Abstract P5-14-03: The Impact of Routine Cavity Margins on Reducing the Need for Re-Excision in Women Undergoing Breast-Conserving Surgery for Invasive or Non-Invasive Breast Cancer

Background: The goal of breast conserving surgery (BCS) in women with invasive breast cancer (IBC) or ductal carcinoma in situ (DCIS) is to remove all malignant cells from the breast or to reduce the residual tumor burden to a level that is likely to be eradicated by adjuvant radiation therapy and/or systemic therapy. Theoretical concerns exist that radiography of lumpectomy specimens and subsequent pathologic processing may lead to artifactually positive lumpectomy margins (LM), and the need for subsequent re-excision. To improve the chances of obtaining negative final margins (FM) (generally defined as 2 mm or greater), a number of surgeons in the US and abroad have adopted a technique in which 4-6 additional margins surrounding the main lumpectomy specimen, so-called “cavity margins” (CM), are routinely obtained. The purpose of this study was to assess the clinical utility of the routine use of CM in reducing the need for re-excision.

Methods: The surgical pathology records at our institution were searched for all cases of BCS with additional complete routine CM sampling performed by a single surgeon between May 2008 and April 2010. Patients in whom additional CM were obtained based on intraoperative findings of grossly close margins were excluded from the analysis. The demographic characteristics of the patients and the histological features of the tumor were recorded. We then tabulated the number of patients who had positive LM, CM, and FM, defined as either DCIS or invasive carcinoma at or less than 2 mm from inked specimen margin. The number needed to treat (NNT) to prevent one re-excision was calculated.

Results: We identified 97 women (74 with IBC and 33 with DCIS-only) who had undergone BCS with routine CM sampling during the study period. Mean patient age was 62. Median specimen volume was 178 cc3. 90% of the IBCs were ductal subtype. Mean IBC size was 1.5 cm. 63% of tumors were ER+, 58% PR+, and 7% HER2+. Of the 97 patients in this study, 64 had +LM and 33 had -LM. Of the 64 with +LM, 38 did not have tumor in the CM and 26 had tumor in the CM. Of these 26, 18 had +FM (re-excision needed) and 8 had -FM (no re-excision needed). The proportion of patients with actual tumor at ink (not just close margins) in the lumpectomy specimen was significantly higher among the group with tumor present in the CM than it was in the group with no tumor present in the CM (14/26 versus 7/38, p = 0.006). The NNT with routine CM compared with standard BCS to prevent one re-excision was 2.0 (95% CI, 1.5 — 2.1).

Discussion: In this study the routine use of CM reduced the need for reexcision in women undergoing BCS for IBC or DCIS; one re-excision was avoided for every two patients treated with this surgical approach. The absence of tumor in the CM in the majority of patients with positive LM suggests that specimen radiography and/or pathologic processing techniques may result in artifactually positive LM. Our results indicate that improved specimen imaging and pathological processing techniques are needed to increase the fidelity of margin assessment. In the meantime, the routine use of cavity margins may reduce the need for re-excision in women undergoing BCS.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-14-03.

Measurement of quality of care for adjuvant chemotherapy of colorectal cancer

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Background: Although adjuvant chemotherapy (CT) is a crucial component of the therapy for stage III colon cancer and stage II and III rectal cancer patients, little is known about how best to measure whether quality care is being delivered. We sought to provide policy-makers and stake-holders with an inventory of the available measures and their usefulness. Methods: The MEDLINE and Cochrane databases were searched for all publications which might contain quality measures (QMs) pertaining to the diagnosis and treatment of patients with colorectal cancer (CRC). Our analysis was confined to QMs pertaining to adjuvant CT for CRC, based on US data, and published after 1990. Identified QMs were quantitatively rated based on the concepts of importance/usability, scientific acceptability, and validity or how well they had been tested. Results: 3,429 abstracts were reviewed, of which 843 articles underwent full text evaluation. Ultimately 74 articles met the established inclusion criteria for containing QMs, 32 of which pertained to adjuvant CT. These 32 articles contained 10 QMs, 8 of which had major flaws limiting their applicability. The two most ideal measures are presented in the table . Among the reasons some measures did not rate highly was the failure to utilize standard staging definitions or reliance on administrative inpatient databases, which do not account for chemotherapy administered on an out-patient basis. Conclusions: Very few measures of the quality of adjuvant CT for CRC have been published to date and fewer rate highly with regard to the concepts of importance/usability, scientific acceptability, and validity. Future research should focus on refining existing QMs and on developing new QMs which target important leverage points with respect to the provision of adjuvant therapy for CRC.

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Adjuvant radiotherapy for pathologic stage T3/4 adenocarcinoma of the prostate: ten-year update

PURPOSE

To determine the role of adjuvant postoperative radiotherapy (RT) following radical prostatectomy (RP) in a group of patients with pathologic Stage T3/4 adenocarcinoma of the prostate followed for a median of 10 years after treatment.

METHODS AND MATERIALS

Between 1970 and 1983, 159 patients underwent RP for newly diagnosed adenocarcinoma of the prostate and were found to have pathologic Stage T3/4. Forty-six received adjuvant RT and 113 did not. Radiotherapy usually consisted of 45-50 Gy to the whole pelvis followed by a boost to the prostate bed of 10-15 Gy, to a total dose of 55-65 Gy. Patients were analyzed with respect to survival, disease-free survival, local control, and freedom from distant metastases. A rising prostate-specific antigen in the absence of other evidence of relapse was scored as a separate category of recurrence.

RESULTS

Both groups of patients have been followed for a median of 10 years. The actuarial survival at 10 and 15 years was 62% and 62% for the RT group compared to 52% and 37%, respectively, for the RP group (p = 0.18). The disease-free survival for the Rt group was 55% and 48% at 10 and 15 years, respectively, compared to 37% and 33% for the RP group (p = 0.16). Similarly, there was no difference in the rate of distant metastases between the two groups. In contrast, the local relapse rate was significantly reduced by the addition of postoperative radiotherapy. The actuarial local control rate at 10 and 15 years was 92% and 82%, respectively, for the RT group vs 60% and 53% for the RP group (p = 0.002).

CONCLUSIONS

While postoperative pelvic RT significantly improves local control compared to RP alone for pathologic Stage T3/4 prostate cancer, it has no impact on distant metastases and consequently does not improve survival. These data are consistent with the conclusion that many patients with pathologic Stage T3/4 prostate cancer have occult metastases at presentation and will not be cured by local therapies alone. The optimal treatment for this patient population remains to be established.