LUMP IN LEFT BREAST - FNAC SAYS Benign Proliferative breast disease

My wife has a lump/cyst in her left breast .
This lump comes in existence in pregnancy she had in june 2007
on doctor suggestion we done ultrasound but it recommends for FNAC or mammogram
doctor said mammogram can't be done in pregnancy ,we terminated the pregnancy with PILLS given by doctor. FNAC reports said it as BENIGN PROLIFERATIVE BREAST DISEASE, when we go for mammography radiologist told us this is not right to do mammography in this age as it may increase the chance of developing cancer with X-Ray radiation and rejects to do it on the basis of FNAC  reports.
now the doctor has giving her tablet vitaxid for 10 days every month.
this lump goes aways when her periods get over and seems small and invisible.
but when her periods date is coming this lump seems reappear and clearly visible.

Help us wat we do ,as i'm very concernet for it.

[gaurav79]

Wife has taken some medicine that  stops periods for several days in may 2007
Do it react and results in this situation or this period stoping medicine have no roll in it.