I believe that in cases of slow growing cancers most oncs prefer to delay treatment until there is a significant change in the status or as long as quality of life remains satisfactory. The reasoning is that too early treatment may not result in longer survival & that as a result side effects may outweight benefits.
However HER+ cancers are usually more agressive & early treatment should be seriously considered.
This also means that markers of early status of the HER+ condition must be available. The currently available tests (FISH, IHC biopsy tests or even the Bayer blood test) are not early markers due to their lack of sufficient sensitivity &/or accuracy & repeatability.
A new blood test (under development for automated operation) called FACCT has shown sensitivities 100 000 times better than the current ELISA process in detecting HER+ protein shed by the surface of cancer cells. (see Ref below).
In humans the new test discovered high levels of HER in 9 out of 10 HER+ patients while ELISA found only 2 out of 10.
In animals implanted with HER+ cancer the presence of HER protein in blood was detected within 2 days (tumours almost invisible) while ELISA did not detect until the tumours had grown to inoperable size.
The authors of the FACCT discovery do comment on the advisability of early treatment of HER+ cancers.
When FACCT testing becomes available to all it will be possible to start treating patients earlier with a greater probability in preventing or delaying progression. Hopefully this may also result in enabling some patients to remain stable or improve on endocrine drugs with their lower side effects
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