Second opinion in oncology: when you need one and how to get it

What a second opinion is and why it matters

A second opinion means asking another specialist – or, better still, another multidisciplinary team – to review your diagnosis and proposed treatment plan. The aim is not to find a better doctor or to show distrust, but to be more confident that the decision is right.

In cancer care this is particularly important because:

• treatment is often long, with significant side effects, and some steps, such as surgery or radiotherapy, cannot be undone;
• for many tumours there is more than one reasonable option – for localised prostate cancer, for example, active surveillance, surgery or radiotherapy;
• progress is rapid, and molecular testing, targeted drugs and immunotherapy keep changing the standards;
• for rare cancers, experience varies considerably between centres.

Studies of pathology reviews at specialist centres show that in some cases the diagnosis or the assessment of how aggressive a tumour is gets refined, and occasionally changes significantly. A second opinion therefore has real medical value.

When a second opinion makes sense

• You have a rare cancer or unusual pathology.
• You are offered major surgery, removal of an organ or amputation.
• There are several possible approaches and you are unsure which is best for you.
• The diagnosis is unclear or results conflict.
• Molecular testing of the tumour has not been done although it matters for your cancer type – for example in lung cancer or breast cancer.
• The cancer has come back or progressed despite treatment.
• You have been told there are no further options – another centre may offer clinical trials or newer approaches.
• You simply do not feel confident, or have not had enough explanation.

In emergencies – such as bowel obstruction, spinal cord compression or bleeding – treatment should not be delayed for a second opinion.

What a good second opinion includes

A high-quality second opinion is more than a conversation; it involves reviewing the original data:

How to prepare: records and samples

The more complete your records, the more useful the second opinion. Gather:

• Your pathology report and, if possible, the paraffin blocks and slides from the biopsy or surgery. These are kept by the pathology laboratory and can usually be released for consultation on request.
• Scan images on disc or via a download link – not just the reports, but the actual CT, MRI, PET-CT or mammography images.
• Hospital letters, operation notes and tumour board recommendations.
• Blood tests, including tumour markers if measured, and any genetic test results.
• A list of your current medicines and other health conditions.
• If your records are in another language, a translation of the key results.

Write down your questions in advance: is the diagnosis and stage confirmed, are there alternatives, what are the goals and risks of each option, and are there suitable clinical trials?

Will a second opinion delay treatment?

For most cancers, the few weeks needed to arrange a second opinion do not worsen the outlook – especially if planned tests continue in the meantime. The original multidisciplinary team also needs time to gather all results. What matters is to organise the second opinion quickly and with a clear purpose, rather than seeing doctor after doctor over a long period.

For fast-growing cancers, such as some lymphomas or small cell lung cancer, or when symptoms are urgent, ask your treating doctor whether treatment can start immediately while the second opinion is obtained in parallel.

What to do if opinions differ

Disagreement does not necessarily mean that one doctor is wrong. Often both options are reasonable and the difference lies in priorities – for example more intensive treatment versus better quality of life. In that case:

• ask both teams to explain their reasoning in writing;
• ask whether your treating oncologist can speak directly with the second team;
• if the pathology diagnosis differs significantly, ask for a third review at a reference laboratory;
• make your decision after discussion with your family and the doctor you trust most.

The decision is always yours, and good practice means the options are presented clearly and without pressure. For an overview of treatment options, see our guide to cancer treatment.

When to talk to your doctor

Raise the idea of a second opinion with your oncologist or GP soon after diagnosis – before any irreversible treatment begins. Ask for a full set of your records. As a patient you have the right to access your medical information, and you can request it in writing if needed. Do not stop treatment that has already started while you wait for a second opinion without first speaking to your treating doctor.

Second opinions abroad and in Türkiye

Many patients from Bulgaria seek a second opinion abroad – within the European Union, where cross-border healthcare is governed by an EU directive, or at large accredited hospital groups in Istanbul, where multidisciplinary tumour boards, pathology review and extended molecular panels are often available within days. The process can frequently start remotely by sending records and scan images. Check the centre's accreditation and the specialty of the doctors reviewing your case, make sure the conclusion is written and signed, and be clear about how treatment would continue if you choose to have it at home. New City Clinic in Istanbul is a health-tourism organiser that coordinates the hospital, doctors, hotel, transfers and interpreter when an in-person visit is needed.