?? 赛尔号祖拉刷谁:恶性黑色素瘤:流行病学、诊断和治疗方法概述(上) - 祖拉的世界|上古卷轴阿祖拉被口爆

恶性黑色素瘤:流行病学、诊断和治疗方法概述(上)

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在浅色皮肤的人群中黑色素瘤的发生率正在迅速增长。除环境因素(暴露于UV)外,观察到的“黑色素瘤流行”其他原因也有待探讨。对于典型的组织病理诊断过程,需要联合免疫组化以及最新的分子技术。在数年寻求新药失败后,目前有效的新型治疗方案能够延长疾病/发展进程和增加总体生存率。

No.1流行病学

黑色素瘤是皮肤肿瘤中最重要的肿瘤。虽然其发生率比上皮皮肤癌低10倍,但由于其具有早期转移能力且在年轻人群中高发,其对年轻患者产生重大的疾病负担。据报道,过去几十年,浅色皮肤人群中的黑色素瘤的发生率迅速增长。发病率的数据显示,在1935年,患有黑色素瘤的终生风险为1:1,500,在1987年为1:120,而现今该风险约为1:55。这表明,黑色素瘤的增长速度比其它类型的肿瘤更快,并且引发了对黑色素瘤的流行病的讨论。经多个研究评估,每年黑色素瘤的增长率为2~7 %,这意味着大约每隔10年,患病率就会增加1倍。由于黑色素瘤的致病因素具有遗传易感性,内源性因素和环境因素都已得到充分证实,过去几十年间,浅色皮肤个体黑色素瘤发病率全球性增长,这可归因于对日光浴看法的改变。已经明确发现,儿童时期间歇性的日光照射(即晒伤),已被公认是发展为黑色素瘤的一个重要风险因素。但是,关于UV辐射对黑色素瘤发生的作用,仍然存在很多不确定性因素。

然而,由于黑色素瘤患者的死亡率很稳定,如果黑色素瘤的流行性是一个真实存在的现象,那么在一些亚组中,其死亡率下降就具争议性。本文提供了一些参数,来解释黑色素瘤发病率急剧增加的原因:

尽管黑色素瘤不是一种好发于老年的恶性肿瘤,但是平均寿命升高导致终生风险的增加。在老年人群中,晒伤皮肤处发病率最高,且生长较慢,通常在检测时都很浅表。因此,对黑色素瘤早期诊断提高了其发病率,而不是死亡率。这种发病率随着年龄增长而升高在所有人类疾病中均可观察到,而与“流行病”无关。公共活动,强化监测和流程筛选,通过更高的检测率间接的导致肿瘤发病率的增加。这表明这些相关流程的有效性。较高的发病率导致更强的公众关注意识,反之亦然。一项研究对该区域有无皮肤癌筛查,最终发展为黑色素瘤的死亡率趋势进行了比较,强有力的证据表明,筛选导致黑色素瘤死亡率减少。但是有人认为,在发病率稳定的情况下,筛选程序只会导致暂时的上升。气候变化也可导致紫外线辐射增加。

组织病理学研究和诊断是色素性肿瘤诊断程序中的金标准。在色素性肿瘤中,组织病理特征系统性变化解读,可能会导致某些诊断频率变化,如,黑色素瘤诊断的增加(见下文)。

有人认为医学-法学思潮能够影响皮肤科医师和皮肤病理医生的诊断程序。据研究,错过黑色素瘤诊断的“诊断焦虑”,可能会导致黑色素瘤的过度诊断。

最近,来自高发黑色素瘤国家的流行病学数据显示,黑色素瘤的发病率在年轻群体中具有相对减少的趋势。这种现象被归因于公共活动,导致人们对自然和人工紫外线辐射危害的认识增强。

No.2色素沉着性皮损的诊断程序

色素沉着性皮损的皮肤病学检查应包括全身体检。色素性皮损的分布和形态对比可揭示出重要的信息(“丑小鸭征”,指该某一皮损表现不同于其他所有皮损)。对于单一皮损患者的初步评估和医护人员的专业评估,可应用A(不对称)B(边界)C(颜色)D(直径)E(进展)规则,尽管并不总是可靠(特别是早期黑色素瘤)。

在专科中心和皮肤科门诊,通过表面光照皮肤镜来检查可疑的色素性皮损是标准程序。皮损内的黑色素沉着的分布和肿瘤中血管图像提供了重要信息。计算机宏观技术分析和表面光照皮肤镜已被广泛应用,并认为是诊断的安全有效工具。然而,这些技术并不能完全代替一个经过培训经验丰富的皮肤科医生。最近几年,研究了一些新型的、无创的辅助诊断程序,如共聚焦扫描显微镜和光学相干断层扫描。

组织病理是诊断黑色素瘤的金标准。如果病理学家或皮肤病理学家获得足够的样本,那么几乎可确诊所有病例。为了提供可靠的组织病理检查,应完全切除肿瘤。通过刮除术,浅表削除术或电灼术取得的肿瘤标本无法进行明确诊断。为了区分色素痣和黑色素瘤,已经建立了许多的形态学标准。大多数标准将重点集中在肿瘤的结构特征,如对称、边界、表皮环形脱屑、色素分布、炎症、衰退等。这些形态学标准大多通过显微镜低倍放大来检查。当然,考虑到细胞学特征(如多形核和核分裂象)同样非常重要。病理医生应该意识到很多皮损可能难以归类:色素痣显示黑色素瘤(与黑色素瘤相似)的形态学标准,而黑色素瘤通??杉缴仞氲男翁П曜迹ㄓ肷仞胂嗨疲?。一些内源性(激素、免疫、特殊部位)和外源性因素(紫外线、搔抓、摩擦)可以影响黑素细胞皮损的组织病理特征。

下附英文原文:

In faired skinned population the incidence of melanoma is rapidly increasing. Beside environmental factors (UV-exposure) certainly other reasons for the observed “melanoma epidemic” have to be discussed. For diagnostic procedure classical histopathology is accompanied by immunohistochemistry and more recently molecular techniques. For therapy new modalities are available which—after many years of frustrating search for new drugs—are now able to prolong both disease/ progression free and overall survival.

Epidemiology

Melanoma is the most important tumor in dermatooncology. Its incidence is around 10-fold lower than that of epithelial skin cancer but because of its capacity to metastasize early and the prevalence in younger patients melanoma has an important disease burden. The incidence of melanoma has been reported to increase rapidly in the last decades in countries with fair-skinned population. Incidence data reveal that in 1935 the lifetime risk to develop melanoma was 1: 1,500, in 1987–1:120 and today the risk is around 1:55. This indicates an increase that is faster than in any other form of cancer and raises the question of a melanoma epidemic [1]. The increase of melanoma incidence per year is estimated in several studies to vary between 2 and 7 %, which means that the incidence doubles around every 10 years [2, 3]. As pathogenetic factors for the development of melanoma genetic predisposition, endogenous and environmental factors are well-documented [4], the worldwide increase of melanoma incidence in fair-skinned individuals is ascribed to changes in sun bathing attitudes during the last decades [5]. Intermittent sun exposure, namely sunburns, during childhood has been specifically found to represent an important risk factor for melanoma development [6]. Nevertheless, a lot of uncertainty concerning the role of UV-light in the development of melanoma still remains [3].

However, because the mortality rate of melanoma patients is quite stable and even in some subgroups decreasing is has been a matter of debate if this melanoma epidemic is a really existing phenomenon [1, 7]. Several arguments are provided to explain this dramatic increase in the incidence of melanoma [1]:

Even though melanoma is not a type of cancer which clearly develops more often at older age, the rise in life expectancy leads to an increased lifelong risk. Especially melanoma on sun-damaged skin with an incidence peak in older ages is a slow-growing tumor, which is most often thin at the time of detection. Therefore, detection of this early manifestation of melanoma accounts for incidence rise but not for mortality. This age-related increase in melanoma incidence is a phenomenon which can be observed in all human diseases and has nothing to do with an “epidemic”. Public campaigns, more intensive surveillance and screening programs are indirectly resulting in incidence of cancer increase through higher detection rates. This reveals the effectiveness of these procedures [8]. Higher incidence rates lead to a better public awareness and vice versa. In a study comparing trends in melanoma mortality in regions with and without skin cancer screening, strong evidence has been revealed that screening results in a reduction of melanoma mortality. However, it has been argued that in case of stable incidence rates, screening procedures only lead to a temporary rise [1]. Climate changes also may contribute to a higher exposure to natural UV-irradiation [10].

Histopathologic investigation and diagnosis are the gold standard in the diagnostic procedures in pigmented tumors. Systematic changes in the interpretation of histopathologic features in pigmented tumors may lead to variation in the frequency of certain diagnosis, e.g., increases of melanoma diagnoses (see below).

The medico-legal climate is thought to be able to influence the diagnostic procedure both in dermatologists and in dermatopathologists. It has been discussed that the “diagnostic anxiety” to miss the diagnosis of melanoma may lead to an overdiagnosis of melanoma [1].

Very recent epidemiologic data from countries with a high risk of melanoma development show a tendency for a relative decrease of melanoma incidence in younger age groups. This phenomenon has been ascribed to the public campaigns, which resulted in an enhanced awareness about natural and artificial UV-radiation [5].

Diagnostic procedures in pigmented lesions

The dermatological examination of pigmented lesions should include a total body examination. Distribution and morphology comparison of the apparent pigmented lesions reveal important information (“Ugly duckling sign”, which means that the appearance of one of the lesions is different to all the others). For an initial evaluation of a single lesion patients and healthcare professionals use the A (asymmetry) B (border) C (color) D (diameter) E (elevation)-rule, which may be helpful, albeit not always reliable (especially in early melanoma).

Investigation of a suspicious pigmented lesion by epiluminescence microscopy should be a standard procedure in specialized centers and the dermatologic office. Both distribution of melanin pigment within the lesion as well as the vascular pattern within the tumor give important information about the dignity [11]. Computerized techniques analyzing macroscopic and epiluminescence features are widely used and have been found to be safe and effective tools in the diagnostic procedure [11, 12]. However, these technologies do not substitute knowledge and skill of a well-trained dermatologist. In recent years, several new technologies have been developed which may be helpful as a non-invasive supplementary diagnostic procedure, e.g., confocal scanning microscopy or optical coherence tomography [13].

The gold standard in the diagnostic approach of melanoma is the histopathology. If the pathologist or dermatopathologist receives an adequate specimen, in almost all the cases a correct diagnosis will be achieved. To allow a reliable histological investigation, a completely excised tumor should be provided. In tumors removed by curettage, superficial shaving, or electrocautery correct diagnosing could be precluded by specimen selection. To differentiate nevus from melanoma a long list of morphologic criteria has been established [14]. Most criteria focus on the architectural features of a given tumor, such as symmetry, borders, maturation, epidermal collerette, pigment distribution, inflammation, regression, etc. These morphological criteria almost always have to be microscopically checked by low magnification. Of course, consideration of cytologic features like pleomorphic nuclei and mitotic figures is also of great importance. Pathologists must be aware that a lot of lesions might be difficult to classify: nevi showing morphologic criteria of melanoma (mimicker of melanoma) and melanomas showing morphologic criteria usually observed in nevi (mimicker of nevus) [13]. Several endogenous (hormonal, immunologic, site-specific) and exogenous factors (UV-light, scratching, rubbing) could influence the histopathologic appearance of a melanocytic lesion [15].

由MediCool医库软件冯飞飞 梁渝苓编译

原文来自:Wien Med Wochenschr (2013) 163:354–358

文章来源转载:皮肤科周迅

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