Faith in the Lord and following his word.
"Whatever you ask for in my name I will do, so that the Father may be glorified in the Son." (Jn.14:13).
"I tell you most solemnly, anything you ask for from the Father he will grant in my name...Ask and you will receive..." (Jn.16:23-24)
"He who obeys the command will come to no harm, and the wise man knows there will be a time of Judgment." (Ec.8:5)
"He who despises the word will destroy himself, he who respects the commandment will be safe." (Pr.13:11).
"Happy the man who cares for the poor and the weak: if disaster strikes, God will come to his help." (Ps.41:l).
Here's your cure for cancer:
"If one of you is ill, he should send for the elders of the church, and they must anoint him with oil in the name of the Lord and pray over him. The prayer of faith will save the sick man and the Lord will raise him up again; and if he has committed any sins, he will be forgiven. So confess your sins to one another, and pray for one another, and this will cure you; the heartfelt prayer of a good man works very powerfully." (James 5:13).
"If one of you is ill, he should send for the elders of the church, and they must anoint him with oil in the name of the Lord and pray over him. The prayer of faith will save the sick man and the Lord will raise him up again; and if he has committed any sins, he will be forgiven. So confess your sins to one another, and pray for one another, and this will cure you; the heartfelt prayer of a good man works very powerfully." (James 5:13).
Of course, back then, there was not as much specialization. A religious elder was as likely or not to be as gifted in medicine as theology. These days, with so much more knowledge, one has to specialize. Therefore the elders we must see are MDs, particularly those specializing in oncology.
Even today, topical administration of medication (i.e., annointing) is one way in which medication is delivered. Oral and rectal administration the only other ways available. Now, of course, we also have injection and, occasionally, surgical implantation.
It's interesting to note that what with medication prescribed to be given just so often, in just so much of a dose, over such-and-such a period of time, medicine takes on the nature of a ritual. Toss in the fact that often the instructions are written at least partially in Latin, and it takes on a certain religious flavor.
As for prayer and confession, it's no secret that a patient's mindset plays a role in the success of a course of medical treatment. A person who is upbeat and believes they will be cured is more likely to recover than a person who is pessimistic and does not expect to recover.
Furthermore, thanking God that we are a species capable of learning how to cure ourselves is certainly appropriate. A combination of education and faith gives me every confidence that diseases that exist today will be cured, if not in my time, than in that of my children or grandchildren.
We do God no service, however, if we do not use the intelligence He endowed us with and the medications and medical procedures that we have discovered. To rely on prayer alone or on "faith" "healing" is a rejection of His gift of human intelligence. To treat such a gift as so much rubbish is a grave insult to Him.