Shackley D C, Whitehurst C, Moore J V, George N J, Betts C D, Clarke N W
Paterson Institute for Cancer Research, Christie Hospital, Departments of Urology, Hope Hospital, Salford Royal Hospitals Trust, Salford, South Manchester University Hospital, and Christie Hospital, Manchester, UK.
BJU Int. 2000 Oct;86(6):638-43. doi: 10.1046/j.1464-410x.2000.00872.x.
To assess (i) the optical properties and depth of penetration of varying wavelengths of light in ex-vivo human bladder tissue, using specimens of normal bladder wall, transitional cell carcinoma (TCC) and bladder tissue after exposure to ionizing radiation; and (ii) to estimate the depth of bladder wall containing cancer that could potentially be treated with intravesical photodynamic therapy (PDT), assuming satisfactory tissue levels of photosensitizer. Materials and methods The study included 11 cystectomy specimens containing invasive TCC (five from patients who had previously received external-beam bladder radiotherapy, but with recurrent TCC) and three 'normal' bladders removed from patients treated by exenteration surgery for extravesical pelvic cancer. Full-thickness bladder wall and tumour samples were taken from these specimens and using an 'intravesical' and a previously validated interstitial model, the optical penetration depths (i.e. the tissue depth at which the light fluence is 37% of incident) were calculated at wavelengths of 633, 673 and 693 nm.
There were no significant differences in light penetration between normal and tumour-affected bladder tissue at each wavelength. There were significant differences in light penetration among wavelengths; light at 693 nm penetrated approximately 40% further than light at 633 nm (P < 0.002). The light currently used in bladder PDT (633 nm) has a mean (SEM) optical penetration depth of 4.0 (0.1) mm within TCC. In addition, at this wavelength, there was 29% greater light penetration in previously irradiated than in unirradiated bladder wall (P = 0.001). This did not occur in the tumour-affected bladder.
Bladder tissue is relatively more translucent than other human tissues and there is therefore great potential for PDT in the treatment of bladder cancer. As there is no difference in light penetration between TCC and normal bladder tissue, a tumour-specific response with diffuse illumination of the bladder will depend on drug localization within the tumour. The currently used wavelength of 633 nm can be expected to exert a PDT effect within bladder tumour up to a depth of 20 mm. Increasing the wavelength will allow deeper pathology to be treated.
(i) 使用正常膀胱壁、移行细胞癌（TCC）以及暴露于电离辐射后的膀胱组织标本，评估不同波长的光在离体人膀胱组织中的光学特性和穿透深度；(ii) 假设光敏剂在组织中的水平令人满意，估计膀胱壁中可能接受膀胱内光动力疗法（PDT）治疗的含癌深度。材料与方法 本研究包括11个含有浸润性TCC的膀胱切除标本（5个来自先前接受过膀胱外照射放疗但出现复发性TCC的患者）以及3个从因膀胱外盆腔癌接受盆腔脏器清除术的患者身上切除的“正常”膀胱。从这些标本中获取全层膀胱壁和肿瘤样本，并使用“膀胱内”和先前验证过的间质模型，计算633、673和693 nm波长下的光穿透深度（即光通量为入射光通量37%时的组织深度）。
在每个波长下，正常膀胱组织和受肿瘤影响的膀胱组织之间的光穿透没有显著差异。不同波长之间的光穿透存在显著差异；693 nm的光比633 nm的光穿透深度大约深40%（P < 0.002）。目前用于膀胱PDT的光（633 nm）在TCC内的平均（SEM）光穿透深度为4.0（0.1）mm。此外，在该波长下，先前照射过的膀胱壁的光穿透比未照射过的膀胱壁大29%（P = 0.001）。在受肿瘤影响的膀胱中未出现这种情况。
膀胱组织比其他人体组织相对更透明，因此PDT在膀胱癌治疗中有很大潜力。由于TCC和正常膀胱组织之间的光穿透没有差异，膀胱弥漫性照明的肿瘤特异性反应将取决于药物在肿瘤内的定位。目前使用的633 nm波长有望在膀胱肿瘤内达到20 mm深度发挥PDT效应。增加波长将允许治疗更深层的病变。
