In patients who had PET scans both before treatment and after the first cycle, we found that this early scan could predict whether they were likely to achieve a complete response by the end of treatment. These findings highlight the potential of early imaging to guide treatment decisions, and now need to be validated in larger, modern clinical trials."
Sheeba Irshad, Senior Co-author and Professor of Cancer Immunology
11 May 2026
Research suggests early scan could help predict cancer treatment response
Research led by King’s College London and The Institute of Cancer Research, London suggests that an early scan taken after one cycle of chemotherapy could help to predict how well a patient’s cancer will respond to treatment.
The study focused on patients with triple-negative breast cancer (TNBC), an aggressive form of the disease in which cancer cells lack receptors for the hormones oestrogen and progesterone, as well as the HER2 protein.
Patients with TNBC are usually treated with upfront systemic therapy prior to surgery. While many respond well, residual disease at surgery - typically around six months late - is associated with a significantly poorer prognosis. Identifying non-responders earlier remains a major clinical challenge.
The research explored whether using a PET imaging shortly after treatment begins - rather than relying only on MRI scans later in the treatment process - could provide earlier insight into how a patient’s cancer is responding. Twenty-two patients were recruited, with fourteen undergoing FDG-PET scans before treatment and after the first cycle of chemotherapy.
The findings showed that changes seen on PET scans after just one cycle were strongly associated with subsequent pathological response, including whether patients went on to achieve a complete response—meaning no detectable cancer—by the end of treatment. Importantly, early PET response showed stronger associations with treatment outcomes than standard mid-treatment MRI scans in this study.
Being able to identify patients who are not responding well at an early stage could allow clinicians to adjust treatment sooner or consider alternative approaches. These findings may also support future strategies to better tailor treatment intensity to individual patients.
The study also compared two types of PET tracers—FDG and FLT—to determine which was most suitable. While both met the study’s technical criteria, FDG-PET was selected for further evaluation due to its better image quality, greater consistency, and wider use in clinical practice.
Research that helps us determine early who is already benefitting from standard neoadjuvant chemotherapy and who might benefit for clinical trials to find better treatments is vital. This study shows that FDG CT-PET may have great value in this regard. We hope to be able to design studies that further investigate and validate these findings.”
Professor Andrew Tutt, Senior Co-author and Director of Breast Cancer Now Research Unit
The research also explored how imaging changes after just one cycle of chemotherapy relate to the body’s immune response to treatment. Biopsies taken before and after the first cycle of chemotherapy showed that an increase in immune cells within the tumour was strongly associated with both early PET changes and improved treatment outcomes.
The researchers emphasise that these findings now need to be validated in larger studies. Future work will aim to confirm these results in a broader patient groups and explore more accessible imaging approaches, such as ultrasound, alongside PET and MRI.
The study was supported by funding from. Breast Cancer Now, CRUK and GSTT charity.
Read the full paper here: https://pubmed.ncbi.nlm.nih.gov/42048392/
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Professor of Cancer Immunology
Director of Breast Cancer Now Research Unit