Last year in the UK over 60,000 cancer patients enrolled on clinical trials aimed at improving cancer treatments and making them available to all.
A trial using PET scans to help decide treatment options for early stage Hodgkin lymphoma (RAPID)
This trial looked at whether PET scans can help doctors decide if radiotherapy is needed after chemotherapy for Hodgkin lymphoma.
More about this trial
Hodgkin lymphoma is a cancer of the lymphatic system. Doctors usually treat early stage Hodgkin lymphoma with chemotherapy and radiotherapy. These treatments often work very well, and between 85 and 95 out of 100 people (85% to 95%) are cured.
At the moment there is no way of knowing for sure how well chemotherapy has worked. So, all patients go on to have radiotherapy after chemotherapy.
But doctors think that some patients may be having radiotherapy (and the unwanted side effects) without really needing it.
A scan called a PET scan may help with this. PET stands for positron emission tomography. It is a scan that shows areas of active cancer in the body, rather than abnormal areas that may be something harmless such as scar tissue. Doctors hoped it would be able to show if chemotherapy alone had killed all the cancer cells or not.
The idea is that if a person’s cancer has completely gone, they will not need to have radiotherapy. If some cancer remains, they will.
The aim of this trial was to see if a PET scan can help doctors decide who needs further treatment for early stage (stage 1a or 2a) Hodgkin lymphoma.
Summary of results
The trial team found that using a PET scan after chemotherapy can help identify people with an excellent outlook (prognosis) and so avoid the need for radiotherapy.
Everyone in the trial had 3 cycles of ABVD chemotherapy then a PET scan. They were divided into groups depending on the results of the scan.
- 571 people had a PET scan
People who had a positive result had another cycle of ABVD and then radiotherapy.
If the results of the scan were negative people were put into 1 of 2 groups by computer (randomised). One group had radiotherapy and the other group no further treatment.
- 209 had radiotherapy
- 211 had no further treatment
The trial team followed up these people for an average of 5 years. They found that
In the group who had radiotherapy
- 8 people’s Hodgkin lymphoma came back
- 8 people died (5 died before receiving radiotherapy)
- 193 people had no signs of any Hodgkin lymphoma
In the group who had no further treatment
- 20 people’s Hodgkin lymphoma came back
- 4 people died
- 187 people had no signs of any Hodgkin lymphoma
From these results the trial team concluded that using a PET scan after 3 cycles of ABVD chemotherapy was an acceptable way of deciding who didn’t need to have radiotherapy (and so avoid potential long term side effects).
The team knew that for the group who had no further treatment the rate of Hodgkin lymphoma coming back would be higher. But they think this is acceptable as these people will be able to have other treatment if needed. Also, not having radiotherapy reduces the risk of some long term side effects such as heart (cardiovascular) disease and the development of second cancers.
The trial team say that longer follow up is needed to confirm their findings that using PET scans can help with decisions about radiotherapy. And confirm that not having radiotherapy does lead to fewer long term side effects and improved overall survival compared to giving radiotherapy to every patient.
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (
How to join a clinical trial
Professor John Radford
Leukaemia and Lymphoma Research
NIHR Clinical Research Network: Cancer
Teenage Cancer Trust
The Lymphoma Research Trust
University College London