Highlights from Mark Renneker, MD – 2025 Symington Public Forum on Healing with Integrative Cancer Care
This post continues our blog series from the 2025 Symington Public Forum on Healing with Integrative Cancer Care, co-hosted by CancerChoices. Each post highlights one powerful talk from the conference.
In his unscripted talk, Dr. Mark Renneker offers what he calls “handwritten field notes” on emerging trends in cancer. Known for his pioneering, patient-centered medical advocacy practice, Renneker works as a medical consultant to patients with complex medical cases who wish to take a no-stone-unturned approach to their care. In his engaging talk, Renneker shares useful insights with the audience, including the following.
Reimagining the map of cancer
At a recent American Association for Cancer Research meeting, Renneker describes seeing something revolutionary: the first full spatial “maps” of tumors, where AI reveals organized ecosystems including immune cells, bacteria, and cancer cells all placed with purpose. “It changes how we think about cancer,” he says. “It’s not chaos. There’s intelligence at work.”
The mast cell connection
Renneker helped convene the first national meeting on mast cell activation syndrome (MCAS) at Commonweal in 2018. Mast cells are a type of white blood cell with ties to allergic reactions and inflammatory and other protective responses. MCAS is the inappropriate activation of these cells. He’s now seeing half of his complex cancer patients test positive for MCAS traits. Stabilizing mast cells with simple H1/H2 antihistamines, he notes, can reduce chemotherapy side effects and improve tolerance, though it’s not yet mainstream.
Small change, big impact
He discusses how modifications to how conventional treatments are administered could have real impacts. Chronomodulated chemotherapy, administering drugs in alignment with circadian rhythms, can double effectiveness and halve toxicity. Immunotherapy, he notes, may work up to 80% better when given in the morning.1Landré T, Karaboué A et al. Effect of immunotherapy-infusion time of day on survival of patients with advanced cancers: a study-level meta-analysis. ESMO Open. 2024 Feb;9(2):102220; Qian DC, Kleber T et al. Effect of immunotherapy time-of-day infusion on overall survival among patients with advanced melanoma in the USA (MEMOIR): a propensity score-matched analysis of a single-centre, longitudinal study. Lancet Oncology. 2021 Dec;22(12):1777-1786; Rizzo A, Monteiro FSM et al. Impact of time-of-day administration of immunotherapy on survival in metastatic renal cell carcinoma: the MOUSEION-09 meta-analysis. Clinical and Experimental Metastasis. 2024 Dec 16;42(1):3.
Resources
Watch Dr. Mark Renneker’s full talk from the 2025 Symington Conference on Healing, as well as other talks from the inspiring conference.
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References