This is the most recent study to report on patterns of colorectal cancer care in this French region. The majority of CRC patients were 70 years or older and most were treated in non-teaching hospitals. Overall, adherence to recommendations was good, but varied across hospitals and districts. For some important steps of cancer care (resection, pathology report, LN examination, chemotherapy in stage III, rectal radiotherapy), adherence was the same or higher than in other studies [19, 20]. Over 70% of patients received standard care with chemotherapy for stage III colon cancer, although the proportion was lower for older patients. For rectal cancer patients, a majority (62%) of patients received preoperative radiotherapy which may reflect more frequent pre-operative use in Europe than in the United States where rates are reportedly on the rise . Moreover, these results across an entire region in the year following guideline implementation show good adherence to the approach directly after. The main factors of non-compliance with recommendations were the high use of chemotherapy in stage II colon cancer and the under-use of diagnostic assessment for rectal cancer.
The examination of ≥12 LNs was associated with five factors: ECOG score, tumor characteristics (location and stage) and hospital characteristics (administrative district and volume of CRC procedures). These factors were concordant with almost all results published to date [12, 22, 23]. Pathological findings concerning resection specimens showed that for most CRC cases ≥12 LNs were examined, yet the proportion was slightly lower among rectal cancer patients compared to colon cancer patients. Radiotherapy before surgery may explain the lower proportion in rectal cancer patients due to reduced lymph node harvests post-radiotherapy [24, 25]. Numerous studies and consensus guidelines have suggested that the 12 LN threshold is a reasonable minimum for adequate nodal evaluation in colon cancer, however there is still some uncertainty regarding the impact on survival [13, 26, 27].
To explain the under-use of chemotherapy in stage III, our study analyzed factors related to the potential risks of chemotherapy, finding very low use for patients over 75 years as has been reported in a similar population-based study . While the efficacy of adjuvant therapy for stage III colon cancer was emphasized in the 1990s, age and comorbidity have always played a role in the decision to use adjuvant therapy in stage III , and it is mostly offered to healthy patients under 75 years old with recent results supporting the under-use for elderly patients [14, 30].
Conversely, we chose to explain the determinants for using chemotherapy in stage II since at the time of study, adjuvant chemotherapy was generally not indicated in these cases. For stage II colon cancer, the present results show that in 2003-2004, younger age, advanced stage, emergency setting and healthcare organization (districts or sector hospitals) were associated with the use of chemotherapy. These results are in accordance with previous work showing that younger age, advanced stage, emergency presentation and discussion in multidisciplinary meetings were associated with adjuvant chemotherapy use for stage II patients . At the time of this study, the national recommendations were not clear in terms of management options for stage II patients but these have since be clarified and adjuvant chemotherapy use appears to be indicated for specific stage II patients , although this still remains to be confirmed .
Although the volume-to-outcome relationship in CRC surgery seems smaller in magnitude than that in other digestive procedures, consideration must be given as to whether regionalization of CRC care is an appropriate mechanism for quality improvement . In our study, we confirmed the importance of district as a source of heterogeneity in cancer colorectal management [4–6] This information could be a confounding factor with the hospital volume procedure, but we took this into account in our multivariate analysis and found an effect for both hospital district and volume. The hospital volume effect on examination of ≥12 LNs has been emphasized recently [23, 34].
Our findings should be interpreted in the light of several limitations. First, our colorectal cohort was not exhaustive since the estimation of CRC incidence in this area was over 2000 new patients. However, similar patient and hospital characteristics were found in studies using data from French cancer registries or regional medical information systems [35, 36]. A second limitation is our study size which is smaller than similar studies [22, 23, 37]. This lower power would explain why we did not identify stage as independent factors for LN examination. In addition, we had no information regarding patients’ socio-economic status  or treatment choice; two factors known to be relevant when explaining differences in care management. We also collected comorbidity information by using patients’ medical records, a method somewhat insufficient to capture the range and severity of the comorbidity.
In terms of interpreting whether the results reported here specifically reflect improvements after implementation of guidelines, with this observational design we cannot infer a definite causality link, although all efforts were undertaken to widely and comprehensively distribute guidelines as described in the methods. To provide an indication of trends in practices across time in France, we collated information from four comparable studies performed between 1900 and 2004 [4, 14, 36, 39]. We note that the general trend for chemotherapy use in stage II patients did not change between 1990-1999 (21.8%)  to 2000 (20.4%)  and 2003/2004 (20.6%) in the present study. For stage III patients, the trend is towards an increase in the use of chemotherapy with usage reported at 47% in 1990-1999 , 61% in 2000  and 71% in our study. Discussion in multidisciplinary meetings also appears to be on the rise. In 2000, between 32%  and 61%  of patients’ files were discussed in multidisciplinary meetings, compared to >85% in our series on the whole. Local population-based cancer registry data (unpublished data, http://www.registres-cancers-aquitaine.fr/) indicate that in one administrative district included in this region, discussion in multidisciplinary meetings for colorectal cancer patients increased from 48% to 63% between 2005 and 2008. We expect that with the creation of the National Institute for Cancer (INCa) in 2005 and standardized national guidelines, this trend is probably robust and continuous. Finally, trends in inspection of ≥12 LNs appear to be increasing with 45.2% compliance in 1997-2004  compared to 70.8% in our study.
A final limitation is the differences in practices that may have occurred between time of observation and this publication, for example with magnetic resonance imaging practices. However, these data provide a validated measure of colorectal cancer care that may be applied in other regions and countries. The three NCCN quality indicators  examined here are supported as good measures of identifying practice variation that may be linked to survival differences.