The Value of a Second Opinion in Cancer Care

A cancer diagnosis is one of the most difficult moments a person can face. In the shock that follows, there is often pressure to begin treatment as quickly as possible. Most specialist teams agree on one point that patients rarely regret: before committing to a treatment path, have the diagnosis and proposed plan reviewed—ideally by a multidisciplinary team at a high-volume cancer center.

Many clinicians welcome a second opinion, particularly when the diagnosis or treatment plan is complex.

What a second opinion actually reviews

A meaningful second opinion does not simply re-read a typed report. Specialists re-examine the original material:

• the pathology slides and tissue blocks, to confirm the cancer type and subtype;

• the imaging files (CT, MRI, PET-CT), to confirm the stage;

• whether biomarker or molecular testing is indicated and whether the results could identify a targeted therapy or clinical-trial opportunity;

• the proposed plan, including surgery, radiation, and drug treatment.

Diagnosis in cancer is often an act of interpretation, and interpretation is where experienced reviewers can reasonably reach different conclusions—especially for rare or hard-to-classify tumors.

How often does a second opinion change something?

The numbers are consistent across studies:

• In a 2023 study of 120 patients seeking second opinions at a high-volume cancer center, 42 patients (35%) received a clinically meaningful change in treatment that was expected to improve morbidity and/or prognosis.

• About 18% of patients had surgery eliminated or reduced in scope. In 9 of the 120 cases (7.5%), the second opinion recommended observation rather than treatment.

• In a review of 6,171 outside surgical pathology cases, 86 cases (1.4%) had a significant diagnostic change; among those 86 cases, 61 (71%) were associated with a better prognosis. (Kronz et al., Cancer, 1999).Although this study is older, it remains a frequently cited demonstration of the potential clinical impact of expert pathology review.

• Subspecialist re-reading of PET-CT scans resulted in a discordant assessment of malignancy or benignity in roughly 13% of cases.

The potential value of expert review may be particularly important in rare, complex, or difficult-to-classify cancers.In one study of soft-tissue sarcoma, concordance with the final expert diagnosis was only 28.3% among cases initially diagnosed in private clinics, compared with 70.5% for diagnoses made by the study institution; expert second-opinion review confirmed or improved the correct primary diagnosis in 73.1% of cases.For lymphoma, major diagnostic revisions have been reported in roughly 15–18% of cases overall, with substantially higher rates in some subtypes.

Crucially, the most common outcome is not a reversal. Most of the time the diagnosis is confirmed, and the value lies in refinement—a clearer subtype, a better sequence of treatment, a less intensive approach when supported by the patient's diagnosis, stage, and clinical circumstances, or a trial you qualify for. Confirmation itself is reassurance.

Why a multidisciplinary team adds a separate layer of value

A multidisciplinary tumor board (MDT) brings specialists together—medical oncology, surgery, radiation oncology, pathology, radiology, and often genetics and palliative care—to review the case jointly rather than sequentially. Guidelines from organizations such as NCCN and ESMO emphasize multidisciplinary evaluation for many cancers.

The evidence for impact is strong:

• In a thoracic cancer MDT study, 45.2% of cases had a change in treatment plan, and 87.2% of the board's recommendations were implemented. (Sailany et al., AUBMC, 2023).

•In a 2023 pancreatic cancer MDT study, assessment of resectability changed in 24.4% of cases evaluated for resectability, and the MDTB's assessment agreed with intraoperative findings in 91.5% of cases. (Frontiers in Surgery, 2023).

A single specialist naturally sees a case through the lens of their own treatment. A board is designed to see the whole patient and choose the best combination—or, sometimes, to recommend no treatment at all.

There can also be a financial case

A 2025 cost analysis of the same 120-patient cohort estimated that treatment costs were lower after the second opinion in 31 of the 43 cases in which treatment changed. Across all 120 patients, the modeled mean treatment-cost difference was approximately US$15,015 per patient. The analysis came from a single U.S. high-volume cancer center and used estimated treatment costs rather than patients' actual out-of-pocket spending, so the figure should not be generalized to other healthcare systems.

How to arrange a review without delaying care

1. Ask your current team or pathology department how to obtain the pathology report, slides or tissue blocks, imaging files, laboratory results, and the proposed treatment plan.

2. Submit to a high-volume center experienced in your exact cancer type; remote review is often possible and can reduce travel.

3. Ask four questions: Is the diagnosis as precise as possible? Is molecular testing important? What are the treatment options and their trade-offs? Do I need treatment now, or is observation reasonable?

4. Do not delay urgent care. For sudden severe symptoms—trouble breathing, chest pain, new weakness, or fever during chemotherapy—seek emergency care immediately rather than waiting for review.

The bottom line

A second opinion most often confirms the original diagnosis and treatment plan, and that confirmation can provide valuable reassurance. In a 120-patient study at a high-volume cancer center, 35% of cases resulted in a clinically meaningful treatment change that reviewers expected to improve morbidity and/or prognosis. These changes more often involved refining or de-escalating treatment than overturning the original diagnosis. In rare or complex cancers, expert pathology, radiology, and multidisciplinary review may also identify clinically important diagnostic differences.