Basal cell carcinoma - what is it and how to treat it.

In this article we will tell about basal cell carcinoma, as well as describe the most effective method of treatment.
Basal cell carcinoma(BCC) is the most common malignant tumor of the skin. Not all studies confirm this, since not all cancer registries classify it as malignant tumors. The 5- and 10-year survival rate in basal cell carcinoma is almost 100%, however, in isolated advanced cases, death is possible as a result of tumor germination into the underlying structures.
Despite the absence of a threat to life, the main danger of basal cell carcinoma is a significant cosmetic defect that can occur if the tumor is not treated for a long time. This is due to the fact that 85% of basal cell carcinomas are located on the skin of the face or neck.

Basal cell carcinoma may be at high and low risk of recurrence.
Types of treatment of basal cell skin cancer

Surgical removal of basal cell carcinoma

  • Micrographic Surgery by Mohs
The main task of any therapeutic approach for basal cell skin cancer is to remove the tumor from the body completely. It usually happens like this:
Area H: Face mask (including eyelids, eyebrows, skin around the eyes, nose, lips [skin and red lip border], chin, lower jaw, skin/furrows in front and behind the auricle, temples, ears), genitals, palms and feet. This area means high risk regardless of size.

Area M: cheeks, forehead, scalp, neck and lower legs. Localization, regardless of size, can be a sign of high risk.

Area L: torso and limbs (excluding shins, palms, feet, nail parts and ankles).

To assign the tumor the status of "high risk of recurrence", even one factor from the right column is sufficient. The tactics of treatment of basal cell carcinoma depends on the degree of risk of recurrence.

Now we will make a detailed review of the most common methods of treating basal cell carcinoma.
1 and 2 – an incision is made on the skin, similar in shape to a spindle
3 – basal cell carcinoma, together with a small fragment of healthy skin is removed, the wound is not sewn up
4 – the wound is sutured with nodular sutures or intradermal suture.
However, what if everything turned out less successfully than in the first picture and the tumor was not completely removed?
What if the capture of healthy tissues was not enough and part of the tumor remained in the skin, and this will inevitably lead to a relapse? It can be assumed that you need to retreat more, but, unfortunately, this option is not always suitable, because 85% of basal cell carcinomas are located on the face and there is usually nowhere to retreat there.

What to do? How, on the one hand, to 100% remove the tumor, and on the other – to remove a minimum of healthy tissues?

American surgeon Frederick Mohs in 1936 proposed to perform a layered removal of the tumor with a histological examination of each removed layer during surgery.

It looks like this:

1) The tumor is removed with the capture of healthy tissues. The removed material immediately falls under the microscope to a pathologist. The doctor looks to see if there is healthy tissue in the edges of the resection.
If there are basal cell cells in one of the edges of the resection, the doctor removes another layer.
And again, the pathologist looks into the microscope and realizes that tumor cells are again detected in the deep edge of the resection.
And in this way, layer by layer is removed until the pathologist sees all the edges of the resection without tumor cells.
That's all. The wound is sewn up and the patient is sent to be treated. Possible complications are standard, as for any surgical intervention:
  • suppuration;
  • bleeding;
  • scar development in the postoperative period.

Disadvantages of the method in comparison with excision with a scalpel:
  • high labor intensity;
  • significant duration of the operation;
  • high cost.

  • complete removal of the tumor;
  • minimum possible percentage of relapse;
  • histological confirmation of the purity of the resection edges;
  • in some cases, the method allows you to remove a smaller volume of healthy tissues than with similar excisions with a scalpel.
  • Excision with a scalpel

With the traditional removal of basal cell carcinoma with a scalpel, the surgeon faces the same task as during Mohs micrographic surgery – to remove the tumor completely.

On the other hand, since with basal cell carcinoma, the doctor most likely works with the skin of the face, it is important for him to avoid a pronounced disfiguring scar after surgery.

There are 3 main types of surgical excision for basal cell carcinoma:

1) Removal from a fusiform incision
2) The closure of a skin defect that occurs after removal of basal cell carcinoma with skin flaps. There are a lot of flap closure techniques, so we will not give the whole spectrum here, but only pay attention to the fact that if the surgeon says something like "no, it cannot be surgically removed here", then perhaps you should get the opinion of another surgeon.

3) Skin grafting. In a situation when neither the first nor the second type of surgery can be applied, plastic remains a free skin flap.
After (sometimes during) the removal of the tumor, the surgeon prepares a skin fragment of the required size on the donor site. As a rule, this is the inner side of the shoulder, the iliac region. Then the donor fragment is placed on the defect formed after the removal of the tumor, and sewn to the surrounding skin.

Electrocoagulation, radio wave method, laser

These methods are used for very small sizes of the basal cell carcinoma, as well as when there is confidence that the tumor does not germinate to the subcutaneous tissue. It is also important to note that electroexcision should be used only when the tumor is located in a low-risk area of recurrence (for example, when the basal cell is located on the lateral surface of the chest).
The skin is dissected using an electrocoagulator, a radio wave apparatus or a laser, the tumor is removed with the capture of healthy tissues.
After removal, the material is sent for histological examination, during which the type of tumor and the completeness of its removal are determined. In case of detection of tumor tissue or aggressive type of skin cancer at the edges of resection, a repeat operation is performed with a large seizure of healthy tissues or a course of radiation therapy. Aggressive histological types include morphine-like, basosquamous (metatypical), and micronodular.
After confirming the diagnosis, the patient is referred for radiation therapy. The device is designed in such a way that the rays do not penetrate deeper than the surface layer of the skin. The impact on the surrounding tissues is minimal.
Radiation therapy of basal cell carcinoma

This type of treatment is used for basal cell carcinoma, when surgery is impossible due to contraindications or difficult due to the location of the tumor, for example, in the eyelid or nose area. In addition, large tumors can also be cured with radiation therapy.

There are 4 types of radiation therapy for basal cell carcinoma:
  • close-focus X-ray therapy;
  • remote gamma therapy;
  • electronic therapy;
  • brachytherapy.

Attention! Before prescribing radiation therapy, the doctor should make sure that it is basal cell carcinoma in front of him. Not melanoma, not Merkel's carcinoma, but basal cell carcinoma.

To confirm the diagnosis, the entire formation or a fragment of it is removed using a punch or razor biopsy and sent for histological examination. Dermatoscopy, scraping or puncture for cytological examination, and even more so a simple visual examination, do NOT replace histology.
The procedure of radiation therapy for basal cell carcinoma is very similar to X-ray examination. One session takes several minutes, the total radiation dose can vary depending on many factors and is delivered to the basal cell carcinoma site in parts, on average, from 3 to 7 weeks. The larger the size of the focus, the more sessions, the longer the treatment and the greater the likelihood of complications. A radiologist should make a treatment plan taking into account the specifics of a particular case.
Treatment of basal cell carcinoma with ointments

For all its attractiveness, the use of this type of treatment is strictly limited. The appointment of any ointment for basal cell carcinoma cannot be carried out without first determining its histological type. This is due to the fact that with morpheaform, micronodular or metatypical form, the risk of relapse increases.
A simple visual examination, dermatoscopy, scraping or puncture does not replace histology.

To do this, before the procedure, with the help of a punch or razor biopsy, a fragment of the tumor or the entire focus is removed and sent for histological examination.
The most important thing in this section is the indications for the use of these ointments for the treatment of basal cell skin cancer. These indications are formulated by the US Food and Drug Administration (FDA) for the ointment with the most proven effectiveness – containing imiquimod:

  • for adults, without immunodeficiency (HIV, hepatitis B and C, organ transplantation);
  • for the primary focus of basal cell carcinoma (not relapse);
  • the size is not more than 2 cm;
  • surface-spreading form;
  • location on the trunk, neck or limbs (except hands and feet).

Photodynamic therapy for basal cell carcinoma

The essence of the method (PDT): By injection, a special substance (photosensitizer) is placed into the tumor or on its surface (in the form of a cream), which increases the sensitivity of all cells of the body to the effects of light of a certain wavelength. Basal cell carcinoma cells accumulate it with much greater intensity than healthy ones. At the last stage, a laser beam is applied to the tumor area, a chemical reaction is triggered, as a result of which malignant cells die. The inflammation that occurs around the focus also activates the immune system to fight skin cancer.
Before starting PDT, the doctor should be sure that it removes basal cell carcinoma of a non-aggressive histological type. In morpheaform, micronodular or metatypical form, the use of PDT is undesirable due to an increased risk of relapse.

This means that before the procedure, a fragment of the tumor or the entire focus is removed and sent for histological examination, after which the diagnosis of "basal cell carcinoma" is confirmed.
The video shows the process of cryodestruction of seborrheic keratosis – the same thing happens with basal cell carcinoma. You can see how when the desired temperature is reached at a specific point, the indicator turns green.
Cryodestruction in basal cell carcinoma

It's simple – the tumor is frozen with liquid nitrogen. As a result, basal cell carcinoma cells are destroyed. There are different ways of delivering nitrogen to the tumor – the classic cotton swab, probe and applicator.
Systemic treatment of basal cell carcinoma

  • Targeted therapy
Treatment with targeted drugs is indicated for patients in two cases:
1) With the development of basal cell metastases (an extremely rare condition, no more than 300 cases have been described in the literature).
2) With a pronounced local spread of the tumor, when it grows into the underlying tissues and surgery, radiation therapy is impossible or contraindicated.

  • Chemotherapy
The main drug for chemotherapy for basal cell carcinoma is Cisplatin. Its effectiveness has not been studied in prospective or randomized clinical trials, and therefore it varies very widely – from minimal changes in size to complete disappearance of the tumor.

The use of the drug in a very large percentage of cases is associated with pronounced side effects, such as toxic effects on the kidneys, nausea and vomiting, diarrhea, hair loss, joint pain, loss of balance, swelling, severe fatigue, ringing in the ears.

In connection with the above, it seems logical to use chemotherapy as a second line of treatment for basal cell carcinoma. This will be especially relevant for patients who do not have tumor regression or have developed resistance to targeted drugs.
How to choose the right method of treating basal cell carcinoma?
The table lists treatment methods in descending order of effectiveness, according to large meta-analyses.

The lower the risk of relapse, the higher the effectiveness of the method.

Source 1. Data from 106 studies and hundreds of patients with basal cell carcinoma are summarized. Rowe DE, Carroll RJ, Day CL Jr. Long-term recurrence rates in previously untreated (primary) basal cell carcinoma: implications for patient follow-up. J Dermatol Surg Oncol.

Source 2. Data from 45 studies on 2204 foci of basal cell carcinoma are summarized. Drucker AM, Adam GP et al. Treatments of Primary Basal Cell Carcinoma of the Skin: A Systematic Review and Network Meta-analysis. Ann Intern Med. 2018 Oct 2; 169 (7): 456–466. doi: 10.7326 / M18–0678.

Source 3. Data from 40 studies, several thousand patients are summarized. Charlotte M. Clark, Megan Furniss, Julian M. Mackay-Wigan. Basal Cell Carcinoma: An Evidence-Based Treatment Update. Am J Clin Dermatol DOI 10.1007 / s 40257-014-0070-z, 2014.
From the data in the table, an obvious conclusion can be drawn: The most effective method of treating basal cell skin cancer is micrographic surgery according to Mohs. Surgical excision can give comparable results. If it is impossible to use surgical methods or for cosmetic reasons, radiation therapy should be used.
All other methods: ointments, photodynamic therapy, cryodestruction, laser, radionoge, electrocoagulation, according to three studies, give a significantly higher percentage of relapses and should not be used to treat foci of basal cell carcinoma with a high risk of relapse.

Summing up, I would like to say that the main idea of this article is that there is no ideal method of treating basal cell carcinoma that suits everyone. There is only a treatment that is optimal for each individual case, taking into account all the features of the situation.

List of literature
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