Episode 17 - Mutation burden of narrowband UVB phototherapy

In this episode of BJD Talks, Sam and Meera discuss the article ‘Mutation burden of narrowband ultraviolet B phototherapy (NB-UVB) in human skin: relevance to NB-UVB lifetime exposures and skin cancer surveillance’ by Fowler et al. The full article can be accessed at https://doi.org/10.1093/bjd/ljaf173 

*This podcast was generated by an AI tool created by 67Bricks for the British Association of Dermatologists* 

Transcript

SPEAKER_01 0:00

Welcome to BJD Talks, the official podcast of the BJD. I'm Sam.

SPEAKER_00 0:04

And I'm Mira. In this episode, we will be discussing the article by Joanna Fowler et al. Mutation Burden of Narrowband Ultraviolet B phototherapy in human skin, relevance to NBUVB Lifetime Exposures and Skin Cancer Surveillance, published in May 2025 and included in the October 2025 issue.

SPEAKER_01 0:28

Let's get straight to it. Narrowband UVB is a common treatment for conditions like psoriasis. However, ultraviolet radiation can cause DNA mutations, which can potentially lead to skin cancer. This study stands out because it quantifies these mutations in the skin after narrowband UVB therapy.

SPEAKER_00 0:45

The researchers used nanorate sequencing, or nano seq, a highly accurate DNA sequencing method that detects mutations at the single cell level. They analyzed DNA from skin biopsies before and after narrowband UVB treatment. What's remarkable is how this technique pinpointed mutational signatures specifically caused by UV radiation.

SPEAKER_01 1:08

The results are striking. The study found narrowband UVB significantly increased the mutation load. For example, the mutation load increased in both the buttock and forearm skin, but the increase was greater in the forearm skin. These mutations were strongly linked to UV-specific signatures SBS7A and SBS7B.

SPEAKER_00 1:28

This has implications for dermatologists. Previous recommendations suggested starting skin cancer surveillance after 500 narrow band UVB sessions. However, this study suggests thresholds should vary based on individual risk factors. For instance, those with lighter skin tones and extensive sun exposure might need surveillance after just 58 exposures.

SPEAKER_01 1:51

Exactly, Mira. Another fascinating aspect was the role of genetics. Two participants of Asian heritage showed significantly lower mutation increases compared to others. This suggests a genetic predisposition, such as the ability to tan rather than burn, might convey some protection. It paves the way for more tailored patient guidance.

SPEAKER_00 2:12

Tailoring surveillance based on genetic backgrounds and lifestyle is a promising idea. But there are caveats. The study included just 16 UK patients, a rather small sample size. Moreover, it couldn't determine which mutations might later expand into dominant clones and cancers, so follow-up studies will be essential to confirm these findings.

SPEAKER_01 2:34

Good point. The study also highlights long-term risks. Some therapy-induced mutations lingered months after UV treatment, and UV damage from therapy years earlier was still detectable. It's a critical reminder for dermatologists to balance the benefits of UV treatments with their potential long-term consequences.

SPEAKER_00 2:53

In summary, this research provides compelling evidence that narrowband UVB therapy has measurable mutagenic effects, suggesting earlier surveillance is needed for high-risk individuals. At the same time, the findings open opportunities to personalize care based on genetic background and lifestyle factors.

SPEAKER_01 3:12

It's a delicate balancing act, ensuring therapies are effective while maintaining vigilance about risks.

SPEAKER_00 3:19

Yes, thank you. Don't forget to read the full article in the BJD for more details. See you next time.