Real-world challenges for patients with breast cancer in sub-Saharan Africa: a retrospective observational study of access to care in Ghana, Kenya and Nigeria oleh Philip Anderson, Joel Yarney, Majid Twahir, Razaq Oyesegun, Andrew Gachii, Clement Edusa, Chukwumere Nwogu, Gitangu Mangutha, Emmanuel Benjamin, Borna Müller, Charles Ngoh