Impact des traitements préopératoires (radiothérapie et chimiothérapie) dans la conservation sphinctérienne des cancers du très bas rectum

[Preoperative chemoradiotherapy for rectal cancer: experience from one centre]

PURPOSE

In recent decades, the management of rectal cancer has been significantly improved by optimizing the surgical treatment with the total mesorectal excision and the development of neoadjuvant radiotherapy with or without chemotherapy. In this study, we investigated the impact of changes in practice over a period of 15 years in an expert centre.

PATIENTS AND METHODS

A monocentric study was conducted retrospectively on cT3-resectable T4 patients who received chemoradiotherapy for a locally advanced rectal adenocarcinoma between 1993 and 2008. We studied sphincter preservation, pathological complete response (ypT0), survival, and toxicities by different concomitant chemotherapy and treatment period.

RESULTS

Among the 179 patients who had a chemoradiotherapy, 56.4% were received concomitant 5-fluoro-uracil-leucovorin, 28.5% with concomitant capecitabine, and 15.1% with concomitant oxaliplatin and capecitabine. The average dose of radiotherapy was 45 Gy (25×1.8 Gy). Five-year disease-free survival was 74.3% and overall survival 68.8%. The rate of local recurrence and distant metastases were 6.1 and 23.6%. In multivariate analysis, concomitant chemotherapy oxaliplatin and capecitabine improved the pathological complete response rate (ypT0; capecitabine: 6%, 5-fluoro-uracil-leucovorin: 10.3%, capecitabine-oxaliplatin: 22.2%), but not significantly (P=0.12) and with more toxicities, and treatment interruptions. Sphincter preservation rate was not improved significantly during the study period (1993-2004 vs. 2005-2008), but disease-free survival improved from 72.2% up to 87.5% (P=0.03).

CONCLUSION

Our results are consistent with those published in the literature. Concomitant chemotherapy with 5-fluoro-uracil or capecitabine remains the standard scheme. Upfront chemotherapy, before chemoradiotherapy, should be investigated with regard to the predominance of metastasis.

Where does pelvic nerve injury occur during rectal surgery for cancer?

AIM

Optimal treatment of rectal adenocarcinoma involves total mesorectal excision with nerve-preserving dissection. Urinary and sexual dysfunction is still frequent following these procedures. Improved knowledge of pelvic nerve anatomy may help reduce this and define the key anatomical zones at risk.

METHOD

The MEDLINE database was searched for available literature on pelvic nerve anatomy and damage after rectal surgery using the key words 'autonomic nerve', 'pelvic nerve', 'colorectal surgery', and 'genitourinary dysfunction'. All relevant French and English publications up to May 2010 were reviewed. Reviewed data were illustrated using 3D reconstruction of the foetal pelvis.

RESULTS

The ligation of the inferior mesenteric artery and dissection of the retrorectal space can cause damage to the superior hypogastric plexus and/or hypogastric nerve. Anterolateral dissection in the 'lateral ligament' area and division of Denonvilliers' fascia can damage the inferior hypogastric plexus and efferent pathways. Perineal dissection can indirectly damage the pudendal nerve.

CONCLUSIONS

In most cases, the pelvic nerves can be preserved during rectal surgery. Complete oncological resection may require dissection close to the nerves where the tumour is located anterolaterally where it is fixed and when the pelvis is narrow.

Traitements préopératoires des cancers rectaux

Surgery alone is no longer appropriate to the treatment of T3-T4 resecable rectal cancer. Preoperative chemoradiotherapy has recently been approved as the new standard treatment. This approach improves local control with local failure rate raranging now around 6-8%. However, it does not impact on overall survival. It becomes urgent to develop new concepts and a basic research in the understanding of the biological mechanisms that may explain the resistance of the micrometastatic process.