Allan E, Pye D A, Levine E L, Moore J V
Dept of Clinical Oncology, Christie Hospital, Manchester, UK.
Lasers Med Sci. 2002;17(4):230-7. doi: 10.1007/s101030200034.
The probability of local control of basal cell carcinomas (BCC) treated by photodynamic therapy (PDT) depends strongly on lesion thickness, thicker lesions often requiring two treatments. We examine the utility of 20 MHz pulsed ultrasound (US) for the non-invasive measurement of thickness and rate of regression after PDT treatment. PDT was by topically applied 20% aminolaevulinic acid, followed at 6 h by a standard 100 J/cm(2) of 630 nm light. Patients ( n=60) were selected as being difficult to treat with existing modalities for reasons of likely poor quality of healing or of cosmesis in this very largely elderly population. Ultrasound 'A' scans were made immediately before treatment, and at first and subsequent follow-ups. Parameters measured non-invasively for BCC, adjacent normal skin, and for fibroses after previous conventional therapies, were (a) thickness of skin or lesion, (b) linear density of ultrasound echoes and (c) linear density of high-amplitude echoes. Prior to treatment, median skin thickness (to the dermal/subcutaneous boundary) was 2.6 mm (range 1.2-5.7), fibroses 2.5 mm (1.4-5.6) and BCC 1.5 mm (0.5-4.4). Median linear density of echoes for normal skin, fibroses and BCC plus underlying tissue were 5.6, 5.5 and 4.5, respectively, the BCC values being significantly lower ( p=0.002). The corresponding medians for high-amplitude echoes were 1.9, 1.9 and 1.1 (skin or fibrosis versus BCC, p=0.001). Patients whose BCCs appeared clinically to be controlled at up to 220 days after a single treatment, all had values of ultrasound parameters corresponding to skin/fibrosis and were significantly different from measurements on the same site prior to treatment. Patients whose tumours appeared to be reverting to the original BCC ultrasound pattern were subsequently found to be recurring as judged clinically. Non-invasive pulsed ultrasound indicates that rates of resolution vary widely between BCC of similar initial thickness and that the probability of clearance of BCC by PDT is determined largely by the deepest, sometimes small, regions within a lesion, with the overall area being relatively unimportant.
光动力疗法（PDT）治疗基底细胞癌（BCC）的局部控制概率很大程度上取决于病变厚度，较厚的病变通常需要进行两次治疗。我们研究了20兆赫脉冲超声（US）在无创测量PDT治疗后病变厚度及消退速率方面的实用性。PDT治疗采用局部涂抹20%的氨基乙酰丙酸，6小时后给予标准剂量的630纳米光，能量为100焦/平方厘米。由于在这个老年人口居多的群体中，愈合质量或美容效果可能较差，所以选择了60名难以用现有方法治疗的患者。在治疗前、首次及后续随访时进行超声“A”扫描。对BCC、相邻正常皮肤以及先前传统疗法后的纤维化组织进行无创测量的参数包括：（a）皮肤或病变的厚度，（b）超声回声的线性密度，以及（c）高振幅回声的线性密度。治疗前，皮肤（至真皮/皮下边界）的中位数厚度为2.6毫米（范围1.2 - 5.7毫米），纤维化组织为2.5毫米（1.4 - 5.6毫米），BCC为1.5毫米（0.5 - 4.4毫米）。正常皮肤、纤维化组织以及BCC及其下方组织的回声线性密度中位数分别为5.6、5.5和4.5，BCC的值显著更低（p = 0.002）。高振幅回声的相应中位数分别为1.9、1.9和1.1（皮肤或纤维化组织与BCC相比，p = 0.001）。单次治疗后长达220天临床显示BCC得到控制的患者，其超声参数值均与皮肤/纤维化组织相对应，且与治疗前同一部位的测量值有显著差异。临床判断肿瘤似乎恢复到原始BCC超声模式的患者，随后被发现出现了复发。无创脉冲超声表明，初始厚度相似的BCC之间消退速率差异很大，且PDT清除BCC的概率很大程度上取决于病变内最深的、有时较小的区域，而总面积相对不太重要。
