Near-Complete Response After Total Neoadjuvant Therapy: Management Options in the Current Landscape

Abstract Advances in neoadjuvant therapies have led to paradigm shifts in rectal cancer management, particularly increased emphasis on organ preservation through nonoperative management (NOM) with active surveillance. Management of patients with near-complete response (NCR) to neoadjuvant therapy remains controversial, though several centers have incorporated these patients into their NOM protocols. This narrative review aims to summarize the historical context, clinical criteria, treatment options, and outcomes for patients who achieve NCR and initiate organ preservation. We also discuss common pitfalls of applying organ preservation strategies within this population, as well as our institutional management algorithm. NCR describes a robust but partial response to total neoadjuvant therapy with lingering findings such as superficial ulceration, small mucosal nodules, or minimal residual signal on magnetic resonance imaging. Recommended timing of initial restaging is at least 8 to 12 weeks following completion of radiotherapy, with longer intervals allowing more time for progressive tumoricidal effects. Patients with stable NCR or evolution to clinical complete response (CCR) have been offered NOM with organ preservation rates ranging from 40 to 70%. While local regrowths are more common among patients with NCR relative to patients with CCR, they appear to be salvageable with total mesorectal excision with comparable oncologic outcomes to immediate proctectomy. Given higher local regrowth rates among patients with NCR, shared decision-making must be used to ascertain patient preferences and ensure surveillance compliance. We found data on the use of NOM among rectal cancer patients who achieve a NCR are heterogeneous but have demonstrated clinically significant organ preservation rates with acceptable oncologic outcomes. The success of NOM depends on multiple factors, including tumor stage at diagnosis, clinical findings at time of restaging evaluation, and the ability of patients to participate in frequent surveillance at experienced centers. With careful patient selection and use of shared decision-making to weigh the benefits and risks of active surveillance, organ preservation strategies have the potential to minimize morbidity for patients with rectal cancer who achieve NCR.