Basal cell carcinoma: a therapeutic virus could ease the treatment of the most difficult forms
Injected into the tumour before surgery, the oncolytic virus T-VEC shrinks difficult basal cell carcinomas, enabling more conservative surgery.
Doctor Florian A. Vallecillo Cabrera
Author
A phase II trial (MedUni Vienna, Nature Cancer) tested the oncolytic virus T-VEC as a neoadjuvant in 18 patients with locally advanced basal cell carcinomas. All tumours regressed, 55.6% with a significant response, one third with no detectable tumour cells, and simplified surgery in nearly half of cases. Promising results to be confirmed in phase III; surgery remains the reference.
Summary
Basal cell carcinoma is the most common skin cancer. In most cases it is treated effectively by surgery. However, some tumours become large or are located in delicate areas, particularly the face, where their removal may require significant reconstruction.
An Austrian study shows that an innovative treatment using a modified virus, injected directly into the tumour before surgery, could considerably reduce its size, or even cause it to disappear completely in some patients.
These results are promising, but they still concern a limited number of patients and require confirmation through phase III trials.
What is a basal cell carcinoma?
Basal cell carcinoma (BCC) is the most common skin cancer. It accounts for about 70% of skin cancers and nearly 90% of non-melanoma skin cancers.
It develops from the basal cells of the epidermis. Unlike melanoma, it very rarely metastasises, but it can progressively destroy neighbouring tissues if left untreated.
What are the risk factors?
The main risk factor is chronic exposure to ultraviolet rays. The risk increases in particular in:
- people with fair skin;
- those who have had many sunburns;
- people working outdoors;
- immunocompromised patients;
- people who have already had a carcinoma.
Most lesions appear on: the nose, eyelids, ears, scalp and neck.
Current treatment
In the vast majority of cases, treatment is based on surgery. When the tumour is removed early, the cure rate is generally excellent.
Some lesions require Mohs micrographic surgery or more complex reconstruction techniques when they are large or located in aesthetic areas.
What is T-VEC?
Talimogene laherparepvec (T-VEC) is an oncolytic virus. It is a genetically modified version of the herpes simplex virus type 1. Unlike the natural virus, this version has been designed to:
- preferentially infect tumour cells;
- destroy them from the inside;
- simultaneously stimulate the immune response against the tumour.
T-VEC is already authorised for certain forms of unresectable melanoma.
How does an oncolytic virus work?
Once injected directly into the tumour:
- the virus penetrates the cancer cells;
- it multiplies inside them;
- the tumour cells burst;
- they release their antigens;
- the immune system is activated against the remaining cancer cells.
The treatment therefore acts both by direct destruction and by stimulating the immune defences.
How was this study conducted?
The researchers included 18 patients with basal cell carcinomas that were difficult to operate on. Each patient received:
- six intratumoral injections of T-VEC;
- spread over a period of thirteen weeks;
- before the scheduled surgery.
The aim was to reduce the tumour size sufficiently to simplify the operation.
What are the results?
The results are particularly encouraging. All the tumours decreased in size. None continued to progress during treatment. Among the patients:
- 55.6% showed a significant response;
- about one third had no detectable tumour cells after the operation;
- in nearly half, the tumour reduction allowed a much simpler surgery, without complex reconstruction.
Six months after treatment, no patient had presented a local recurrence.
Why is this discovery important?
In some locations, particularly the face, every millimetre of preserved tissue is precious. Reducing the size of the tumour before the operation could allow:
- more discreet scars;
- fewer skin grafts;
- fewer reconstruction flaps;
- better preservation of anatomical structures;
- faster recovery.
What are the limitations?
This study has several important limitations. It involves only 18 patients. It is only a phase II trial. The follow-up remains relatively short.
A phase III study, including a larger number of patients, will be essential before any modification of international guidelines.
What this study does not demonstrate
This study does not show that:
- T-VEC will replace surgery;
- all basal cell carcinomas require this treatment;
- a virus cures all skin cancers;
- this treatment is already indicated routinely.
It is a strategy intended mainly for locally advanced forms or those that are particularly difficult to treat.
The Valorian analysis
This study illustrates the current evolution of dermatological oncology towards increasingly targeted and less mutilating treatments. T-VEC, already used in certain forms of melanoma, demonstrates here an interesting potential as a neoadjuvant treatment, i.e. given before surgery to reduce the tumour volume.
For localised basal cell carcinomas, surgery remains today the reference treatment with cure rates above 95%. On the other hand, in some patients with large lesions or lesions located in complex aesthetic areas, this approach could preserve more healthy tissue and improve functional and aesthetic outcomes.
At Valorian, we consider this strategy to be one of the most promising developments in oncological dermatology. It perfectly illustrates the complementarity between immunotherapy, virotherapy and conservative surgery. If phase III trials confirm these results, T-VEC could become a valuable tool in the management of the most complex basal cell carcinomas, without calling into question the central role of early diagnosis and surgical excision.
Key points
- ◆Basal cell carcinoma is the most common skin cancer (~70%); it very rarely metastasises but destroys tissue if untreated.
- ◆T-VEC is a genetically modified herpes virus: it destroys tumour cells from the inside and stimulates anti-tumour immunity.
- ◆Used before surgery (neoadjuvant), 6 injections over 13 weeks: all tumours regressed, 55.6% significant responses, ~1/3 with no residual tumour cells.
- ◆Key benefit on the face: simpler surgery, more discreet scars, fewer grafts/flaps, better tissue preservation.
- ◆Phase II study of only 18 patients: surgery remains the reference (cure >95%); confirmation by phase III is needed.
Valorian level of evidence
- Scientific quality(5/5)
Phase II clinical trial published in Nature Cancer, one of the leading journals in oncology, conducted by a recognised university centre.
- Current clinical application(3/5)
T-VEC is already authorised for certain melanoma indications, but its use in basal cell carcinoma remains experimental and reserved for clinical research.
- Future potential(5/5)
This approach could transform the management of locally advanced basal cell carcinomas by reducing the extent of surgical interventions and improving aesthetic and functional outcomes.
References
- Étude de phase II publiée dans Nature Cancer par des chercheurs de la Medical University of Vienna (MedUni Vienna) et de l'Hôpital Universitaire de Vienne.
- Les travaux ont évalué l'utilisation du talimogene laherparepvec (T-VEC), un virus oncolytique déjà autorisé dans certaines formes de mélanome, chez des patients atteints de carcinomes basocellulaires localement avancés.
Frequently asked questions
Does T-VEC replace surgery for basal cell carcinoma?
No. Surgery remains the reference treatment (cure >95%). T-VEC is studied as a neoadjuvant treatment (before surgery) to reduce tumour volume in locally advanced forms or those difficult to operate on.
How does this therapeutic virus work?
Injected into the tumour, T-VEC (a modified herpes virus) preferentially infects cancer cells, destroys them from the inside and releases their antigens, which activates the immune system against the remaining cells.
Is this treatment already available?
Not for basal cell carcinoma: its use remains experimental (clinical research). T-VEC is, however, already authorised for certain forms of unresectable melanoma.
What is the main advantage on the face?
By shrinking the tumour before the operation, more healthy tissue is preserved: more discreet scars, fewer grafts and reconstruction flaps, better preservation of structures and faster recovery.
Topics
