Dataset Information

Radiation dose-response model for locally advanced rectal cancer after preoperative chemoradiation therapy.

ABSTRACT: Preoperative chemoradiation therapy (CRT) is part of the standard treatment of locally advanced rectal cancers. Tumor regression at the time of operation is desirable, but not much is known about the relationship between radiation dose and tumor regression. In the present study we estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT.A total of 222 patients, treated with consistent chemotherapy and radiation therapy techniques, were considered for the analysis. Radiation therapy consisted of a combination of external-beam radiation therapy and brachytherapy. Response at the time of operation was evaluated from the histopathologic specimen and graded on a 5-point scale (TRG1-5). The probability of achieving complete, major, and partial response was analyzed by ordinal logistic regression, and the effect of including clinical parameters in the model was examined. The radiation dose-response relationship for a specific grade of histopathologic tumor regression was parameterized in terms of the dose required for 50% response, D50,i, and the normalized dose-response gradient, ?50,i.A highly significant dose-response relationship was found (P=.002). For complete response (TRG1), the dose-response parameters were D50,TRG1=92.0 Gy (95% confidence interval [CI] 79.3-144.9 Gy), ?50,TRG1=0.982 (CI 0.533-1.429), and for major response (TRG1-2) D50,TRG1&2=72.1 Gy (CI 65.3-94.0 Gy), ?50,TRG1&2=0.770 (CI 0.338-1.201). Tumor size and N category both had a significant effect on the dose-response relationships.This study demonstrated a significant dose-response relationship for tumor regression after preoperative CRT for locally advanced rectal cancer for tumor dose levels in the range of 50.4-70 Gy, which is higher than the dose range usually considered.

SUBMITTER: Appelt AL

PROVIDER: S-EPMC3539741 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Radiation dose-response model for locally advanced rectal cancer after preoperative chemoradiation therapy.

Appelt Ane L AL Pløen John J Vogelius Ivan R IR Bentzen Søren M SM Jakobsen Anders A

International journal of radiation oncology, biology, physics 20120703 1

<h4>Purpose</h4>Preoperative chemoradiation therapy (CRT) is part of the standard treatment of locally advanced rectal cancers. Tumor regression at the time of operation is desirable, but not much is known about the relationship between radiation dose and tumor regression. In the present study we estimated radiation dose-response curves for various grades of tumor regression after preoperative CRT.<h4>Methods and materials</h4>A total of 222 patients, treated with consistent chemotherapy and rad ...[more]

PMID: 22763027

Similar Datasets

Project description:ImportanceAlthough both short-course radiotherapy and long-course chemoradiotherapy have been practiced in parallel for more than 15 years, no cost-effectiveness analysis comparing these 2 approaches in patients with locally advanced rectal cancer has been published.ObjectiveTo analyze the cost-effectiveness of short-course radiotherapy vs long-course chemoradiotherapy for the treatment of patients with locally advanced rectal cancer.Design, setting, and participantsThis economic evaluation used a cost-effectiveness model simulating 10-year outcomes for 1 million hypothetical patients aged 65 years with locally advanced rectal cancer treated with either short-course radiotherapy or long-course chemoradiotherapy, followed by surgery and chemotherapy. Utilities and probabilities from the literature and costs from the Healthcare Bluebook and Medicare fee schedules were used to determine incremental cost-effectiveness ratios. It was assumed that long-course chemoradiotherapy would result in higher rates of low anterior resection (LAR). To model preference-sensitive care, a 2-way sensitivity analysis was conducted in which the utilities of the no-evidence-of-disease (NED) states with LAR and abdominoperineal resection (APR) were simultaneously varied. The analysis was repeated for patients with distal rectal tumors. Analysis was conducted from January to October 2018.ExposuresShort-course radiotherapy and long-course chemoradiotherapy.Main outcomes and measuresIncremental cost-effectiveness ratios.ResultsShort-course radiotherapy was the cost-effective strategy compared with long-course chemoradiotherapy (incremental cost-effectiveness ratio, $133 495 per quality-adjusted life-year). Two-way sensitivity analysis revealed that the cost-effective approach for a given patient depended on the utilities for the NED-LAR and NED-APR states. Assuming that a greater proportion of patients with locally advanced distal tumors undergoing long-course chemoradiotherapy (39%) would proceed to LAR compared with those treated with short-course radiotherapy (19%), long-course chemoradiotherapy was the cost-effective approach (incremental cost-effectiveness ratio, $61 123 per quality-adjusted life-year).Conclusions and relevanceShort-course radiotherapy was the cost-effective strategy compared with long-course chemoradiotherapy for patients with locally advanced rectal cancer. The cost-effectiveness of short-course radiotherapy vs long-course chemoradiotherapy was sensitive to the utilities of the NED-LAR and NED-APR health states, highlighting the importance of care that is sensitive to patient preference. Long-course chemoradiotherapy was the cost-effective approach for patients with distal tumors.

Project description:BackgroundPelvic radiation plus sensitizing chemotherapy with a fluoropyrimidine (chemoradiotherapy) before surgery is standard care for locally advanced rectal cancer in North America. Whether neoadjuvant chemotherapy with fluorouracil, leucovorin, and oxaliplatin (FOLFOX) can be used in lieu of chemoradiotherapy is uncertain.MethodsWe conducted a multicenter, unblinded, noninferiority, randomized trial of neoadjuvant FOLFOX (with chemoradiotherapy given only if the primary tumor decreased in size by <20% or if FOLFOX was discontinued because of side effects) as compared with chemoradiotherapy. Adults with rectal cancer that had been clinically staged as T2 node-positive, T3 node-negative, or T3 node-positive who were candidates for sphincter-sparing surgery were eligible to participate. The primary end point was disease-free survival. Noninferiority would be claimed if the upper limit of the two-sided 90.2% confidence interval of the hazard ratio for disease recurrence or death did not exceed 1.29. Secondary end points included overall survival, local recurrence (in a time-to-event analysis), complete pathological resection, complete response, and toxic effects.ResultsFrom June 2012 through December 2018, a total of 1194 patients underwent randomization and 1128 started treatment; among those who started treatment, 585 were in the FOLFOX group and 543 in the chemoradiotherapy group. At a median follow-up of 58 months, FOLFOX was noninferior to chemoradiotherapy for disease-free survival (hazard ratio for disease recurrence or death, 0.92; 90.2% confidence interval [CI], 0.74 to 1.14; P = 0.005 for noninferiority). Five-year disease-free survival was 80.8% (95% CI, 77.9 to 83.7) in the FOLFOX group and 78.6% (95% CI, 75.4 to 81.8) in the chemoradiotherapy group. The groups were similar with respect to overall survival (hazard ratio for death, 1.04; 95% CI, 0.74 to 1.44) and local recurrence (hazard ratio, 1.18; 95% CI, 0.44 to 3.16). In the FOLFOX group, 53 patients (9.1%) received preoperative chemoradiotherapy and 8 (1.4%) received postoperative chemoradiotherapy.ConclusionsIn patients with locally advanced rectal cancer who were eligible for sphincter-sparing surgery, preoperative FOLFOX was noninferior to preoperative chemoradiotherapy with respect to disease-free survival. (Funded by the National Cancer Institute; PROSPECT ClinicalTrials.gov number, NCT01515787.).

Dataset Information

Radiation dose-response model for locally advanced rectal cancer after preoperative chemoradiation therapy.

Publications

Radiation dose-response model for locally advanced rectal cancer after preoperative chemoradiation therapy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets