From DTML:
<dtml-call "RESPONSE.setHeader('Cache-Control', 'no-cache')">
<dtml-call "RESPONSE.setHeader('Pragma', 'no-cache')">
From python/python script:
def noCache(self, REQUEST):
REQUEST.RESPONSE.setHeader('Cache-Control', 'no-cache')
REQUEST.RESPONSE.setHeader('Pragma', 'no-cache')