The NHS needs to cut the number and type of chest radiotherapy procedures and allow more patients to get the treatment, a study says.
It also says that reducing chest radiography to a lower level could reduce the cost of care.
The NHS, which has previously proposed introducing a cap on the number that could be done, is looking at lowering the cap to no more than 40 per cent, said the report.
However, that could cause problems if the caps on the numbers of procedures and treatments are not met.
The report says the government could reduce or remove some of the restrictions.
It is looking into a number of measures, including the introduction of a cap to 30 per cent or lower.
The findings will be presented to the Royal College of General Practitioners next month.
The report has been published ahead of the annual meeting of the British Medical Association.