LONDON, ONTARIO – Progress is being made against many types of cancer, with more patients surviving longer, thanks to research on two fronts: improved methods for earlier detection, and development of therapies that are more effective and less toxic. Indeed, it is estimated that there are now more than 10 million cancer survivors in the United States alone, and this number has been steadily increasing. Similar numbers, in proportion to population sizes, are found in other developed countries.
Cancers that are detected early – when they are small and less likely to have metastasized (spread away from the primary tumor) – are more likely to be treatable with local therapy, whereas successful treatment is ultimately unlikely once metastatic tumors develop. And improved therapies mean that patients can be treated with drugs that work better (and that patients are more likely to receive the full dose needed).
But our dramatic progress in detecting and treating cancer has also led to growing awareness of the problem of tumor dormancy: a patient appears to be cured, only to have the same cancer return years or even decades later. In breast cancer or melanoma, for example, recurrences 25 years after initial treatment have been reported.