B r e a s t T u m o rs: C o m p a ra tiv e A c c u ra c y o f MR Im a g in g R elativ e to M a m m o g ra p h y a n d US fo r D e m o n s tra tin g E x te n t1 A PURPOSE; To evaluate the compara tive accuracy of magnetic resonance (MR) imaging relative to mammogra phy and ultrasonography (US) for assessing the extent of breast tumors. MATERIALS A N D METHODS:His tologic results and preoperative im aging findings (mammography, US, MR imaging) were analyzed regard ing tumor size and multifocality of 61 tumors in 60 women undergoing mastectomy for carcinoma. RESULTS:In 10% of cases, the index tumor was not seen at mammogra phy. With US, 15% of the index tu mors were not recognized, while MR imaging missed 2% of the index tu mors. On mammographic and US images, tumor size was underesti mated significantly (P < .005), by 14% and 18%, respectively, while MR im aging showed no significant differ ence in size compared with that found in a pathologic evaluation. Mammography showed 31% of the additional invasive lesions, w hile US showed 38% and MR imaging showed 100%. CONCLUSION: MR imaging was the most accurate of the three preopera tive imaging modalities in assessing the size and number of malignant lesions in the breast.

Purpose: The success of immunotherapy with dendritic cells (DC) to treat cancer is dependent on effective migration to the lymph nodes and subsequent activation of antigen-specificTcells. In this study, we investigated the fate of DC after intradermal (i.d.) or intranodal (i.n.) administration and the consequences for the immune activating potential of DC vaccines in melanoma patients. Experimental Design: DC were i.d. or i.n. administered to 25 patients with metastatic melanoma scheduled for regional lymph node resection. To track DC in vivo with scintigraphic imaging and in lymph nodes by immunohistochemistry, cells were labeled with both [ 111 In]-indium and superparamagnetic iron oxide. Results: After i.d. injection, maximally 4% of the DC reached the draining lymph nodes. When correctly delivered, all DC were delivered to one or more lymph nodes after i.n. injection. Independent of the route of administration, large numbers of DC remained at the injection site, lost viability, and were cleared by infiltrating CD163+ macrophages within 48 hours. Interestingly, 87 F 10% of the surviving DC preferentially migrated into the T-cell areas, where they induced antigen-specificT-cell responses. Even though more DC reached theT-cell areas, i.n. injection of DC induced similar antigen-specific immune responses as i.d. injection. Immune responses were already induced with <5 Â 10 5 DC migrating into theT-cell areas. Conclusions: Monocyte-derived DC have high immune activating potential irrespective of the route of vaccination. Limited numbers of DC in the draining lymph nodes are sufficient to induce antigen-specific immunologic responses.

A B S T R A C T PurposeTumor-specific immunomonitoring is essential to evaluate the efficacy of vaccination against cancer. In this study, we investigated the predictive value of the presence or absence of antigen-specific T cells in biopsies from delayed-type hypersensitivity (DTH) sites. Patients and MethodsIn our ongoing clinical trials, HLA-A2.1ϩ melanoma patients were vaccinated with mature dendritic cells (DC) pulsed with melanoma-associated peptides (gp100 and tyrosinase) and keyhole limpet hemocyanin. ResultsAfter intradermal administration of a DTH challenge with gp100-and tyrosinase peptideloaded DC, essentially all patients showed a positive induration. In clinically responding patients, T cells specific for the antigen preferentially accumulated in the DTH site, as visualized by in situ tetramer staining. Furthermore, significant numbers of functional gp100 and tyrosinase tetramer-positive T cells could be isolated from these DTH biopsies, in accordance with the applied antigen in the DTH challenge. We observed a direct correlation between the presence of DC vaccine-related T cells in the DTH biopsies of stage IV melanoma patients and a positive clinical outcome (P ϭ .0012). ConclusionThese findings demonstrate the potency of this novel approach in the monitoring of vaccination studies in cancer patients.

FDG-PET as a complementary staging method improves the therapeutic management of patients with colorectal liver metastases, especially by detecting unsuspected extrahepatic disease.