This is a very difficult one to call.

It is rare for a GP to make a cancer diagnosis.  For suspected lymphoma, the correct process is for the GP to take blood tests and then make an urgent referral to suitable specialist.  Of course, the GP should share his/her suspicions with the patient, and this is the point where misunderstandings can occur.  It is quite possible for a shocked patient to mis-hear "I'm referring you for suspected cancer" as "You've got cancer".  

Once referred, there is a standard protocol most hospitals follow- which is a sequence of tests, all of which can be overwhelming and scary.  Patients can be afraid to ask questions because they're scared what the answer might be. 

Whether this applies to this person I can't begin to speculate.  My advice, for what it's worth, is to accept her story at face value and don't call her out on it.