BMJ Best Practice has dedicated topics for Women's Health and Oncology with subjects organised either by alphabetical order or emergency. An OpenAthens account is required to access this resource.
Women's health | BMJ Best Practice
NICE (National Institute for Health and Care Excellence)
In the NICE you can find various guidance and advice on breast care (see below the link to them)
breast | Search results | NICE
BNF (British National Formulary)
Accessible online, in the BNF you can find information by drugs and you can find treatment summaries.
BNF (British National Formulary) | NICE