Complete Response after Neoadjuvant Therapy in Rectal Cancer: To Operate or Not to Operate?

Abstract

Background/Aims: Evidence exists to support both surgical and nonoperative observational approaches to the management of patients with distal rectal cancer who achieve a complete response following neoadjuvant chemoradiotherapy (CRT). This article summarizes findings from key studies on management strategies for complete pathologic and clinical responders after neoadjuvant CRT for rectal cancer. Methods: A comprehensive literature review was undertaken comparing complete responders to neoadjuvant CRT who underwent surgical procedures or nonoperative observation. Results: The sensitivity and specificity of clinical assessment tools following neoadjuvant CRT are generally low. Endoscopic ultrasound and MRI are widely used for rectal cancer staging; PET/CT is applied for detecting residual cancer, although limitations exist in assessing mesorectal disease. In patients with rectal cancer who receive neoadjuvant CRT, rates of complete pathologic response vary from 5 to 44%. Rates of nodal disease in patients with complete pathologic response vary from 0 to 15%. In patients with stage 0 rectal cancer, excellent long-term oncologic results have been reported for both surgical resection and nonoperative observation; therefore, some authors consider that surgical resection may result in unnecessary morbidity. Whereas neoadjuvant CRT followed by total mesorectal excision (TME) reduces local recurrence and improves 5-year survival, TME is associated with significant morbidity and suboptimal functional results. Conclusion: Informed consent in patients with distal rectal cancer who achieve a complete response to neoadjuvant CRT must address both the potential risks of recurrence following nonoperative observation and the increased risks of postoperative morbidity and compromised function following extirpative surgery.

Oncological outcomes of local excision compared with radical surgery after neoadjuvant chemoradiotherapy for rectal cancer: a systematic review and meta-analysis

“…Of 90 patients, 23 had local recurrence only, 5 had combined systemic and local recurrence and 8 patients had only systemic recurrence. However, overall recurrence was 40 % [9,10]. Dedemadi and Wexner in a review reported excellent long-term survival in patients who had a complete clinical response after neoadjuvant CRT treated both with surgery and non-surgical management [9].…”

The emerging role of FDG PET/CT in rectal cancer management: is it time to use the technique for early prognostication?

“…In patients with rectal cancer who receive neoadjuvant CRT, rates of complete pathologic response range from 5 to 44 %, while rates of pathologic complete response of nodal disease in patients with pathologic complete response of the primary tumour range from 0 to 15 %. Given the possibility of performing "interim" metabolic and functional evaluation, experts are now beginning to debate the question of what to do in patients with a pathologic complete response also demonstrated by FDG PET/CT; it is still necessary to expose them to the rigours of aggressive surgery or would a wait-and-see strategy be more appropriate [22]? In an interesting paper, just published in the European Journal of Nuclear Medicine and Molecular Imaging, Murcia Duréndez et al stated that PET/CT is a reliable technique for assessing response to neoadjuvant radiochemotherapy (RCT) in locally advanced rectal cancer, with a view to considering more conservative surgical treatment [23].…”

“…From this perspective, the work of Calvo et al is worthy of attention and calls for further, SUV-based and clinically oriented investigations. We are well aware that the various problems surrounding SUVs-for example, problems in SUV calculation and reproducibility, clearly set out in the European Journal of Nuclear Medicine and Molecular Imaging editorial [22]-are still far from resolved. A partial solution to these problems, as outlined by Calvo et al in their work, could possibly lie in correct standardization of the method and the accumulation of experience, by single centres, in order to increase confidence and familiarity with imaging and its clinical implications.…”

Profiling of rectal cancers MRI in pathological complete remission states after neoadjuvant concurrent chemoradiation therapy

“…6,7 The capacity to predict pCR states in rectal cancers through preoperative clinical assessment thus has substantial benefit, not only in terms of prognostication but also in planning individualised therapies. 8 Unfortunately, routine clinical practices (digital rectal examinations and sigmoidoscopy) are far from satisfactory for this purpose. 1,9,10 Magnetic resonance imaging (MRI) is a valuable imaging tool that is widely utilised for local staging of rectal cancer.…”