Is sentinel lymph node biopsy several weeks after partial mastectomy as reliable as sentinel lymph node biopsy done at the time of partial mastectomy?  

Great question! We do it all the time in the setting of invasion found after lumpectomy for DCIS or after a surgical biopsy finds an invasive cancer but the question is whether it's as accurate in this scenario? Does a previous surgery alter the lymphatic drainage pattern to a degree that renders se...

Yes, and it should be done in the scenario described. Similarly, if a patient who undergoes lumpectomy without SLNB for DCIS, and then is found to have invasive ductal carcinom, the patient should be brought back to the OR for SLNB, even if it is several weeks later.