The chemicals in the cream are activated by the light therapy
Researchers claim to have "greatly improved" the effectiveness of a skin cancer treatment by adding an extra ingredient.
Photodynamic therapy involves applying a cream to the affected area and then shining a red light onto it to activate the cancer fighting chemicals.
Now scientists have modified the cream by adding an ingredient called CP94.
The work has been carried out at the Peninsula Medical School in Truro, Cornwall.
By adding the CP94 the research team claims they were able to reduce the depth of tumours currently considered too thick to be treated by usual forms of photodynamic therapy.
Trials have been taking place at the Royal Cornwall Hospitals NHS trust in Truro.
Graham O'Neil, who suffers from basal cell carcinoma, one of the most common form of skin cancer, was one of the first patients to undergo the treatment.
He said: "You just feel a certain amount of heat in the area where the cancer is treated, afterwards there's no pain."
Dr Alison Curnow from the Peninsula Medical School, said: "Through years of research we have been able to develop a modified PDT treatment enabling for the first time for thicker nodular basal cell carcinomas to be treated effectively with a single PDT treatment.
"This is important, as this is a very common form of skin cancer."