Gunther Jillian R, Chadha Awalpreet S, Shin Ui Sup, Park In Ja, Kattepogu Kiran V, Grant Jonathan D, Weksberg David C, Eng Cathy, Kopetz Scott E, Das Prajnan, Delclos Marc E, Kaur Harmeet, Maru Dipen M, Skibber John M, Rodriguez-Bigas Miguel A, You Y Nancy, Krishnan Sunil, Chang George J
Department of Radiation Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas.
Department of Surgical Oncology, The University of Texas, MD Anderson Cancer Center, Houston, Texas.
Adv Radiat Oncol. 2017 Apr 12;2(3):455-464. doi: 10.1016/j.adro.2017.04.001. eCollection 2017 Jul-Sep.
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.
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.
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; = .02). Although tumor downstaging was higher in the CB cohort (76% vs 51%; < .01), pathologic complete response rates did not differ (CB, 17.1% vs SD, 15.8%, = 1.00). The incidence of grade ≥3 radiation-related toxicities was low and similar in both groups (CB, 10% vs SD, 3%, = .22). Postoperative (anastomotic leak, wound complications/abscess, bleeding) and late (small bowel obstruction, stricture) complication rates did not differ between the groups ( > .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 ( = .01). CB patients had higher rates of 10-year progression-free survival (71.9% vs 57.6%, < .01) and overall survival (71.6% vs 62.4%, = .01) compared with SD patients.
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.
新辅助放化疗（CRT）后的病理完全缓解与局部晚期直肠癌（LARC）患者预后改善相关。有报道称增加放疗剂量可提高缓解率，但这些研究往往缺乏长期预后和/或毒性数据。我们对接受确定性CRT的LARC患者进行了病例对照分析，以确定采用同步加量（CB）方法强化治疗的疗效和安全性。
1995年至2003年，一项2期方案对LARC患者采用5-氟尿嘧啶和CB放疗（5周内52.5 Gy）进行CRT。76例方案患者（病例对照法）在手术类型、肿瘤（T）分期和临床淋巴结（N）分期方面与接受标准剂量（SD）CRT（5-氟尿嘧啶，45 Gy）的患者进行匹配。进行了病历审查。采用McNemar检验和Kaplan-Meier分析进行统计分析。
SD组和CB组在肿瘤周向受累情况和长度方面无差异，但CB组患者肿瘤距肛缘更近（4.7 vs 5.7 cm；P = 0.02）。尽管CB队列中肿瘤降期率更高（76% vs 51%；P < 0.01），但病理完全缓解率无差异（CB组为17.1%，SD组为15.8%，P = 1.00）。两组中≥3级放疗相关毒性的发生率均较低且相似（CB组为10%，SD组为3%，P = 0.22）。两组间术后（吻合口漏、伤口并发症/脓肿、出血）和晚期（小肠梗阻、狭窄）并发症发生率无差异（P > 0.05）。中位随访时间为11.9年。CB组患者的5年局部控制率（100.0%）高于SD组患者（90.0%）（P = 0.01）。与SD组患者相比，CB组患者的10年无进展生存率（7l.9% vs 57.6%，P < 0.01）和总生存率（71.6% vs 62.4%，P = 0.01）更高。
LARC患者CRT剂量递增是安全有效的。在CB组患者中观察到的T降期改善和局部控制应鼓励进一步开展剂量递增研究。
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