Clinical characteristics of rectal cancer patients with neoadjuvant chemoradiotherapy: a nationwide population-based cohort study in South Korea

Purpose@#Neoadjuvant chemoradiotherapy has been accepted as a standard treatment for stage II–III rectal cancer. This study aimed to evaluate the clinical characteristics of patients who underwent neoadjuvant chemoradiotherapy for rectal cancer and effects on overall survival (OS) of neoadjuvant chemoradiotherapy in South Korea. @*Methods@#Patients who underwent curative resection for rectal cancer from 2014 to 2016 were retrospectively reviewed from the database of the National Quality Assessment program in South Korea. Patients were categorized into the upfront surgery group and neoadjuvant chemoradiotherapy group. We evaluated factors associated with the administration of neoadjuvant chemoradiotherapy and its effects on OS. Inverse probability of treatment weighting was performed to account for baseline differences between subgroups. @*Results@#A total of 6,141 patients were categorized into the upfront surgery group (n = 4,237) and neoadjuvant chemoradiotherapy group (n = 1,904). The neoadjuvant chemoradiotherapy was more frequently administered to male, midrectal cancer, and younger patients. In the neoadjuvant chemoradiotherapy group, old age, underweight, and pathologic stage were significant risk factors of OS, and male sex, the level of tumor and clinical stages were not associated with OS.After adjustment, the OS of the neoadjuvant chemoradiotherapy group followed the OS of the upfront surgery group of the same pathologic stage. @*Conclusion@#Male sex and the level of tumor were not related to the OS of rectal cancer patients with neoadjuvant chemoradiotherapy. The OS of patients who underwent neoadjuvant chemoradiotherapy was decided by their pathologic stages regardless of clinical stages.

Guidelines for accreditation of endoscopy units: quality measures from the Korean Society of Coloproctology

Purpose@#Colonoscopy is an effective method of screening for colorectal cancer (CRC), and it can prevent CRC by detection and removal of precancerous lesions. The most important considerations when performing colonoscopy screening are the safety and satisfaction of the patient and the diagnostic accuracy. Accordingly, the Korean Society of Coloproctology (KSCP) herein proposes an optimal level of standard performance to be used in endoscopy units and by individual colonoscopists for screening colonoscopy. These guidelines establish specific criteria for assessment of safety and quality in screening colonoscopy. @*Methods@#The Colonoscopy Committee of the KSCP commissioned this Position Statement. Expert gastrointestinal surgeons representing the KSCP reviewed the published evidence to identify acceptable quality indicators and indicators that lacked sufficient evidence. @*Results@#The KSCP recommends an optimal standard list for quality control of screening colonoscopy in the following 6 categories: training and competency of the colonoscopist, procedural quality, facilities and equipment, performance indicators and auditable outcomes, disinfection of equipment, and sedation and recovery of the patient. @*Conclusion@#The KSCP recommends that endoscopy units performing CRC screening evaluate 6 key performance measures during daily practice.

Prognostic implication of systemic inflammatory markers in young patients with resectable colorectal cancer

Purpose@#The prognosis of young colorectal cancer (CRC) patients has not fully been addressed. The prognostic significance of systemic inflammatory markers was examined in those patients. @*Methods@#A total of 965 patients with resectable CRC were divided into young (≤ 50 years, n = 101) and old groups (>51 years, n = 864). Neutrophil-to-lymphocyte ratio (NLR) > 5, derived NLR (dNLR) > 3, lymphocyte-to-monocyte ratio (LMR) 150, and prognostic nutritional index (PNI) 5, LMR 3 and those markers showed significance for PFS. LMR 150 (HR, 1.45; P = 0.036) and PNI < 45 (HR, 1.73; P = 0.002) were significant markers for PFS. @*Conclusion@#Systemic inflammation might be one of biologic factors that influence on prognosis of young CRC.

Clinical characteristics of rectal cancer patients with neoadjuvant chemoradiotherapy: a nationwide population-based cohort study in South Korea

Purpose@#Neoadjuvant chemoradiotherapy has been accepted as a standard treatment for stage II–III rectal cancer. This study aimed to evaluate the clinical characteristics of patients who underwent neoadjuvant chemoradiotherapy for rectal cancer and effects on overall survival (OS) of neoadjuvant chemoradiotherapy in South Korea. @*Methods@#Patients who underwent curative resection for rectal cancer from 2014 to 2016 were retrospectively reviewed from the database of the National Quality Assessment program in South Korea. Patients were categorized into the upfront surgery group and neoadjuvant chemoradiotherapy group. We evaluated factors associated with the administration of neoadjuvant chemoradiotherapy and its effects on OS. Inverse probability of treatment weighting was performed to account for baseline differences between subgroups. @*Results@#A total of 6,141 patients were categorized into the upfront surgery group (n = 4,237) and neoadjuvant chemoradiotherapy group (n = 1,904). The neoadjuvant chemoradiotherapy was more frequently administered to male, midrectal cancer, and younger patients. In the neoadjuvant chemoradiotherapy group, old age, underweight, and pathologic stage were significant risk factors of OS, and male sex, the level of tumor and clinical stages were not associated with OS.After adjustment, the OS of the neoadjuvant chemoradiotherapy group followed the OS of the upfront surgery group of the same pathologic stage. @*Conclusion@#Male sex and the level of tumor were not related to the OS of rectal cancer patients with neoadjuvant chemoradiotherapy. The OS of patients who underwent neoadjuvant chemoradiotherapy was decided by their pathologic stages regardless of clinical stages.

The Effect of Epidermal Growth Factor Receptor Mutation on Intracranial Progression-Free Survival of Non-Small Cell Lung Cancer Patients with Brain Metastasis Underwent Gamma Knife Radiosurgery

Background@#The aim of this study was to survey prognostic factors, particularly those focusing on epidermal growth factor receptor (EGFR) mutations, of patients with non-small cell lung cancer (NSCLC) after Gamma Knife Radiosurgery (GKRS) for metastatic brain tumors. @*Methods@#We retrospectively reviewed the medical records of 98 patients with NSCLC who underwent GKRS for brain metastases from August 2010 to July 2017. The primary endpoint was progression-free survival (PFS) of the intracranial disease. We analyzed variables such as age, sex, Karnofsky Performance Status, recursive partitioning analysis (RPA) class, smoking status, primary cancer pathology, EGFR mutations, and time to brain metastases as prognostic factors. @*Results@#The median overall survival (OS) of the patients was 16 months [95% confidence interval (CI), 13-21 months]. Median systemic PFS and intracranial PFS were 9 months (95% CI, 8-11 months) and 11 months (95% CI, 7-14 months), respectively. Kaplan-Meier survival analysis revealed that the patients with EGFR mutations had longer intracranial PFS than those without EGFR mutation (median intracranial PFS: 19 vs. 10 months with p=0.01) while they had no benefits in OS and systemic PFS. Furthermore, the patients harboring adenocarcinoma had longer OS ( p<0.01) and intracranial PFS ( p<0.01) and the patients with lower RPA class had longer OS ( p=0.02) and intracranial PFS ( p=0.03). @*Conclusion@#EGFR mutations, primary cancer pathology, and RPA class may be proposed as prognostic factors for intracranial PFS in NSCLC patients after GKRS for brain metastasis in this study.

Anatomical distribution and detection rate of colorectal neoplasms according to age in the colonoscopic screening of a Korean population

PURPOSE: Because data as a basis for the determination of proper age and modality for screening of colorectal neoplasms is lacking, we evaluated detection rates and anatomical distribution of colorectal neoplasms according to age in healthy individuals who underwent total colonoscopy for health checkup. METHODS: A total of 16,100 cases that had received the colonoscopic examination from January to December in 2014 were analyzed. The total number of individuals who received total colonoscopy were divided by the number of individuals harboring colorectal adenoma to calculate the detection rate of colorectal adenoma. Individuals ≤50 years old were classified as young-age group and aged >50 were old-age group. Differences in anatomical locations of colorectal neoplasms were analyzed in the 2 age groups by chi-square test. Risk factors for colorectal adenoma in each age group were analyzed using univariate and multivariate logistic regression analyses. RESULTS: Detection rates of colorectal adenoma were 13.7% in all cases and 12.8% for those in their 40′s. The main anatomical location of colorectal adenoma was proximal colon in both age groups (P < 0.001). Hyperplastic polyp was mainly distributed to the distal colon in both age groups (P < 0.001). Distal colon was the major site for colorectal cancer in the old-age group (P = 0.001). Proximal location of neoplasms was a risk factor for colorectal adenoma in both age groups with multivariate analysis. CONCLUSION: These data could be the bases for earlier initiation of screening for colorectal neoplasms with total colonoscopy to detect clinically significant colorectal polyps.

Concurrent Chemoradiotherapy with Temozolomide Followed by Adjuvant Temozolomide for Newly Diagnosed Glioblastoma Patients: A Retrospective Multicenter Observation Study in Korea / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this study was to investigate the feasibility and survival benefits of combined treatment with radiotherapy and adjuvant temozolomide (TMZ) in a Korean sample. MATERIALS AND METHODS: A total of 750 Korean patients with histologically confirmed glioblastoma multiforme, who received concurrent chemoradiotherapy with TMZ (CCRT) and adjuvant TMZ from January 2006 until June 2011, were analyzed retrospectively. RESULTS: After the first operation, a gross total resection (GTR), subtotal resection (STR), partial resection (PR), biopsy alone were achieved in 388 (51.7%), 159 (21.2%), 96 (12.8%), and 107 (14.3%) patients, respectively. The methylation status of O6-methylguanine-DNA methyltransferase (MGMT) was reviewed retrospectively in 217 patients. The median follow-up period was 16.3 months and the median overall survival (OS) was 17.5 months. The actuarial survival rates at the 1-, 3-, and 5-year OS were 72.1%, 21.0%, and 9.0%, respectively. The median progression-free survival (PFS) was 10.1 months, and the actuarial PFS at 1-, 3-, and 5-year PFS were 42.2%, 13.0%, and 7.8%, respectively. The patients who received GTR showed a significantly longer OS and PFS than those who received STR, PR, or biopsy alone, regardless of the methylation status of the MGMT promoter. Patients with a methylated MGMT promoter also showed a significantly longer OS and PFS than those with an unmethylated MGMT promoter. Patients who received more than six cycles of adjuvant TMZ had a longer OS and PFS than those who received six or fewer cycles. Hematologic toxicity of grade 3 or 4 was observed in 8.4% of patients during the CCRT period and in 10.2% during the adjuvant TMZ period. CONCLUSION: Patients treated with CCRT followed by adjuvant TMZ had more favorable survival rates and tolerable toxicity than those who did not undergo this treatment.

Efficacy and safety of a novel partially absorbable mesh in totally extraperitoneal hernia repair

PURPOSE: Partially absorbable mesh has been introduced and used for inguinal hernia repair for the purpose of minimizing pain and improving abdominal wall compliance. In this study, we evaluate the efficacy and safety of ProFlex mesh, a partially absorbed mesh with new structural architecture. METHODS: We retrospectively reviewed 64 cases of totally extraperitoneal herniorrhapy (TEP) from January 2013 to December 2014 for their clinical features, including operation time, pain, postoperative complications, and recurrence. RESULTS: There were no significant differences in operation time, hospital stay, postoperative pain, or complications between the 28 patients who received the ProFlex mesh and the 36 who received nonabsorbable lightweight mesh, although one patient who received the nonabsorbable had a recurrence during follow-up. There were differences in operation time, complications, and hospital stay according to the surgeon's previous operation volume. CONCLUSION: This study showed that there were significant differences in the fixation strength of different polypropylene meshes in combination with various fibrin glues. ProFlex, a partially absorbable mesh with new architecture, was feasible and safe in TEP.

Efficacy and safety of a novel partially absorbable mesh in totally extraperitoneal hernia repair

PURPOSE: Partially absorbable mesh has been introduced and used for inguinal hernia repair for the purpose of minimizing pain and improving abdominal wall compliance. In this study, we evaluate the efficacy and safety of ProFlex mesh, a partially absorbed mesh with new structural architecture. METHODS: We retrospectively reviewed 64 cases of totally extraperitoneal herniorrhapy (TEP) from January 2013 to December 2014 for their clinical features, including operation time, pain, postoperative complications, and recurrence. RESULTS: There were no significant differences in operation time, hospital stay, postoperative pain, or complications between the 28 patients who received the ProFlex mesh and the 36 who received nonabsorbable lightweight mesh, although one patient who received the nonabsorbable had a recurrence during follow-up. There were differences in operation time, complications, and hospital stay according to the surgeon's previous operation volume. CONCLUSION: This study showed that there were significant differences in the fixation strength of different polypropylene meshes in combination with various fibrin glues. ProFlex, a partially absorbable mesh with new architecture, was feasible and safe in TEP.

Transsylvian-Transinsular Approach for Deep-Seated Basal Ganglia Hemorrhage: An Experience at a Single Institution

OBJECTIVE: Treatment of spontaneous intracerebral hemorrhage (ICH) remains controversial. However, an extensive hemorrhage with a poor mental status is suitable for surgical evacuation. Our experience with the transsylvian-transinsular (TS-TI) microsurgical approach for deep-seated basal ganglia (BG) ICH was investigated. MATERIAL AND METHODS: A retrospective review was conducted on 86 patients with BG ICH who underwent an operation at the Department of Neurosurgery of our Hospital from September 2011 to October 2014. Thirteen patients underwent craniotomy and the TS-TI microsurgical approach for hematoma evacuation. Twenty-seven patients underwent conventional craniotomy with the trans-cortical transtemporal (TC-TT) approach, and 46 patients underwent a burrhole operation and hematoma drainage using a frameless stereotaxic device (ST). RESULTS: The average age distribution was similar. The preoperative Glasgow coma scale (GCS) was similar for the TC-TT and TS-TI groups. The pre-operative hematoma levels were higher in the TC-TT (109.4 +/- 48.6 mL) and TS-TI (96.0 +/- 39.0 mL) groups than in the ST group (46.5 +/- 23.5 mL). The hematoma removal rate was 77% in the TC-TT group, 88% in the TS-TI group, and 34% in the ST group. The mean maintenance period of a hematoma catheter was 3.6 days in the ST group. The clinical outcome showed correlation with the preoperative neurological symptoms. CONCLUSION: The TS-TI group was superior to the TC-TT group for evacuation of an intracerebral hematoma.

Reliability of Stereotactic Coordinates of 1.5-Tesla and 3-Tesla MRI in Radiosurgery and Functional Neurosurgery

OBJECTIVE: The aims of this study are to identify interpersonal differences in defining coordinates and to figure out the degree of distortion of the MRI and compare the accuracy between CT, 1.5-tesla (T) and 3.0T MRI. METHODS: We compared coordinates in the CT images defined by 2 neurosurgeons. We also calculated the errors of 1.5T MRI and those of 3.0T. We compared the errors of the 1.5T with those of the 3.0T. In addition, we compared the errors in each sequence and in each axis. RESULTS: The mean difference in the CT images between the two neurosurgeons was 0.48+/-0.22 mm. The mean errors of the 1.5T were 1.55+/-0.48 mm (T1), 0.75+/-0.38 (T2), and 1.07+/-0.57 (FLAIR) and those of the 3.0T were 2.35+/-0.53 (T1), 2.18+/-0.76 (T2), and 2.16+/-0.77 (FLAIR). The smallest mean errors out of all the axes were in the x axis : 0.28-0.34 (1.5T) and 0.31-0.52 (3.0T). The smallest errors out of all the MRI sequences were in the T2 : 0.29-0.58 (1.5T) and 0.31-1.85 (3.0T). CONCLUSION: There was no interpersonal difference in running the Gamma Plan(R) to define coordinates. The errors of the 3.0T were greater than those of the 1.5T, and these errors were not of an acceptable level. The x coordinate error was the smallest and the z coordinate error was the greatest regardless of the MRI sequence. The T2 sequence was the most accurate sequence.

The Pterional Approach and Extradural Anterior Clinoidectomy to Clip Paraclinoid Aneurysms

OBJECTIVE: The surgical clipping of paraclinoid segment internal carotid artery aneurysms is considered difficult because of the complex anatomical location and important neighboring structures. Our experiences of pterional craniotomy and extradural anterior clinoidectomy (EAC) to clip paraclinoid aneurysms are reported herein. METHODS: We present two patients with paraclinoid aneurysms who underwent surgical clipping using pterional craniotomy and EAC. The clinical results and operative techniques were reviewed from the patients' medical records. RESULTS: EAC improves the surgical field in the suprasellar and periclinoid regions. Clinically, a good outcome was obtained in both cases. No surgical complications directly resulting from the EAC were observed. CONCLUSION: Favorable surgical results can be obtained with pterional craniotomy and EAC for the clipping of paraclinoid aneurysms. EAC is advocated for the clipping of paraclinoid aneurysms.

Jailing Technique Using a Catheter-based Open-cell Stent System in Internal Carotid Artery Sidewall Aneurysms Unfeasible to Simple Coiling

OBJECTIVE: An open cell stent system may offer better apposition of cell struts to vessel wall than a closed cell stent system in acute vasculature. The purpose of this study was to evaluate the feasibility of coiling using the jailing technique with the Neuroform EZ stent system. METHODS: The jailing technique using the open-cell stent system of the Neuroform EZ stent was planned in 22 consecutive patients with 22 cerebral aneurysms. We retrospectively evaluated the technical success of the jailing technique and the occurrence of interference between two microcatheters as well as the factors influencing this interference. RESULTS: The jailing technique was successful in 19/22 patients (86.4%), and interference between two microcatheters occurred in 6/21 (28.6%). The jailing technique failed in 3/22 patients, with problems that included failure of the stent delivery system to advance into the positioned microcatheter in one, interference between the microcatheters during the advancement of the stent delivery system in one, and failure of microcatheter insertion into the aneurysm sac in the remaining patient. Interference between the two microcatheters developed during the advance of the stent delivery system into the positioned microcatheter in all cases. One factor that influences interference between two microcatheters more than expected by chance is the carotid siphon angle (p = 0.019). CONCLUSION: The acuteness of the carotid siphon angle influences the interference between two microcatheters. Therefore, the jailing technique using the Neuroform EZ stent should be performed carefully in cerebral aneurysms with an acute carotid siphon angle because the procedure may possibly fail.

Delayed Symptomatic Thromboembolism After Unruptured Middle Cerebral Artery Aneurysm Embolization

Endovascular treatment has been increasingly performed for unruptured intracerebral aneurysms. However, thromboembolic complications, which develop mostly within 48 hours after the procedure, are the most common and major complications of endovascular treatment. We present a rare case of delayed symptomatic thromboembolism in an ischemic stroke patient who had undergone coil embolization for unruptured middle cerebral artery (MCA) aneurysm.

Spontaneous Complete Occlusion of Middle Cerebral Artery Aneurysm: Case Report

There are few observation papers regarding the natural history of an aneurysm. We report on a case of a completely occluded middle cerebral artery (MCA) aneurysm. A 47-year-old female patient presented with a headache and was diagnosed with rupture of a right MCA aneurysm. Due to a high risk of direct neck clipping, she received conservative treatment after craniotomy and wrapping of her aneurysm. The patient's condition showed improvement, with complete occlusion of the aneurysm and considerable reduction of the aneurysm in size after approximately three years. This is a rare case of an aneurysm of MCA that showed spontaneous resolution. Finally, on the angiogram, characteristics of an aneurysm to occlude spontaneously will be presumed based on literature reviews.

Significance of Follow-up in Detection of Pulmonary Metastasis of Colorectal Cancer

PURPOSE: This study was performed to evaluate the effectiveness of conventional chest radiography, carcinoembrionic antigen (CEA) level and abdominal computed tomography (CT) or chest CT for early detection of pulmonary metastasis after a curative resection of colorectal cancer. METHODS: We retrospectively reviewed 84 cases of pulmonary metastasis from a group of colorectal cancer patients who had a curative surgical resection from 2000 to 2006 at the Korea University Medical Center. RESULTS: Stage I tumors were detected in 4 patients, stage II tumors in 18, stage III tumors in 43 and stage IV tumors in 19. The detection rates for pulmonary metastasis were 28.5% by conventional chest radiography, 40.5% by increased CEA level and 28.5% by abdominal CT or chest CT. Among them, fourteen patients underwent a radical pneumonectomy. After detection of pulmonary metastasis, the survival outcome for the patients who underwent a resection of the lung was superior to the survival outcome of the patients who did not undergo a resection of the lung (43.7 months vs. 17.4 months, P = 0.001). For patients who underwent resections of the lung, pulmonary metastasis was detected by conventional chest radiography in 2 (14%) patients, by elevated CEA level in 6 (42%) patients, and by abdominal CT or chest CT in 6 (42%) patients. CONCLUSION: Conventional chest radiography is no more useful in detecting early pulmonary metastasis after a curative colorectal surgery than a routine chest CT. Thus, we propose the use of routine chest CT for screening for lung metastasis.

Laparoscopic Extraperitoneal Resection of Urachal Cyst

Remnant urachal cyst is a rare anomaly with an incidence of 1:5,000 and the majority are benign. The treatment of urachal cyst is complete surgical resection, and the cases of laparoscopic surgery for the resection have been reported since 1993. Most of the reports were about transabdominal laparoscopic approach, and it has been revealed that multiple skin incisions and trocar placements on upper abdomen were ineludible. With this condition, we are able to describe an extraperitoneal approach modified from total extraperitoneal herniorrhaphy, and to report a case of successful management of a urachal cyst by total extraperitoneal laparoscopic excision.

Safety of Early Chemotherapy after a Laparoscopic Colorectal Cancer Resection: A Case-Control Study

PURPOSE: Since micrometastasis is generally inhibited by primary cancer, surgical ablation of the tumor may stimulate the growth of residual cancer cells, if they exist. This supports the importance of early administration of postoperative chemotherapy. METHODS: We reviewed the cases of patients who underwent a laparoscopic resection and then received chemotherapy (5 fluorouracil+leucovorin or FOLFOX4) between September 2006 and May 2008. The chemotherapy was scheduled on the 7th or the 8th postoperative day, but was postponed when a final pathologic report was delayed or patients were discharged early. The safety of chemotherapy was evaluated in two ways. Early safety, such as the presence of surgical complications and medical toxicity, was prospectively assessed just before the beginning of the second cycle of chemotherapy. Late safety, such as medical toxicity, was retrospectively estimated from the 2nd to the last cycle. These safeties were compared between the two groups: the early chemotherapy group (n=50) for which chemotherapy started on the 7th or 8th postoperative day as scheduled and the delayed chemotherapy group (n=31) for which chemotherapy started after the 14th postoperative day. RESULTS: Patient demographics were not different between the two groups. With regards to early safety, no differences in surgical complications existed between the two groups. In medical toxicities, there were no differences, except for a higher rate of nausea in the early chemotherapy group (20 percent vs. 10 percent, P=0.01). With regards to late safety, the two groups were not different in the development of medical toxicities. CONCLUSION: Because nausea is an easily controllable toxicity, we conclude that chemotherapy is safely started on the 7th or the 8th day after a laparoscopic colorectal cancer resection.

Intradural Retroclival Chordoma

A 43-year-old woman presented with dizziness, ataxia and right hearing difficulty. Her magnetic resonance images demonstrated an inhomogeneously contrast-enhanced large tumor growing into right cavernous sinus and Meckel's cave located totally within intradural retroclival region. She underwent retromastoid suboccipital craniotomy to resect the tumor mass and adjuvant gamma knife radiosurgery for remnant tumor at 1 month after operation. Adjuvant radiosurgery after surgical excision seems to be effective for the treatment of intradural extraosseous chordomas.

What Is the Significance of a Large Number of Ruptured Aneurysms Smaller than 7 mm in Diameter?

OBJECTIVE: The International Study of Unruptured Intracranial Aneurysms (ISUIA) reported that the 5-year cumulative rupture rate of small unruptured aneurysms less than 7 mm in diameter is very low depending on the aneurysm's location. However, we have seen a large number of ruptured aneurysms less than 7 mm in clinical practice. The purpose of this study was to review our experience and to measure the size and location at which aneurysms ruptured in our patient population. METHODS: We reviewed the characteristics of aneurysms, such as size and location, from the original angiograms of patients who were admitted to our hospital between January 2004 and December 2007. All aneurysms were treated surgically or through endovascular procedures. RESULTS: Interventional or surgical treatment was given to a total of 889 patients, including 568 females and 321 males. At the time of our study, 627 cases were ruptured aneurysms and 262 cases were unruptured aneurysms. Of the ruptured cases, the mean diameter of the aneurysm was 6.28 mm. We found that 71.8% of ruptured aneurysms were smaller than 7 mm in diameter, and 87.9%, were smaller than 10 mm. Based on location, the data show that anterior communicating artery aneurysms most often presented with rupture sizes less than 7 mm (76.8%) and 10 mm (92.1%) in diameter. Most ruptured aneurysms were less than 7 mm in size, although recent studies have noted that small aneurysms are less likely to rupture. CONCLUSION: Although the natural history of unruptured intracranial aneurysms remains controversial, the aneurysm size and location play a signigicant role in determining the risk of rupture. Larger sample sizes and a long term study are needed to reveal the natural history and the rupture risk of unruptured intracranial aneurysms because the size of most ruptured aneurysms was less than 7 mm in diameter in our series.