Kuala Lampur, June 7 -- Over the past ten years, cancer death rates have steadily dropped, giving millions of families a real reason to celebrate. Between advanced radiation techniques, targeted molecular drugs and immunotherapies, we are seeing clinical breakthroughs that used to feel entirely out of reach. The medical community deserves all the credit for this massive shift. For a lot of people, surviving a diagnosis that used to be a definitive death sentence is now just a reality of modern care.

But if we look at a patient's life long after they leave the clinic, clearing the tumour turns out to be only the first half of the struggle. What good is beating a life-threatening illness if the treatment itself ends up quietly affecting th...