The skin is the largest organ of the body consists of three layers: outer epidermis inner dermis subcutaeous tissues

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1 Topic: Speaker: Skin Cancer Dr. Anthony C.H. YING, Clinical Oncologist Chairman, Cancer Prevention & Detection Subcommittee The Hong Kong Anti-Cancer Society Date: 29 May 2010 The skin is the largest organ of the body consists of three layers: outer epidermis inner dermis subcutaeous tissues The three most common skin cancers are: Non-melanoma skin cancers basal cell carcinoma squamous cell carcinoma Melanoma Other skin cancers, such as soft tissue sarcoma involving dermis and subcutaneous tissues and adnexal carcinomas, are much less frequent. Although not all skin cancers are sun-related, exposure to ultraviolet radiation and skin type are the two most important aetiologic factors of skin cancers. Nowadays, the incidence of skin cancer is increasing rapidly worldwide. Non-melanoma skin cancers (NMSCs) basal cell carcinoma squamous cell carcinoma Non-melanoma skin cancers (NMSCs) Compared with white population, NMSCs in Hong Kong Chinese are much less common. However, over the past ten years, the incidence of NMSCs was increasing quite rapidly. In 1990, new cases was 346. In 2007, it jumped to 762, which represented a 140% increase. 8 th most common cancer in HK Melanoma is highly dangerous 1/8

2 Non-melanoma skin cancer 762 new cases 14 death (1.8%) Melanoma 53 new cases 33 death (62%) Causative factors exposure to ultraviolet radiation and skin type are the two most important aetiologic factors of skin cancers the risks of excessive sun exposure and importance of adequate sun protection should be made known to general public. Characteristics of UVA UVB UVC 紫外線 A 紫外線 B 紫外線 C 波長 ( 納米 )* 被臭氧層的吸收程度能穿透臭氧層 大部分被臭氧層所吸收 差不多全部被臭氧層所吸 收 到達地面的輻射量 超過百分之九十八的不足百分之二的紫外線是幾乎零紫外線是紫外線 A 紫外線 B 深入皮膚層 因波長較長, 故能深 入真皮及皮下組織 真皮 對皮膚影響曬黑皮膚, 皮膚癌曬紅及曬黑皮膚, 皮膚癌 * 定義根據 國際光照委員會 (1 納米 =10-9 米 ) Causative factors Other risk factors of skin cancer include exposure to chemical carcinogen, ionizing radiation, chronic skin irritation or inflammation and immuno-suppression. Non-melanoma skin cancers Basal cell carcinoma (BCC) a slow growing malignant skin tumour derived from epithelium of pilosebaceous follicle. the commonest skin malignancy as well as the commonest human cancer. 2007, HK had 535 new cases of BCC accounts for about 75% of all NMSCs Men are affected more often than women and most of the cases occur after age 2/8

3 of 50 Basal cell carcinoma (BCC) BCC invades locally and tends to grow along the path of least resistance. Local invasion can lead to infection, necrosis and eventually pain and impairment of vital organs. Of all the skin malignancies, BCC is the slowest growing and is the least likely to metastasize. The incidence of metastatic BCC is in the order of 0.1% or even less. Most cases of BCC can be completely cured by surgical excision or radiotherapy. Other methods of treatment include cryotherapy and curettage with cautery. About 5-10%.of the treated cases will recur, which is more common at nose, ears and near eyes. New lesions may also occur at other sites especially in patients with underlying predisposing factors. Thus long-term follow up is essential. Non-melanoma skin cancers Squamous cell carcinoma (SCC) the second commonest human cancer after BCC HK 200:170 new cases _SCC = 1_ BCC 3-4 Squamous cell carcinoma (SCC) Most cases of SCC can be completely cured by adequate surgical excision. Radiotherapy is another useful option which is especially suitable for treating elderly or debilitated patients who are poor surgical candidates. After treatment, patients should be followed up at regular interval to screen for recurrence or new lesions. RT: BCC at left lower eye lid 4.2 Gy / fraction x 10 fractions Required protective eye shield during each treatment Radiotherapy effect for BCC SCC BCC relapsed Size of tumour BCC new cases cases SCC new cases SCC relapsed cases < 1 cm 64/66 (97%) 22/23 (96%) 11/11 (100%) 10/12 (83%) cm 71/75 (95%) 27/36 (75%) 19/21 (90%) 7/13 (54%) cm 11/13 (85%) 7/9 (78%) 7/8 (88%) 6/9 (67%) 3/8

4 > 5 cm 12/13 (92%) 1/2 (50%) 3/5 (60%) 6/11 (55%) Non-specific 4/4 (100%) 1/1 (100%) 0/1 (0%) 4/6 (67%) Total 162/171 (95%) 58/71 (82%) 40/46 (87%) 33/51 (65%) Adapted from Lovett, et al., 1990 Radiotherapy treatment for NMSC Gy Cases 20 Gy single dose Old and frail patients 30 Gy / 5 times / 1 week or 40 Gy / 10 times / 2 weeks small (1cm) skin cancers Media sized skin cancers or 45 Gy / 15 times / 3 weeks Cancer cells at incision (3 Gy each time) margin Melanoma highly malignant cutaneous neoplasm derived from melanocytes of epidermis. very dangerous skin disease with high tendency of early metastasis. In 2007, HK had 53 new cases Predisposing factors include excessive ultraviolet irradiation (which can be cumulative or due to episodes of intense and brief severe sunburn), pre-existing naevus (especially congential pigmented naevus or dysplastic naevus) family history of skin cancers. Suspicious Symptoms and signs Rapidly increasing size Itch Inflammation and pain Bleeding Ulceration Variation in colour Satellite lesions Suspicious signs ABCDE A Asymmetry B Border irregularity C Colour variation D Diameter > 6mm E Enlargement Melanoma Stage I: 2 mm 4/8

5 Stage II:> 2 mm Stage III:lymphatic spread Stage IV:spread to lung, bone, brain Curative rate for melanoma 100 生存病人百份比 第三期 第一期 第二期 20 第四期 0 0 年 2 年 4 年 6 年 8 年 10 年 12 年 14 年 生存年數 Primary treatment for Melanoma Complete surgical resection is the main stay of treatment with wide excision of primary tumour + / - lymph node biopsy / dissection. Principles of surgical margins for wide excision of primary melanoma Tumour thickness Recommended clinical margins In situ 0.5cm </= 1.0mm 1cm mm 1-2 cm mm 2 cm > 4mm 2 cm Adjuvant treatment after primary resection Adjuvant interferon alfa2b is an option for Stage IIB, III or limited resectable stage IV if very keen and good PS </=2. RT to nodal basin if Stage IIIC disease with multiple involved nodes, or extranodal extension Adjuvant interferon treatment ECOG trial MU / m2 / day IV, 5 days/week x 4 wks 10 MU/ m2 SC, 3 times / week x 11 months Interferon trial results: median FU 6.9 years Treated group Control Median relapse-free survival 20.6 mths 11.8 mths (P<0.01) 5/8

6 Median overall survival 45.8 mths 33.4 mths (P=0.047) 5-year relapse- free survival 37% 26% 5-year overall survival 46% 37% Interferon adjuvant treatment side effects Malaise, flu-like symptoms, muscle pain WBC Liver toxicities : liver enzymes Neurologic : 67% had severe (grade 3) toxicity at some point during treatment Dose delays & / or dose reductions required in 37% during induction, 36% during maintenance With dose modification, 74% patients able to continue treatment on protocol until 1 year Randomized Phase III study of 1 J Clin Oncol mth vs 1-year interferon treatment Arm A : 15 x 10 6 unit / m2, IV x 5/7 days weekly x 4 weeks Arm B : Above + 10 x 10 6 unit, SC, 3 times / week x 48 weeks 1- mth vs 1-year interferon treatment results : median FU 63 mths Arm A (1 mth) Arm B (1yr) Median RFS 24.1 mths 27.9 (P = 0.9) Median OS 64.4 mths 65.3 mths (P=0.49) Conclusion from this study No significant difference in OS & RFS between 1-month & 1-year treatment 1-month treatment non-inferior to 1-year treatment 1-month treatment : fewer side effects Disseminated disease Palliative RT : painful sites and haemorrhage Systemic treatment for metastatic disease Drugs Dacarbazine (DTIC) Temozolomide ( SFI alternative to dacarbazine) Dacarbazine (DTIC) 6/8

7 Dacarbazine 200 mg/m2 IV Day 1-5 every 28 days, short infusion Response rate ~ 10-20% Overall median survival was 8.9 months. Temozolomide (Temodal) Temozolomide : oral drug 200mg / m2/ day oral Day 1-5 every 28 days Randomized phase III study : Temodal demonstrated efficacy equal to that of DTIC and is an oral alternative Median survival ~ 7 months Sun Protection UV Sun Protection Factor Sun protection products useful? Sun Protection Factor SPF15 protective time:15 x 10 minutes = 150 minutes SPF only protects against UVB,not for UVA Sun protection products SPF 15 : 93% UVB SPF 30 : 97% UVB Adequate application of SPF15 or SPF30 is more protective than thin application of SPF 60 / 100 For face, 1 tea spoon For whole body, 30 mls Recommend to use sun products of SPF 15 or above and PA++/+++ Sun protection products Apply sun protection lotions 30 mins before exposure Stay in shades even after application of sun protective lotions Ultraviolet Protection Factor (UPF) for clothing material 衣料的防曬指數 (UPF) 衣料的防曬指數 (Ultraviolet Protection Factor, UPF) 是用來量度其防禦紫外線的能力 例如一件 UPF 為 50 的衣料只會讓五十分之一的紫外線穿過, 換句話說, 該衣料阻擋了五十分之四十九或 98% 的紫外線 直至目前為止,UPF 仍未是一個國際所採用的標準 在衣料的標籤上顯示 UPF 值的例子 7/8

8 Sun protection for young children Very important Because 80% of the damage caused by sun exposure occur before the age of 18 Indoor Tanning increases the risk of skin cancer US Dermatology Society and W.H.O. warns people under 18 not to undertake indoor tanning It increases the risk of developing skin cancer in adult life Some US cities pass laws to prohibit the under 18s to undertake indoor tanning unless with parental consent 香港防癌會對曬燈的立場 本會絕不贊成照太陽燈以達至古銅膚色, 因會引致皮膚受損, 嚴重者更可引致皮膚癌, 特別是 18 歲或以下人士 曬燈場所亦應清楚提醒使用者的健康風險及張貼警告字眼 Preventing Skin Cancer Studies found 80% of the skin cancer is preventable It must begin in children Urges schools, teachers to take precaution during school outdoor activities 8/8