Oropharyngeal HPV Detection Techniques in HPV-associated Head and Neck Cancer Patients

BACKGROUND/AIM

The incidence of human papilloma virus (HPV)-related head and neck squamous cell carcinoma (HNSCC) has been increasing in the last decades. Analysis of oral brushing or rinsing samples for screening or stratification could potentially improve screening and prevention.

PATIENTS AND METHODS

Oral brushes and mouthwashes were taken from 20 patients with HPV-associated HNSCC before definite therapy. HPV genotyping was performed for the detection of 14 high-risk HPV subtypes and correlated to DNA isolated from tumor tissue.

RESULTS

Ten of 20 patients were tested HPV positive by using either method. There was a significant correlation between macroscopic visibility of tumor and positive HPV detection (p<0.001) and HPV detection and tumor size (p<0.001). HPV was detected in all macroscopically visible tumors. Half of the HPV cases who had macroscopically invisible tumors were missed by both methods.

CONCLUSION

Both techniques are limited in the detection of macroscopically non-visible and small tumors. Therefore, the application of these techniques for screening or diagnosis of HNSCC is not recommended.

Indocyanine green fluorescence imaging during partial adrenalectomy

BACKGROUND

Indocyanine green (ICG) fluorescence imaging represents an emerging technology that facilitates the assessment of tissue vascularity, tissue distinction, and tumor localization during surgery. The aim of this study was to investigate the potential role of ICG imaging during laparoscopic partial adrenalectomy.

METHODS

Indocyanine fluorescence imaging was carried out during laparoscopic partial adrenalectomy for bilateral pheochromocytoma and bilateral Cushing's syndrome. A first bolus of 5 mg ICG was applied intravenously upon exposure of the retroperitoneal plane to identify the adrenal borders. The fluorescence was visualized using a Storz^® NIR/ICG endoscopic system. As the camera of this system detects NIR light as a blue signal, the well-vascularized adrenal tissue was expected to show a strong fluorescence in the blue color channel in contrast to the surrounding adipose tissue. Following partial adrenalectomy, a second bolus of 5 mg ICG was applied intravenously to evaluate the vascularity of the remaining adrenal tissue.

RESULTS

We investigated six adrenal glands from three patients undergoing bilateral partial adrenalectomy. The indication for surgery was pheochromocytoma in two patients and Cushing's syndrome with bilateral adenomas in one patient. Regarding left adrenalectomies, ICG imaging was helpful in visualizing the adrenal borders and the adrenal vein. Further, it facilitated the identification of the hypofluorescent pheochromocytoma and to resect the entire tumor. On the right side, due to the more apparent anatomy, ICG imaging did not contribute to the conduct of the operation. Four adrenal remnants showed a strong vascularization and two remnants were only reasonably vascularized.

CONCLUSION

ICG fluorescence may be helpful in guiding partial adrenalectomy and assessing the vascularity of remaining adrenal tissue.

Parathyroid Autofluorescence-How Does It Affect Parathyroid and Thyroid Surgery? A 5 Year Experience

Injury to parathyroid glands during thyroid and parathyroid surgery is common and postoperative hypoparathyroidism represents a serious complication. Parathyroid glands possess a unique autofluorescence in the near-infrared spectrum which could be used for their identification and protection at an early stage of the operation. In the present study parathyroid autofluorescence was visualized intraoperatively using a standard Storz laparoscopic near-infrared/indocyanine green (NIR/ICG) imaging system with minor modifications to the xenon light source (filtered to emit 690 nm to 790 nm light, less than 1% in the red and green above 470 nm and no blue light). During exposure to NIR light parathyroid tissue was expected to show autofluorescence at 820 nm, captured in the blue channel of the camera. Over a period of 5 years, we investigated 205 parathyroid glands from 117 patients. 179 (87.3%) glands were correctly identified by their autofluorescence. Surrounding structures such as thyroid, lymph nodes, muscle, or adipose tissue did not reveal substantial autofluorescence. We conclude that parathyroid glands can be identified by their unique autofluorescence at an early stage of the operation. This may help to preserve these fragile structures and their vascularization and lower the rate of postoperative hypocalcemia.

Prevalence of oral HPV infection in cervical HPV positive women and their sexual partners

PURPOSE

Human papillomavirus (HPV) infection represents the primary cause of anogenital premalignant and malignant disease. Regarding the high prevalence of cervical HPV infection and the increasing incidence of HPV associated oropharyngeal cancer in recent years, a significant viral transmission from the cervical to the oral site, possibly depending on the sexual behavior must be considered. The present study aims to determine the prevalence of oral HPV infection in cervical HPV positive and negative women and their sexual partners.

METHODS

Cervical HPV positive and negative women and their sexual partners took part in the study. Cervical smears, oral smears and mouthwashes were taken from women attending gynecological outpatient clinics in two different institutions. Further, oral smears as well as mouthwashes of their sexual partners were obtained whenever possible. HPV genotyping was performed using the Cobas^® polymerase chain reaction and nucleic acid hybridization assay for the detection of 14 high-risk HPV types. In addition, all participants were invited to complete a personal questionnaire.

RESULTS

144 HPV positive and 77 HPV negative women and altogether 157 sexual partners took part in the study. Age, sexual behaviour, medication, smoking and alcohol consumption were distributed equally in both groups. Cervical HPV positive women had a significantly higher number of sexual partners. One woman with a HPV positive cervical smear and one partner of a woman with a HPV positive cervical smear showed an oral HPV infection. No oral HPV infections were detected in the HPV negative control group. The overall incidence of oral HPV infection was 0.5%, the incidence of oral HPV infection in women with a positive cervical smear was 0.7%.

CONCLUSION

The data demonstrate that the overall risk of an oral HPV infection is low. HPV transmission to the oropharynx by autoinoculation or oral-genital contact constitute a rare and unlikely event.

Intraoperative Near-Infrared Autofluorescence and Indocyanine Green Imaging to Identify Parathyroid Glands: A Comparison

OBJECTIVE

To investigate the feasibility of near-infrared autofluorescence (AF) and indocyanine green (ICG) fluorescence to identify parathyroid glands intraoperatively.

METHODS

Fluorescence imaging was carried out during open parathyroid and thyroid surgery. After visual identification, parathyroid glands were exposed to near-infrared (NIR) light with a wavelength between 690 and 770 nm. The camera of the Storz® NIR/ICG endoscopic system used detects NIR light as a blue signal. Therefore, parathyroid AF was expected to be displayed in the blue color channel in contrast to the surrounding tissue. Following AF imaging, a bolus of 5 mg ICG was applied intravenously. ICG fluorescence was detected using the same NIR/ICG imaging system. Well-vascularized parathyroid glands were expected to show a strong fluorescence in contrast to surrounding lymphatic and adipose tissue.

RESULTS

We investigated 78 parathyroid glands from 50 patients. 64 parathyroid glands (82%) displayed AF showing the typical bluish violet color. 63 parathyroid glands (81%) showed a strong and persistent fluorescence after application of ICG. The sensitivity of identifying a parathyroid gland by AF was 82% (64 true positive and 14 false negative results), while ICG imaging showed a sensitivity of 81% (63 true positive and 15 false negative results). The Fisher exact test revealed no significant difference between both groups at p < 0.05. Neither lymph nodes nor adipose tissue revealed substantial AF or ICG fluorescence.

CONCLUSION

AF and ICG fluorescence reveal a high degree of sensitivity in identifying parathyroid glands. Further, ICG imaging facilitates the assessment of parathyroid perfusion. However, in the current setting both techniques are not suitable as screening tools to identify parathyroid glands at an early stage of the operation.

Intraoperative near-infrared autofluorescence imaging of parathyroid glands

OBJECTIVE

To identify parathyroid glands intraoperatively by exposing their autofluorescence using near-infrared light.

METHODS

Fluorescence imaging was carried out during minimally invasive and open parathyroid and thyroid surgery. After identification, the parathyroid glands as well as the surrounding tissue were exposed to near-infrared (NIR) light with a wavelength of 690-770 nm using a modified Karl Storz near-infrared/indocyanine green (NIR/ICG) endoscopic system. Parathyroid tissue was expected to show near-infrared autofluorescence, captured in the blue channel of the camera. Whenever possible the visual identification of parathyroid tissue was confirmed histologically.

RESULTS

In preliminary investigations, using the original NIR/ICG endoscopic system we noticed considerable interference of light in the blue channel overlying the autofluorescence. Therefore, we modified the light source by interposing additional filters. In a second series, we investigated 35 parathyroid glands from 25 patients. Twenty-seven glands were identified correctly based on NIR autofluorescence. Regarding the extent of autofluorescence, there were no noticeable differences between parathyroid adenomas, hyperplasia and normal parathyroid glands. In contrast, thyroid tissue, lymph nodes and adipose tissue revealed no substantial autofluorescence.

CONCLUSION

Parathyroid tissue is characterized by showing autofluorescence in the near-infrared spectrum. This effect can be used to distinguish parathyroid glands from other cervical tissue entities.

Optical coherence tomography as a method to identify parathyroid glands

BACKGROUND AND OBJECTIVE

The identification of parathyroid glands can be a major problem in parathyroid surgery. The purpose of this study was to evaluate the feasibility of optical coherence tomography (OCT) in distinguishing between parathyroid tissue, thyroid tissue, lymph nodes, and adipose tissue.

METHODS

Ex vivo OCT images as well as histological sections were generated from parathyroid glands, thyroid tissue, lymph nodes and fat in order to define significant morphologic differences between these entities. As a second step all OCT images were separately evaluated by two blinded investigators and later compared to the corresponding histology. Sensitivity and specificity of OCT in distinguishing between the different tissues were determined. To assess the interobserver agreement, κ coefficients were calculated from the ratings of each investigator for each OCT image seen.

RESULTS

A total of 320 OCT images from 32 patients undergoing thyroid surgery, parathyroidectomy or lymphadenectomy were compared with the corresponding histology. The sensitivity and specificity in distinguishing parathyroid tissue from the other entities was 84% (second investigator: 82%) and 94% (93%) respectively. Unweighted κ using four diagnostic categories was 0.97 (95% CI, 0.94-0.99) showing substantial agreement between both investigators.

CONCLUSION

OCT is highly sensitive in distinguishing between parathyroid tissue, thyroid tissue, lymph nodes and adipose tissue. These ex vivo results should be confirmed by using OCT imaging intraoperatively.