Prognostic implication of the neoadjuvant rectal score and other biomarkers of clinical outcome in Hong Kong Chinese patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiotherapy

BACKGROUND

Neoadjuvant chemoradiotherapy is a standard treatment for locally advanced rectal cancer, for which pathological complete response is typically used as a surrogate survival endpoint. Neoadjuvant rectal score is a new biomarker that has been shown to correlate with survival. The main objectives of this study were to investigate factors contributing to pathological complete response, to validate the prognostic significance of neoadjuvant rectal score, and to investigate factors associated with a lower neoadjuvant rectal score in a cohort of Hong Kong Chinese.

METHODS

Data of patients with locally advanced rectal cancer who received neoadjuvant chemoradiotherapy from August 2006 to October 2018 were retrieved from hospital records and retrospectively analysed.

RESULTS

Of 193 patients who had optimal response to neoadjuvant chemoradiotherapy and surgery, tumour down-staging was the only independent prognostic factor that predicted pathological complete response (P<0.0001). Neoadjuvant rectal score was associated with overall survival (hazard ratio [HR]=1.042, 95% confidence interval [CI]=1.021-1.064; P<0.0001), disease-free survival (HR=1.042, 95% CI=1.022-1.062; P<0.0001), locoregional recurrence-free survival (HR=1.070, 95% CI=1.039-1.102; P<0.0001) and distant recurrence-free survival (HR=1.034, 95% CI=1.012-1.056; P=0.002). Patients who had pathological complete response were associated with a lower neoadjuvant rectal score (P<0.0001), but pathological complete response was not associated with survival. For patients with intermediate neoadjuvant rectal scores, late recurrences beyond 72 months from diagnosis were observed.

CONCLUSION

Neoadjuvant rectal score is an independent prognostic marker of survival and disease recurrence in a cohort of Hong Kong Chinese patients who received neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Receptor tyrosine kinase fusions act as a significant alternative driver of the serrated pathway in colorectal cancer development

Serrated polyps are a clinically and molecularly heterogeneous group of lesions that can contribute to the development of colorectal cancers (CRCs). However, the molecular mechanism underlying the development of serrated lesions is still not well understood. Here, we combined multiple approaches to analyze the genetic alterations in 86 colorectal adenomas (including 35 sessile serrated lesions, 15 traditional adenomas, and 36 conventional adenomatous polyps). We also investigated the in vitro and in vivo oncogenic properties of a novel variant of the NCOA4-RET fusion gene. Molecular profiling revealed that sessile serrated lesions and traditional serrated adenomas have distinct clinicopathological and molecular features. Moreover, we identified receptor tyrosine kinase translocations exclusively in sessile serrated lesions (17%), and the observation was validated in a separate cohort of 34 sessile serrated lesions (15%). The kinase fusions as well as the BRAF and KRAS mutations were mutually exclusive to each other. Ectopic expression of a novel variant of the NCOA4-RET fusion gene promoted cell proliferation in vitro and in vivo, and the proliferation was significantly suppressed by RET kinase inhibitors. All of these underscored the importance of mitogen-activated protein kinase (MAPK) pathway activation in the serrated pathway of colorectal tumorigenesis. In addition, we demonstrated that the kinase fusion may occur early in the precursor lesion and subsequent loss of TP53 may drives the transformation to carcinoma during serrated tumorigenesis. In conclusion, we identified kinase fusions as a significant alternative driver of the serrated pathway in colorectal cancer development, and detecting their presence may serve as a biomarker for the diagnosis of sessile serrated lesions. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

BACKGROUND

Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.

METHODS

This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.

FINDINGS

Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p<0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05-2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p<0·001).

INTERPRETATION

Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication.

FUNDING

DFID-MRC-Wellcome Trust Joint Global Health Trial Development Grant, National Institute of Health Research Global Health Research Unit Grant.

Same-day assessment and management of urgent (2-week wait) colorectal referrals: an analysis of the outcome of 1606 patients attending an endoscopy unit-based colorectal clinic

AIM

The Rapid Access Diagnosis and Remedy (RADAR) clinic combines 2-week wait (TWW) specialist consultation with 'straight-to-test' flexible sigmoidoscopy (FS) for left-sided 'red-flag' TWW criteria (excluding right-sided mass or iron-deficiency anaemia). The study aims were to determine the effectiveness of RADAR in differentiating colorectal cancer from benign disease and to evaluate the need for whole colonic investigation (WCI) following FS, in symptomatic patients.

METHOD

Prospectively collated data of all RADAR patients from November 2005 to November 2009 were analysed, excluding patients referred internally for a FS. The local histology database was later interrogated to detect any missed cancers.

RESULTS

Of 1690 patients (729 men; median (range) age: 68 (18-96) years) assessed in RADAR, 84 were excluded. Colorectal cancer (CRC) was diagnosed in 117 (7.3%). Eighty-seven cancers were diagnosed on the day of attendance and a further 13 within a week (88.9% overall). Two patients after a cancer-free FS were found to have a right-sided CRC on WCI (0.24%) and one synchronous cancer was found. No patient with a cancer-free FS having a WCI was subsequently found to have CRC at a median of 35 (12-58) months.

CONCLUSION

Flexible sigmoidoscopy, in the context of an endoscopy unit TWW clinic, allows same-day diagnosis of most patients referred with left-sided symptoms, and immediate reassurance and treatment of most benign diagnoses. For these patients, the use of routine WCI following a cancer-free FS does not appear to be beneficial. Adopting this system would significantly reduce the number of barium enemas and colonoscopies currently performed.