Rudolph R, Tripuraneni P, Koziol J A, McKean-Matthews M, Frutos A
Division of Plastic Surgery, Scripps Clinic and Research Foundation, La Jolla, California 92037.
Cancer. 1994 Dec 1;74(11):3063-70. doi: 10.1002/1097-0142(19941201)74:11<3063::aid-cncr2820741126>3.0.co;2-c.
Chronic deleterious changes in human skin after radiation therapy often have been ascribed to progressive ischemia (decreased blood supply and oxygenation). Recent studies suggest, however, that damaged irradiated skin is not ischemic. Transcutaneous oxygen pressure (TCPO2), that accurately reflects skin oxygenation, was studied in 100 patients who had undergone prior extensive radiation therapy for cancer.
In the 100 patients, the mean time since radiation was 7.86 +/- 10.56 years (mean, +/- SD) (range, 1-58 years). Radiation skin effects were graded (0-4+), and TCPO2 was measured in irradiated and control nonirradiated sites, with patients first breathing room air, then 100% O2 6 l/min for 10 minutes. Data were stratified according to skin grades, sex, time since irradiation, site, type, and dose of radiation.
The mean TCPO2 in patients breathing room air was 52.0 17.8 mm Hg (mean +/- SD) for all irradiated skin, compared with 131.8 +/- 51.1 at the same irradiated sites in response to oxygen breathing (P < 0.0001); the mean TCPO2 for normal, nonirradiated skin was 56.5 +/- 12.6 when patients were breathing room air, compared with 151.5 +/- 48.1 when breathing 100% oxygen (P < 0.0001). Higher skin damage grades correlated with increasing time after radiation therapy. However, neither increasing time after irradiation nor grade of skin damage correlated with TCPO2, which was normal in 88% of the patients.
Human skin, even many decades after radiation therapy, retains normal tissue oxygenation and TCPO2 response to inspired oxygen. Postradiation scarring, poor healing, and rare ulceration are not solely due to ischemia and may be caused by other radiation effects, such as permanent changes in fibroblasts.
放射治疗后人体皮肤出现的慢性有害变化常被归因于进行性缺血（血液供应和氧合减少）。然而，近期研究表明，受照射受损的皮肤并非缺血状态。对100例曾接受过广泛癌症放射治疗的患者进行了经皮氧分压（TCPO2）研究，该指标能准确反映皮肤氧合情况。
这100例患者自放疗后的平均时间为7.86±10.56年（均值±标准差）（范围1 - 58年）。对放射皮肤效应进行分级（0 - 4 +），并在受照射部位和对照未受照射部位测量TCPO2，患者先呼吸室内空气，然后以6升/分钟的速度呼吸100%氧气10分钟。数据根据皮肤分级、性别、放疗后时间、部位、放疗类型和剂量进行分层。
所有受照射皮肤在患者呼吸室内空气时的平均TCPO2为52.0±17.8毫米汞柱（均值±标准差），而在相同受照射部位呼吸氧气时为131.8±51.1（P < 0.0001）；正常未受照射皮肤在患者呼吸室内空气时的平均TCPO2为56.5±12.6，呼吸100%氧气时为151.5±48.1（P < 0.0001）。较高的皮肤损伤分级与放疗后时间增加相关。然而，放疗后时间增加和皮肤损伤分级均与TCPO2无关，88%的患者TCPO2正常。
人体皮肤即使在放疗后数十年，仍保持正常的组织氧合以及对吸入氧气的TCPO2反应。放疗后瘢痕形成、愈合不良和罕见的溃疡并非 solely 由于缺血，可能由其他放射效应引起，如成纤维细胞的永久性变化。 （注：原文中“solely”翻译为“仅仅”更合适，但按要求未添加解释说明）
