Comparison of migraine with left- versus right-sided headache: A cross-sectional study

OBJECTIVE

The goal of this study was to clarify whether clinical differences exist between patients with migraine who experience headache that is typically left-sided ("left-migraine") versus right-sided ("right-migraine") during attacks.

BACKGROUND

Migraine has been associated with unilateral headache for millennia and remains a supportive trait for the clinical diagnosis of migraine of the International Classification of Headache Disorders. It is currently unknown why headache in migraine is commonly unilateral, and whether headache-sidedness is associated with other clinical features.

METHODS

This is a cross-sectional study comparing left- versus right-migraine using all available intake questionnaires of new patients evaluated at an academic tertiary headache center over a 20-year period. Eligibility was based on patient written responses indicating the typical location of headache during attacks. In our analyses, the side of headache (left or right) was the predictor variable. The outcomes included various migraine characteristics and psychiatric comorbidities.

RESULTS

We identified 6527 patients with migraine, of which 340 met study eligibility criteria. Of these, 48.8% (166/340) had left migraine, and 51.2% (174/340) had right migraine. When comparing patients with left- versus right-migraine, patients with left migraine experienced 3.6 fewer headache-free days (95% confidence interval [CI] 1.3-5.9; p = 0.002) and 2.4 more severe headache days (95% CI 0.8-4.1; p = 0.004) in the previous 4 weeks. No significant differences in age, sex, handedness, migraine characteristics, or psychiatric comorbidities were identified between the two groups.

CONCLUSIONS

Patients with migraine with typically left-sided headache during attacks reported a higher burden of headache frequency and severity than those with typically right-sided headache during attacks. These findings may have implications for our understanding of migraine pathophysiology, treatment, and clinical trial design.

Electrophysiological characteristics of right- and left-sided Mahaim accessory pathways: A single-center experience in China

Background

Mahaim-type accessory pathways (MAPs) are rare accessory pathways (APs) with specific properties. They are mostly located in the right side of the heart but rarely exist on the left side.

Objectives

This study aims to analyze the clinical and electrophysiological (EP) characteristics of both-sided MAPs.

Methods

A total of 2,249 patients with AP from our center were enrolled between 1 January 2011 and 27 March 2022. During the EP study (EPS) 17 patients were diagnosed with MAPs (right-sided: n = 13, left-sided: n = 4) according to the properties of Mahaim fibers.

Results

MAPs constitute 0.75% of all APs. Out of 1,553 patients with left-sided APs, four patients (0.26%) were diagnosed with Mahaim fiber-mediated tachycardia. Out of 696 patients with right-sided APs, 13 patients (1.9%) were diagnosed with Mahaim fiber. Most Mahaim fibers were located at the free wall of the tricuspid and mitral annuli. Seven patients of right-sided MAPs were of atriofasicular type, six patients had right-sided MAPs, and all of the patients with left-sided MAPs were of atrioventricular (AV) type. The M potential only was detected in long-length MAPs. Coexistence with other supraventricular tachycardias (SVTs) was also observed both in patients with right-sided and left-sided MAPs. All the patients underwent radiofrequency ablation successfully. Only one patient had tachycardia recurrence during a follow-up.

Conclusion

Although MAPs are commonly located at right sides, left sites are not impossible. The M potential contributes to the improvement of the successful ablation.

Comparison of Short-term Outcomes of a Self-expandable Metallic Stent as a Bridge to Laparoscopic Surgery between Right- and Left-sided Obstructive Colorectal Cancers: A Retrospective Observational Study

OBJECTIVES

Few studies have compared the tumor-site-based postoperative short-term outcomes of a bridge to surgery using self-expandable metallic stents. This study compared the perioperative outcomes following stent placement between right- and left-sided obstructive colorectal cancers, focusing on patients undergoing laparoscopic surgery.

METHODS

This study included 127 patients with stage I-IV obstructive colorectal cancer (right-sided, n = 25 [19.7%]; left-sided, n = 102 [80.3%]) who underwent laparoscopic-assisted surgery following stent placement between May 2012 and September 2021. We compared the postoperative complication rates and the success rates of stent placement.

RESULTS

The clinical success rate was not significantly different (92% vs. 97.1%, P = 0.254). The rates of all-grade complications (36% vs. 16.7%, P = 0.05) and postoperative ileus or small-bowel obstruction (20% vs. 2%, P = 0.003) were significantly higher in the right-sided group. The rates of the Clavien-Dindo classification ≥ III complications (8% vs. 6.9%, P = 1) and the median durations of postoperative hospital stay (8 days vs. 8 days, P = 1) were not significantly different. On multivariate analysis, right-sided colon cancer was an independent risk factor for postoperative ileus or small-bowel obstruction (odds ratio [OR]: 16.5, 95% confidence interval [CI]: 2.42-112, P = 0.004) but not for all grades of complications (OR: 2.63, 95% CI: 0.976-7.09, P = 0.056).

CONCLUSIONS

Although the rates of clinical success, postoperative Clavien-Dindo classification ≥ III severe complications, and postoperative hospital stay were comparable, the bridge to surgery following stent placement for right-sided obstructive colon cancer raises concerns about ileus or small-bowel obstruction.

Right-sided Mahaim-mediated tachycardia combined with atypical atrioventricular nodal reentrant tachycardia and left free wall accessory pathway: A case report

A 37-year-old man was admitted to our hospital with paroxysmal palpitation for half year. A previous electrogram showed a narrow complex tachycardia. Electrophysiologic study (EPS) found a concealed left-sided free wall pathway accessory. In addition, a transseptal approach was used for radiofrequency ablation. After successful ablation, EPS induced a wide complex tachycardia and a narrow complex tachycardia. The wide complex tachycardia was diagnosed as a right-sided Mahaim fiber atriofascicular accessory pathway, and the narrow complex tachycardia was diagnosed as atypical atrioventricular nodal reentrant tachycardia (AVNRT). Then, the right-sided Mahaim fiber atriofascicular accessory pathway and atypical AVNRT were successfully ablated. Herein, we report a rare case of a concealed left-sided accessory pathway combined with a right atriofascicular Mahaim fiber and atypical AVNRT.

Identification and Validation in a Novel Quantification System of Ferroptosis Patterns for the Prediction of Prognosis and Immunotherapy Response in Left- and Right-Sided Colon Cancer

Background

This study aimed to establish a novel quantification system of ferroptosis patterns and comprehensively analyze the relationship between ferroptosis score (FS) and the immune cell infiltration (ICI) characterization, tumor mutation burden (TMB), prognosis, and therapeutic sensitivity in left-sided and right-sided colon cancers (LCCs and RCCs, respectively).

Methods

We comprehensively evaluated the ferroptosis patterns in 444 LCCs and RCCs based on 59 ferroptosis-related genes (FRGs). The FS was constructed to quantify ferroptosis patterns by using principal component analysis algorithms. Next, the prognostic value and therapeutic sensitivities were evaluated using multiple methods. Finally, we performed weighted gene co-expression network analysis (WGCNA) to identify the key FRGs. The IMvigor210 cohort, TCGA-COAD proteomics cohort, and Immunophenoscores were used to verify the predictive abilities of FS and the key FRGs.

Results

Two ferroptosis clusters were determined. Ferroptosis cluster B demonstrated a high degree of congenital ICI and stromal-related signal enrichment with a poor prognosis. The prognosis, response of targeted inhibitors, and immunotherapy were significantly different between high and low FS groups (HSG and LSG, respectively). HSG was characterized by high TMB and microsatellite instability-high subtype with poor prognosis. Meanwhile, LSG was more likely to benefit from immunotherapy. ALOX5 was identified as a key FRG based on FS. Patients with high protein levels of ALOX5 had poorer prognoses.

Conclusion

This work revealed that the evaluation of ferroptosis subtypes will contribute to gaining insight into the heterogeneity in LCCs and RCCs. The quantification for ferroptosis patterns played a non-negligible role in predicting ICI characterization, prognosis, and individualized immunotherapy strategies.

Prognostic Immunity and Therapeutic Sensitivity Analyses Based on Differential Genomic Instability-Associated LncRNAs in Left- and Right-Sided Colon Adenocarcinoma

Background: The purpose of our study was to develop a prognostic risk model based on differential genomic instability-associated (DGIA) long non-coding RNAs (lncRNAs) of left-sided and right-sided colon cancers (LCCs and RCCs); therefore, the prognostic key lncRNAs could be identified.

Methods: We adopted two independent gene datasets, corresponding somatic mutation and clinical information from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Identification of differential DGIA lncRNAs from LCCs and RCCs was conducted with the appliance of “Limma” analysis. Then, we screened out key lncRNAs based on univariate and multivariate Cox proportional hazard regression analysis. Meanwhile, DGIA lncRNAs related prognostic model (DRPM) was established. We employed the DRPM in the model group and internal verification group from TCGA for the purpose of risk grouping and accuracy verification of DRPM. We also verified the accuracy of key lncRNAs with GEO data. Finally, the differences of immune infiltration, functional pathways, and therapeutic sensitivities were analyzed within different risk groups.

Results: A total of 123 DGIA lncRNAs were screened out by differential expression analysis. We obtained six DGIA lncRNAs by the construction of DRPM, including AC004009.1, AP003555.2, BOLA3-AS1, NKILA, LINC00543, and UCA1. After the risk grouping by these DGIA lncRNAs, we found the prognosis of the high-risk group (HRG) was significantly worse than that in the low-risk group (LRG) (all p < 0.05). In all TCGA samples and model group, the expression of CD8⁺ T cells in HRG was lower than that in LRG (all p < 0.05). The functional analysis indicated that there was significant upregulation with regard to pathways related to both genetic instability and immunity in LRG, including cytosolic DNA sensing pathway, response to double-strand RNA, RIG-Ⅰ like receptor signaling pathway, and Toll-like receptor signaling pathway. Finally, we analyzed the difference and significance of key DGIA lncRNAs and risk groups in multiple therapeutic sensitivities.

Conclusion: Through the analysis of the DGIA lncRNAs between LCCs and RCCs, we identified six key DGIA lncRNAs. They can not only predict the prognostic risk of patients but also serve as biomarkers for evaluating the differences of genetic instability, immune infiltration, and therapeutic sensitivity.

Recurrence after complete mesocolic excision for right-sided colon cancer: post hoc sensitivity analyses-early recurrence, surgery by specialist and dissection in the mesocolic plane

AIM

The aim was to investigate whether the previously reported causal treatment effect of complete mesocolic excision on the risk of recurrence was biased by inclusion of patients with potentially undiagnosed disseminated disease at the time of surgery, by non-specialist surgery, or caused by mesocolic plane dissection.

METHOD

A population of 1069 patients, 813 undergoing conventional resection and 256 complete mesocolic excision for colon cancer during the period 2008-2013, was stepwise reduced in the following order by excluding patients with recurrence diagnosed within 6 months of the resection, having surgery performed by a non-specialist without supervision, and specimens assessed as not being mesocolic plane dissection. The primary outcome measure was risk of recurrence after 5.2 years using competing risk analyses.

RESULTS

The absolute risk reduction of complete mesocolic excision was 6.0% (95% CI 1.8-10.2; P = 0.0049) after excluding patients with recurrence within 6 months of resection, 6.1% (95% CI 1.9-10.4; P = 0.0045) after excluding non-specialist surgery, and 7.5% (95% CI 2.9-12.0; P = 0.0013) after the exclusion of patients whose specimens were assessed as dissections not being performed in the mesocolic plane.

CONCLUSION

The absolute risk reduction of recurrence after complete mesocolic excision for right-sided colon cancer in our previous study was not biased by potentially undiagnosed disseminated disease at the time of surgery or non-specialist surgery, and was not solely caused by dissection in the mesocolic plane. Central vascular dissection with central lymphadenectomy seems a major factor for better oncological results.

The prevalence of right-sided colonic diverticulosis in a New Zealand population

BACKGROUND

Once considered to be a congenital condition, the epidemiology of right-sided colonic diverticulosis (RCD) is evolving. Acute diverticulitis (AD) is a complication of RCD which is frequently misdiagnosed as appendicitis, resulting in unnecessary surgery, as there is strong evidence supporting medical management for right-sided AD. In general, the incidence of AD correlates with the prevalence of RCD, which shows marked geographic variation. Few data reporting RCD prevalence come from Western countries, so the aim of this study is to define the prevalence of RCD in a New Zealand population.

METHODS

Independent review of the imaging from 1000 consecutive patients undergoing a computed tomography Kidney/Ureter/Bladder scan for suspected urolithiasis at Christchurch Hospital between January and November 2017 was undertaken, to determine the presence or absence, and distribution of colonic diverticulosis. Patients were excluded if they had a history of colonic resection, known IBD, or were less than 18-years old.

RESULTS

Thirty-one patients were excluded, leaving 969 eligible patients. Overall, 95 patients (9.8%) had RCD identified. The prevalence of RCD increased significantly with advancing age, being present in 2.3% of those aged 18-29, increasing to 20.3% in those greater than 70-years old (p < 0.001).

CONCLUSION

The prevalence of RCD in a New Zealand population is relatively high and increases significantly with age. This adds support to the role of cross-sectional imaging in the evaluation of suspected appendicitis, to exclude right-sided AD. The association with advancing age supports RCD being an acquired condition rather than a congenital condition as was previously thought.

Prognostic Immune-Related Analysis Based on Differentially Expressed Genes in Left- and Right-Sided Colon Adenocarcinoma

Background

Colon adenocarcinoma (COAD) can be divided into left-sided and right-sided COAD (LCCs and RCCs, respectively). They have unique characteristics in various biological aspects, particularly immune invasion and prognosis. The purpose of our study was to develop a prognostic risk scoring model (PRSM) based on differentially expressed immune-related genes (IRGs) between LCCs and RCCs, therefore the prognostic key IRGs could be identified.

Methods

The gene sets and clinical information of COAD patients were derived from TCGA and GEO databases. The comparison of differentially expressed genes (DEGs) of LCCs and RCCs were conducted with appliance of “Limma” analysis. The establishment about co-expression modules of DEGs related with immune score was conducted by weighted gene co-expression network analysis (WGCNA). Furthermore, we screened the module genes and completed construction of gene pairs. The analysis of the prognosis and the establishment of PRSM were performed with univariate- and lasso-Cox regression. We employed the PRSM in the model group and verification group for the purpose of risk group assignment and PRSM accuracy verification. Finally, the identification of the prognostic key IRGs was guaranteed by the adoption of functional enrichment, “DisNor” and protein-protein interaction (PPI).

Results

A total of 215 genes were screened out by differential expression analysis and WGCNA. A PRSM with 16 immune-related gene pairs (IRGPs) was established upon the genes pairing. Furthermore, we confirmed that the risk score was an independent factor for survival by univariate- and multivariate-Cox regression. The prognosis of high-risk group in model group (P < 0.001) and validation group (P = 0.014) was significantly worse than that in low-risk group. Treg cells (P < 0.001) and macrophage M0 (P = 0.015) were highly expressed in the high-risk group. The functional analysis indicated that there was significant up-regulation with regard of lymphocyte and cytokine related terms in low-risk group. Finally, we identified five prognostic key IRGs associated with better prognosis through PPI and prognostic analysis, including IL2RB, TRIM22, CIITA, CXCL13, and CXCR6.

Conclusion

Through the analysis and screening of the DEGs between LCCs and RCCs, we constructed a PRSM which could predicate prognosis of LCCs and RCCs, and five prognostic key IRGs were identified as well. Therefore, the basis for identifying the benefits of immunotherapy and immunomodulatory was built.

Bridge to Surgery for Obstructing Colonic Cancer: A Comparison between Right- and Left-sided Lesions

Objectives:

Few studies have compared management and outcomes of bridge to surgery (BTS) for obstructive colonic cancer according to the location of the tumor. Additional information is needed about this procedure's characteristics and short-term and long-term outcomes. We aimed to compare patient and tumor characteristics, and outcomes of BTS for obstructive right-sided versus left-sided colonic cancers.

Methods:

This was a retrospective, single center, cohort study. The study cohort comprised 149 patients, including 48 with right-sided and 101 with left-sided obstructive colonic cancers, who were treated with BTS between January 2007 and December 2017. Data on medical history, investigations, treatments, and prognosis were collected from an electronic database of a single hospital. The primary end points were overall (OS) and disease-free (DFS) survival and short-term surgical outcomes.

Results:

Significantly more patients with right-sided cancers had postoperative complications (29.2% vs. 14.9%, p = 0.039). Additionally, postoperative chemotherapy was administered to a marginally significantly greater proportion of patients with left-sided cancers (29.2% vs 45.5%, p = 0.057). The long-term outcomes were comparable between the two groups (the 5-year OS rates were 67.6% and 80.9% [p = 0.117] and the 5-year DFS rates were 62.2% and 58.6% [p = 0.671]). Multivariate analyses using all studied variables showed that lymphovascular invasion, advanced T stage, and adjuvant chemotherapy were independent poor prognostic factors.

Conclusions:

The long-term outcome was not different between the right- and left-sided groups. In a BTS setting, postoperative complications may reduce the compliance of adjuvant chemotherapy in right-sided cancers and affect long-term outcomes.

Facilitating right-sided axillary artery access for transcatheter aortic valve replacement using the Edwards Sapien 3 and ultra valves: Technical considerations

Trans-Axillary Transcatheter Aortic Valve Replacement (TAVR) has become established as the safest arterial approach when femoral arterial anatomy is unfavorable. Although a left sided axillary approach is generally preferred, patient specific factors may require use of the right axillary artery. In this case series we describe procedural modifications that are required to overcome the challenge of restricted space in the ascending aorta for in situ valve preparation of balloon-expandable valve systems when a right sided trans-Axillary approach is taken. These steps permit implantation of both the Edwards LifeSciences Sapien 3 and Ultra prostheses via the right trans-Axillary approach, allowing patients a greater range of valve options when this arterial route is required for TAVR.

Surgical treatment of right-sided infective endocarditis

OBJECTIVE

Right-sided infective endocarditis is increasing because of increasing prevalence of predisposing conditions, and the role and outcomes of surgery are unclear. We therefore investigated the surgical outcomes for right-sided infective endocarditis.

METHODS

From January 2002 to January 2015, 134 adults underwent surgery for right-sided infective endocarditis. Patients were grouped according to predisposing condition. Hospital outcomes, time-related death, and reoperation for infective endocarditis were analyzed.

RESULTS

A total of 127 patients (95%) had tricuspid valve and 7 patients (5%) pulmonary valve infective endocarditis; 66 patients (49%) had isolated right-sided infective endocarditis, and 68 patients (51%) had right- and left-sided infective endocarditis. Predisposing conditions included injection drug use (30%), cardiac implantable devices (26%), chronic vascular access (19%), and other/none (25%). One native tricuspid valve was excised, 76% were repaired or reconstructed, and 23% were replaced. Intensive care unit and postoperative hospital stays were similar among groups. Injection drug users had the best early survival (no hospital mortality), and patients with chronic vascular access had the worst late survival (18% at 5 years). Survival was worst for concomitant mitral valve versus isolated right-sided infective endocarditis or concomitant aortic valve infective endocarditis. Survival after tricuspid valve replacement was worse than after repair/reconstruction. Estimated glomerular filtration rate was the strongest risk factor for death, not predisposing condition. Eleven patients underwent 12 reoperations for infective endocarditis; more reoperations occurred in injection drug users (P = .03).

CONCLUSIONS

Overall outcomes after surgery are variable and affected by patient condition, not predisposing condition. Injection drug use carries a higher risk of reoperation for infective endocarditis. Earlier surgery may permit more valve repairs and improve outcomes. Whenever possible, tricuspid valve replacement should be avoided.

Tumor LINE-1 methylation level and colorectal cancer location in relation to patient survival

Colorectal tumors arise with genomic and epigenomic alterations through interactions between neoplastic cells, immune cells, and microbiota that vary along the proximal to distal axis of colorectum. Long interspersed nucleotide element-1 (LINE-1) hypomethylation in colorectal cancer has been associated with worse clinical outcome. Utilizing 1,317 colon and rectal carcinoma cases in two U.S.-nationwide prospective cohort studies, we examined patient survival according to LINE-1 methylation level stratified by tumor location. Cox proportional hazards model was used to assess a statistical interaction between LINE-1 methylation level and tumor location in colorectal cancer-specific mortality analysis, controlling for potential confounders including microsatellite instability, CpG island methylator phenotype, and KRAS, BRAF, and PIK3CA mutations. A statistically significant interaction was found between LINE-1 methylation level and tumor location in colorectal cancer-specific mortality analysis (Pinteraction = 0.011). The association of LINE-1 hypomethylation with higher colorectal cancer-specific mortality was stronger in proximal colon cancers (multivariable hazard ratio [HR], 1.66; 95% confidence interval [CI], 1.21 to 2.28) than in distal colon cancers (multivariable HR, 1.18; 95% CI, 0.81 to 1.72) or rectal cancers (multivariable HR, 0.87; 95% CI, 0.57 to 1.34). Our data suggest the interactive effect of LINE-1 methylation level and colorectal cancer location on clinical outcome.

Comprehensive genomic sequencing detects important genetic differences between right-sided and left-sided colorectal cancer

OBJECTIVES

Anti-epidermal growth factor receptor (EGFR) therapy has been found to be more effective against left-sided colorectal cancer (LCRC) than right-sided colorectal cancer (RCRC). We hypothesized that RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy and tested this using comprehensive genomic sequencing.

MATERIALS AND METHODS

A total of 201 patients with either primary RCRC or LCRC were analyzed. We investigated tumors for genetic alterations using a 415-gene panel, which included alterations associated with resistance to anti-EGFR therapy: TK receptors (ERBB2, MET, EGFR, FGFR1, and PDGFRA), RAS pathway (KRAS, NRAS, HRAS, BRAF, and MAPK2K1), and PI3K pathway (PTEN and PIK3CA). Patients whose tumors had no alterations in these 12 genes, theoretically considered to respond to anti-EGFR therapy, were defined as "all wild-type", while remaining patients were defined as "mutant-type".

RESULTS

Fifty-six patients (28%) and 145 patients (72%) had RCRC and LCRC, respectively. Regarding genetic alterations associated with anti-EGFR therapy, only 6 of 56 patients (11%) with RCRC were "all wild-type" compared with 41 of 145 patients (28%) with LCRC (P = 0.009). Among the 49 patients who received anti-EGFR therapy, RCRC showed significantly worse progression-free survival (PFS) than LCRC (P = 0.022), and "mutant-type" RCRC showed significantly worse PFS compared with "all wild-type" LCRC (P = 0.004).

CONCLUSIONS

RCRC is more likely to harbor genetic alterations associated with resistance to anti-EGFR therapy compared with LCRC. Furthermore, our data shows primary tumor sidedness is a surrogate for the non-random distribution of genetic alterations in CRC.

The prognostic implications of primary colorectal tumor location on recurrence and overall survival in patients undergoing resection for colorectal liver metastasis

BACKGROUND AND OBJECTIVES

The prognostic impact of primary colorectal cancer (CRC) location following resection of colorectal liver metastasis (CRLM) remains largely unknown. We sought to characterize the prognostic implications of primary tumor location among patients who underwent curative-intent hepatectomy for CRLM.

METHODS

Tumors of the cecum, ascending, and transverse colon were defined as right-sided; tumors of the sigmoid flexure, descending, and sigmoid colon were defined as left-sided. Clinicopathologic and long-term survival data were collected and assessed using univariable and multivariable analyses.

RESULTS

About 475 patients who underwent CRLM resection at a single institution were included; most patients had left-sided tumors (n = 284). Median and 5-year RFS was 20.2 months and 28.0%, respectively. Patients who had a left-sided primary tumor had a shorter RFS compared with patients who had a right-sided tumor (P = 0.01). Although site of and time to recurrence did not differ between the two groups (P > 0.05), patients with right-sided primary tumors were more likely to recur with advanced disease (i.e., ≥4 recurrent lesions) (P < 0.01). In turn, patients with right-sided tumors had both worse OS (P = 0.03) and worse survival after recurrence (P = 0.01).

CONCLUSION

While patients with right-sided tumors experienced longer RFS, when these patients did recur following CRLM resection, disease extent was more advanced. In turn, OS following recurrence was shorter among patients with right-sided CRC. J. Surg. Oncol. 2016;114:803-809. © 2016 2016 Wiley Periodicals, Inc.

Right- and left-sided colon cancer - clinical and pathological differences of the disease entity in one organ

INTRODUCTION

Some researchers suggest that cancers located in the right vs. the left side of the colon are different and they can be regarded as distinct disease entities. The aim of this study was to analyze differences in clinical, epidemiological and pathological features of patients with right-sided (RCC) and left-sided (LCC) colon cancer.

MATERIAL AND METHODS

One thousand two hundred and twenty-four patients were operated on due to colorectal cancer. A group of 477 patients (254 women, mean age 65.5 ±11 for the whole group) with colon cancer was included (212 RCC vs. 265 LCC).

RESULTS

Right colon cancer patients were older (67.8 ±11.3 vs. 63.2 ±11.2; p = 0.0087). Left colon cancer patients underwent surgery for urgent indications more often (17.0% vs. 8.5%; p = 0006). Tumor diameter was greater in the RCC group (55 ±60 mm vs. 38 ±21 mm; p = 0.0003). Total number of removed lymph nodes was higher in the RCC group (11.7 ±6 vs. 8.3 ±5; p = 0.0001). Lymph node ratio was higher in the LCC group (0.45 ±0.28 vs. 0.30 ±0.25; p = 0.0063). We found a strong positive correlation between tumor diameter and the number of removed lymph nodes in the LCC group (r = 0.531).

CONCLUSIONS

These differences may result from the fact that RCC patients are diagnosed at an older age. The smaller number of removed lymph nodes in LCC patients may result in incorrect staging. It is still necessary to find other biological dissimilarities of adenocarcinoma located on different sides of the colon.

Primary tumor site and anti-EGFR monoclonal antibody benefit in metastatic colorectal cancer: a meta-analysis

AIM

This meta-analysis aimed to document the impact of primary tumor site on anti-EGFR monoclonal antibody (mAb) benefit in metastatic colorectal cancer.

MATERIALS & METHODS

Tumors with metastatic left-sided colorectal cancer (LCC) were compared with tumors with metastatic right-sided colon cancer (RCC) with respect to anti-EGFR mAb objective response rate (ORR), overall survival (OS) and progression-free survival (PFS) benefit.

RESULTS

Comparing LCC with RCC, LCC was found to have significantly superior anti-EGFR mAb ORR (p < 0.00001), OS (p < 0.00001) and PFS (p < 0.00001) benefit. Additionally, anti-EGFR mAb therapy significantly improved both OS and PFS for LCC compared with no anti-EGFR mAb therapy, but not for RCC. The test of interaction was also apparent for OS (p = 0.0002) and PFS (p = 0.0002).

CONCLUSION

This meta-analysis demonstrated that LCC had markedly superior anti-EGFR mAb treatment benefit compared with RCC.

Right-sided colon cancer and left-sided colorectal cancers respond differently to cetuximab

INTRODUCTION

Right-sided colon cancer (RSCC) and left-sided colorectal cancer (LSCRC) differ with respect to their biology and genomic patterns. This study aimed to examine whether the primary tumor location is associated with the response to cetuximab in patients with metastatic colorectal cancer (mCRC).

METHODS

Patients with mCRC treated with cetuximab and standard chemotherapy as first- or second-line treatments were compared with randomly chosen patients who were treated with chemotherapy alone between 2005 and 2013. The main outcome measures were the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). The differences in the outcome were analyzed by using the chi-squared test, Student's t test, and Kaplan-Meier method.

RESULTS

The treatment results of 206 patients with mCRC treated with cetuximab and standard chemotherapy as first- or second-line treatments were compared with those of 210 patients who were treated with chemotherapy alone. As a first-line treatment, cetuximab with chemotherapy was associated with a significantly higher ORR (49.4 % vs. 28.6 %, P = 0.005) as well as longer PFS (9.1 vs. 6.2 months, P = 0.002) and OS (28.9 vs. 20.1 months, P = 0.036) than chemotherapy alone in patients with LSCRC. However, cetuximab neither improved the ORR (36.4 % vs. 26.2 %, P = 0.349) nor prolonged PFS (5.6 vs. 5.7 months, P = 0.904) or OS (25.1 vs. 19.8 months, P = 0.553) in patients with RSCC. As a second-line treatment, cetuximab exhibited a tendency to improve the ORR (23.5 % vs. 10.2 %, P = 0.087) and prolong PFS (4.9 vs. 3.5 months, P = 0.064), and it significantly prolonged OS (17.1 vs. 12.4 months, P = 0.047) compared with chemotherapy alone in the patients with LSCRC. In contrast, as a second-line treatment, cetuximab neither improved the ORR (7.1 % vs. 11.4 %, P = 0.698) nor prolonged PFS (3.3 vs. 4.2 months, P = 0.761) or OS (13.4 vs. 13.0 months, P = 0.652) in patients with RSCC.

CONCLUSIONS

The addition of cetuximab to chemotherapy in both first- and second-line treatments of mCRC may only benefit patients with primary LSCRC.

An atypical case of right-sided bochdalek hernia in an adult

Bochdalek hernias are usually congenital in nature and normally present after birth. However, in rare cases, these hernias are present in adulthood. We report an unusual case of a posttraumatic right-sided Bochdalek hernia found incidentally in an adult and treated successfully with conservative management.