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.
The Ulama did not find in consuming betel nut any damaging harm to the health, that is why we don't see a verdict against it. Some materials which are mixed with betel nut can be very harmful like tobacco. Consuming any item which damagingly harmful must be avoided.
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.