VNPI SIZE PARAMETER

In considering DCIS for conservative breast surgery (CBS), the closest we can come to a correct size measurement of DCIS is when the entire tumor is removed and studied and measured by a pathologist determined to make an accurate measurement. So, decisions for or against conservative surgery are via some sort of pre-operative "presumptive size" estimates...we presume the tumor size from radiographic images and core biopsy results. Along with size, one has to consider "shape" [round, skinny elongated, flattened elongated, etc....round being more likely to have clear margins with CBS] and "texture" [smooth-bordered, highly ill-defined bordered, etc....smooth-bordered being more likely to have clear margins with CBS]. All of this is evaluated in view of breast size [CBS not usually reasonable with large-sized tumor in a relatively small breast], tumor location [CBS not usually satisfactory when tumor is central and beneath the nipple] and situation [elongated tumor "crosswise...more than one quadrant..." is more of a CBS problem] within the breast, and the shape of the breast [CBS more of a problem in a flattened, drooping breast]. RULE of THUMB: a palpable tumor 4 cm. or larger is most likely a mastectomy candidate; a non-palpable tumor 5 cm. or greater in size is more likely to harbor one or more small areas of invasive cancer. So, whereas lymph node sampling is indicated for invasive breast cancers, SLN biopsy or low-node sampling may be indicated as part of the surgical procedure when dealing with large tumors (4-5 cm. or greater, or otherwise suspect for invasion) thought...so far...to be non-invasive (this will avoid the potential morbidity and risk of added follow-up node surgery).

Very high quality mammograms, expertly obtained and interpreted, give us the initial presumptive size of a finding which appears "suspicious" or "worrisome" or "concerning". Ultrasound exam helps to search for any "solid" tumor areas (such areas are more likely to contain invasive cancer). Both of these procedures are widely available in medical communities. If the tumor seems relatively large and is in danger of ruling out CBS, the newly available combination "true PET scan with CT and computer reconstruction" gives an impressive picture of even narrow-diameter radiations of tumor from an ill-defined lesion. In early 2001, our program is due to bring on a less expensive, lesser quality version of this scanner (FDG coincidence scanner with CT and computer reconstruction"). The state of South Carolina "certificate of need" laws have procedurally blocked us from the true PET option.

The reason that you don't see us actually calculate the VNPI in our pathology reports is that it is tough for us to be independently sure about the exact figures for size and margin parameters.

By whatever measure, the following are the criteria for assignment of size points (such were originally assigned from the pathology tissue studies):

• equal to or less than 1.5cm...............1 point 
• from 1.6 cm. to 4.0 cm.........................2 points 
• equal to or greater than 4.1 cm.......3 points 

VNPI SCORE= tumor-size pts x 0.749 [_____] plus nuclear pts x 0.869 [_____]
plus margin pts x 0.864 [_____]=_____total VNPI points

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(posted 17 Dec. 2000)