Survey data reveals extreme heterogeneity in patient risk tolerance for adjuvant chemotherapy. A significant cohort, about one-third, would endure treatment for a minimal 1% improvement in survival, while a smaller group of 10-15% would decline it even for a 10% absolute benefit. This underscores the importance of personalized, value-based discussions.

Historically, discussing adjuvant therapy for Stage III colon cancer was quick and straightforward, while Stage II was complex. The advent of ctDNA testing has reversed this dynamic. Stage II decisions are now clearer (treat if positive), while Stage III discussions have become much longer and more nuanced as clinicians integrate ctDNA data with patient preferences.

The landmark DYNAMIC-2 study showed that using ctDNA to guide adjuvant therapy decisions in Stage II colon cancer cut chemotherapy use by 50% (from 30% to 15% of patients). This de-escalation was achieved without any negative impact on patient outcomes, validating the approach.

The practice-changing DYNAMIC trial showed that a ctDNA-guided strategy for stage II colorectal cancer reduces adjuvant chemotherapy use by 50%. Despite this significant de-escalation of treatment, patient outcomes and survival rates were identical to the standard-of-care approach.

Despite the success of ctDNA-guided de-escalation in Stage II disease, the DYNAMIC-3 trial in Stage III patients showed that ctDNA-negative patients had worse outcomes with de-escalated therapy. This serves as a critical warning against this de-escalation strategy in higher-risk patients for now.

Oncologists are more comfortable using a positive ctDNA test to escalate care (e.g., recommend chemo for a low-risk Stage II patient). However, they are more hesitant to use a negative test to de-escalate or withhold standard chemo for higher-risk patients, pending more definitive trial data.

In late-stage metastatic colorectal cancer, the goal shifts from achieving significant tumor shrinkage to stabilizing the disease. This recalibration of 'success' focuses on maintaining quality of life and managing symptoms for patients who have undergone multiple prior therapies.

Despite billions invested over 20 years in targeted and genome-based therapies, the real-world benefit to cancer patients has been minimal, helping only a small fraction of the population. This highlights a profound gap and the urgent need for new paradigms like functional precision oncology.

A meta-analysis of over 3,000 patients shows that neoadjuvant chemotherapy for MSS colon cancer provides a 5% improvement in survival. This benefit is clinically meaningful and equivalent in magnitude to the landmark addition of oxaliplatin to 5-FU in the original MOSAIC trial.