I've never understood why in the case of worrying persistent clusters of symptoms they don't immediately do everything to rule out the worst case scenarios before advising "lifestyle changes" or whatever.
My Mum had what was finally diagnosed as ovarian cancer after two years of being told it was "probably" IBS and religiously following the Fodmap diet. She didn't improve and when her fatigue became unmanageable her GP decided HRT might help (She was in her early 70s) and the blood test she had to have for it showed sky high cancer markers. Treatment bought her a miserable four extra years, a second round of chemo nearly finished her off anyway, and she was on palliative care for nearly a year after that. She died a horrible death. Her sister had died of the same thing some years earlier.
To be fair, as a genetic component was suspected but couldn't be proved, my cousin and I both had our ovaries removed, but we still have a risk of omentum or peritoneal cancer as they couldn't be 100% sure of the definitive diagnosis.
Similarly my SF presented with persistent bowel changes and was persistently fobbed off by various GPs until he presented with shoulder pain. Was referred pain from liver cancer secondary to advanced bowel cancer. He was dead within 6 months.
I've always thought if the big nasties can be ruled out first, then fine, lifestyle etc can be factored in and might even be more beneficial as the stress of a potential unknown festering condition being eliminated will possibly boost a commitment to self help and wellness from a psycholigical perspective.
I think that age should be irrelevant, hearing all the stories about being too young for x,y or z - everyone's physiology is unique, and while some things may have been identified as more prevalent in certain age groups at one time, so much has changed regarding environment, what we ingest etc etc, that some diagnostic criteria being applied are probably out of date by decades.
It used to be 1 in 3 were "likely" to have cancer, it's now 1 in 2. Whatever is going on, this should be kept in mind at diagnostic level.
As for GPs who are elderly avoidant past the bare minimum, don't get me started.