Long-Term Outcomes of De-Intensified Chemoradiotherapy for Human Papillomavirus-Associated Oropharyngeal Squamous Cell Carcinoma

PURPOSE/OBJECTIVE(S)

To report long-term oncologic outcomes among patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) treated with definitive de-intensified chemoradiotherapy.

MATERIALS/METHODS

Major criteria for de-intensification were (1) AJCC 7th edition T0-T3, N0-N2c, M0 (AJCC 8th edition T0-T3, N0-N2, M0), (2) pathologically confirmed p16 positive, and (3) no or minimal/remote smoking history (non-mutated p53 if ≥30 pack-years). Treatment was 60 Gy intensity-modulated radiotherapy with first-choice concurrent cisplatin 30 mg/m2 once per week (alternative regimens permissible for cisplatin ineligible patients). Patients with T0-T2 N0-1 (AJCC 7th edition) were recommended 60 Gy radiation alone. Systemic therapy received included: cisplatin 30 mg/m2 (n = 122), cetuximab (n = 15), cisplatin 40 mg/m2 (n = 12), carboplatin/paclitaxel (n = 2), and radiation alone (n = 25). Kaplan Meier estimates for overall survival (OS), progression-free survival (PFS), locoregional control (LRC), and freedom from distant metastasis (FFDM) were calculated. Cox regression models were used for comparisons among subgroups.

RESULTS

A total 176 patients received de-intensified treatment (n = 153 prospective protocol, n = 23 off-protocol). Median follow-up was 52.6 months (range 5.3 - 102.0, 90.8% with minimum 2-year follow-up); 56.8% (n = 100) were never smokers and 43.2% (n = 76) former smokers; former smokers had median 9 pack-years smoking history (range 0.25 - 50) with 46% ≥10 pack-years. Outcomes were as follows: 2-year OS 99.4% and 5-year OS 91.8%; 2-year PFS 94.1% and 5-year PFS 84.3%; 2-year LRC 98.3% and 5-year LRC 95.8%; 2-year FFDM 95.8% and 5-year FFDM 93.2%. Median time to progression events were 21.1 months (range, 7.2 - 54.1) with 37.5% (6 of 16) of recurrences occurring after 24 months. Six total locoregional events occurred (five recurrences and one site of persistent disease), within the 60 Gy planning target volume. Twenty-three patients with T0-T2 N0-1 disease received radiation alone with 2-year PFS 92.9% (5-year 83.8%) and 2-year LRC 100% (5-year 95.2%). Outcomes for former smokers with ≥10 pack-years were comparable to patients with less or no smoking history (2-year PFS 94.1% vs 94.1%; 5-year PFS 90.6% vs 82.7%; HR 0.58, p = 0.38). Early results suggest similar oncologic outcomes among those treated off-protocol (median follow-up 25.6 months) with 1 of 23 patients experiencing locoregional recurrence.

CONCLUSION

Dose de-intensification of 60 Gy radiotherapy with weekly cisplatin results in favorable long-term tumor control in patients with HPV-associated OPSCC. De-intensified 60 Gy alone may be efficacious in carefully selected patients with T0-T2 N0-1 (AJCC 7th edition) disease. Inclusion of biologically favorable patients with more extensive former smoking history in de-intensification clinical trials may be warranted.

Accuracy of remote chest X-ray interpretation using Google Glass technology

OBJECTIVES

We sought to explore the accuracy of remote chest X-ray reading using hands-free, wearable technology (Google Glass, Google, Mountain View, California).

METHODS

We compared interpretation of twelve chest X-rays with 23 major cardiopulmonary findings by faculty and fellows from cardiology, radiology, and pulmonary-critical care via: (1) viewing the chest X-ray image on the Google Glass screen; (2) viewing a photograph of the chest X-ray taken using Google Glass and interpreted on a mobile device; (3) viewing the original chest X-ray on a desktop computer screen. One point was given for identification of each correct finding and a subjective rating of user experience was recorded.

RESULTS

Fifteen physicians (5 faculty and 10 fellows) participated. The average chest X-ray reading score (maximum 23 points) as viewed through the Google Glass, Google Glass photograph on a mobile device, and the original X-ray viewed on a desktop computer was 14.1±2.2, 18.5±1.5 and 21.3±1.7, respectively (p<0.0001 between Google Glass and mobile device, p<0.0001 between Google Glass and desktop computer and p=0.0004 between mobile device and desktop computer). Of 15 physicians, 11 (73.3%) felt confident in detecting findings using the photograph taken by Google Glass as viewed on a mobile device.

CONCLUSION

Remote chest X-ray interpretation using hands-free, wearable technology (Google Glass) is less accurate than interpretation using a desktop computer or a mobile device, suggesting that further technical improvements are needed before widespread application of this novel technology.

Cetuximab-related hypersensitivity reactions associated with pre-existing cetuximab-specific IgE antibody

9097

Background: Cetuximab is a chimeric (mouse/human) IgG1 monoclonal antibody against the epidermal growth factor receptor and is approved for use in patients (pts) with colorectal cancer and head and neck squamous cell carcinoma. Hypersensitivity reactions caused by cetuximab (C-HSR) have been reported; however, the mechanism underlying these reactions is unknown. We hypothesize that C-HSR are mediated by pre-existing cetuximab-specific IgE antibodies (C-IgE). Methods: A total of 140 serum samples were obtained under IRB approved protocols and retrospectively analyzed across 2 cohorts: 1) 71 pretreatment sera from cetuximab-treated pts collected from multiple centers (47 pts with no HSR and 24 pts with any grade HSR; samples were biased for HSR pts), and 2) 69 sera from healthy volunteers in the Nashville TN area. The samples were analyzed for total-, cetuximab-specific and mouse-specific IgE levels using a modified ImmunoCAP assay (Phadia US Inc.). Severe HSR was defined as grade 3/4 reactions during the first infusion by NCI CTC version 3.0 Allergic reaction/hypersensitivity criteria by a reviewer blinded to the immunoCAP assay results. Results: Of the 71 cetuximab-treated pts from cohort 1, 21 experienced severe HSR by retrospective evaluation. All C-IgE(+) pts (15/15) experienced severe HSR and were immediately discontinued from therapy. Of the remaining 6 severe HSR pts with C-IgE(-), 4 pts were re-challenged and completed their cetuximab infusion without any further reaction, suggestive of a non-IgE mediated mechanism, while 2 pts were not re-challenged. Also, the C- IgE(+) pts tended to have higher levels of total IgE compared to the C-IgE(-) pts. All 47 non-HSR pts were C-IgE(-). Mouse-specific IgE was not detected in any sera from the pts. Analysis of sera from healthy volunteers from the cohort 2 revealed that 15/69 (21.7%) were C-IgE(+), suggestive of pre-existing C-IgE; however, the association with C-HSR could not be made. Conclusion: Our data suggest that C-IgE antibodies are present prior to treatment and appears highly predictive of severe HSR during the first infusion; however, IgE-mediated reactions may not account for all cases of HSR. Prospective validation of the association between C-IgE and cetuximab-induced HSR is warranted.

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High gene copy number of epidermal growth factor receptor by fluorescence in situ hybridization is frequent in head and neck squamous cell carcinomas and associates with worse recurrence-free survival

5502

Background: Epidermal growth factor receptor (EGFR) is expressed in 90–95% of head and neck squamous cell carcinoma (HNSCC). High EGFR gene copy number and activating mutations correlate with response and survival in lung cancer upon the treatment with EGFR tyrosine kinase inhibitors, but such findings have not been reported for HNSCC. A better understanding of the EGFR pathway may improve the use of EGFR inhibitors and provide a rationale for combination therapy. Methods: Tumor samples were obtained from 47 patients and analyzed for increased EGFR copy numbers by fluorescence in situ hybridization (FISH) (Vysis/Abbot) (N = 47), by immunohistochemistry (IHC) using antibodies against EGFR, phospho-EGFR (Tyr1173) and phospho-AKT (Ser473) (N = 31), for activating mutations in EGFR exons 18, 19 and 21 (N = 29), and for gene expression using Affymetrix Human 133U Plus 2.0 GeneChip (N = 18). Results from these assessments were tested for associations with patient characteristics and clinical endpoints. Univariate analysis was performed to test for differences in recurrence-free survival (RFS) and overall survival. Results: Twenty-six (63%) of 41 samples with FISH result demonstrated EGFR high polysomy and/or gene amplification (FISH+). The FISH(+) group did not differ from the FISH(−) group with regard to age, sex, race, tumor grade and site, disease stage, total EGFR, phospho-EGFR, or phospho-AKT, although the total EGFR protein score was close to significance (p = 0.10, Chi2-test for trend). The FISH(+) were associated with worse RFS, although this association did not reach significance (p = 0.057, Wilcoxon test). No activating EGFR point mutations were found. Using the FISH results as a supervising parameter, microarray data was interrogated and expression of genes involved in wnt signalling, cell motility, G-protein regulation and epithelial-mesenchymal transition pathways were found to be enhanced in the FISH(+) group (FDR <25%). Conclusions: High gene copy number of EGFR by FISH is frequent in HNSCC and may be a poor prognosticator. This data suggests that FISH(+) may be a marker of clinical benefit upon EGFR inhibition in HNSCC and further investigation is indicated.

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The androgen-binding protein gene is expressed in CD1 mouse testis

Androgen-binding protein (ABP) is a testicular Sertoli cell secretory protein that acts as a carrier of androgen in the male reproductive tract. ABP has been characterized from a wide range of animal species, including man, rabbit and rat. However, it has been widely accepted that mice do not produce testicular ABP. We have used immunological and molecular biological techniques to demonstrate that the ABP gene is expressed in the CD1 mouse. Steroid-binding, radioimmunoassay and immunocytochemical studies demonstrated that ABP is present in mouse testis and epididymis, but at 1/50 to 1/25 the level of rat epididymis. A 1.7 kilobase mRNA, homologous with rat ABP cDNA, was identified in mouse testis and Sertoli cells by Northern blot hybridization, but at a much lower level than in the rat. An ABP cDNA was isolated from a mouse testis cDNA library and encoded a protein (403 residues) with 89% of the amino acid residues identical to rat ABP, including a signal peptide. Our results indicate that ABP is expressed in the mouse and past failures to detect androgen-binding activity were due to the low level of ABP protein.

Structure of the rat androgen-binding protein gene

To study hormonal regulation of rat androgen-binding protein (ABP) we have cloned and sequenced the gene. A 5.3-kbp genomic DNA fragment was found to contain the entire coding region of the gene, which consists of 8 exons. The major site of transcription initiation in the testis was localized by primer extension and is located 36 bases upstream from the site of translation initiation. The gene does not contain a "TATA box" immediately upstream from the major start site. The sequence TACCTA occurs at residue -23, which is a functional TATA-like element in the SV40 major late gene. A sequence related to the cAMP response element is at residue -126 bp. Southern blot analysis of rat genomic DNA indicated a single gene for ABP in the rat. The existence of one gene supports the idea that sex steroid-binding protein (SBP) produced by fetal rat liver is coded by the same gene. The possibility that an alternate promoter region is active in the fetal liver is discussed.

Primary penile reanastomosis

Two cases of penile amputation with the techniques of reanastomosis are presented. Other techniques are briefly reviewed. A microvascular anastomosis of the dorsal vessels or nerves does not appear to be necessary, although gentle thorough reconstruction of the urethra and corpora obviously is.