Non-Operative Management (NOM) in Rectal Cancer: Current Evidence and Future Directions

Non-Operative Management (NOM) in Rectal Cancer: Current Evidence and Future Directions: History

Please note this is an old version of this entry, which may differ significantly from the current revision.

Contributor: Vincenzo Schiavone , Gabriella Teresa Capolupo , Gianluca Mascianà , Filippo Carannante , Gianluca Costa , Valentina Miacci , Marco Caricato

Rectal cancer has become a significant health concern in current years, but there are very effective current neo-adjuvant treatment modalities which can result in the complete disappearance of the disease without surgery, which is often associated with severe post-surgical sequelae. Therefore, a significant effort has been made to identify the subset of patients who can avoid surgery and to investigate the long-term oncologic and functional results associated with the Non-Operative Management of such a disease.

rectal cancer
non-operative management
total neo-adjuvant treatment and LARS

Rectal cancer remains a major global health concern, with new cases increasing annually ^[1]. The standard treatment for locally advanced disease has traditionally included neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision (TME). Although oncologically effective, surgery is associated with considerable morbidities, including bowel, urinary, and sexual dysfunction ^[2]^[3].

The concept of Non-Operative Management (NOM), also known as the “Watch-and-Wait” (WW) strategy, has emerged as an alternative for patients achieving a clinical complete response (cCR) after neoadjuvant therapy ^[4]^[5]. Early data from the International Watch & Wait Database (IWWD) demonstrated promising long-term oncologic outcomes ^[6]^[7]. More recent evidence, including updated National Comprehensive Cancer Network (NCCN) and European Society For Medical Oncology (ESMO) guidelines, supports NOM in carefully selected patients, provided rigorous surveillance protocols are followed ^[8]^[9].

Advances in Total Neoadjuvant Therapy (TNT) have increased cCR rates, expanding the pool of patients eligible for organ preservation ^[10]^[11]. Novel immunotherapy approaches, particularly in mismatch repair-deficient (dMMR) rectal cancers, have demonstrated unprecedented response rates, raising the possibility of NOM as a curative option without radiation or surgery ^[12]^[13].

Given these developments, we present a narrative review focusing on NOM protocols, oncologic and functional outcomes, patient selection, and long-term feasibility.

This entry is adapted from the peer-reviewed paper 10.3390/encyclopedia5040165

References

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Lelong, B.; de Chaisemartin, C.; Meillat, H.; Cournier, S.; Boher, J.M.; Genre, D.; Karoui, M.; Tuech, J.J.; Delpero, J.R.; The French Research Group of Rectal Cancer Surgery (GRECCAR). A multicentre randomised controlled trial to evaluate the efficacy, morbidity and functional outcome of endoscopic transanal proctectomy versus laparoscopic proctectomy for low-lying rectal cancer (ETAP-GRECCAR 11 TRIAL): Rationale and design. BMC Cancer 2017, 17, 253.
Carannante, F.; Piozzi, G.N.; Miacci, V.; Bianco, G.; Melone, G.; Schiavone, V.; Costa, G.; Caricato, M.; Khan, J.S.; Capolupo, G.T. Quadruple Assessment of Colorectal Anastomosis after Laparoscopic Rectal Resection. J. Clin. Med. 2024, 13, 5092.
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Conroy, T.; Bosset, J.F.; Etienne, P.L.; Rio, E.; François, É.; Mesgouez-Nebout, N.; Vendrely, V.; Artignan, X.; Bouché, O.; Gargot, D.; et al. Neoadjuvant chemotherapy with FOLFIRINOX and preoperative chemoradiotherapy for patients with locally advanced rectal cancer (UNICANCER-PRODIGE 23): A multicentre, randomised, open-label, phase 3 trial. Lancet Oncol. 2021, 22, 702–715.
Cercek, A.; Lumish, M.; Sinopoli, J.; Weiss, J.; Shia, J.; Lamendola-Essel, M.; El Dika, I.H.; Segal, N.; Shcherba, M.; Sugarman, R.; et al. PD-1 blockade in mismatch repair–deficient rectal cancer. N. Engl. J. Med. 2022, 386, 2363–2376.
Lin, Z.Y.; Zhang, P.; Chi, P.; Xiao, Y.; Xu, X.M.; Zhang, A.M.; Qiu, X.F.; Wu, J.X.; Yuan, Y.; Wang, Z.N.; et al. Neoadjuvant short-course radiotherapy followed by camrelizumab and chemotherapy (UNION trial). Ann. Oncol. 2024, 35, 882–891.

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