以雷射紅光照射之局部光動力療法及液態氮噴槍冷動療法治療口腔癌前病變

Abstract

背景：口腔癌前病變的早期診斷與治療，是治療口腔癌的有效策略之一。我們團隊過去的研究顯示，以發光二極體 (LED)為光源，局部塗抹5-胺基酮戊酸的光動力療法 (5-aminolevulinic acid-mediated photodynamic therapy, ALA-PDT) 和棉棒冷凍療法 (cotton-swab cryotherapy, CSC)，是兩種保守且可有效治療口腔癌前病變的方法。本研究中，我們改採雷射紅光照射局部塗抹5-胺基酮戊酸的光動力療法 (laser light-mediated topical ALA-PDT)，以及液態氮噴槍之冷凍療法 (cryogun cryotherapy, CC)，治療口腔癌前病變，同時評估其治療成效。 方法：在光動力治療部份，本研究使用雷射紅光 (635 nm)為光源，以局部 ALA-PDT ，治療40 例口腔疣狀增生 (OVH)、40例口腔紅白斑 (OEL)，以及 40 例口腔白斑 (OL) 病變，每週治療一次。我們也選擇另外40 例OL病變，以相同的光動力療法，每週治療二次， 並以統計學方法分析其療效。同時我們也利用對抗Bcl-2、Bax、Mcl-1、Bak蛋白的抗體，以免疫組織化學染色法 (IHC)，來觀察15例OVH、26例OEL與39例OL病變，在接受PDT前的活體切片組織中，上述蛋白的表現量。我們利用Bcl-2, Bax、Mcl-1及Bak的標記指數（labeling indices, LIs，陽性染色細胞/全部上皮細胞），以比較完全反應(CR)與部分反應及無反應 (PR/NR)兩組之間，其標記指數平均值的差異。在冷凍治療部份，本研究使用液態氮噴槍之冷凍療法（CC），治療54位病人共60例OL病變，患者每兩週治療一次，直到病變完全消除(CR)為止。並將其治療成效與先前棉棒冷凍療法 (CSC) 的治療成效，互相比較。 結果：雷射紅光照射局部光動力治療部份，40例 OVH 經平均3.6次的治療後，皆達成CR。40例 OEL 經過平均3.4次的治療後，38例 OEL為CR，另外2例 為部分反應（PR）。40例OL病變，以局部ALA-PDT每週治療一次，發現有7例為CR，20例為PR，13例為NR。另外40例OL病變，以相同的局部ALA-PDT療法治療，但每週治療兩次，發現有17例為CR，23例為PR。因此對OL病變而言，每週治療兩次的模式，比每週治療一次的模式，其療效較佳，且達到統計學上有義意的差異。此外，當OVH病變的外形為腫塊、最大徑小於1.5公分、外觀為粉紅色、上皮發生變異，以及表面角質層厚度小於或等於40微米時，比起其外形呈現斑狀或合併中間為腫塊但周圍為斑狀（P = 0.000）、最大徑大於或等於1.5公分（P = 0.000）、外觀呈現白色（P = 0.000）、上皮無變異（P = 0.000）或是表面角質層厚度大於40微米（P = 0.000）者，只需要較少的治療次數，就能達到CR。以多變項統計分析顯示，OVH病變的大小（P = 0.006），為預測局部ALA-PDT療效的唯一獨立因子。另一方面，當OEL病變最大徑小於1.5公分，以及表面角質層厚度小於或等於30微米時，比起其最大徑大於或等於1.5公分（P = 0.000）、或是表面角質層厚度大於30微米（P = 0.000）者，其達到CR治療次數明顯較少。 IHC的結果顯示，CR組別的Bax以及Bak的標記指數（P < 0.001）及Bak/Mcl-1標記指數的比值（Bak/Mcl-1）（P < 0.001），遠高於PR/NR組。在冷凍治療方面，所有60例OL病變，在經過平均3.1次CC治療之後，均呈現CR。當OL病變位於舌以外的口腔黏膜上、相對面積小於2平方公分、上皮發生變異、或表面角質層厚度小於55微米時，其達到CR所需要的治療次數，明顯少於其位於舌（P = 0.006）、相對面積大於或等於2平方公分（P = 0.000）、上皮無變異（P = 0.044）、或表面角質層厚度大於或等於55微米（P = 0.000）者。以多變項統計分析顯示，OL病變表面角質層厚度，為影響 CC達到CR療效的獨立預測因子。 結論：雷射紅光照射的局部ALA-PDT，是治療OVH及OEL病變相當有效的療法，但其對OL病變之療效稍差。對OVH、OEL及OL病變之治療而言，雷射紅光照射的局部ALA-PDT 和LED紅光照射的局部ALA-PDT，其療效相當，無明顯差異。 OVH、OEL及OL病變於PDT之前的活體切片組織中，其Bax LI和Bak LI，以及Bak/Mcl-1 LI的比值，可當作預測局部ALA-PDT療效的生物標記。CC對OL病變而言，是一種簡單、安全、方便、保守與有效的療法。就CC與CSC對OL的病變的療效上，CC的療效較CSC的療效明顯較佳。

Background: One of the best strategies for oral cancer treatment is to eliminate oral cancers at their precancerous stage to stop their further malignant transformation. Oral leukoplakia (OL), oral erythroleukoplakia (OEL), and oral verrucous hyperplasia (OVH) are three common oral precancerous lesions in Taiwan. Our previous studies showed that topical 5-aminolevulinic acid-mediated photodynamimc therapy (topical ALA-PDT) using the 635-nm light-emitting diode (LED) light and cotton-swab cryotherapy (CSC) are effective alternative treatment modalities for oral precancerous lesions. Methods: In this study, 40 OVH, 40 OEL and 40 OL lesions were treated with a topical ALA-PDT protocol (fluence rate, 100 mW/cm2; light dose, 100 J/cm2) using the 635-nm laser light once a week. Another 40 OL lesions were treated with the same protocol twice a week. Statistical analyses were used to compare the efficacy of PDT treatment between two different groups. Clinicopathological parameters were further investigated to assess their influence on the PDT treatment outcome. Immunohistochemical studies were performed to demonstrate the expressions of the Bcl-2, Bax, Mcl-1 and Bak in the biopsied specimens of oral precancerous lesions prior to PDT. The Bcl-2, Bax, Mcl-1 and Bak labeling indices (LIs), defined as the ratio of positive cells to total cells in the same tissue section, was used to evaluate whether the expressions of Bcl-2, Bax, Mcl-1 and Bak proteins in biopsied specimens of OVH, OEL and OL lesions could be used to predict the clinical outcomes of 15 OVH, 26 OEL and 39 OL lesions treated with topical ALA-PDT using the laser red light. In the third part of this study, we used liquid nitrogen spray with a cryogun (cryogun cryotherapy, CC) to treat 60 OL lesions in 54 patients. Results: We found that all the 40 OVH lesions exhibited complete response (CR) after an average of 3.6 PDT treatments. Of the 40 OEL lesions, 38 showed CR after an average of 3.4 PDT treatments and 2 showed partial response (PR). The 40 OL lesions treated once a week demonstrated CR in 7, PR in 20 and no response (NR) in 13. Furthermore, the 40 OL lesions treated twice a week showed CR in 17 and PR in 23. Chi-square test showed that the twice-a-week treatment modality was better than the once-a-week treatment modality for OL lesions. In general, better PDT outcomes were significantly associated with OVH, OEL and OL lesions with the smaller size, pink to red color, epithelial dysplasia, or thinner surface keratin layer. The mean Bax and Bak LIs and the mean Bak/Mcl-1 LI ratio were significantly higher in the CR group than in the PR/NR group. However, there was no significant difference in the Bcl-2 LI, Mcl-1 LI or Bax/Bcl-2 LI ratio between the CR and PR/NR groups. CR was achieved in all 60 OL lesions after an average of 3.1 ± 1.3 treatments of CC. We found that 60 OL lesions treated with CC needed significantly fewer treatments to achieve CR than 60 previously reported OL lesions treated with CSC (mean, 6.3 ± 3.8 treatments). The number of CC treatments required to achieve CR was significantly fewer for OL lesions on oral mucosal sites other than the tongue, those with a relative surface area < 2 cm2, those with epithelial dysplasia, and those with a surface keratin thickness of < 55 μm. However, only the surface keratin thickness (P = 0.005) was an independent factor influencing the number of CC treatments required to achieve CR by multivariate Cox proportional hazard regression analyses. Conclusion: The laser light-mediated topical ALA-PDT is very effective for OVH and OEL lesions but is less effective for OL lesions. There is no significant difference in clinical outcome of topical ALA-PDT using either the laser or LED red light. Therefore, topical ALA-PDT using either the laser or LED light may serve as the first-line treatment of choice for OVH and OEL lesions. By immunohistochemistry, we conclude that the Bax LI, Bak LI and Bak/Mcl-1 LI ratio may be useful biomarkers to predict the clinical outcomes of OL, OEL and OVH lesions treated with laser light-mediated topical ALA-PDT. CC is a simple, safe, convenient, conservative and effective treatment modality for OL lesions. In addition, CC is a more effective treatment modality than the CSC for treatment of OL lesions.