Melanoma cell targeted by radiation and immune cells.

Melanoma Treatment: Can Combining Radiation with Immunotherapy Improve Outcomes?

Samir D’Costa in Health & Wellness December 2025 • 4 min read.

"A new study suggests concurrent radiotherapy and anti-PD-1 therapy could be a safe, effective strategy for metastatic melanoma."

Metastatic melanoma, a challenging form of skin cancer to treat, has seen significant advancements with the advent of immune-checkpoint inhibitors. These drugs, particularly those targeting programmed-death 1 (PD-1), have shown promise in improving survival rates. However, many patients still require additional treatments like radiation therapy (RT) at some point during their care.

Radiation therapy has long been used to target cancer cells directly, but emerging evidence suggests it can also trigger a systemic anti-tumor response known as the abscopal effect. This effect occurs when radiation not only destroys cancer cells in the treated area but also stimulates the immune system to attack cancer cells throughout the body. Combining immune-checkpoint inhibitors with radiation therapy is a logical strategy to harness both local and systemic anti-cancer effects.

A recent study investigated the safety and efficacy of combining RT with anti-PD-1 immunotherapy in patients with metastatic melanoma. By retrospectively analyzing patient data, researchers aimed to determine if this combination could lead to better outcomes without increasing toxicity.

Decoding the Study: Combining Radiation and Immunotherapy

Melanoma cell targeted by radiation and immune cells.

The study, conducted at a single institution, retrospectively collected data from 59 patients with metastatic melanoma who received anti-PD-1 immunotherapy (either pembrolizumab or nivolumab) between August 2014 and December 2015. Of these patients, 17 also received palliative RT to a total of 21 sites. The researchers then compared survival data, overall response rates, and the occurrence of toxicities between patients who received concurrent RT (IR group) and those who did not (NIR group).

The results of the study revealed some compelling findings:

Toxicity: The acute and late toxicity profiles were similar between the two groups, indicating that adding RT to anti-PD-1 therapy did not significantly increase adverse effects.
Response Rate: The objective response rate (complete or partial response) was significantly higher in the IR group (64.7%) compared to the NIR group (33.3%). This suggests that combining RT with anti-PD-1 therapy may enhance the treatment's effectiveness in shrinking tumors.
Abscopal Effect: One patient in the IR group experienced a complete response that was compatible with an abscopal effect, meaning that the radiation not only affected the targeted tumor but also triggered a response in tumors outside the irradiated field.
Survival: While the 6-month disease-free survival and overall survival rates were numerically higher in the IR group, the differences were not statistically significant.

These findings suggest that combining RT and anti-PD-1 immunotherapy is well-tolerated and may lead to a higher tumor response rate, potentially through the abscopal effect. However, the study also highlights the need for further research to confirm these benefits and determine the optimal way to combine these therapies.

Future Directions: Optimizing the Combination

This study contributes to the growing body of evidence supporting the potential of combining radiation therapy with immune-checkpoint inhibitors for cancer treatment. The results suggest that this combination can be safe and effective, but several questions remain.

Further research is needed to determine the optimal timing and fractionation of RT in combination with anti-PD-1 therapy. Clinical trials are also needed to confirm these findings and to identify which patients are most likely to benefit from this approach.

As research continues to unravel the complex interplay between radiation and the immune system, we can expect to see further advances in the use of combined modality therapy for metastatic melanoma and other cancers. These advancements offer hope for improved outcomes and a better quality of life for patients facing these challenging diseases.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1097/cmr.0000000000000386, Alternate LINK

Title: Concurrent Radiotherapy For Patients With Metastatic Melanoma And Receiving Anti-Programmed-Death 1 Therapy: A Safe And Effective Combination

Subject: Cancer Research

Journal: Melanoma Research

Publisher: Ovid Technologies (Wolters Kluwer Health)

Authors: Amélie Aboudaram, Anouchka Modesto, Léonor Chaltiel, Carlos Gomez-Roca, Serge Boulinguez, Vincent Sibaud, Jean-Pierre Delord, Ciprian Chira, Martine Delannes, Elizabeth Moyal, Nicolas Meyer

Published: 2017-10-01

Everything You Need To Know

What is metastatic melanoma, and why is it a challenge to treat?

Metastatic melanoma is a severe form of skin cancer. It is a stage where the cancer has spread from the initial site to other parts of the body, making it more challenging to treat. The use of immune-checkpoint inhibitors like anti-PD-1 therapy has improved survival rates for this condition. However, some patients still need additional treatments like radiation therapy to manage their cancer.

How does anti-PD-1 therapy work, and why is it important in treating cancer?

Anti-PD-1 therapy works by blocking the PD-1 protein on immune cells, which prevents cancer cells from suppressing the immune system. This allows the immune system to recognize and attack cancer cells. This is significant because it directly targets the way cancer evades the body's natural defenses, leading to improved survival rates for patients. Combining this therapy with radiation therapy further enhances the treatment approach.

What is the role of radiation therapy, and how does it interact with the immune system?

Radiation therapy (RT) uses high-energy rays to target and destroy cancer cells locally. Beyond this, RT can trigger a systemic anti-tumor response, known as the abscopal effect. This means RT can stimulate the immune system to attack cancer cells throughout the body, even those not directly exposed to the radiation. Combining RT with anti-PD-1 therapy leverages both local and systemic anti-cancer effects, potentially improving outcomes.

What were the main findings of the study on combining radiation therapy with anti-PD-1 immunotherapy?

The study examined the safety and effectiveness of combining radiation therapy with anti-PD-1 immunotherapy for metastatic melanoma. Researchers studied 59 patients receiving anti-PD-1 therapy (pembrolizumab or nivolumab), and compared those who also received palliative RT (IR group) to those who did not (NIR group). Findings included similar toxicity profiles between the groups, a higher objective response rate in the IR group, and an instance of the abscopal effect. This indicates that the combination is well-tolerated and could improve tumor response.

What do the study results suggest for the future of metastatic melanoma treatment?

The study found that combining RT with anti-PD-1 therapy might increase tumor response rates, potentially through the abscopal effect. However, the study also suggests the need for further research to confirm these benefits and determine the best way to combine these treatments. This is important to ensure that this combination of therapies can be used safely and effectively to improve outcomes for patients with metastatic melanoma. Future studies will focus on optimizing the combination of these therapies.