Search

Background Despite an extensive literature suggesting that high microsatellite instability ( MSI-H) enhances survival and protects against recurrence after colorectal cancer resection, such effects remain controversial as many studies show only a weak bivariate association or no multivariable association with outcome. This study examined the relationship between MSI status and colorectal cancer outcomes with adjustment for death from other causes as a competing risk. Methods A hospital database of patients following colorectal cancer resection was interrogated for clinical, operative, pathology, adjuvant therapy and follow-up information. MSI-H status was determined by immunohistochemistry for mismatch repair protein deficiency. The cumulative incidence of recurrence and colorectal cancer-specific death was evaluated by competing risks methods. Results Among 1009 patients who had a resection between August 2002 and December 2008, and were followed to at least December 2013, there were 114 (11·3 per cent) with MSI-H (72·8 per cent aged at least 70 years; 63·2 per cent women). After potentially curative resection, with adjustment for non-colorectal cancer death as a competing risk and adjustment for 22 clinical, operative and pathological variables, there was no association between MSI-H and recurrence (hazard ratio ( HR) 0·81, 95 per cent c.i. 0·42 to 1·57) or colorectal cancer-specific death ( HR 0·73, 0·39 to 1·35) in this patient population. For palliative resections, there was no association between MSI-H and colorectal cancer-specific death ( HR 0·65, 0·21 to 2·04). MSI-H was associated with non-colorectal cancer death after both curative ( HR 1·55, 1·04 to 2·30) and palliative ( HR 3·80, 1·32 to 11·00) resections. Conclusion Microsatellite instability status was not an independent prognostic variable in these patients. [ABSTRACT FROM AUTHOR]

Aim Several recent studies have attempted to evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in predicting the likelihood of tumour involvement of the postoperative circumferential resection margin (CRM) in rectal cancer with the intention of selecting patients who might benefit from neoadjuvant therapy and as a guide to surgery. The aim of this study was to assess whether such studies can provide a valid answer as to whether preoperative MRI can accurately predict CRM involvement by tumour. Method The study design and methodology of studies on this topic were critically examined. Results Features identified as affecting the efficacy of these studies were: representativeness of patients, definition of the margin assessed by MRI and by histology, lack of blinding of surgeons and pathologists to MRI results, effect of neoadjuvant treatment, and number of patients studied. Conclusion Because of methodological inadequacies in studies completed to date, there is insufficient evidence of the ability of a positive MRI result to predict an involved CRM. Although MRI may be able to identify a tumour that has extended to the mesorectal fascia and/or intersphincteric plane, logically, it cannot indicate where the surgical boundary of the resection will ultimately lie, and therefore cannot validly predict an involved CRM and should not be relied upon for this purpose. [ABSTRACT FROM AUTHOR]

The authors discuss the tumour staging in colorectal cancer (CRC) to categorize the patients into groups with various prognosis after resection. They state the current multidisciplinary approach to patient care depends on accurate staging, not only to advise patients and their relatives on prognosis, but also selecting the patients that will benefit from adjuvant therapy. They note that TNM Classification of Malignant Tumours (TNM) staging has come a long way, but challenges still remain.