi-original lesions, which was not found in non-elderly group. The overall rate of surgery and R0 resection rate were 77.8% and 70.9% respectively, which were similar in both groups. The overall rate of chemotherapy was 98%. The ratio was one third compared with younger patients who received three and more than three lines chemotherapy (3.3% vs. 9.3%), but did not reach statistical difference. More elderly patients chose FOLFOX / XELOX regimen (73.3%) compared with younger arm. The median survival time was 26.5 months in elderly group and 28.0 months in non-elderly group (P=0.835). Subgroup analysis showed that the median survival time of stage 4 gastric cancer was longer in elderly group than in non-elderly group (22.7 months and 16.1 months, respectively; P=0.057), which was marginally statistically significant.</p><p><b>CONCLUSIONS</b>More old men may get gastric cancer. More elderly patients may present with weight loss. Cardia is the most common tumor location. The ratio of multi-original lesions and secondary tumors is higher for elderly patients. Elderly patients with good performance status can receive surgery and chemotherapy safely. The resection rate is similar between elderly and non-elderly patients. Elderly patients receive more two-drug combination regimens. The overall prognoses are similar between elderly patients and non-elderly patients.</p>