Using light to treat melanoma

A Finnish study has found a new way of eliminating lymphatic vessels bound to cancerous tumours, and the cancer cells conveyed by the vessels.

Using light to treat melanoma

The impact of this, called photodynamic therapy (PDT), on melanoma and lung cancer was presented in a recent issue of the Science Translational Medicine journal.

Regarding the spreading routes of cancer, lymphatic vessels have been researched the least extensively. A cancerous tumour and lymphatic vessels taken over by cancer can be surgically removed, but at the same time, cancer cells may already be heading to a new location.

– We started to investigate whether the PDT could be used to reduce or prevent the growth of metastases by eliminating the lymphatic vessels connected to the main tumour, as well as the cancer cells inside the vessels, says Tuomas Tammela, who works in the laboratory of Academy Professor Kari Alitalo at the Meilahti campus.

In PDT, a pharmaceutical is dispensed in the target tissue, making it sensitive to light. After this, the tissue is exposed to infrared laser. The reaction triggered by this eliminates the sensitised cells. The same method is already in established use for restraining the excessive blood vessel growth related to the age dystrophy of the fundus of the eye.

– The treatment shrunk the lymphatic vessels, broke their structure and they started to leak, says Tammela, referring to the study conducted with mice.

When PDT was combined with the surgical removal of the tumour and the lymph nodes, the frequency of cancer recurrence decreased substantially.

– Since the pharmaceutical and the treatment concept already are in clinical use, it is likely that they are also relatively easy to implement in the treatment of cancer patients, says Tammela.

– These are new and interesting findings because so far, not that much attention has been paid to the cancer cells which are travelling in the lymphatic system to form metastases.

Science Translational Medicine journal » »

Text: Päivi Lehtinen
Photo: Tuomas Tammela
Translation: AAC Global

News of the month »»
News archive »»
University of Helsinki