Quantitative lymph node evaluation as an independent marker of long-term prognosis in stage III rectal cancer

Background: The prognostic significance of lymph node evaluation is not well described for rectal cancer due to a lack of reproducibility in nodal counts and variable use of adjuvant and neoadjuvant therapy. The aim of this study was to examine the role of quantitative lymph node evaluation as an independent marker of prognosis in stage III rectal cancer. Methods: New Zealand Cancer Registry data were retrieved for consecutive patients with rectal cancer from January 1995 to July 2003. Cases with node‐negative tumours, distant metastases, death within 30 days of surgery and incomplete data fields were excluded. Three nodal stratification systems were investigated – Total Number of Nodes examined (TNN), Absolute number of Positive Nodes (APN) and Lymph Node Ratio (LNR). Univariate and Cox regression analyses were performed with 5‐year all‐cause mortality as the primary end point. Results: The study identified 895 stage III rectal cancer cases. The mean APN and LNR were significantly higher in patients who died within 5 years. An increasing APN or LNR was associated with a significant increase in 5‐year mortality. The APN and LNR were also powerful predictors of 5‐year mortality after correcting for other factors using Cox regression. The TNN was of no prognostic significance. Conclusions: Both the APN and LNR are highly effective at independently predicting and stratifying 5‐year mortality in stage III rectal cancer. The significant predictive value of the LNR is likely to be a reflection of the APN rather than one functioning in autonomy, given that the TNN was of no prognostic significance.     

Lymph node examination as a predictor of long-term outcome in Dukes B colon cancer

Background  Mortality from cancer recurrence in Dukes B patients is approximately 25–30%. Outcome in Dukes B patients improves in direct relation to the number of lymph nodes examined. Examining fewer lymph nodes risks understaging and also such patients are less likely to receive chemotherapy. The aim of this study was to assess the impact of the number of lymph nodes examined on recurrence and mortality in Dukes B colon cancers. Materials and methods  A retrospective database was constructed of 328 consecutive patients who underwent resection for Dukes B colorectal cancer between January 1993 and December 2001 at Middlemore Hospital. Patients with incomplete data, previous colorectal cancer, or perioperative deaths were excluded as were cases of rectal cancer. Data for the remaining 216 patients was subjected to multivariate and logistic regression analysis with ‘patient death’ or ‘cancer recurrence’ (CRec5) within 5 years as endpoints. A graph was constructed depicting CRec5 as broken down by lymph node strata. Receiver operator characteristic (ROC) curves were constructed for mortality and CRec5. Results  The mean number of lymph nodes examined was 16.0 (median 14; range 2–48). The mean number of lymph nodes examined in those who died within 5 years was 12.8 vs. 17.5 in those who remained alive (p = 0.0027). The mean number of lymph nodes examined in those with evidence of recurrence within 5 years was 11.8 vs. 17.1 in those without recurrence (p = 0.0007). Analysis at various lymph node strata showed a sharp and statistically significant drop in the recurrence rate after the 16the node mark. The ROC curve for CRec5 showed that examination of 12 lymph nodes provided maximum sensitivity (0.60) and specificity (0.64). Conclusion  Examination of more than 16 lymph nodes is associated with a significant reduction in cancer recurrence. This supports the current clinical practice of harvesting and analysing as many nodes as possible during surgical resection and pathological analysis.     

Comparison of the possum, P-POSSUM and Cr-POSSUM scoring systems as predictors of postoperative mortality in patients undergoing major colorectal surgery

BACKGROUND: Physiologic and operative severity score for the enumeration of mortality and morbidity (POSSUM), 'Portsmouth'-physiologic and operative severity score for the enumeration of mortality and morbidity (P-POSSUM) and 'Colorectal'-physiologic and operative severity score for the enumeration of mortality and morbidity (Cr-POSSUM) are three related scoring systems, which uses individual patient parameters to predict postoperative mortality. POSSUM overpredicts mortality in low-risk patients and underpredicts mortality in elderly and emergency patients. P-POSSUM was developed to compensate for these weaknesses. Cr-POSSUM was developed specifically for colorectal surgery. We aim to establish which of these scoring systems would be most useful in an Australasian context. METHODS: Data were collected for 308 patients and predicted mortality risk values were generated using each of the three systems. The Mann-Whitney U-test was then carried out on the scores for each system. Receiver-operator characteristic curves were designed to determine the relative accuracy of each approach at discriminating between death and survival. RESULTS: All three POSSUM scoring systems showed a statistically significant ability to predict postoperative mortality. Additionally, in each system there was a significant difference in the raw physiologic and operative severity scores between survivors and those who died. A risk-stratification model was applied to each set of data, showing a correlation between an increase in risk and an increase in mortality rate. Finally, the receiver-operator characteristic curves generated showed that in this study group POSSUM, P-POSSUM and Cr-POSSUM were all satisfactory predictive tools although the latter tended to be relatively less accurate. CONCLUSION: Physiologic and operative severity score for the enumeration of mortality and morbidity, P-POSSUM and Cr-POSSUM are all reliable predictors of postoperative mortality in the Australasian context; although there was a trend towards POSSUM and P-POSSUM being better predictors than Cr-POSSUM. However, Cr-POSSUM requires fewer individual patient parameters to be calculated and is thus easier to generate. An ideal preoperative scoring system remains to be developed for predicting mortality in patients undergoing colorectal surgery.     

Uncomplicated Acute Diverticulitis: Identifying Risk Factors for Severe Outcomes

Background

The management of uncomplicated (Modified Hinchey Classification Ia) acute diverticulitis (AD) has become increasingly conservative, with a focus on symptomatic relief and supportive management. Clear criteria for patient selection are required to implement this safely. This retrospective study aimed to identify risk factors for severe clinical course in patients with uncomplicated AD.

Materials and methods

Patients admitted to General Surgery at two New Zealand tertiary centres over a period of 18 months were included. Univariate and multivariate analyses were carried out in order to identify factors associated with a more severe clinical course. This was defined by three endpoints: need for procedural intervention, admission >7 days and 30-day readmission; these were analysed separately and as a combined outcome.

Results

Uncomplicated AD was identified in 319 patients. Fifteen patients (5%) required procedural intervention; this was associated with SIRS (OR 3.92). Twenty-two (6.9%) patients were admitted for >7 days; this was associated with patient-reported pain score >8/10 (OR 5.67). Thirty-one patients (9.8%) required readmission within 30 days; this was associated with pain score >8/10 (OR 6.08) and first episode of AD (OR 2.47). Overall, 49 patients had a severe clinical course, and associated factors were regular steroid/immunomodulator use (OR 4.34), pain score >8/10 (OR 5.9) and higher temperature (OR 1.51) and CRP ≥200 (OR 4.1).

Conclusion

SIRS, high pain score and CRP, first episode and regular steroid/immunomodulator use were identified as predictors of worse outcome in uncomplicated AD. These findings have the potential to inform prospective treatment decisions in this patient group.