Complete Response of Metastatic Melanoma to Local Radiation and Immunotherapy: 6.5 Year Follow-Up

Abstract

The combined use of immunotherapy and radiation therapy is emerging as a potentially effective treatment for patients with immunogenic tumors such as melanoma; however, evidence for long-term treatment outcomes is lacking. Herein, we summarize our previously described case study of a patient with metastatic melanoma treated with two cycles of ipilimumab, followed by stereotactic body radiotherapy to two of seven liver metastases, with two additional cycles of ipilimumab. In the longest follow-up to date, we report a successful treatment outcome at 6.5 years. Our patient remains in complete remission, with no evidence of disease or recurrence 6.5 years after treatment. He continues to manage chronic hypophysitis developed secondary to immunotherapy and has developed osteopenia from prolonged systemic glucocorticoid use. The use of radiotherapy in combination with targeted immune therapy appears to be an effective treatment strategy, with long-lasting efficacy.

Keywords: abscopal effect; immunotherapy in cancer; ipilimumab; metastatic melanoma; radiation therapy.

Figure 1. PET-CT scan of liver prior to radiation therapy

PET-CT - positron emission tomography-computed tomography

Figure 2. SBRT radiation plan

Margins for the two treated liver metastases are outlined in red SBRT - stereotactic body radiotherapy

Figure 3. Five-year follow-up MIP scan

MIP - maximum intensity projection