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Abstract：
BACKGROUND: Radiotherapy (RT) has numerous effects on the oral mucosa, primarily genetic alterations and changes in the microenvironment. The characteristics of oral leukoplakia (OL) may differ between patients who have received previous head and neck cancer (HNC) treatment with radiation therapy and those who have not. Due to a lack of data on this scenario, we aimed to investigate the surgical outcomes of OL by comparing these two patient groups.
METHODS: This retrospective cohort study enrolled a total of 224 OL lesions in 124 patients who underwent carbon dioxide laser (CO2 laser) surgery from July 2002 to Aug 2021. All patients had received previous treatments for HNC, with 59 patients undergoing only surgical approach, 65 patients undergoing RT, and 46 patients undergoing concurrent chemotherapy during RT. The analysis was performed on a per-lesion basis, not a per-capita basis. We investigated the associations of clinicopathological characteristics and treatment outcomes of OL lesions that developed from irradiated or nonirradiated oral mucosa.
RESULTS: The median follow-up time was 5.87 years. Postoperative recurrence of OL occurred in 30 patients. Malignant transformation occurred in 17 patients with the incidence rate 4.19% annually and 13.7% cumulatively. The average time for OL transforming into squamous cell carcinoma was 3.27 ± 3.26 years (median 1.82, range 0.11 - 11.90). In univariate analysis, non-homogeneous morphology (P = 0.042), moderate to high-grade dysplasia (P = 0.041), and nonirradiated oral mucosa (P = 0.0047) were predictors for malignant transformation. However, in the Cox proportional hazard model, only nonirradiated oral mucosa remained an independent prognostic factor related to postoperative malignant transformation of OL (P = 0.031, HR 5.08, CI95 1.16 - 22.25).
CONCLUSIONS: In the population whose OL is strongly aetiologically linked to environmental carcinogens such as betel nut and tobacco, OL lesions that develop on previously irradiated oral mucosa have a lower risk for postoperative malignant transformation compared to those that develop on nonirradiated mucosa. This finding highlights the potential impacts of radiation on OL. Further research is needed to confirm this observation and elucidate the underlying mechanism.
METHODS: This retrospective cohort study enrolled a total of 224 OL lesions in 124 patients who underwent carbon dioxide laser (CO2 laser) surgery from July 2002 to Aug 2021. All patients had received previous treatments for HNC, with 59 patients undergoing only surgical approach, 65 patients undergoing RT, and 46 patients undergoing concurrent chemotherapy during RT. The analysis was performed on a per-lesion basis, not a per-capita basis. We investigated the associations of clinicopathological characteristics and treatment outcomes of OL lesions that developed from irradiated or nonirradiated oral mucosa.
RESULTS: The median follow-up time was 5.87 years. Postoperative recurrence of OL occurred in 30 patients. Malignant transformation occurred in 17 patients with the incidence rate 4.19% annually and 13.7% cumulatively. The average time for OL transforming into squamous cell carcinoma was 3.27 ± 3.26 years (median 1.82, range 0.11 - 11.90). In univariate analysis, non-homogeneous morphology (P = 0.042), moderate to high-grade dysplasia (P = 0.041), and nonirradiated oral mucosa (P = 0.0047) were predictors for malignant transformation. However, in the Cox proportional hazard model, only nonirradiated oral mucosa remained an independent prognostic factor related to postoperative malignant transformation of OL (P = 0.031, HR 5.08, CI95 1.16 - 22.25).
CONCLUSIONS: In the population whose OL is strongly aetiologically linked to environmental carcinogens such as betel nut and tobacco, OL lesions that develop on previously irradiated oral mucosa have a lower risk for postoperative malignant transformation compared to those that develop on nonirradiated mucosa. This finding highlights the potential impacts of radiation on OL. Further research is needed to confirm this observation and elucidate the underlying mechanism.
摘要：
背景：放射治疗（RT）对口腔粘膜有许多影响，主要是遗传改变和微环境的变化。口腔白斑（OL）的特征可能在先前接受过头颈癌（HNC）放射治疗的患者和未接受过放射治疗的患者之间有所不同。由于缺乏关于这种情况的数据，我们的目的是通过比较这两个患者组来调查OL的手术结局.
方法：这项回顾性队列研究纳入了2002年7月至2021年8月接受二氧化碳激光（CO2激光）手术的124例患者的224个OL病变。所有患者都曾接受过HNC治疗，59例患者仅接受手术方法，65例接受RT的患者，46例患者在放疗期间接受同步化疗。分析是在每个病变的基础上进行的，不是人均基础。我们调查了由辐照或非辐照口腔粘膜形成的OL病变的临床病理特征和治疗结果的关联。
结果：中位随访时间为5.87年。术后30例发生OL复发。恶性转化17例，年发生率4.19%，累计发生率13.7%。OL转化为鳞状细胞癌的平均时间为3.27±3.26年（中位数为1.82，范围为0.11-11.90）。在单变量分析中，非均匀形态（P=0.042），中度至高度发育不良（P=0.041），和未照射的口腔粘膜（P=0.0047）是恶性转化的预测因子。然而,在Cox比例风险模型中，仅未照射的口腔黏膜仍是与OL术后恶性转化相关的独立预后因素(P=0.031,HR5.08,CI951.16~22.25)。
结论：在其OL在病因上与槟榔和烟草等环境致癌物密切相关的人群中，与未照射的口腔粘膜相比，在先前照射的口腔粘膜上发生的OL病变发生术后恶性转化的风险较低。这一发现突出了辐射对OL的潜在影响。需要进一步的研究来证实这一观察结果并阐明潜在的机制。
方法：这项回顾性队列研究纳入了2002年7月至2021年8月接受二氧化碳激光（CO2激光）手术的124例患者的224个OL病变。所有患者都曾接受过HNC治疗，59例患者仅接受手术方法，65例接受RT的患者，46例患者在放疗期间接受同步化疗。分析是在每个病变的基础上进行的，不是人均基础。我们调查了由辐照或非辐照口腔粘膜形成的OL病变的临床病理特征和治疗结果的关联。
结果：中位随访时间为5.87年。术后30例发生OL复发。恶性转化17例，年发生率4.19%，累计发生率13.7%。OL转化为鳞状细胞癌的平均时间为3.27±3.26年（中位数为1.82，范围为0.11-11.90）。在单变量分析中，非均匀形态（P=0.042），中度至高度发育不良（P=0.041），和未照射的口腔粘膜（P=0.0047）是恶性转化的预测因子。然而,在Cox比例风险模型中，仅未照射的口腔黏膜仍是与OL术后恶性转化相关的独立预后因素(P=0.031,HR5.08,CI951.16~22.25)。
结论：在其OL在病因上与槟榔和烟草等环境致癌物密切相关的人群中，与未照射的口腔粘膜相比，在先前照射的口腔粘膜上发生的OL病变发生术后恶性转化的风险较低。这一发现突出了辐射对OL的潜在影响。需要进一步的研究来证实这一观察结果并阐明潜在的机制。
