Everybody's going to die eventually, but it's still troubling that Mary Tamm and Elizabeth Sladen died roughly two decades or so before the average Western life expectancy in their sixties. Caroline John also died at the somewhat older but still rather saddening age of 71. All from particularly nasty sounding cancers.
And another former female companion has been diagnosed with cancer recently (and I hope she pulls through).
Was it something the BBC put in its water? People have pointed at the possibility of asbestos used in the construction material.
If you mean Janet Fielding I believe she's doing ok.
Reading what her family wrote at the time I think Lis died from a bad reaction to the medication rather than directly due to the cancer, they were hopeful of a recovery before that. I think both Lis and Carrie had fought it before in the 90s.
Frazer has beaten it too.
Still, it's probably just a sad set of coincidences. And very probably the smoking.
I think this is it really. With regard to asbestos it would be interesting to see what the wider situation was with regard to all BBC staff, not just companions; the camera men, lighting technicians, producers, directors, grips, cleaners....obviously a lot of companions and Doctors from that era are still alive and still healthy.
There's probably more Dr Who directors still around from the 60s than 70s and 80s combined, and very few writers from the 60s - but thats mostly an age thing, the show started off with mostly new directors, and JNT prefered to use more experienced ones.
Its a sad point of note that the first episode to loose its entire credited cast isn't even a Black and White story - it's Spearhead From Space 4 from 1970. Only two actors left from the whole story.