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If you are considering a watch-and-wait policy for patients with a complete clinical response (cCR), you should consider treating cT2N0 low rectal tumors with neoadjuvant chemoradiation.
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The best tool to assess cCR is digital rectal examination and endoscopy. Endoscopic biopsy results may be misleading.
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Radiological imaging does not diagnose cCR; it just confirms it. In the absence of cCR, do not look for radiological evidence to support nonoperative management.
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Local excision (full excisional
Nonoperative Management of Rectal Cancer: Identifying the Ideal Patients
Section snippets
Key points
Indications for neoadjuvant therapy
Classic indications for neoadjuvant therapy in rectal cancer are mostly derived from randomized controlled studies that showed a local control benefit among patients with cT3-4 or cN+ tumors treated with radiation or chemoradiation (CRT), followed by radical surgery.2, 3 However, recent updates with a longer follow-up of these same cohorts suggest that the benefits in local disease control following neoadjuvant CRT and radical surgery are marginal or even outweighed by treatment-related
Types of neoadjuvant therapy
Considering neoadjuvant therapy will be used for the purpose of tailoring surgical therapy for patients based on the tumor response, strategies associated with significant tumor regression are preferred.1 Therefore, combined association of chemotherapy and radiation (ie, long-course with hyperfractionated radiation therapy (RT) doses) has been shown to result in greater tumor regression rates and an increased chance of a complete response.7, 13 In contrast, short-course RT alone may only lead
Why?
The rationale for assessing the tumor response after neoadjuvant therapy is to define the final treatment strategy based on the current status of the tumor, that is, after therapy.
In a significant proportion of patients undergoing neoadjuvant CRT, complete tumor regression may develop. The problem is that most of the time radical surgery is required to appropriately confirm the presence of a pCR. In an effort to spare patients from potentially unnecessary surgery, colorectal surgeons have
Local excision of the tumor site
For patients with small residual lesions, the authors usually offer a FTLE, preferably with the use of TEM as a diagnostic procedure (Video 2)
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Small lesions (≤3 cm)
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Low lesions, otherwise candidate for abdominal-perineal excision (APE) or a coloanal intersphincteric resection
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No evidence of mesorectal dissemination by imaging studies
It has been the authors’ policy to offer strict follow-up to patients with a final pathologic specimen showing ypT0 after this diagnostic FTLE because the risk of
Radiological imaging
Radiological assessment of response is of paramount importance to appropriately select patients for an alternative treatment strategy, such as the watch-and-wait approach, following a cCR. As a matter of fact, the developments in radiological imaging, including both PET/CT and MR, have been quite significant. Proper MRI with the use of diffusion-weighted techniques are now used routinely for the assessment of response in these patients.40 Currently, the authors would only consider a true
Carcinoembryonic antigen
Pretreatment carcinoembryonic antigen (CEA) levels have been shown to be predictors of the response to neoadjuvant CRT and ultimately survival.41, 47 Posttreatment CEA levels are also relevant, and normal levels after CRT have been associated with increased cCR rates.48 Abnormal CEA levels before or after CRT should raise the suspicion of an incomplete response to CRT and/or metastatic dissemination (Box 9).49
Final Decision Management
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Patients are usually assessed for tumor response to neoadjuvant CRT at least 8 to 12 weeks from treatment completion.
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Assessment
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Clinical and endoscopic features should be assessed using DRE and rigid proctoscopy.
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Flexible proctoscopy is used solely for video documentation.
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CEA levels should be normal both before and after treatment, otherwise additional studies are strongly recommended.
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MR should be performed for 2 purposes:
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Confirmation of findings consistent with a complete response within the
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Local recurrence and salvage
Local recurrence after no immediate surgery following a cCR may develop at any time during the follow-up of these patients. Even though there is no accepted standard definition of recurrence in terms of timing after CRT, it has been the authors’ policy to consider early recurrences developing within the initial 12 months of follow-up as early tumor regrowths.16 Early tumor regrowths have been reported in up to 19% of patients undergoing standard CRT regimens and the watch-and-wait approach
Systemic recurrence
Patients with pCR are still at risk for the development of systemic recurrences. In a pooled analysis of more than 3000 patients with pCR, the distant metastases rate was 11%. Curiously, nearly 40% of this cohort ultimately received adjuvant chemotherapy.9
Distant metastases have been reported in 14% of patients with cCR managed nonoperatively. Ultimately, 18% of patients with local recurrences and 13% without any local recurrence were found to have metastatic disease at follow-up. Only patients
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2021, Revista de Gastroenterologia de MexicoWatch-and-Wait Compared to Operation for Patients with Complete Response to Neoadjuvant Therapy for Rectal Cancer
2020, Journal of the American College of SurgeonsCitation Excerpt :Early iterations of WW discouraged use of pelvic imaging because of concern that equivocal findings would lead patients unnecessarily to surgery. However, in recent years and with greater experience, MRI has gained wider acceptance in response evaluation, and it is now standard at most institutions practicing WW.14,15,25 The years captured by our study were a period of increasing use of MRI for response assessment at our institution.
MR-based artificial intelligence model to assess response to therapy in locally advanced rectal cancer
2019, European Journal of RadiologyCitation Excerpt :However, after surgery, 20% to 25% of patients present pathologic complete response (CR) [4]. In those patients, TME can be considered a substantial overtreatment, since they might benefit from either less invasive surgical approach (i.e trans-anal endoscopic microsurgery) or wait-and-watch strategy [5–7]. The opposite scenario includes patients who do not respond to therapy, i.e., non-responders (NR).
Toward less invasive coloproctology: The future is out there
2024, World Journal of GastroenterologyMRI in rectal cancer patients on ‘watch and wait’: patterns of response and their evolution
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2023, World Journal of Surgery