The county studied has an incidence of 22 cases of periocular BCC per 100,000. This is much higher than the 4.5 cases per 100,000 across England reported by Saleh et al, although they state likely underestimation due to regional variation in BCC registration and under-reporting [7]. Quigley et al found a rate of 13-16 per 100,000 in nearby Ireland, although the Irish population is younger (<15% over 65), and proportionally less Caucasian (91.7% vs 96.5% here), so fewer NMSC would be expected [8, 9]. These studies excluded eyebrow lesions; excluding eyebrow lesions from our results reduces the incidence to 18 cases per 100,000, which remains the highest value. The higher rate in this county is likely due to the population demographic and environment. Of note this area is relatively rural with significant agricultural and maritime activity, however Paavilainen et al found no significant difference between different occupation categories or social class in relation to rates of BCC in Finland [3].
SCCs are more likely to metastasize and have a higher mortality rate relative to BCCs [10]. We report an incidence of 1.3 cases per 100,000, reducing to 0.7 cases if eyebrow lesions are excluded. This is comparable to an England-wide study with a mean incidence of 0.6, but lower than the 1.4-2.1 cases per 100,000 found in Quigley et al’s study [8, 11]. They found a rate of periocular melanoma of 1 per million in Ireland, similar to this study (1.4 excluding eyebrow melanomas) [8]. Melanomas account for only a minority of periocular malignancies, but have a much higher rate of mortality than any other lesion [1]. England and Ireland have similar latitudes and populations. Studies have shown a relationship between latitude and rate of skin cancer in Caucasian populations, more so for SCC than BCC [12]. In Australia where there is a predominantly Caucasian population exposed to a lot of sunshine, skin cancers have a much higher incidence [13].
The remaining 26 periocular lesions were a mixture of rarer cancers. Porocarcinomas were most often found on the brow given the relative abundance of sweat glands there. SGCs are more commonly found in on the head and neck than elsewhere on the body due to the distribution of sebaceous glands [14]. We found SGCs were most common on the upper lid, correlating with the more numerous sebaceous glands found there compared to the rest of the periocular area.
Table 3 compares our results for malignant lesions to other large studies performed elsewhere in the world, specifically incorporating later studies as incidence changes over time [2–4, 8, 15–22]. Eyebrow lesions from our study have been excluded for better comparison. Differences may be due to factors such as inclusion criteria, cancer registration, ease of access to healthcare (England's National Health Service is free), and healthcare policy. The proportions of malignant lesions align with similar studies in predominantly Caucasian population [8, 15]. Specifically our results mirror those found by Cook and Bartley in an USA study in Minnesota [16]. Our populations are similar (both 96% Caucasian, middle class) with a similar latitude (Minnesota 47, our county 53). Our study population was on average older however, with a greater proportion over the age of 45. Our results were also similar to the proportions found in Greece and Iran which is of surprise given that Mediterranean and Middle-Eastern skin tends to be more pigmented and at lower risk of BCC [17, 18].
Table 3
Comparison of the proportions of periocular malignancies based on latitude (excluding eyebrow lesions)
|
Quigley[9]
|
Lin
|
Deprez15]
|
Cook[16]
|
Asproudis[17]
|
Bagheri[18]
|
Lin[2]
|
Kaliki[19]
|
Domingo[20]
|
|
Country
|
Ireland
|
Eastern County
(England)
|
Switzerland
|
Minnesota
(USA)
|
Greece
|
Iran
|
Taiwan
|
Hyderabad
(India)
|
Philippines
|
|
Latitude
|
53.1
|
52.6
|
46.8
|
46.7
|
39.1
|
32.4
|
23.7
|
17.4
|
12.9
|
|
Total cases
|
5457
|
983
|
894
|
174
|
351
|
100
|
1121
|
536
|
170
|
|
Basal cell carcinoma
(n)
|
88%
(4824)
|
94%
(921)
|
86%
(772)
|
91%
(158)
|
86%
(303)
|
83%
|
65%
(730)
|
24%
(128)
|
31%
(52)
|
|
Squamous cell carcinoma
(n)
|
10%
(528)
|
4%
(37)
|
7%
(67)
|
9%
(15)
|
7%
(25)
|
8%
|
13%
(141)
|
18%
(99)
|
17%
(29)
|
|
Melanoma
(n)
|
1%
(50)
|
1%
(7)
|
|
<1%
(1)
|
2%
(6)
|
2%
|
2%
(21)
|
2%
(12)
|
12%
(20)
|
|
Lymphoma
(n)
|
|
<1%
(6)
|
|
|
|
1%
|
|
<1%
(2)
|
6%
(11)
|
|
Sebaceous gland carcinoma (n)
|
|
<1%
(6)
|
3%
(29)
|
|
|
6%
|
8%
(89)
|
53%
(285)
|
31%
(52)
|
|
Basosquamous
(n)
|
|
<1%
(4)
|
|
|
5%
(17)
|
|
1%
(10)
|
|
|
|
Merkel cell carcinoma
(n)
|
|
<1%
(2)
|
<1%
(4)
|
|
|
|
|
<1%
(1)
|
|
|
Adenocarcinoma
(n)
|
|
|
|
|
|
|
2%
(19)
|
<1%
(1)
|
|
Racial differences are evident for SGCs, which are more common in Asian populations but account for less than 1% of cases in this study [2, 19, 20]. The proportion of BCCs is lower in Asia; a comprehensive study in Taiwan showed a lower percentage of BCCs (65% ie two thirds), and higher proportions of SCCs (13%) and SGCs (8%) [2]. Domingo et al's study in a Phillipino population found only 31% of lesions to be BCCs, and 31% of lesions to be SGCs [20]. In India, the proportion of SGCs was 53% [19]. Dasgupta et al found no racial predilection for SGCs, only a relative lack of other skins cancers in more pigmented races[14]. Darker, more pigmented skin is protective against certain dermatological malignancies, however lighter skin is seen as culturally desirable in some part of Asia, leading to sun avoidance and again reducing the rate of dermatological malignancy [14]. In countries with a high proportion of Muslims, wearing the niqab reduces sun exposure in women. In Saudi Arabia, the incidence of BCCs was found to be 0.8 per 100,000, compared to 18 in this study [23].
Periocular malignancies are more likely to be located where the skin is exposed to sunlight. Accordingly, the lower lid was most likely to be affected (38.2%) and the upper lid least so (5.9%). One finding of interest is the higher number of lesions distributed on the right compared to the left, although the difference did not reach statistical significance. In England the driver sits on the right, and so their right side is more exposed to the sun. Other studies in Australia and Israel concur with this finding based on the side the driver sits [24, 25]. Fewest lesions were found in the orbit, although the county does host orbital, maxillofacial and ENT surgeons, and thus orbital lesions would not have been referred elsewhere.
The strengths of this study are the number of tumours, and the inclusiveness of all specialties, resulting in fewer periocular lesions missed. We have also included lesions excised in private practice and from Mohs surgery. There are no other histopathology departments in the county. Our results are therefore likely to be representative of the true incidence.
Limitations of this study include reliance on the subjective descriptions of the operating surgeon to determine lesion location rather than using photographs. Not all malignant periocular lesions are treated with margin control (e.g. curettage) or surgical excision, and although those numbers are small, the incidence rates here may be an underestimate despite being higher than the UK average.
In summary, our results show the incidence of periocular basal cell carcinomas in our predominantly elderly Caucasian population in this east of England county was at least three times the national average. The ratios of each type of periocular malignancy is in fitting with published data for this homogenous population demographic. The relatively high incidence of periocular tumours in is set to increase as the proportion of over 65 year olds in the population is predicted to nearly double within two decades, and subsequently surgical caseload will also rise.