Matched pair analysis of sequential short course radiotherapy and FOLFOX chemotherapy as preoperative therapy for rectal cancer compared to neoadjuvant long course chemoradiotherapy.

Authors

null

Fady Youssef

Washington University School of Medicine in St. Louis, St. Louis, MO

Fady Youssef , Stephanie Subasic Markovina , Shariq S. Khwaja , Todd A. DeWees , Steven R. Hunt , Benjamin R. Tan Jr., Robert J. Myerson , Parag J. Parikh , Jeffrey R. Olsen

Organizations

Washington University School of Medicine in St. Louis, St. Louis, MO, Division of Oncology, Washington University in St. Louis, St. Louis, MO, Washington University in St. Louis, St. Louis, MO

Research Funding

No funding sources reported

Background: A recently completed institutional phase II trial evaluated near-total neoadjuvant therapy (nTNT) for locally advanced rectal cancer using short course radiotherapy (SCRT) followed by four cycles of FOLFOX prior to total mesorectal excision (TME). A matched pair analysis is presented to compare clinical outcomes for nTNT with conventional chemoradiotherapy (CRT), TME, and postoperative chemotherapy (CT) for patients treated at our institution. Methods: 80 patients with cT3-4N0-2M0-1 rectal adenocarcinoma planned for resection of all tumor enrolled on a phase II study of preoperative SCRT (25 Gy to the involved mesorectum, 20 Gy to elective nodes, in 5 fractions) followed by four cycles of mFOLFOX6 before TME, with 6-8 cycles of adjuvant FOLFOX suggested. 69 patients with cM0 disease comprised the study cohort for this analysis. Patients treated with conventional CRT, followed by TME and adjuvant CT (63% ≥4 cycles adjuvant FOLFOX) were identified and matched 2:1 for exact cTNM stage. Kaplan-Meier with log-rank analysis was used to compare local control (LC), distant metastasis free survival (DMFS), disease free survival (DFS), and overall survival (OS), and two-tailed Mann-Whitney and Chi-squared tests used to compare cohort characteristics. Results: Median follow-up was 26 and 49 months for the study and control groups, respectively. Median age (57 vs. 55 years, p = 0.98) and distance from the anorectal ring (6 vs. 5 cm, p = 0.16) were similar for study and control groups, respectively. Pathologic complete response (pCR) and T-downstaging rates were 30% vs. 23% (p = 0.26) and 75% vs 50% (p = 0.001) in the study and match cohort, respectively. Actuarial 2-year LC (97% vs. 98%, p = 0.69) and OS (100% vs. 95% at 2 years, p = 0.57) were similar between the study and control groups, respectively. Two-year DMFS (94% vs. 80%, p = 0.016) and DFS (94% vs. 80%, p = 0.027) were significantly better in the study cohort. Conclusions: Controlling for institutional bias, exact cTNM stage, and tumor location, nTNT resulted in increased T-downstaging, superior DMFS and DFS, and similar LC and OS compared to conventional CRT.

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Abstract Details

Meeting

2015 Gastrointestinal Cancers Symposium

Session Type

Poster Session

Session Title

General Poster Session C: Cancers of the Colon, Rectum, and Anus

Track

Cancers of the Colon, Rectum, and Anus

Sub Track

Multidisciplinary Treatment

Citation

J Clin Oncol 33, 2015 (suppl 3; abstr 665)

DOI

10.1200/jco.2015.33.3_suppl.665

Abstract #

665

Poster Bd #

D7

Abstract Disclosures