ABSTRACT
AIM: To provide an update on the aetiology, pathogenesis, diagnosis, staging and management of rectal squamous cell carcinoma (SCC). METHODS: A systematic review was conducted according to the preferred reporting items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of Ovid MEDLINE was performed with the reference list of selected articles reviewed to ensure all relevant publications were captured. The search strategy was limited to the English language, spanning from 1946 to 2015. A qualitative analysis was undertaken examining patient demographics, clinical presentation, diagnosis, staging, treatment and outcome. The quantitaive analysis was limited to data extracted on treatment and outcomes including radiological, clinical and pathological complete response where available. The narrative and quantitative review were synthesised in concert. RESULTS: The search identified 487 articles in total with 79 included in the qualitative review. The quantitative analysis involved 63 articles, consisting of 43 case reports and 20 case series with a total of 142 individual cases. The underlying pathogenesis of rectal SCC while unclear, continues to be defined, with increasing evidence of a metaplasia-dysplasia-carcinoma sequence and a possible role for human papilloma virus in this progression. The presentation is similar to rectal adenocarcinoma, with a diagnosis confirmed by endoscopic biopsy. Many presumed rectal SCC's are in fact an extension of an anal SCC, and cytokeratin markers are a useful adjunct in this distinction. Staging is most accurately reflected by the tumour-node-metastasis classification for rectal adenocarcinoma. It involves examining locoregional disease by way of magnetic resonance imaging and/or endorectal ultrasound, with systemic spread excluded by way of computed tomography. Positron emission tomography is integral in the workup to exclude an external site of primary SCC with metastasis to the rectum. While the optimal treatment remains as yet undefined, recent studies have demonstrated a global shift away from surgery towards definitive chemoradiotherapy as primary treatment. Pooled overall survival was calculated to be 86% in patients managed with chemoradiation compared with 48% for those treated traditionally with surgery. Furthermore, local recurrence and metastatic rates were 25% vs 10% and 30% vs 13% for the chemoradiation vs conventional treatment cohorts. CONCLUSION: The changing paradigm in the treatment of rectal SCC holds great promise for improved outcomes in this rare disease.
ABSTRACT
BACKGROUND: In 2009, Barwon Health designed a risk stratification model for mortality in major colorectal surgery with the use of only preoperative risk factors. The Barwon Health 2009 model was shown to predict mortality reliably, and it was comparable to other models, such as the original, POSSUM. However, the Barwon Health 2009 model was never validated with data other than those used to develop the model. OBJECTIVE: The aim of this study was to perform temporal and external validation of the Barwon Health 2009 model and to compare it with other published models. DESIGN: : The temporal validation was a prospective observational study, whereas the external validation was a retrospective observational study. The discrimination and calibration of the models were assessed by using the area under receiver operator characteristic and χ test of Hosmer-Lemeshow goodness-of-fi technique. SETTINGS: This is a multi-institutional study. Data were collected from 2008 to 2010. RESULTS: There were 474 major colorectal cases at Geelong Hospital (temporal validation) and 389 cases at Western Hospital (external validation). The overall mortality rate was 5.10% and 1.03%. In the comparison of the 2 demographics, Geelong Hospital had a higher proportion of patients who were older and had higher ASA scores and comorbidity counts, whereas Western Hospital surgeons were operating on a higher number of urgent cases. Despite the differences, the Barwon Health 2009 model was able to discriminate mortality reliably (area under receiver operator characteristic = 0.753) but had poor model calibration (p < 0.001) on temporal validation. Hence, the model was recalibrated to predict mortality accurately(area under receiver operator characteristic = 0.772; p = 0.83), and this was successfully validated at Western Hospital (area under receiver operator characteristic = 0.788; p = 0.24). CONCLUSIONS: We have developed a model that can accurately predict mortality after major colorectal surgery by using only data that are available preoperatively. After recalibration, the model was successfully validated in a second hospital.
