These days lung biopsies are performed with CT scan guidance (CT was only invented in 1974, widespread use came much later), endobronchial ultrasound (post 2000

These days lung biopsies are performed with CT scan guidance (CT was only invented in 1974, widespread use came much later), endobronchial ultrasound (post 2000), or surgical exploration. Minimally invasive surgical techniques have only been around for 20 years. Patients sometimes cough up cancer cells in sputum, so a definitive diagnosis could have been done that way. But faced with the prospect of a major surgical procedure, he or his doctors may have declined to pursue that, particularly as there wasn’t really any treatment. I don’t have the necessary evidence to say for sure, but misdiagnosis is at least an order of magnitude more likely than spontaneous/Ikarian lifestyle induced lung cancer regression.