Evidence in Cancer Medicine: When Is a Cancer Treatment Considered Scientifically Supported?

Why Modern Oncology Recognizes More Than Simply “Proven” or “Unproven”

Patients diagnosed with cancer understandably want a treatment whose benefits are supported by scientific evidence. At the same time, they may encounter terms such as “innovative,” “experimental,” or “off-label.” In public discussion, this can create the impression that treatments can be divided into two simple categories: scientifically proven or unproven.

The reality of modern oncology is more nuanced. New medicines are continuously being developed, biomarkers increasingly influence treatment decisions, and rare cancers naturally have less extensive study data available than more common malignancies.

The decisive question is therefore not only whether a treatment has received formal regulatory approval, but also how robust the scientific evidence is for its use in the specific individual case.

What Does Evidence-Based Medicine Really Mean?

In medicine, the term “evidence” refers to the scientific basis of a treatment decision. Evidence-based medicine, however, does not mean that only the results of large statistical trials are considered.

According to its classical definition, evidence-based medicine combines three central elements:

1. the best available scientific evidence, including clinical data
2. the clinical expertise of the treating medical team
3. the individual circumstances, values, and preferences of the patient

This understanding also informs the international recommendations of organizations such as the European Society for Medical Oncology (ESMO), the American Society of Clinical Oncology (ASCO), and the National Comprehensive Cancer Network (NCCN). Evidence is therefore not a rigid seal of approval. It forms the basis of a structured and individualized medical assessment.

The Changing Clinical Trial Landscape in Precision Oncology

In traditional drug development, randomized Phase III trials are generally regarded as the gold standard. However, for targeted therapies directed at rare molecular alterations present in only a small percentage of patients, large-scale studies involving thousands of participants are often not feasible.

For this reason, alternative and internationally recognized sources of evidence are becoming increasingly important in modern cancer medicine:

• Basket and umbrella trials:
  Innovative study designs that evaluate treatments according to molecular characteristics rather than solely by the anatomical origin of the tumor
• Real-world data:
  Clinical information collected from routine medical practice outside highly selected clinical trial populations
• Biological plausibility:
  A scientifically supported understanding of cellular mechanisms and signaling pathways

To evaluate genetic tumor alterations more precisely, oncology uses structured classification systems. The ESMO Precision Medicine Working Group developed the ESCAT classification — the ESMO Scale for Clinical Actionability of Molecular Targets — for this purpose.

This framework categorizes biomarkers according to the strength of the supporting clinical evidence and helps prevent treatment decisions from being based on an unstructured trial-and-error approach.

Regulatory Approval Is Not the Same as Evidence: The Role of Off-Label Therapies

Regulatory approval always applies to a specific indication at a particular point in time. Because medical science evolves rapidly, new data may demonstrate therapeutic activity in additional clinical settings before an indication is formally expanded by regulatory authorities.

For this reason, off-label use — the use of an approved medication outside its formally authorized indication — may be considered in precision oncology. This may be relevant, for example, when the same genetic alteration occurs across different tumor types.

Such treatment is not undertaken without a scientific basis. Oncologists carefully assess whether published clinical data support the proposed use and whether the anticipated benefits justify the potential risks in the individual patient.

Evidence-Based Precision Oncology at the Hallwang Clinic

At the Hallwang Clinic, every treatment plan is based on a structured evaluation of the available scientific evidence.

Advanced diagnostic methods, including molecular tumor profiling and liquid biopsy, are used to analyze the individual biological characteristics of the tumor. The interdisciplinary medical team then evaluates these findings in relation to international clinical guidelines, current study results, and the patient’s specific clinical situation.

The objective is to develop a transparent and medically justified treatment concept that combines clinical innovation with rigorous evidence standards.

Would You Like to Better Understand Which Treatment Options May Be Relevant to You?

Whether a treatment is medically appropriate cannot be determined solely on the basis of a diagnosis or an individual medication. The patient’s tumor biology, molecular findings, overall clinical situation, and the available scientific evidence must all be considered together.

The Hallwang Clinic supports national and international patients through a comprehensive review of their medical records and the development of a transparent, scientifically grounded treatment concept based on the available findings.