Abstract P3-07-49: Residual cancer burden (RCB) with veliparib/carboplatin in the I-SPY2 trial

Background: I-SPY2 is a multicenter phase 2 trial in high risk stage II/III breast cancer (BC) using adaptive randomization within biomarker subtypes to evaluate novel agents added to standard neoadjuvant chemotherapy. The first regimen to graduate based on the predicted probability of a higher pCR rate within predefined subsets was veliparib/carboplatin + paclitaxel (VC+T→AC vs T→AC) in triple negative BC (TNBC). In TNBC the residual cancer burden (RCB) is prognostic, whether as a continuous index or grouped into classes, with pCR (RCB-0) and RCB-I classes having identical survival. Therefore, we evaluated the use of RCB to further discriminate between investigational and control arms.

Methods: Site pathologists reported RCB for 99% of subjects in the primary efficacy analysis based on pCR (n=114/115). We compared the distribution of RCB reported as a continuous index in each treatment-subset combination to matched concurrently randomized controls using the Wilcoxon rank sum test for RCB index, and Fisher's Exact test for RCB classes (RCB-0/I vs RCB-II/III). The statistics are descriptive rather than inferential, and given the small sample size have no claim on generalizability. We modified the Bayesian model used to compute the estimated probability of success in a future, randomized, phase 3 trial of 300 subjects, if response were defined by either pCR or RCB-I (RCB0/I), or separately if it were defined by pCR alone.

Results: VC+T→AC led to a significantly lower RCB index than T→AC in TNBC (p=0.0021), with a near-significant trend when those with pCR were excluded (p=0.06). There was no significant difference in RCB distributions in the other breast cancer subtypes treated. In TNBC, the odds ratio (OR) for achieving RCB-0/I in the VC+T→AC arm vs control was 8.2 (95% confidence interval (CI): 2.1–35), whereas the OR for achieving pCR was 4.56 (95% CI: 1.25–19.53). The simulations using response information from I-SPY2 to predict the probability of success for VC+T→AC for TNBC in a future phase 3 trial estimated this probability to be 0.99 if modeled using RCB-0/I as the response endpoint, and 0.90 if modeled using pCR as the response endpoint.

Conclusions: Use of RCB index and classes provided additional insight into the effect of adding VC to T, appearing to magnify the improved treatment response that had been observed with pCR rates in TNBC. It will be important to test in randomized trials whether a decrease in the RCB index relative to controls, and/or increased rates of RCB-0/I class, are predictive of survival benefit in TNBC.

Citation Format: Liu MC, Symmans WF, Yau C, Chen Y-Y, Rugo HS, Olopade OF, Datnow B, Chen B, Feldman M, Kallakury B, Hasteh F, Tickman R, Ritter J, Troxel M, Mhawech-Fauceglia P, Duan X, Berry D, Esserman L, DeMichele A. Residual cancer burden (RCB) with veliparib/carboplatin in the I-SPY2 trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-49.

The Utility of Intraoperative Evaluation of Sentinel Lymph Nodes in Breast Cancer

BACKGROUND

In breast cancer treatment, intraoperative sentinel lymph node (SLN) evaluation is used to identify patients who may potentially benefit from immediate completion of axillary lymph node dissection.

METHODS

Prospectively collected breast cancer registry data identified 516 SLN biopsies between January 2003 and December 2005. Intraoperative evaluation (IE) of the SLNs was performed in 479 axillae. Final pathology by hematoxylin and eosin and, for negative nodes, by immunohistochemical stains was compared with the IE result. The effect of IE and final pathology on surgical treatment was examined.

RESULTS

The sensitivities for IE of N0(i+) (n = 39), N1mi (n = 41), and N1a-3a (n = 89) metastases were 0%, 5%, and 63%, respectively. The specificity was 99.7%. IE identified 57 (44%) of SLN-positive (N1mi and N1a-3a) axillae, thus resulting in synchronous axillary lymph node dissection for those patients. Reoperation for false-negative IEs (N1mi or N1a-3a with negative IE) occurred in only 27 axillae (39%).

CONCLUSIONS

IE of SLNs has adequate sensitivity and excellent specificity. In addition to allowing patients to benefit from synchronous surgery, IE helped patients to receive care in concordance with recommended practice guidelines. The false-negative IE of SLNs highlights uncertainty with the clinical significance of axillary nodal staging when only small amounts of metastatic disease are identified in the axilla.

Metaplastic breast cancer: clinical significance

BACKGROUND

Metaplastic breast carcinoma (MBC) is a rare poorly differentiated breast cancer characterized by coexistence of ductal carcinoma with areas of matrix producing, spindle-cell, sarcomatous, or squamous differentiation; ER/PR/HER2 negativity; and a reputation for poor outcome.

METHODS

The Swedish Cancer Institute prospective breast cancer database (> 6500 patients; 1990-2005) has 24 MBC cases that were compared with typical breast cancer cases matched for age, date of diagnosis, stage, and ER/PR/HER2 status.

RESULTS

The mean metaplastic primary tumor diameter was 2.5 cm. The histological/nuclear grade was high in 21 of 24 cases. No patient had distant metastasis. ER and/or PR receptor status was negative in all cases. HER2 was negative in 10 of 11 cases tested. EGFR (HER1) was positive in 7 of 7 cases tested. All patients had sentinel and/or axillary lymph node dissection and surgical resection; 18 received chemotherapy and 22 had radiation therapy. Four patients had distant recurrences 5 to 88 months from diagnosis. Five-year survival was 83% (95% confidence interval, 66-100%). Comparison with matched typical breast cancer cases revealed no major significant difference in multidisciplinary treatment patterns, recurrence, or survival.

CONCLUSION

MBC is associated with poor prognostic indicators, but outcomes comparable with matched typical breast cancer cases can be achieved with routine aggressive multidisciplinary care. Increased, expression of EGFR (HER1) provides an opportunity for targeted tumor therapy.

Image-Guided Tissue Sampling: Where Radiology Meets Pathology

Image-guided breast tissue sampling has become an acceptable alternative to open surgical biopsy for nonpalpable lesions. Advantages of minimally invasive core biopsy compared to open surgical biopsy include lower cost, lower complication rates, and less cosmetic deformity for patients. However, false-negative core biopsies can occur. Thus the imaging of a breast lesion and the histologic result of the core biopsy must be carefully correlated. This involves communication between radiology and pathology.

Association of human papillomavirus with penile carcinoma: a study using polymerase chain reaction and in situ hybridization

Although carcinoma of the uterine cervix has been shown to be strongly associated with human papillomavirus (HPV) infection, a sexually transmitted disease, similar detailed data are lacking in penile carcinoma. To determine the association of HPV with penile carcinoma, we examined 30 specimens of penile carcinoma from 23 patients by the highly sensitive polymerase chain reaction (PCR) and in situ hybridization assays. We also examined nonneoplastic penile foreskins from 20 adults using the polymerase chain reaction assay. Human papillomavirus type 16 genome was found in 15 patients (65%), HPV type 30 was found in three (13%), and HPV type 6/11 was found in two (9%). These HPV types were not detected in any of the nonneoplastic foreskins. As in cervical carcinoma, HPV, particularly type 16, is strongly associated with penile carcinoma and may play an etiologic role in the development of this neoplasm.

A 37-pound scrotal leiomyosarcoma: a case report and literature review

We report a case of a 37-pound scrotal leiomyosarcoma. The literature is reviewed, and the presentation, diagnosis, treatment and survival of patients with scrotal leiomyosarcoma are discussed.