Immunotherapy and radiotherapy combinations to treat melanoma spread to the brain

This study evaluated the use of immunotherapy (IT) and/or radiotherapy (RT) for the treatment of melanoma with brain metastasis (MBM). The study found that combining IT with RT improved survival outcomes for these patients.

The spread of cancer from the original tumor to other parts of the body is called metastasis. Melanoma is associated with a high rate of metastasis to the brain. The prognosis for melanoma with brain metastasis (MBM) is poor. Improved therapeutic options are being developed and include IT and RT.

IT activates the immune system to target and kill cancer cells. RT uses high-energy radiation to kill cancer cells by damaging their DNA. RT to the whole brain (WBRT) can result in severe side effects. For this reason, stereotactic radiosurgery (SRS) was developed. SRS delivers RT directly to the area of the brain that contains the tumor.

IT and RT can be given in combination to treat MBM. IT can be given at the same time as RT (concurrent) or after RT (non-concurrent). It is not yet clear what combination of IT and RT best improves patient outcomes.

This study evaluated data from 3008 patients with MBM. There were 6 different treatment groups. Group 1 included IT + SRS. Group 2 included SRS alone and group 3 included IT alone. Group 4 included WBRT + IT, group 5 included WBRT alone and group 6 had no treatment for MBM. Survival was compared among groups. 

The longest survival was seen in the IT + SRS group (15.77 months). SRS alone had an overall survival of 9.33 months and IT alone of 7.29 months. WBRT +IT was associated with a 4.89 months survival. WBRT alone had a 3.12 months survival while no RT or IT was associated with a 3.29 months survival.

In the IT + SRS group, survival tended to be longer when the treatments were given at the same time (concurrent) compared to sequential (19.8 months vs 13.8 months).

The study concluded that a combination of IT + SRS given concurrently gave patients with MBM the best outcomes.

Data from previous trials was evaluated so treatment was not randomized. All patients were not given the same type of IT. Any additional therapies given to patients were not recorded. The study did not evaluate the side effects of each treatment. More controlled studies are needed to confirm these results.