Preoperative radiation dose escalation for rectal cancer using a concomitant boost strategy improves tumor downstaging without increasing toxicity: A matched-pair analysis

Jillian R. Gunther, MD, PhD; Awalpreet S. Chadha, MD; Ui Sup Shin, MD; In Ja Park, MD; Kiran V. Kattepogu, MD; Jonathan D. Grant, MD; David C. Weksberg, MD, PhD; Cathy Eng, MD; Scott E. Kopetz, MD, PhD; Prajnan Das, MD, MS, MPH; Marc E. Delclos, MD; Harmeet Kaur, MD; Dipen M. Maru, MD; John M. Skibber, MD; Miguel A. Rodriguez-Bigas, MD; Y. Nancy You, MD; Sunil Krishnan, MD; George J. Chang, MD, MS

doi:10.1016/j.adro.2017.04.001

Advances in Radiation Oncology (Jul 2017)

Preoperative radiation dose escalation for rectal cancer using a concomitant boost strategy improves tumor downstaging without increasing toxicity: A matched-pair analysis

Jillian R. Gunther, MD, PhD,
Awalpreet S. Chadha, MD,
Ui Sup Shin, MD,
In Ja Park, MD,
Kiran V. Kattepogu, MD,
Jonathan D. Grant, MD,
David C. Weksberg, MD, PhD,
Cathy Eng, MD,
Scott E. Kopetz, MD, PhD,
Prajnan Das, MD, MS, MPH,
Marc E. Delclos, MD,
Harmeet Kaur, MD,
Dipen M. Maru, MD,
John M. Skibber, MD,
Miguel A. Rodriguez-Bigas, MD,
Y. Nancy You, MD,
Sunil Krishnan, MD,
George J. Chang, MD, MS

Affiliations

Jillian R. Gunther, MD, PhD: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Awalpreet S. Chadha, MD: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Ui Sup Shin, MD: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
In Ja Park, MD: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Kiran V. Kattepogu, MD: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Jonathan D. Grant, MD: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
David C. Weksberg, MD, PhD: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Cathy Eng, MD: Department of Gastrointestinal Medical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Scott E. Kopetz, MD, PhD: Department of Gastrointestinal Medical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Prajnan Das, MD, MS, MPH: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Marc E. Delclos, MD: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Harmeet Kaur, MD: Department of Diagnostic Radiology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Dipen M. Maru, MD: Department of Pathology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
John M. Skibber, MD: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Miguel A. Rodriguez-Bigas, MD: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Y. Nancy You, MD: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
Sunil Krishnan, MD: Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas
George J. Chang, MD, MS: Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas

DOI: https://doi.org/10.1016/j.adro.2017.04.001
Journal volume & issue: Vol. 2, no. 3
pp. 455 – 464

Abstract

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Purpose: Pathologic complete response to neoadjuvant chemoradiation therapy (CRT) is associated with improved outcomes for patients with locally advanced rectal cancer (LARC). Increased response rates have been reported with higher radiation doses, but these studies often lack long-term outcome and/or toxicity data. We conducted a case-control analysis of patients with LARC who underwent definitive CRT to determine the efficacy and safety of intensified treatment with a concomitant boost (CB) approach. Methods and materials: From 1995 to 2003, a phase 2 protocol examined CRT with 5-fluorouracil and CB radiation therapy (52.5 Gy in 5 weeks) for patients with LARC. Seventy-six protocol patients were matched (case-control approach) for surgery type, tumor (T) stage, and clinical nodal (N) stage with patients who received standard dose (SD) CRT (5-fluorouracil, 45 Gy). A chart review was performed. McNemar's test and Kaplan-Meier analyses were used for statistical analysis. Results: The SD and CB groups did not differ in tumor circumferential involvement and length, but the tumors of CB patients were closer to the anal verge (4.7 vs 5.7 cm; P = .02). Although tumor downstaging was higher in the CB cohort (76% vs 51%; P .05). The median follow-up was 11.9 years. The 5-year local control rates were higher for CB (100.0%) compared with SD (90.0%) patients (P = .01). CB patients had higher rates of 10-year progression-free survival (71.9% vs 57.6%, P < .01) and overall survival (71.6% vs 62.4%, P = .01) compared with SD patients. Conclusions: CRT dose escalation for patients with LARC is safe and effective. The improved T-downstaging and local control observed in CB patients should encourage further dose escalation studies.

Published in Advances in Radiation Oncology

ISSN: 2452-1094 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Medicine: Medicine (General): Medical physics. Medical radiology. Nuclear medicine; Medicine: Internal medicine: Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Website: http://www.journals.elsevier.com/advances-in-radiation-oncology/

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