One Lump or Two

[Maureenly]

Prior to my lumpectomy, ultrasound indicated a 2.1 cm tumor.  However, it turned out to be two side-by-side tumors, one measuring 1.1 cm and one 1.0 cm.  My breast surgeon said she'll discuss with oncologist to determine staging; her view is that since counting both lumps together just puts it a whisker into Stage 2, she'd go with looking at only the larger, and classifying as Stage 1 invasive ductal cancer.  My question: Is there a best practice or guideline to determine staging in this kind of situation, or is it the oncologist/surgeon's experience coupled with other info from pathology?  My other pathology results include no node involvement or vascular invasion identified, histologic grade 2, ER+/PR+ and HER2Neg.  

Also, on my pathology report, my S-Phase Faction is 7.1% marked "borderline." I can't find a lot of info about the scale being used, other than that lower is better than higher.  Can you tell me what the range is, i.e., 1- 10?

Thanks so much -- I want to ask right questions when I meet with my oncologist to discuss my prognosis and treatment, and this will be a big help.

[Maureenly]

Thank you so much for your prompt response!

[CCF-RN,MSN-rf]

Dear Maureenly:  In classifying 2 primary tumors in the same breast, the American Joint Committee on Cancer Staging manual states that the largest tumor is considered and the tumor size staged accordingly.  However, it should be noted that there are multiple primary tumors.  Therefore if the largest invasive component of disease is 1.1cm than this is a stage 1 breast cancer.  Regarding the S-Phase Fraction, this test determines the rate of dividing cells. It's value helps to determine who might benefit from chemotherapy.  In terms of interpretation, you will be best off discussing this with your oncologist.