{'fraction_non_alphanumeric': 0.020596438532503755, 'fraction_numerical': 0.0025745548165629693, 'mean_word_length': 5.457063711911357, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Simulating watch and wait for rectal cancer.

for decades, it has been accepted that surgical resection is the cornerstone for the curative treatment of rectal cancer. Conventional treatment for patients with locally advanced stages ii and iii rectal cancers has included preoperative radiation with concurrent chemotherapy, before radical resection, to improve local control. unfortunately, surgery is not without its risk for serious complications, which can include anastomotic leak, perineal wound dehiscence, and even mortality. moreover, surgery for rectal cancer may necessitate a permanent colostomy or have significant impact on subsequent bowel function and quality of life. historically, surgery has been deferred in patients who have been too ill or have refused surgery. however, building on the pioneering work of habr-Gama et al, several units have reported their preliminary experiences with a watch-and-wait strategy among patients with rectal cancer that responds well to preoperative chemoradiation. the rationale for a watch-and-wait strategy is appealing. after contemporary neoadjuvant chemoradiotherapy, approximately 50% of patients will experience a significant clinical response, and 10% to 20% of patients will have a pathologic complete response (pCR), with no evidence of residual tumor. thus, clinicians and patients not infrequently engage in the sometimes unsettling discussion of the good news of a pCR, but with the reality that the rectum had to be removed and a permanent ostomy was required or that lifelong bowel dysfunction could be anticipated. although there is increasing interest in such a strategy, questions remain regarding the oncologic safety, particularly when compared with the excellent outcomes that can be achieved with surgical resection. in the article that accompanies this editorial, the authors have used a decision-analytic approach to tackle this question. Decision analysis can be a particularly useful approach for comparing the effectiveness of alternative approaches with treatment where the benefits and harms must be balanced for individual patients or patient cohorts. ultimately, inferences regarding the choice of treatment will depend on the probability of the potential outcomes and the patient’s value of the outcomes; thus, the approach inherently involves a trade-off. the result of decision analysis is particularly robust when there is strong evidence regarding the input data or assumptions regarding the likelihood for each of the base-case conditions or intermediate outcomes of interest (eg, detection of pCR, rate of relapse, or potential for salvage) and the utilities of the given health states (ie, the quantitative measure of the value that a patient places on a given outcome state relative to perfect health). Consistent with its roots in comparative effective research, the primary outcome of interest is, thus, typically overall or absolute survival that can be measured in quality-adjusted life expectancy. however, as is not uncommon in situations where decision-analytic methods are used to address clinical questions for which high-quality randomized data is lacking, investigators must often rely on lowerquality data or expert opinion to fill in the gaps. in their analysis, smith et al specifically evaluated the impact of age on the treatment decisions by modeling both fit and comorbidity-affected hypothetical 60and 80-yearold patients separately and concluded that survival was not compromised by a watch-and-wait strategy in any patient group and that, in fact, it was associated with significantly improved absolute but not disease-free survival in both the hypothetical fit and comorbid 80-year-old cohorts. their findings are in contrast to a previous analysis in Diseases of the Colon & Rectum, which used almost the same evidence base but concluded that, in the base case, surgery is beneficial for the average patient with rectal cancer and clinical complete response after neoadjuvant therapy. these simulations highlight many of the issues concerning watch and wait after neoadjuvant treatment for rectal cancer. these important issues include the ability to clinically identify patients with a pCR and the assumption that, among complete responders, long-term oncologic outcomes are equal to those after surgical resection. in addition, important model parameters, such as baseline estimates of surgical mortality, risks for relapse after surgery vs observation, outcomes after salvage resection for local relapse after observation, and utilities associated with the outcome states, have critical impacts on Simulating Watch and Wait for Rectal Cancer