A high positive lymph node ratio is associated with distant recurrence after surgical resection of ampullary carcinoma.

BACKGROUND: For ampullary carcinoma (AC), the lymph node ratio (LNR) has been associated with overall survival. However, the use of the LNR to predict distant recurrence risk remains unknown. The purpose of this study was to determine if the LNR is associated with distant recurrence risk. METHODS: One hundred forty three patients with AC who underwent pancreaticoduodenectomy between 1989 and 2011 were identified from a single-institution prospective database. Data on clinicopathologic factors and recurrence were analyzed. RESULTS: At a median follow-up of 43 months (62 months for survivors), 55 patients (38 %) had developed recurrent disease, with a median time to recurrence of 13 months. Patients with a LNR ≥ 0.15 were more likely to have T3/4 tumors, advanced stage lymphovascular (LVI), or perineural invasion (PNI) and develop recurrent disease. Univariate analysis demonstrated that T-stage, lymph node status, AJCC stage, LVI, PNI, and LNR were significantly associated with decreased time to distant recurrence (TTDR). In multivariate stepwise regression, only LNR and LVI were significantly associated with decreased TTDR. CONCLUSIONS: A high positive LNR is associated with distant recurrence after surgical resection of AC. Given the high risk of disease recurrence, consideration for adjuvant therapy is warranted in patients with a LNR ≥ 0.15.

Impact of heterogeneity-based dose calculation using a deterministic grid-based Boltzmann equation solver for intracavitary brachytherapy.

PURPOSE: To investigate the dosimetric impact of the heterogeneity dose calculation Acuros (Transpire Inc., Gig Harbor, WA), a grid-based Boltzmann equation solver (GBBS), for brachytherapy in a cohort of cervical cancer patients. METHODS AND MATERIALS: The impact of heterogeneities was retrospectively assessed in treatment plans for 26 patients who had previously received (192)Ir intracavitary brachytherapy for cervical cancer with computed tomography (CT)/magnetic resonance-compatible tandems and unshielded colpostats. The GBBS models sources, patient boundaries, applicators, and tissue heterogeneities. Multiple GBBS calculations were performed with and without solid model applicator, with and without overriding the patient contour to 1 g/cm(3) muscle, and with and without overriding contrast materials to muscle or 2.25 g/cm(3) bone. Impact of source and boundary modeling, applicator, tissue heterogeneities, and sensitivity of CT-to-material mapping of contrast were derived from the multiple calculations. American Association of Physicists in Medicine Task Group 43 (TG-43) guidelines and the GBBS were compared for the following clinical dosimetric parameters: Manchester points A and B, International Commission on Radiation Units and Measurements (ICRU) report 38 rectal and bladder points, three and nine o'clock, and (D2cm3) to the bladder, rectum, and sigmoid. RESULTS: Points A and B, D(2) cm(3) bladder, ICRU bladder, and three and nine o'clock were within 5% of TG-43 for all GBBS calculations. The source and boundary and applicator account for most of the differences between the GBBS and TG-43 guidelines. The D(2cm3) rectum (n = 3), D(2cm3) sigmoid (n = 1), and ICRU rectum (n = 6) had differences of >5% from TG-43 for the worst case incorrect mapping of contrast to bone. Clinical dosimetric parameters were within 5% of TG-43 when rectal and balloon contrast were mapped to bone and radiopaque packing was not overridden. CONCLUSIONS: The GBBS has minimal impact on clinical parameters for this cohort of patients with unshielded applicators. The incorrect mapping of rectal and balloon contrast does not have a significant impact on clinical parameters. Rectal parameters may be sensitive to the mapping of radiopaque packing.