Marker ups & downs on Herceptin alone?
 

While on Herceptin alone, this elderly lady in my family had the following monthly CEA readings:
129 just before starting on Herceptin (highest reading ever)
102
75
98

The sudden reversal from a monthly average decrease of 20% to a 30% increase is quite worrysome if it means resistance to Herceptin.

Has anyone experienced such sharp reversals in CEA or other markers & still continued to benefit from Herceptin?
Or was the trend in markers continuously down?

She was found HER+ ER- in april 2006 (after being ER+ for over more than 20 years)