Clinical Target Volume for Rectal Cancer: In Regard to Roels et al. (Int J Radiat Oncol Biol Phys 2006;65:1129–1142)

Excluding the ischiorectal fossa irradiation during neoadjuvant chemoradiotherapy with intensity-modulated radiotherapy followed by abdominoperineal resection decreases perineal complications in patients with lower rectal cancer

BACKGROUND

The aim of this study was to explore the impact of including or excluding the ischiorectal fossa (IRF) within the clinical target volume during neoadjuvant chemoradiotherapy (NCRT) using intensity modulated radiotherapy, in locally advanced lower rectal cancer (LALRC).

METHODS

We retrospectively analysed the data of 220 LALRC patients who received NCRT followed by abdominoperineal resection between January 2009 and January 2015. Six patients were excluded because of loss to follow-up, 90 patients received IRF irradiation (IRF group) while 124 patients did not (NIRF group). Survival, patterns of recurrence, and treatment toxicities were compared between the two groups.

RESULTS

Overall, patient/treatment variables were well balanced except for surgical technique. Perineal wound complications in the IRF and NIRF groups, were 40.0 and 24.2%, respectively (p = 0.010); corresponding 3-year perineal recurrence rates, local recurrence free survival, overall survival, and distant relapse free survival were 4.4% vs. 2.4% (p = 0.670), 88.1% vs. 95.0% (p = 0.079), 82.6% vs. 88.4% (p = 0.087), and 61.9% vs. 81.0% (p = 0.026), respectively. Multivariate analyses demonstrated the following factors to be significantly related to perineal wound complications: irradiation of the IRF (odds ratio [OR] 2.892, p = 0.002), anaemia (OR 3.776, p = 0.010), operation duration > 180 min (OR 2.486, p = 0.007), and interval between radiotherapy and surgery > 8 weeks (OR 2.400, p = 0.010).

CONCLUSIONS

Exclusion of the IRF from the clinical target volume during NCRT using intensity-modulated radiotherapy in LALRC could lower the incidence of perineal wound complications after abdominoperineal resection, without compromising oncological outcomes.

International consensus guidelines on Clinical Target Volume delineation in rectal cancer

INTRODUCTION

The delineation of Clinical Target Volume (CTV) is a critical step in radiotherapy. Several guidelines suggest different subvolumes and anatomical boundaries in rectal cancer (RC), potentially leading to a misunderstanding in the CTV definition. International consensus guidelines (CG) are needed to improve uniformity in RC CTV delineation.

MATERIAL AND METHODS

The 7 radiation oncologist experts defined a roadmap to produce RC CG. Step 1: revision of the published guidelines. Step 2: selection of RC cases with different clinical stages. Step 3: delineation of cases using Falcon following previously published guidelines. Step 4: meeting in person to discuss the initial delineation outcome, followed by a CTV proposal based on revised and if needed, adapted anatomical boundaries. Step 5: peer review of the agreed consensus. Step 6: peer review meeting to validate the final outcome. Step 7: completion of RC delineation atlases.

RESULTS

A new ontology of structure sets was defined and the related table of anatomical boundaries was generated. The major modifications were about the lateral lymph nodes and the ischio-rectal fossa delineation. Seven RC cases were made available online as consultation atlases.

CONCLUSION

The definition of international CG for RC delineation endorsed by international experts might support a future homogeneous comparison between clinical trial outcomes.

Update on advances and controversy in rectal cancer treatment

Changes in the multidisciplinary treatment of rectal cancer have been recently proposed. We performed a comprehensive review of the current data on neoadjuvant and adjuvant treatment of rectal cancer, focussing on chemoradiotherapy treatment and timing of surgery. Six components were proposed as the framework for the treatment of rectal cancer: neoadjuvant therapy and changing patterns in patient selection, long- or short-course radiotherapy, adverse effects of radiotherapy, timing of surgery, non-operative management of rectal cancer and postoperative adjuvant therapy. Lack of a consistent difference in terms of local recurrence has been observed between short-course radiotherapy and long-course chemoradiotherapy. Indications for preoperative radiotherapy have been reconsidered in the last years. An interval of 10-11 weeks seemed to be the optimal timing, with no impact on patient safety. Since assessment criteria of clinical complete response are not well defined, and the basis for non-operative management of rectal cancer is still not clear, further investigations are required. There is controversy about standard treatments for patients with locally advanced rectal cancer that are being analyzed by ongoing studies. Tailored treatments could avoid over-treatment for a large number of patients without any impairment of the oncologic results.