Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements.
We don’t have such claim regarding cancer in our authentic books of Hadeeth.
We have in Sunni and Shia books that every lover of Ahlul Bayt ( AS) dies as Shaheed ( martyr). من مات على حب آل محمد مات شهيدا
Tafseer Al-Kashshaf, Tafseer Al-Razi and other Sunni books.