Perez C A, Grigsby P W, Lockett M A, Chao K S, Williamson J
Radiation Oncology Center, Mallinckrodt Institute of Radiology, Washington University Medical Center, St. Louis, MO 63108, USA.
Int J Radiat Oncol Biol Phys. 1999 Jul 1;44(4):855-66. doi: 10.1016/s0360-3016(99)00111-x.
To quantitate the impact of total doses of irradiation, dose rate, and ratio of doses to bladder or rectum and point A on sequelae in patients treated with irradiation alone for cervical cancer.
Records were reviewed of 1456 patients (Stages IB-IVA) treated with external-beam irradiation plus two low-dose rate intracavitary insertions to deliver 70 to 90 Gy to point A. Follow-up was obtained in 98% of patients (median, 11 years; minimum, 3 years; maximum, 30 years). The relationships among various dosimetry parameters and Grade 2 or 3 sequelae were analyzed.
In Stage IB, the frequency of patients developing Grade 2 morbidity was 9%, and Grade 3 morbidity, 5%; in Stages IIA, IIB, III, and IVA, Grade 2 morbidity was 10% to 12% and Grade 3 was 10%. The most frequent Grade 2 sequelae were cystitis and proctitis (0.7% to 3%). The most common Grade 3 sequelae were vesicovaginal fistula (0.6% to 2% in patients with Stage I-III tumors), rectovaginal fistula (0.8% to 3%), and intestinal obstruction (0.8% to 4%). In the bladder, doses below 80 Gy correlated with less than 3% incidence of morbidity and 5% with higher doses (p = 0.31). In the rectosigmoid, the incidence of significant morbidity was less than 4% with doses below 75 Gy and increased to 9% with higher doses. For the small intestine, the incidence of morbidity was less than 1% with 50 Gy or less, 2% with 50 to 60 Gy, and 5% with higher doses to the lateral pelvic wall (p = 0.04). When the ratio of dose to the bladder or rectum in relation to point A was 0.8 or less, the incidence of rectal morbidity was 2.5% (8 of 320) vs. 7.3% (80 of 1095) with higher ratios (p < or = 0.01); bladder morbidity was 2.3% (7 of 305) and 5.8% (64 of 1110), respectively (p = 0.02). The incidence of Grade 2 and 3 bladder morbidity was 2.9% (10 of 336) when the dose rate was less than 0.80 Gy/h, in contrast to 6.1% (62 of 1010) with higher dose rates (p = 0.07). Rectal morbidity was 2% to 5% in Stage IB, regardless of dose rate to the rectum; in Stages IIA-B and III, morbidity was 5.2% (28 of 539) with a dose rate of 0.80 Gy or less and 10.7% (37 of 347) with higher dose rates (p < 0.01). Multivariate analysis showed that dose to the rectal point was the only factor influencing rectosigmoid sequelae, and dose to the bladder point affected bladder morbidity.
Various dosimetric parameters correlate closely with the incidence of significant morbidity in patients treated with definitive irradiation for carcinoma of the uterine cervix. Careful dosimetry and special attention to related factors will reduce morbidity to the lowest possible level without compromising pelvic tumor control.
定量分析单纯放疗治疗宫颈癌患者时，总照射剂量、剂量率以及膀胱或直肠与A点剂量之比对后遗症的影响。
回顾了1456例（IB-IVA期）接受外照射加两次低剂量率腔内插植治疗以向A点给予70至90 Gy剂量的患者记录。98%的患者获得随访（中位随访时间11年；最短3年；最长30年）。分析了各种剂量学参数与2级或3级后遗症之间的关系。
在IB期，发生2级并发症的患者频率为9%，3级并发症为5%；在IIA、IIB、III和IVA期，2级并发症为10%至12%，3级为10%。最常见的2级后遗症是膀胱炎和直肠炎（0.7%至3%）。最常见的3级后遗症是膀胱阴道瘘（I-III期肿瘤患者中为0.6%至2%）、直肠阴道瘘（0.8%至3%）和肠梗阻（0.8%至4%）。在膀胱，低于80 Gy的剂量与低于3%的并发症发生率相关，高于80 Gy时为5%（p = 0.31）。在直肠乙状结肠，低于75 Gy的剂量时严重并发症发生率低于4%，高于该剂量时升至9%。对于小肠，50 Gy及以下剂量时并发症发生率低于1%，50至60 Gy时为2%，盆腔侧壁较高剂量时为5%（p = 0.04）。当膀胱或直肠与A点的剂量比为0.8或更低时，直肠并发症发生率为2.5%（320例中的8例），而较高比例时为7.3%（1095例中的80例）（p≤0.01）；膀胱并发症发生率分别为2.3%（305例中的7例）和5.8%（1110例中的64例）（p = 0.02）。当剂量率低于0.80 Gy/h时，2级和3级膀胱并发症发生率为2.9%（336例中的10例），相比之下较高剂量率时为6.1%（1010例中的62例）（p = 0.07）。在IB期，无论直肠剂量率如何，直肠并发症发生率为2%至5%；在IIA-B期和III期，剂量率为0.80 Gy或更低时并发症发生率为5.2%（539例中的28例），较高剂量率时为10.7%（347例中的37例）（p < 0.01）。多因素分析表明，直肠点剂量是影响直肠乙状结肠后遗症的唯一因素，膀胱点剂量影响膀胱并发症。
各种剂量学参数与宫颈癌根治性放疗患者严重并发症的发生率密切相关。仔细的剂量学分析并特别关注相关因素将在不影响盆腔肿瘤控制的情况下将并发症降至尽可能低的水平。
