Study Reveals Immune Checkpoint Inhibitor Treatment and Monitoring Practices Post-Remission

Following complete melanoma remission, immune checkpoint inhibitor (ICI) treatment typically continues for the next 3 to 36 months, with 66% of German Dermatologic Cooperative Oncology Group centers continuing treatment for 6 months, according to a study published in the Journal der Deutschen Dermatologischen Gesellschaft.¹

Within the first full year after discontinuing treatment with ICIs, researchers found that most centers conducted staging intervals via imaging every 3 months, with greater than 60% of centers continuing imaging annually as far out as 4 to 5 years post treatment discontinuation.

Image Credit: © Arif Biswas - stock.adobe.com

Background and Methods

Combined ICIs have significantly improved survival rates for metastatic melanoma, though real-world treatment often deviates from the standard 2-year duration used in clinical trials. Early discontinuation may occur due to toxicity, complete response, or patient-driven factors like "treatment fatigue."²

The present study involved a questionnaire developed in September 2023. The survey focused on the decision-making process for discontinuing ICIs in metastatic melanoma and subsequent follow-up practices. It included questions on criteria for ICI discontinuation, the role of whole-body PET/CT scans, and the frequency of post-treatment diagnostic tests.

Findings

The survey included 51 certified skin cancer centers across Germany, Switzerland, and Austria and centered around the discontinuation of ICIs in patients achieving various stages of response, including complete remission, partial response, and stable disease.

The process of discontinuing ICI treatment was predominantly influenced by tumor board recommendations (88.2%) and patient-reported treatment fatigue (90.0%). In contrast, decisions solely based on the treating physician's judgment were less common (28.0%).

The duration of ICI treatment varied significantly based on the type of response. 66.0% of centers discontinued ICI within 6 months of achieving complete response. A minority extended treatment beyond 12-18 months.

The majority (41.7%) recommended treatment durations of 24 months, with only 22.2% discontinuing within 6 months. Most centers (51.4%) favored a 24-month duration, with only 13.5% stopping within 6 months.

Diagnostic imaging and assessments were pivotal in determining ICI discontinuation. Cranial MRI was used by 94.1% of centers as a standard cerebral imaging modality, while whole-body PET/CT scans were utilizedby 86.3% of centers for comprehensive imaging.

In order to evaluate residual findings, 64.7% reported conducting biopsies. While PET/CT was a preferred modality, 12.2% of centers lacked access to this diagnostic tool. Whole-body CT and cranial CT were less frequently used.

Additionally, follow-up protocols varied across the surveyed centers.

Most centers conducted imaging, such as MRI/CT and PET/CT, at intervals shorter than those recommended by the German S3 guideline. For instance, 3-month intervals were common in the first year, transitioning to 6-month intervals in subsequent years.

Despite guideline recommendations to reduce imaging, over 60% of centers continued to perform whole-body positron emission tomography/computed tomography and MRI/CT during the 4 to 5 years post-discontinuation period. PET/CT was used less frequently, aligning with the guideline.

Blood tests, including markers such as LDH and S100, were universally conducted during the first 3 years post-ICI discontinuation. However, laboratory monitoring diminished over time.

In the first year, 82.4% of centers performed blood tests at 3-month intervals, while during years 2 to 5, the number of centers conducting these tests steadily decreased, with intervals lengthening to 6 months by the third year.

Conclusions

“The rapid advancements in diagnostics and therapy pose immense challenges for skin cancer centers in adapting and keeping pace with the evolving landscape of melanoma management,” according to study authors Reitmajer et al. “However, this dynamic environment demands a structured approach to establish a consistent framework regarding the discontinuation of ICI therapy and follow-up examinations.”

Moving forward, researchers noted the need for revision of Germany’s S3 guideline for melanoma. At present, the guidelines do not contain any recommendation or consensus for managing the care of patients achieving complete remission with ICIs in under 24 months of treatment.³

References

1. Reitmajer M, Livingstone E, Thoms KM, et al. Real-world management of patients with complete response under immune-checkpoint inhibition for advanced melanoma. J Dtsch Dermatol Ges. Published online January 2, 2025. doi:10.1111/ddg.15604
2. Amiot M, Mortier L, Dalle S, et al. When to stop immunotherapy for advanced melanoma: the emulated target trials. EClinicalMedicine. 2024;78:102960. Published 2024 Dec 4. doi:10.1016/j.eclinm.2024.102960
3. Deutsche Dermatologische Gesellschaft DK. S3-Leitlinie Diagnostik, Therapie und Nachsorge des Melanoms. AWMF online. 05.05.2024, Updated 07.2020. Available from: https://register.awmf.org/de/leitlinien/detail/032-024OL