Use of panitumumab-IRDye800 to image microscopic head and neck cancer in an orthotopic surgical model.

BACKGROUND: Fluorescence imaging hardware (SPY) has recently been developed for intraoperative assessment of blood flow via detection of probes emitting in the near-infrared (NIR) spectrum. This study sought to determine if this imaging system was capable of detecting micrometastatic head and neck squamous cell carcinoma (HNSCC) in preclinical models. METHODS: A NIR fluorescent probe (IRDye800CW) was covalently linked to a monoclonal antibody targeting epidermal growth factor receptor (EGFR; panitumumab) or nonspecific IgG. HNSCC flank (SCC-1) and orthotopic (FADU and OSC19) xenografts were imaged 48-96 h after systemic injection of labeled panitumumab or IgG. The primary tumor and regional lymph nodes were dissected using fluorescence guidance with the SPY system and grossly assessed with a charge-coupled NIR system (Pearl). Histologic slides were also imaged with a NIR charged-coupled device (Odyssey) and fluorescence intensity was correlated with pathologic confirmation of disease. RESULTS: Orthotopic tongue tumors were clearly delineated from normal tissue with tumor-to-background ratios of 2.9 (Pearl) and 2.3 (SPY). Disease detection was significantly improved with panitumumab-IRDye compared to IgG-IRDye800 (P < 0.05). Tissue biopsy samples (average size 3.7 mm) positive for fluorescence were confirmed for pathologic disease by histology and immunohistochemistry (n = 25 of 25). Biopsy samples of nonfluorescent tissue were proven to be negative for malignancy (n = 28 of 28). The SPY was able to detect regional lymph node metastasis (<1.0 mm) and microscopic areas of disease. Standard histological assessment in both frozen and paraffin-embedded histologic specimens was augmented using the Odyssey. CONCLUSIONS: Panitumumab-IRDye800 may have clinical utility in detection and removal of microscopic HNSCC using existing intraoperative optical imaging hardware and may augment analysis of frozen and permanent pathology.

Use of panitumumab-IRDye800 to image cutaneous head and neck cancer in mice.

OBJECTIVE: To assess the feasibility of panitumumab in real-time fluorescent imaging and histologic processing of cutaneous squamous cell carcinoma (cSCC) in mice. DESIGN: A near-infrared (NIR) fluorescent probe (IRDye800CW) was covalently linked to a monoclonal antibody-targeting epidermal growth factor receptor (panitumumab) or nonspecific IgG and injected into mice bearing flank xenografts from a cSCC cell line (SCC-13 or SRB-12; n = 7), human split-thickness skin grafts (STSGs; n = 3), or a human tumor explant (n = 1). The tumor and lymph nodes were imaged and dissected using fluorescence guidance with the SPY imaging system and verified with a charge-coupled NIR system. An NIR scanning device (Odyssey) was used to measure fluorescence intensity in histological sections. SUBJECTS: Immunodeficient mice. SETTING: In vivo and in vitro imaging lab. RESULTS: Tumor tissue could be delineated from the human STSG with tumor-to-background ratios of 4.5 (Pearl) and 3.4 (SPY). Tumor detection was substantially improved with panitumumab-IRDye800 compared with IgG-IRDye800. Biopsies positive for fluorescence were assessed by histology and immunohistochemistry (n = 18/18) to confirm the presence of tumor, yielding a 100% sensitivity. Biopsies of nonfluorescent tissue negative for malignancy (n = 18/18) yielded a specificity of 100%. Furthermore, the SPY system was able to detect residual disease as small as 200 µm in diameter. In addition, the Odyssey confirmed fluorescence of microscopic disease (in tumor samples of frozen and paraffin-embedded histologic specimens) but not in adjacent noncancerous tissue. CONCLUSIONS: These data suggest panitumumab-IRDye800 may have clinical utility in detection and removal of subclinical cSCC using Food and Drug Administration-approved imaging hardware.

Identification of the optimal therapeutic antibody for fluorescent imaging of cutaneous squamous cell carcinoma.

Intraoperative, real-time fluorescence imaging may significantly improve tumor visualization and resection and postoperatively, in pathological assessment. To this end, we sought to determine the optimal FDA approved therapeutic monoclonal antibody for optical imaging of human cutaneous squamous cell carcinoma (cSCC). A near-infrared (NIR) fluorescent probe (IRDye800) was covalently linked to bevacizumab, panitumumab or tocilizumab and injected systemically into immunodeficient mice bearing either cutaneous tumor cell lines (SCC13) or cutaneous human tumor explants. Tumors were then imaged and resected under fluorescent guidance with the SPY, an FDA-approved intraoperative imaging system, and the Pearl Impulse small animal imaging system. All fluorescently labeled antibodies delineated normal tissue from tumor in SCC13 xenografts based on tumor-to-background (TBR) ratios. The conjugated antibodies produced TBRs of 1.2-2 using SPY and 1.6-3.6 using Pearl; in comparison, isotype control antibody IgG-IRDye produced TBRs of 1.0 (SPY) and 0.98 (Pearl). Comparison between antibodies revealed them to be roughly equivalent for imaging purposes with both the SPY and Pearl (p = 0.89 SPY, p = 0.99 Pearl; one way ANOVA). Human tumor explants were also imaged and tumor detection was highest with panitumumab-IRDye800 when using the SPY (TBR 3.0) and Pearl (TBR 4.0). These data suggest that FDA approved antibodies may be clinically used for intraoperative detection of cSCC.

Phase 1 study of erlotinib plus radiation therapy in patients with advanced cutaneous squamous cell carcinoma.

PURPOSE: To assess the toxicity profile of erlotinib therapy combined with postoperative adjuvant radiation therapy in patients with advanced cutaneous squamous cell carcinoma. METHODS AND MATERIALS: This was a single-arm, prospective, phase 1 open-label study of erlotinib with radiation therapy to treat 15 patients with advanced cutaneous head-and-neck squamous cell carcinoma. Toxicity data were summarized, and survival was analyzed with the Kaplan-Meier method. RESULTS: The majority of patients were male (87%) and presented with T4 disease (93%). The most common toxicity attributed to erlotinib was a grade 2-3 dermatologic reaction occurring in 100% of the patients, followed by mucositis (87%). Diarrhea occurred in 20% of the patients. The 2-year recurrence rate was 26.7%, and mean time to cancer recurrence was 10.5 months. Two-year overall survival was 65%, and disease-free survival was 60%. CONCLUSIONS: Erlotinib and radiation therapy had an acceptable toxicity profile in patients with advanced cutaneous squamous cell carcinoma. The disease-free survival in this cohort was comparable to that in historical controls.

MRSA and non-MRSA otorrhea in children: a comparative study of clinical course.

OBJECTIVE: To test the perception that post-tympanostomy tube otorrhea caused by methicillin-resistant Staphylococcus aureus (MRSA) is a more virulent disease than otorrhea caused by other pathogens by analyzing the clinical differences and disease courses in children diagnosed with otorrhea caused by MRSA bacteria vs non-MRSA bacteria. DESIGN: Retrospective review. SETTING: Tertiary children's hospital. PATIENTS: We retrospectively examined the medical records of children who presented to a tertiary children's hospital from January 1, 2003, to December 31, 2008, with otorrhea that occurred after tympanostomy tube insertion. MAIN OUTCOME MEASURES: Otorrhea culture records were used to group the 1079 patients into those whose otitis media was due to MRSA (n = 170) and those with non-MRSA otitis media (n = 909). From the non-MRSA group, we randomly selected an age-matched group of 170 and examined the differences between the MRSA and age-matched non-MRSA groups in organisms isolated by culture, demographic factors (including type of medical insurance), medical history, treatments, surgical procedures performed, audiometric data, and other admissions for infection-related illnesses. RESULTS: The overall incidence of MRSA in this series was about 16% (170 of 1079 patients). Of the 170 eligible children in each age-matched group, 135 with MRSA otorrhea and 141 with non-MRSA otorrhea had data in every category selected for statistical analysis. The groups did not differ significantly in type of insurance; history of tympanostomy tube placement, cholesteatoma, or prematurity; number or type (minor/major) of surgical procedures performed; or risk of subsequent infection-related diagnoses. More patients in the MRSA group received intravenous antibiotic therapy (11% vs 3.6%; P < .001). CONCLUSION: In this study, a diagnosis of otorrhea due to MRSA did not carry an increased risk for surgical procedures or infection-associated sequelae compared with a diagnosis of non-MRSA otorrhea.