Prosnitz Robert G, Hubbs Jessica L, Evans Elizabeth S, Zhou Su-Min, Yu Xiaoli, Blazing Michael A, Hollis Donna R, Tisch Andrea, Wong Terence Z, Borges-Neto Salvador, Hardenbergh Patricia H, Marks Lawrence B
Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Cancer. 2007 Oct 15;110(8):1840-50. doi: 10.1002/cncr.22965.
Radiation therapy (RT) to the left breast/chest wall has been linked with cardiac dysfunction. Previously, the authors identified cardiac perfusion defects in approximately 50% to 60% of patients 0.5 to 2 years post-RT. In the current study, they assessed the persistence of these defects 3 to 6 years post-RT.
From 1998 to 2006, 160 patients with left-sided breast cancer were enrolled onto an Institutional Review Board-approved, prospective study. All patients received tangential photons to the left breast/chest wall. Patients had pre-RT and serial post-RT single-photon emission computed tomography (SPECT) scans to assess changes in regional cardiac perfusion, wall motion, and ejection fraction (EF). Forty-four patients had SPECT scans 3 to 6 years post-RT and were evaluable for the current analysis.
The overall incidence of perfusion defects at 3 years, 4 years, 5 years, and 6 years was 52% (11 of 21 patients), 71% (17 of 24 patients), 67% (12 of 18 patients), and 57% (4 of 7 patients), respectively. The rate of abnormal SPECT scans 3 to 6 years post-RT in patients who had scans at 0.5 to 2 years that were either all abnormal, intermittently abnormal, or all normal was 80%, 67%, and 63%, respectively. The incidence of wall motion abnormalities in patients with or without perfusion defects 3 to 6 years post-RT was low and did not differ statistically (17% vs 7.1%, respectively; P = .65), as was the incidence of reductions in EF of >/=5% (27% vs 36%, respectively; P = .72).
The results from this study indicated that RT-induced perfusion defects may persist or initially may appear 3 to 6 years post-RT in a high percentage of patients. However, these defects were not associated with changes in regional wall motion or EF. Additional study will be needed to determine the clinical relevance of these defects. In the meantime, the authors believe that every effort should be made to minimize incidental irradiation of the heart while maintaining adequate coverage of target volumes.
左侧乳腺/胸壁的放射治疗（RT）与心脏功能障碍有关。此前，作者发现在放疗后0.5至2年，约50%至60%的患者存在心脏灌注缺损。在本研究中，他们评估了放疗后3至6年这些缺损的持续情况。
1998年至2006年，160例左侧乳腺癌患者被纳入一项经机构审查委员会批准的前瞻性研究。所有患者均接受左侧乳腺/胸壁的切线光子放疗。患者在放疗前及放疗后进行系列单光子发射计算机断层扫描（SPECT），以评估局部心脏灌注、壁运动和射血分数（EF）的变化。44例患者在放疗后3至6年进行了SPECT扫描，可用于当前分析。
3年、4年、5年和6年时灌注缺损的总体发生率分别为52%（21例患者中的11例）、71%（24例患者中的17例）、67%（18例患者中的12例）和57%（7例患者中的4例）。在放疗后0.5至2年进行的扫描全部异常、间歇性异常或全部正常的患者中，放疗后3至6年SPECT扫描异常的发生率分别为80%、67%和63%。放疗后3至6年有或无灌注缺损的患者壁运动异常的发生率较低，且无统计学差异（分别为17%和7.1%；P = 0.65），射血分数降低≥5%的发生率也无统计学差异（分别为27%和36%；P = 0.72）。
本研究结果表明，放疗引起的灌注缺损在放疗后3至6年可能持续存在，或在高比例患者中最初出现。然而，这些缺损与局部壁运动或射血分数的变化无关。需要进一步研究以确定这些缺损的临床相关性。同时，作者认为应尽一切努力在维持靶区充分覆盖的同时，尽量减少心脏的附带照射。
