Stromal Optic Anisotropy as a Prostate Prognosis Marker
Shamira Sridharan, Virgilia Macias, Krishnarao Tangella, Andre Kajdacsy-Balla, Gabriel Popescu. University of Illinois at Urbana-Champaign, Urbana, IL; University of Illinois at Chicago, Chicago, IL; Christie Clinic, Urbana, IL
Background: We obtained prostate cancer tissue microarray (TMA) set of patients who underwent prostatectomy from the Cooperative Prostate Cancer Tissue Resource (CPCTR) collection. Each patient with prostate cancer recurrence was matched by Gleason score, pTNM stage, and age at prostatectomy to another patient who did not show recurrence (nested case-control design). We measured the unstained TMA slide using spatial light interference microscopy (SLIM) which measures the refractive index of tissue.
Design: 400 cores from 112 patients (approximately 4 cores per patient) obtained from CPCTR were imaged using SLIM with the 40X/0.75NA objective. 56 patients in this group had prostate cancer recurrence and 56 patients did not have recurrence. We measured optical anisotropy, which is the square of the ratio of phase gradient to phase variance, in a single layer of stroma adjoining 8-14 glands per patient. Most subjects (93%) are in the D'Amico intermediate risk category.
Results: We observed that the value of anisotropy in stroma was higher for patients with prostate cancer recurrence than for patients who did not have recurrence of prostate cancer. Using a cut-off un-scaled anisotropy value of 17, we are able to predict recurrence with a sensitivity of 80% and specificity of 60%, the AUC is 0.7. We scaled the anisotropy value to a linear 0-4 scale, 0 corresponded to 25% chance of recurrence, 1 to 36% chance of recurrence, 2 or 3 to 60% chance of recurrence and 4 to 80% chance of recurrence. SLIM performed better than CAPRA-S, arguably one of the best prognostic tools used by urologists to predict risk of recurrence (sensitivity = 46%; specificity= 68%; AUC= 0.57).
Conclusions: SLIM is a sensitive tool in the prediction of prostate cancer recurrence. Further studies need to be performed to develop risk-group specific cut-offs and to validate current results.
Category: Genitourinary (including renal tumors)
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 179, Tuesday Afternoon