Finding Your Best Match: How Precision Diagnostics Identify Which Cancer Treatments Are Most Likely to Work

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Your Health Magazine Contributor

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Finding Your Best Match: How Precision Diagnostics Identify Which Cancer Treatments Are Most Likely to Work

A cancer diagnosis used to come with one playbook. Doctors matched the tumor type to a standard protocol and hoped for the best. Today, many oncologists instead approach the diagnosis differently. They can consider what the tumor looks like at the molecular level and determine which treatment gives the patient the best odds.

Genetic testing, biomarker panels, liquid biopsies and AI-assisted pathology tools now help clinicians read a tumor’s unique signature before choosing a therapy, often meaning fewer trial-and-error treatment cycles.

Understanding Precision Medicine in Cancer Care

Precision medicine treats cancer as a disease with countless molecular variations rather than a single condition with one standard response. Two patients with the same type of breast cancer can have tumors driven by entirely different genetic changes, meaning a drug that helps one may do almost nothing for the other.

The National Cancer Institute tested this idea through its NCI-MATCH trial, enrolling more than 1,200 patients with advanced cancer. The teams assigned treatment based on genetic changes in their tumors rather than where the cancer started, according to NCI’s research on precision medicine trials. Results showed that genomic sequencing can expand care beyond the standard approach.

Finding a Patient’s Best Treatment Match

Several diagnostic tools work together to identify which therapies are worth trying and which ones patients can reasonably skip. Each targets a different layer of information hidden in a tumor’s biology, from its DNA to the proteins on its surface.

1. Genetic and Genomic Testing

Genomic profiling sequences the DNA in tumor cells to identify mutations that drive cancer growth. A single test can screen dozens or hundreds of genes at once, revealing whether a tumor carries a driver mutation that a targeted drug can block.

A 2024 study summarized by the LUNGevity Foundation found that comprehensive genomic profiling identified at least one actionable biomarker in 32% of patients with advanced non-small cell lung cancer, more than double the rate found through older single-gene testing. Patients whose treatment matched their genomic results also lived substantially longer.

2. Biomarker Analysis

Biomarkers, also called tumor markers, are measurable substances in tumor tissue or blood that signal how a cancer is likely to behave. Some indicate whether a tumor will respond to hormone therapy, immunotherapy or a targeted therapy. Others measure a particular protein in cancer cells, which can determine treatment eligibility.

According to the NCI’s overview of biomarker testing for cancer treatment, tumor mutational burden testing can even help predict whether immunotherapy is likely to work for a given patient.

3. Liquid Biopsies

Traditional biopsies require cutting into tissue, which is not always possible depending on the tumor location. A liquid biopsy instead analyzes a simple blood draw, searching for fragments of tumor DNA that cancer cells shed into the bloodstream.

Two liquid biopsy tests already carry FDA approval, giving doctors a faster, less invasive way to check for treatable mutations without surgery. This option helps patients who are too frail for a tissue biopsy or whose tumors are hard to reach.

4. AI-Powered Companion Diagnostics

The newest advancement combines digital pathology with artificial intelligence, letting computers support more objective, sensitive measurement of biomarker levels than visual scoring alone typically allows. This precision medicine tool matters most for antibody-drug conjugates, a fast-growing class of targeted therapy designed for patients whose tumors express specific protein levels.

David Rimm, a pathologist at Yale School of Medicine, has studied why traditional pathology methods struggle to keep pace with precision medicine’s newest drugs. Pathologists have long scored biomarker levels by eye, a method Rimm compares to weighing mice on a scale built for elephants.

Moving from subjective reading to objective biomarker measurement lets pathologists detect low biomarker levels that older tests missed. That precision can determine whether a breast cancer patient qualifies for a newer targeted therapy. One example is an antibody-drug conjugate, undetectable by earlier testing, based on biomarker levels detectable only under the newer method.

Measuring How Treatment Matching Improves Outcomes

The value of precision diagnostics becomes clear once treatment matching starts changing how long patients live. In the aforementioned analysis by the LUNGevity Foundation, patients who received comprehensive genomic profiling and a matched targeted therapy had a median real-world overall survival of 34 months, compared with 14 months for those who did not receive it.

Despite these outcomes, testing gaps remain common, with many eligible patients missing biomarker-driven therapies due to delayed test ordering, insufficient tissue samples or gaps in insurance coverage.

Building the Next Generation of Cancer Diagnostics

Pharmaceutical and diagnostics companies are increasingly partnering to close that gap before new drugs even reach the market. In 2025, Danaher entered a collaboration with AstraZeneca to develop the next generation of AI-powered diagnostic tools that match more patients with the right precision medicine.

Precision medicines “require precision diagnostics to determine which patients are most likely to benefit,” says Julie Sawyer Montgomery, Executive Vice President at Danaher. She adds that the AstraZeneca collaboration aims to widen access to precision medicines so fewer patients get left behind. The partnership will first target digital pathology tools that identify likely antibody-drug conjugate responders.

Preparing to Discuss Testing With a Care Team

Patients navigating a new diagnosis can use a few key questions to start the biomarker testing conversation with their care team. Useful starting points include the following:

• Whether the care team has tested the tumor for relevant biomarkers, and what the results showed
• Whether a liquid biopsy could replace another tissue biopsy
• Which targeted therapies or nearby clinical trials match the patient’s biomarker profile
• How soon results will be available, and whether treatment should wait for them

Choosing a Treatment With Better Information

Precision diagnostics will not replace an oncologist’s judgment. What the tools offer is better information earlier in the process, giving patients and their care teams a real chance to choose a treatment likely to work rather than starting with guesswork.

About Author

Rose Morrison is a journalist with 10 years of experience translating complex medical advances into accessible, patient-centered guidance. She specializes in covering emerging diagnostic technologies, personalized treatment approaches and the latest cancer care innovations that help patients and their families make informed healthcare decisions. Rose is dedicated to bridging the gap between cutting-edge medical research and the practical information readers need to advocate for their own health.