research article

Histologic and Demographic Profile of Nonmelanoma Skin Cancer (NMSC) in Filipinos Seen in a Tertiary Care Clinic: A Retrospective Study from 2018 To 2021

Juan Paolo David S. Villena1* and Eileen Liesl A. Cubillan2

1Primary Investigator, Dermatopathology Fellow, Department of Dermatology, University of the Philippines Manila-Philippine General Hospital, Philippines

2Adviser and Professor, Department of Dermatology, University of the Philippines Manila-Philippine General Hospital, Philippines

*Corresponding author: Juan Paolo David S. Villena, Primary Investigator, Dermatopathology Fellow, Department of Dermatology, University of the Philippines Manila-Philippine General Hospital, Philippines

Received Date: 17 March 2023

Accepted Date: 24 March 2023

Published Date: 28 March 2023

Citation: Villena JPDS, Cubillan ELA (2023) Histologic and Demographic Profile of Nonmelanoma Skin Cancer (NMSC) in Filipinos Seen in a Tertiary Care Clinic: A Retrospective Study from 2018 To 2021. Clin Exp Dermatol Ther 8: 206. DOI:https://doi.org/10.29011/2575-8268.100206

Abstract

Introduction: Nonmelanoma Skin Cancer (NMSC) is the most frequent type of malignancy in humans. It includes a variety of cutaneous malignancies that are not melanocytic in origin. Demographic and histologic characteristics are helpful in prognosticating patients with NMSC. Available data on the demographic and histologic profile of NMSCs only include Caucasians and data from developed countries. This study provides an updated profile on NMSC prevalence in Filipinos, providing an avenue to further strengthen knowledge, hasten advancement of research, and facilitate creation of better health policies and programs regarding NMSC in Filipino skin. Study design: Retrospective study. Methodology: Medical records and biopsy logbooks of patients seen at a tertiary care center in the Philippines who were diagnosed with a nonmelanoma skin cancer from 2018-2021 from the available medical records and biopsy logbooks were included in this study. One hundred sixty-five (165) patient records and 189 available slides were reviewed. Data for age were analyzed using means and standard deviation. Data for tumor location, histopathologic diagnosis and histologic characteristics were analyzed using frequencies and proportions. Results: The mean age of patients affected with nonmelanoma skin cancer at diagnosis is 62.75  15.12 years old with a range of 21 years old to 97 years old. There is female preponderance, with a sex ratio of 0.53:1. The head and neck area are the most common affected site in the patients included in this study, comprising of 135 out of 188 tumors (71.81%). The most common nonmelanoma skin cancer upon review of slides in this study is basal cell carcinoma accounting for 64.36% (121 out of 188) tumors biopsied, with the nodular type being the most common histopathologic subtype. There was no perineural and lymphovascular invasion seen in the slides reviewed. Squamous cell carcinoma was the second most common NMSC, comprising 22 patients and 22 tumors reviewed, composed mostly of well-differentiated tumors with two exhibiting acantholysis, a poor prognostic feature. Eleven (11) patients had squamous cell carcinoma-in-situ, none exhibiting eccrine gland involvement. Nine (9) patients with actinic keratosis were found on review of records and slides with 3 patients having hypertrophic actinic keratosis, a high-risk feature for progression to overt malignancy. Patients with Paget’s disease were composed of 8 of the Mammary-type and 2 of the extramammary-type. Dermal, perineural and lymphovascular invasion were not seen in the cases of Paget’s disease reviewed. Of the 4 cases of porocarcinoma reviewed, all exhibited a pushing border, without necrosis within the tumor, and absence of lymphovascular and perineural invasion, with <14 mitotic figures/ 10 High Power Field (HPF). Only one case each of angiosarcoma, Kaposi sarcoma and dedifferentiated liposarcoma were reviewed in this study. Conclusion: Nonmelanoma skin cancer affects a great proportion of the population. Identifying certain histologic features aid in prognosticating patients with NMSC. Further studies on the histopathologic characteristics and their association with patient outcomes may prove to be beneficial.

Keywords: Nonmelanoma skin cancer; Filipinos; NMSC

Introduction

The integumentary system is an intricate and complex organ of the human body that has derivations from both the ectoderm and mesoderm [1]. Because of the multiplicity of origins, it may be a host to a variety of both benign and malignant tumors. Cutaneous malignancies or skin cancers are the most common form of cancer in humans, comprising around 1 million of the new cases of cancers diagnosed yearly in the United States [2] and is continuously increasing in an exponential pattern globally [1,3-5]. Ultraviolet radiation (UVR) is the most significant risk factor for the development of cutaneous malignancies [4-6]. Skin cancer may be broadly divided into two groups, melanoma, which involves all cutaneous malignancies from the aberrant proliferation of melanocytes, and nonmelanoma skin cancer.

Nonmelanoma skin cancer (NMSC) includes a vast array of cutaneous malignancies that are not of melanocytic origin. NMSC is the most frequent type of malignancy in humans, comprising approximately 1/3 of all cancers worldwide [5]. The most common of these NMSCs are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) [5]. Together, they comprise more than 90% of all diagnosed NMSCs [5,7]. Other diseases in the NMSC category include Merkel cell carcinoma, dermatofibrosarcoma protuberans, Kaposi sarcoma, angiosarcoma, porocarcinoma, sebaceous carcinoma, etc. [5]. In comparison to melanoma, NMSCs are more common in terms of occurrence but pose a lower risk of mortality. However, NMSCs, being the most common form of cutaneous malignancy, also pose a significantly higher degree of morbidity in patients diagnosed. If treatment is inadequate or not initiated early in the course of the disease, there is a perceived rise in morbidity, and mortality rates rise due to significant disfigurement, local recurrence, or distant metastasis.

Data on the demographic and histologic profile of NMSCs are widely available; however, these researches and reports only include Caucasians and data from developed countries. A handful of research on NMSC in Asian skin are accessible but upon extensive literature search, Filipino data on NMSC is lacking. This study will hopefully provide a new and updated perspective on NMSC prevalence in Filipinos, for which current data is lacking.

Identification of the demographic and histologic profile of Filipino patients diagnosed with NMSC will provide an avenue to further strengthen knowledge, hasten advancement of research, and facilitate creation of better health policies and programs regarding NMSC, particularly in Filipino skin.

Objectives

General Objective: To describe the histologic and demographic profile of patients diagnosed with a nonmelanoma skin cancer and who were biopsied at the UP-PGH Department of Dermatology from 2018-2021.

Specific Objectives

  1. To describe the demographic profile of patients with nonmelanoma skin cancer in terms of age and sex,
  2. To identify the common sites where lesions arise in patients diagnosed with nonmelanoma skin cancer,
  3. To identify the types of nonmelanoma skin cancer that arose in these patients based on histopathologic diagnosis,
  4. And to identify the histologic characteristics of these nonmelanoma skin cancers.

Methodology

Study design

This is a retrospective study of patients who were biopsied at the UP-PGH Department of Dermatology between January 2018 and December 2021 with a final histopathologic diagnosis of a nonmelanoma skin cancer. These patients include cases seen at the out-patient department as well as cases referred to the PGH Department of Dermatology in the emergency room and in-patient facilities (charity service). Only patients with a final histopathologic diagnosis of a nonmelanoma skin cancer were included in this retrospective study. Patients with irretrievable histopathologic slides or block specimens were excluded from this study. This study was submitted for approval to the University of the Philippines Manila Research Ethics Board prior to conduction. Waiver of informed consent process was requested by the researchers under the provisions that the research procedures entail no more than the minimal risk.

Data Collection, Management and Statistical Analysis

The primary investigator assigned a unique identification number to each patient. The following data were extracted by the primary investigator from the biopsy records: age, sex, location of tumor and final histopathologic diagnosis. Biopsy slides and block specimens were obtained from the archive and was preread by the primary investigator. All slides were read and verified by the adviser, a board-certified dermatopathologist. Descriptive analysis using mean, standard deviation, and range were done for age, which is a continuous variable. For sex, location of tumor, final histopathologic diagnosis and tumor characteristics on histopathology, enumeration, and frequencies and proportions were used to analyze the data collected.

Results and Discussion

From the years 2018 to 2021, a total of 186 patients were diagnosed with a nonmelanoma skin cancer. Out of the 186 patients, with some having multiple tumors, 212 tumors were biopsied and reported to be a NMSC since some patients had multiple tumors. Only 188 slides from 165 patients were available for review. Nine (9) patients had multiple tumors while 156 patients had a solitary tumor. Only the 165 patients with available records and biopsy slides for review were included in the data analysis with regards to age and sex. All 188 slides available for slide review were included in the data analysis with regards to location of tumor, histopathologic diagnosis, and tumor characteristics (Figure 1).

 

Figure 1: Inclusion and exclusion of data reviewed.

Age and Sex

A total of 165 patients histologically proven to have NMSC were included in the analysis for age and sex. Fifty-seven (57) of the patients are male, which constituted 34.55% of the study population, while 108 patients or 65.45% are females, with a male: female sex ratio of 0.53:1. The mean age of patients with NMSC upon diagnosis is 62.75 ± 15.12 years old with a range of 21 years old to 97 years old. Accounting for sex, males have a lower mean age upon diagnosis of a NMSC (57.95 ± 16.95 years old) compared to women (65.29 ± 13.47 years old). In terms of age at initial diagnosis of NMSC, the data gathered in this study is congruent with the available data in the literature [8], particularly in the elderly population. In terms of sex predilection, NMSCs are known to be more common in men that in women [6-9]. A plausible explanation as to the higher percentage of women affected in this study may be attributed to their better health-seeking behavior for suspicious-looking lesions on their body.

Tumor location

In the 165 patients included in this study, there were 188 unique tumors biopsied. Nine (9) patients had multiple tumors, explaining the difference in the patient number and slide count. Most of the NMSC tumors biopsied and included in this study were located on the head and neck area (135/188 tumors, 71.81%). The succeeding area to have the most tumors was the trunk (31/188 tumors, 16.49%), followed by the upper extremities (13/188 tumors, 6.91%) and the lower extremities (9/188 tumors, 4.79%). As was mentioned earlier, UVR is a potent risk factor for the development of NMSC lesions [4-6]. The head and neck area are considered to have incurred more UVR damage due to its relative exposure to sunlight compared to other parts of the body and may possibly explain the preferential appearance of NMSC lesions in this location. This finding is similar to that of Bas, et al. epidemiologic study on NMSC [8].

Histologic diagnosis and tumor characteristics

In terms of histopathologic diagnosis of NMSC, basal cell carcinoma is the most common NMSC tumor histologically diagnosed, comparable to available international data [6,8,10,11]. Listed in Table 1 are the number of patients diagnosed with other NMSC in this study.

Histologic diagnosis

Number patients

Number of tumors

Basal cell carcinoma

105

121

Squamous cell carcinoma

22

22

Squamous cell carcinoma-insitu

11

18

Actinic keratosis

9

9

Paget’s disease

11

11

Porocarcinoma

4

4

Kaposi sarcoma

1

1

Angiosarcoma

1

1

Dedifferentiated liposarcoma

1

1

TOTAL

165

188

Table 1: Histologic diagnosis of patients with nonmelanoma skin cancer.

Basal cell carcinoma (BCC)

A total of 105 patients with 121 tumors had basal cell carcinoma. Most patients with BCC were female (75 patients, 71.43%). The mean age at the time of diagnosis of patients with BCC in this study is 64.34 ± 14.18 years old. The most common location of a BCC was the head and neck (109/121 tumors, 90.08%) followed by the trunk (7/121 tumors, 5.79%) and upper extremities (4/121 tumors, 3.31%). There was only 1 patient who had a BCC in the lower extremity (0.83%). According to available literature, there is a male predominance in terms of patients afflicted with BCC [8]. This conflicting data in our study may be attributed to the fact that female patients in our country may have a better healthseeking attitude and translates to seeking earlier consultation for suspicious lesions. According to other previous studies done, the head and neck area was also the most common site for a basal cell carcinoma to appear [1,8].

The most common histologic type of BCC seen in these patients was the nodular type (55/121, 45.45%) followed by the superficial type (6/121 tumors, 4.96%), micronodular (5/121 tumors, 4.13%) and basosquamous carcinoma (1/121, 0.83%). Fifty-four (54) patients (44.63%) had a combination of 2 or more types of BCC. The most common combination of BCC subtypes seen in one biopsy were nodular and micronodular (26/121 tumors, 21.49%) followed by nodular and infiltrative (12/121 tumors, 9.92%), nodular and superficial (9/121 tumors, 7.44%), and nodular, micronodular, and infiltrative types (7/121 tumors, 5.78%). In previous studies done, the nodular type was also considered as the most frequent type of BCC histologically diagnosed [1,7-9].

Perineural and lymphovascular invasion were not seen in any of the slides reviewed. Perineural invasion is an important histologic feature to be identified as it is associated with a higher risk of recurrence [11]. Lymphovascular invasion is not a common finding in patients with BCC, but multiple case reports have linked its presence with metastatic basal cell carcinoma [12] (Figure 2).