Analysis of re-recurrent rectal cancer after curative treatment of locally recurrent rectal cancer

Purpose

Substantiating data guiding clinical decision making in locally recurrent rectal cancer (LRRC) is lacking, specifically in target volume (TV) definition for chemoradiotherapy (CRT). A case-by-case review of local re-recurrences (re-LRRC) after multimodal treatment for LRRC was performed, to determine location of re-LRRC and assess whether treatment could have been improved.

Methods

All patients treated with curative intent for LRRC at the Catharina Hospital Eindhoven from October 2016 onwards, in whom complete imaging of (re-)LRRC and radiotherapy was available, were retrieved. Patients were discussed in plenary meetings with expert colorectal surgeons, radiation oncologists and radiologists. Each case was classified based on re-LRRC location, whether it was in accordance with the (current) radiotherapy protocol, and whether multimodal management would have been different in retrospect.

Results

Thirty-three cases were discussed. LRRC treatment was deemed suboptimal in 17/33 patients, due to different target volumes (13/17) and/or different surgery (9/17). 15/33 (46 %) of re-LRRC developed in-field of the prior radiotherapy TV, possibly showing RT-resistant disease. Other re-LRRCs developed out-field (n = 5, 15 %), marginally (n = 6, 18 %), or in a combined fashion (n = 7, 21 %). In retrospect, 48 % of cases were irradiated in line with current TV recommendations. TVs of 13/33 cases would have been altered if irradiated today.

Conclusion

This study highlights room for improvement within current standard-ofcare treatment for LRRC. Different surgical management or TVs may have improved outcome in up to half of discussed cases. Further delineation guideline development, incorporating the results from this study, may improve oncological outcome, specifically local control, for LRRC patients.