In the current study, the recurrence rate for BCC after Mohs surgery in 4 years was 9.5%, which is significantly higher than the recurrence rate in all previous studies. This might be due to the fact that in this study, BCC in all parts of the body was investigated, while most other studies investigated the recurrence rate for face BCC. Because of different follow-up periods in different studies, an exact comparison is not possible.
Different studies have used different methods in order to determine the recurrence rate in BCC after Mohs surgery. Essers et al. conducted a randomized clinical trial in 408 cases of BCC, a treated in a skin clinic of Netherland’s University Hospital with a 30-month statistical follow-up. Their results showed that the recurrence rate in face BCC after Mohs surgery is 1.47% (
9). Mosterd et al. in another randomized clinical trial on 408 cases of face primary BCC in 7 hospitals in the Netherlands and after a 5-year follow-up period concluded that the recurrence rate in this surgery is 2.5% (
10). In another randomized clinical trial on 408 cases of BCC in 7 hospitals in southern Netherlands by van Loo et al. the 10-year cumulative incidence of face BCC recurrence after Mohs surgery was 4.4% (
11). In another study in Sweden, the recurrence rate of BCC in 5 years after Mohs surgery was 6.5% (
12). Paoli et al. also conducted a study in order to determine the recurrence rate in face BCC tumors in 5 years after Mohs surgery, which showed a 2.1% recurrence rate (
13).
The results of several non-randomized prospective studies show a 1% to 3.4% recurrence rate in BCC after Mohs surgery in 5 years (
13-
16). Rowe et al. in their study showed that 66% of the recurrences in BCC after Mohs surgery happen in less than 3 years after treatment, while 18% of the recurrences happen between 6 to 10 years after initial surgery (
17,
18). The results of the current study show that 85% of the recurrence cases happen in the first 2 years after surgery.
In this study, the majority of BCC patients were male, while in a study conducted by Leibovitch et al. (
19), the majority of the cases were female. In Iran, women usually use clothes with more protection against sunlight compared to men. In this study, the most common location of BCC was in the head and face area. Leibovitch et al. reported that 98% of the BCC cases were in the face and head area (
19). Scrivener et al. (
20) reported that 85% of the BCC tumors were in the face area, while McGovern et al. reported that 70% of BCC occur in the face area (
21). In another study investigating the location of face BCC, the most common location of tumors was the nose (
13). The study conducted by Leibovitch et al. also showed that the most common location of recurrence in BCC lesion is in the nose and cheek area (
14). The results of the current study show that the most common locations of BCC recurrence are the scalp, nose, and around the eye.
Previous results indicate that lesions between 1 cm to 3 cm had a higher recurrence rate than those of > 3 cm (
14); but, the result of this study showed that the highest recurrence rate was in lesions smaller than 2 cm. This can be due to the different accuracy of surgeons performing Mohs surgery. Also, Mohs surgery is a more suitable treatment method for larger lesions due to lower recurrence rate. Some studies report that the rate of recurrence in BCC is related to factors such as larger lesion size, location of the lesion in face area, and invasiveness of histological procedures (
21-
23). In a study carried out by Smeets et al. the results showed that having more than 4 stages of Mohs surgery and lesion size of 4 cm or higher increase the chances of recurrence (
15), while Paoli et al. showed no significant relationship between different factors and recurrence (
13). Leibovitch et al. showed that previous recurrence, longer tumor lifetime, and the higher number of surgery stages increase the chances of recurrence (
14). However, the results of this study showed that the recurrence was related to the location of initial lesion with lesions in body, arms, feet, head, neck, hands, legs, or genital organs having a higher recurrence rate, while in Leibovitch’s study, which is similar to the current study, there was no significant relationship between the size and location of lesion and recurrence.
The results of this study showed that only the lesion size had a significant effect on treatment cost; it means that the treatment cost in tumor size less than 2 cm was more than lesion size ≥ 2 cm. Other studies investigate factors affecting the cost of treatment for Mohs surgery in BCC. The study by Smeets et al. showed that the cost of BCC treatment with a 5-year follow-up period was 405.79 Euros. The details of these costs included the direct costs of personnel involved in treatment based on work hours, the cost of materials used, procedure costs, and the costs of histopathological tests (
24).
In a study by Essers et al. the average cost of BCC treatment with a 5-year follow-up was 254 Euros with the costs being divided based on pre-surgery costs, surgery costs (personnel, materials, pathological costs, and hospitalization), complication costs, treatment, after surgery visits, and phone consultations. The highest and lowest costs belonged to surgery (406 Euros) and pre-surgery (147 Euros), respectively (
9).
Mosterd et al. calculated that the average cost of 5-year initial BCC Mohs surgery treatment including personnel, procedures, and materials used during surgery, pathology tests, and doctor visits was 1248 Euros (
10). In this study, the cost of treatment along with 4-year follow-up period was 409 US dollars including surgery cost and surgery medicine (176 $), after surgery visits and medicines (135 $), restoration (67 $), and pathology tests (31 $).
Although the average surgery costs calculated in this study are lower than the costs reported in other mentioned studies, given that some of these studies consider personnel costs while others, like our study, ignore these costs, and because different studies use different calculating methods and different number of follow-up years, it is difficult to compare the costs between different studies.
Some other studies investigated the cost of Mohs surgery in non-melanoma skin cancer. Cook et al. calculated the total cost of Mohs surgery for skin cancer with a 5-year follow-up to be 1243 $. These costs include initial diagnosis, skin biopsy, diagnostic pathology, the costs of a 5-year follow-up period, and the cost of treatment for recurrent tumors (
25). Bialy et al. reported that the cost of treatment for non-melanoma skin cancer with a 3-year follow-up period was 937 $ (
26). In a study carried out by Seidler et al., the cost of Mohs surgery and 5-year follow-up for non-melanoma skin cancer were divided into surgery and reparation costs, which were in average 745.4 $ and 79.9 $, respectively (
27). Ravitskiy et al. reported the average cost of 804.72 $ for Mohs surgery and 5-year follow-up for non-melanoma skin cancer including the costs of initial diagnosis, skin biopsy, and diagnostic pathology (
28).
Due to a retrospective cohort method of the study, the information about patients was extracted from their medical files. Therefore, it is entirely possible that at different times, different surgeons were responsible for the treatment. Given the difference in the proficiency of different surgeons and increase in surgeon proficiency over time, it is possible for the number of recurrence cases to chance over time, which can lead to information bias. Another limitation of this study is the lack of histology report on BCC and its possible effects on recurrence. Also, in order to increase the sample size and improve the power of the study, the follow-up period was 4 years. However, some studies have used a 5-year follow-up period, which can be another limitation of this study.
5.1. Conclusions
In this study, the results showed that the most common location for BCC lesions is in the face area and lesions in this area can lead to scarring and future psychological problems for patients.
The causes of recurrence can include the less use of protective equipment in front of sunlight or low precision of doctors in the lesion surgery in locations of the body, arms, feet, head, neck, hands, legs, or genital organs.