Impact of Preoperative Staging and Chemoradiation Versus Postoperative Chemoradiation on Outcome in Patients With Rectal Cancer: A Decision Analysis

Defining optimum treatment of patients with pancreatic adenocarcinoma using regret-based decision curve analysis

OBJECTIVE

To use regret decision theory methodology to assess three treatment strategies in pancreatic adenocarcinoma.

BACKGROUND

Pancreatic adenocarcinoma is uniformly fatal without operative intervention. Resection can prolong survival in some patients; however, it is associated with significant morbidity and mortality. Regret theory serves as a novel framework linking both rationality and intuition to determine the optimal course for physicians facing difficult decisions related to treatment.

METHODS

We used the Cox proportional hazards model to predict survival of patients with pancreatic adenocarcinoma and generated a decision model using regret-based decision curve analysis, which integrates both the patient's prognosis and the physician's preferences expressed in terms of regret associated with a certain action. A physician's treatment preferences are indicated by a threshold probability, which is the probability of death/survival at which the physician is uncertain whether or not to perform surgery. The analysis modeled 3 possible choices: perform surgery on all patients; never perform surgery; and act according to the prediction model.

RESULTS

The records of 156 consecutive patients with pancreatic adenocarcinoma were retrospectively evaluated by a single surgeon at a tertiary referral center. Significant independent predictors of overall survival included preoperative stage [P = 0.005; 95% confidence interval (CI), 1.19-2.27], vitality (P < 0.001; 95% CI, 0.96-0.98), daily physical function (P < 0.001; 95% CI, 0.97-0.99), and pathological stage (P < 0.001; 95% CI, 3.06-16.05). Compared with the "always aggressive" or "always passive" surgical treatment strategies, the survival model was associated with the least amount of regret for a wide range of threshold probabilities.

CONCLUSIONS

Regret-based decision curve analysis provides a novel perspective for making treatment-related decisions by incorporating the decision maker's preferences expressed as his or her estimates of benefits and harms associated with the treatment considered.

Optimizing adjuvant treatment decisions for stage t2 rectal cancer based on mesorectal node size: a decision analysis

RATIONALE AND OBJECTIVES

The aim of this study was to optimize treatment decisions for patients with suspected stage T2 rectal cancer on the basis of mesorectal lymph node size at magnetic resonance imaging.

MATERIALS AND METHODS

A decision-analytic model was developed to predict outcomes for patients with stage T2 rectal cancer at magnetic resonance imaging. Node-positive patients were assumed to benefit from chemoradiation prior to surgery. Imperfect magnetic resonance imaging performance for primary cancer and mesorectal nodal staging was incorporated. Five triage strategies were considered for administering preoperative chemoradiation: treat all patients; treat for any mesorectal node >3, >5, and >7 mm in size; and treat no patients. If nodal metastases or unsuspected stage T3 disease went untreated preoperatively, postoperative chemoradiation was needed, resulting in poorer outcomes. For each strategy, rates of acute and long-term chemoradiation toxicity and of 5-year local recurrence were computed. Effects of input parameter uncertainty were evaluated in sensitivity analysis.

RESULTS

The optimal strategy depended on the outcome prioritized. Acute and long-term chemoradiation toxicity rates were minimized by triaging only patients with nodes >7 mm to preoperative chemoradiation (18.9% and 10.8%, respectively). A treat-all strategy minimized the 5-year local recurrence rate (5.6%). A 7-mm nodal triage threshold increased the 5-year local recurrence rate to 8.0%; when no patients were treated preoperatively, the local recurrence rate was 10.1%. With improved primary tumor staging, all outcomes could be further optimized.

CONCLUSIONS

Mesorectal nodal size thresholds for preoperative chemoradiation should depend on the outcome prioritized: higher size thresholds reduce chemoradiation toxicity but increase recurrence rates. Improvements in nodal staging will have greater impact if primary tumor staging can be improved.

Preoperative versus postoperative radiotherapy for rectal cancer in a decision analysis and outcome prediction model

PURPOSE

Reduction of local recurrences has been achieved by radiotherapy, but also by improved surgical technique (total mesorectal excision). Radiotherapy has adverse effects and cannot exceed local dose limits. Neoadjuvant radiotherapy may result in overtreatment. We aimed to define the minimum local benefit that would have to be postulated for radiotherapy in order to bring a benefit to the overall cohort. We hypothesized that saving radiotherapy as treatment for a subset of patients with high-risk tumors and local recurrences improves the outcome of the overall cohort. We sought to simulate preoperative versus postoperative radiotherapy in theoretical decision analysis model based on published recurrence rates, with overall survival being the primary end point.

METHODS

Computerized literature search for studies published between 1996 and 2011, supplemented by manual review of the retrieved reference lists.

RESULTS

Postoperative radiotherapy evolved as preferred strategy with cure rates of 65.6 % vs. 63.7 % for postoperative and neoadjuvant radiotherapy, respectively, and a decrease of radiation exposure to 42.9 % of the cohort. The system was sensitive to (1) the fraction of stage I cancers included in the cohort, (2) the difference between local recurrence rates (LRR) for neoadjuvant radiotherapy, adjuvant radiotherapy, or surgery-only approach, and (3) the compliance with the postoperative radiotherapy. If the surgery-only recurrence was set to the published 10 %, 13 %, and 27 %, respectively, adjuvant radiotherapy had to achieve LRR below the threshold values of 6.3 %, 8.5 %, and 18.3 % to reverse the impact of compliance.

CONCLUSIONS

Radiotherapy only improves cancer-specific survival of the cohort if there is a large difference in LRR with versus without it. Routine treatment may therefore be inferior to a tailored radiotherapy regimen.

Estándares de calidad de la cirugía del cáncer de recto

The results of surgery for rectal cancer have classically been measured through indicators such as morbidity, mortality, and length of hospital stay. In the last few years other parameters have been included that evaluate healthcare quality such as the functional results of the surgical technique employed and quality of life. Total resection of the mesorectum, performed by experienced surgeons, is the surgical technique of choice. Currently, the sphincter can be preserved in 70% of patients. Anastomotic dehiscence after anterior resection of the rectum is the most serious complication and the most important risk factor is the height of the anastomosis. The overall dehiscence rate should be less than 15% and operative mortality should be between 2% and 3%. The colonic reservoir improves functional outcome and consequently it is the procedure of choice to reconstruct transit after low anterior resection. Local recurrence should be less than 10% and 5-year survival should be between 70% and 80%. In general, quality of life is better after anterior resection of the rectum than after abdominoperineal amputation, despite the functional deterioration presented by some patients.

Preoperative chemoradiation with oral tegafur within a multidisciplinary therapeutic approach in patients with T3-4 rectal cancer

PURPOSE

The aim of this study was to evaluate the activity in terms of downstaging histologic patterns of residual tumor and clinical tolerance of a neoadjuvant chemoradiation program with oral tegafur for rectal cancer.

METHODS AND MATERIALS

From May 1998 to May 2001, 62 consecutive patients with cT(3-4) or cN(+) rectal cancer, or both, were treated with 45-50 Gy (1.8 Gy/day; 25 fractions) and oral tegafur 1200 mg/day. Surgery was performed 6 weeks after the completion of chemoradiation. All patients received a boost with intraoperative electron beam radiotherapy (IOERT) over the presacral space.

RESULTS

Grade 3-4 hematologic toxicity consisted on Grade 3 anemia in 1 patient. Nonhematologic toxicity was mild. Fifteen patients (23%) had Grade 3 dermatitis, 16 (25%) had Grade 3, and 2 (3%) had Grade 4 proctitis. The median dose of radiotherapy was 50.4 Gy. Surgery consisted on anterior resection in 38 patients (61%) and abdominoperineal amputation in 24 (39%). Five complete pathologic responses were observed (8%), and 29 patients (47%) had a minimal microscopic residual tumor (mic category). The total downstaging rate was 68%. With a median follow-up of 46 months, the pelvic control rate was 95%, disease-free survival 74.1%, and overall survival 76.5%.

CONCLUSIONS

Neoadjuvant chemoradiation with oral tegafur is feasible, well tolerated, and active, with the additional advantage of offering the convenience of oral chemotherapy.

Immediate radical resection after local excision of rectal cancer: an oncologic compromise?

PURPOSE

Local excision for early-staged rectal cancers is controversial. Preoperative understaging is not uncommon and radical resection after local resection may be needed for a curative treatment. The aim of this study was to determine the frequency and outcome of radical resection (within 30 days) after local excision for rectal adenocarcinoma.

METHODS

All locally excised rectal cancers (curative intent) that required radical surgery within 30 days were reviewed (1980-2000). T2-3N0-1 stage cancers were each matched to three primary radical surgery controls for stage, age (+/- 5 years), gender, date (+/- 1 years), and type (abdominoperineal resection or low anterior resection) of operation. T1N0-1 cancers were compared with stage-matched rectal cancers treated by either primary radical surgery (n = 78) or local excision alone (n = 77).

RESULTS

Fifty-two locally excised rectal adenocarcinomas (29 transanal and 23 polypectomies) were followed by radical surgery (24 abdominoperineal resection and 28 low anterior resection) within 7 (range, 1-29) days. Radical surgery was performed because of a cancerous polyp (n = 42), positive margins (5), lymphovascular invasion (3), and T3-staged cancer (2). Twelve of 52 cancers (23 percent) were found to have nodal involvement and 15 of 52 (29 percent) showed residual cancer in the resected specimen. The T2-3N0-1 stage controls were well matched. No significant difference in tumor location, size, adjuvant therapy, or length of follow-up was noted. Local and distant recurrence occurred in 2 of 4 T2-3N1 tumors and in 2 of 11 T2-3N0 cancers and were comparable to the matched controls, as was survival, with the exception of shorter survival in T3N1 cases, but numbers were too small for a definitive conclusion. Length of follow-up was not different. For T1 cancers, the controls were also comparable regarding patient and tumor demographics and adjuvant therapy. Nodal involvement was 21 percent in T1 study cases and 15 percent in T1 primary radical-surgery controls, with a trend toward location in the lower third of the rectum in both groups (58 percent and 50 percent, respectively). Local recurrence rates were 3 percent in the study group, 5 percent for patients undergoing primary radical surgery, and 8 percent for local excision alone. Distant metastasis (11 percent, 12 percent, and 13 percent, respectively) and overall five-year survival were also not significantly different (78 percent, 89 percent, and 73 percent, respectively).

CONCLUSIONS

Nodal involvement in attempted locally excised rectal cancers is not uncommon. Local excision of rectal tumors followed by radical surgery within 30 days in cancer patients does not compromise outcome compared with primary radical surgery. Even after radical surgery for superficial T1 rectal cancers, recurrence rates are not insignificant. Future improvements in preoperative staging may be helpful in selecting tumors for local excision only.