Gordon B. Snow

Regional lymph node involvement and its significance in the development of distant metastases in head and neck carcinoma

Background. The incidence of distant metastases in head and neck cancer patients is rising because of greater locoregional control of the disease.

The Use of General Primers in the Polymerase Chain Reaction Permits the Detection of a Broad Spectrum of Human Papillomavirus Genotypes

A novel polymerase chain reaction (PCR) method was developed that permits the detection of 11 different human papillomavirus (HPV) genotypes using two general primer sets. By computer-assisted sequence analysis, two pairs of general primers were selected from the conserved L1 open reading frame and tested in the PCR on a set of cloned HPV genotypes. Experimental analysis showed that up to three mismatches between primers and target DNA did not influence the efficiency of the assay. The use of these primers in the PCR enabled the detection of HPV genotypes HPV-1a, -6, -8, -11, -13, -16, -18, -30, -31, -32 and -33, and was also successfully applied to well characterized cervical carcinoma cell lines and clinical samples. For the HPV types tested sub-picogram amounts of cloned DNA could be detected after general primer-mediated PCR and subsequent hybridization. The specificity of the amplification products was confirmed by blot hybridization procedures and RsaI restriction enzyme digestion. The results indicate that this PCR method can be a powerful tool for identifying novel HPV genotypes in dysplasias and squamous cell carcinomas suspected of having an HPV aetiology.

Recurrence at the primary site in head and neck cancer and the significance of neck lymph node metastases as a prognostic factor

Background. Biologic aggressiveness of head and neck carcinoma is reflected in its capability to metastasize to regional lymph nodes and its propensity to recur after treatment.

The incidence of micrometastases in neck dissection specimens obtained from elective neck dissections

Although modern imaging techniques become more accurate for the assessment of lymph node metastases in the neck as criteria and technology evolve, micrometastases remain occult with any technique. Even the routine histopathological examination of neck dissection specimens is unable to detect all micrometastases. Because knowledge on the incidence of micrometastases in the clinically N0 neck might be of importance for decision making regarding elective treatment, a retrospective study on 96 elective neck dissections was conducted. Meticulous histopathological examination of the neck dissection specimens yielded 3092 lymph nodes of which 67 (2.2%) were tumor‐positive. Twenty‐six of these 67 lymph node metastases were micrometastases. Of the 36 tumor‐positive neck dissection specimens, 21 contained micrometastases. In 9 tumor‐positive specimens only micrometastases were found. This high incidence of micrometastases has important implications for the diagnostic work‐up, the treatment, and histopathological examination of the N0 neck.

Biological evidence that human papillomaviruses are etiologically involved in a subgroup of head and neck squamous cell carcinomas

High‐risk human papillomaviruses (HPVs) have been proposed to be associated with a subset of head and neck cancers (HNSCCs). However, clear biological evidence linking HPV‐mediated oncogenesis to the development of HNSCC is hardly available. An important biological mechanism underlying HPV‐mediated carcinogenesis is the inactivation of p53 by the HPV E6 oncoprotein. In the present study we investigated this biological relationship between HPV and HNSCC. In total 84 HNSCC tumors were analyzed for the presence of high‐risk HPV nucleic acids by DNA polymerase chain reaction‐enzyme immunoassay (PCR‐EIA) and E6 reverse transcriptase (RT)‐PCR as well as for the presence of mutations in the p53 gene. We found 20/84 HPV16 DNA‐positive cases with one or more DNA assays, 10 of which were consistently positive with all assays. Only 9/20 cases showed E6 mRNA expression, indicative for viral activity. Only these nine E6 mRNA‐positive cases all lacked a p53 mutation, whereas both the other HPV DNA‐positive and HPV‐DNA negative tumors showed p53 mutations in 36% and 63% of the cases, respectively. Moreover, only in lymph node metastases of HPV E6 mRNA‐positive tumors both viral DNA and E6 mRNA were present. Our study provides strong biological evidence for a plausible etiological role of high‐risk HPV in a subgroup of HNSCC. Analysis of E6 mRNA expression by RT‐PCR or alternatively, semiquantitative analyses of the viral load, seem more reliable assays to assess HPV involvement in HNSCC than the very sensitive DNA PCR analyses used routinely.

The impact of nutritional status on the prognoses of patients with advanced head and neck cancer

Malnutrition has been recognized as a poor prognostic indicator for cancer treatment–related morbidity and mortality in general, and it is reported to affect 30–50% of all patients with head and neck cancer. In this study, the correlation of nutritional status with 3‐year survival was studied prospectively in 64 patients with T2–T4 carcinomas of the head and neck who were treated surgically with curative intent; the surgery was often followed by radiotherapy.

Second primary tumors and field cancerization in oral and oropharyngeal cancer: Molecular techniques provide new insights and definitions†

Second primary tumors (SPTs) are a significant problem in treating oral and oropharyngeal squamous cell carcinoma and have a negative impact on survival. In most studies the definition of SPT is based on the criteria of Warren and Gates, published in 1932. These criteria, however, are ill‐defined and lead to confusion. Recent molecular studies have shown that a tumor can be surrounded by a mucosal field consisting of genetically altered cells. Furthermore, evidence has been provided that SPTs (defined by classical criteria) can share some or even all genetic markers with the index tumor, indicating that both tumors have arisen from a common cell clone. We propose that these secondary neoplastic lesions should not be considered SPTs, implying that the present concept of SPT needs revision. This review describes a novel classification of the secondary tumors that develop after treatment of a carcinoma in the oral cavity or oropharynx. On the basis of the molecular analysis of the tumors and the genetically altered mucosal field in between, we propose definitions for a “true SPT,” a local recurrence, a “SFT” (second field tumor derived from the same genetically altered mucosal field as the primary tumor), and a metastasis. Considering the etiologic differences of these lesions, we believe that an accurate molecular definition is essential to make headway with the clinical management of oral and oropharyngeal cancer.

Screening for distant metastases in patients with head and neck cancer.

Objectives The detection of distant metastases at initial evaluation may alter the selection of therapy in patients with head and neck squamous cell carcinoma (HNSCC). In this study the value of screening for distant metastases is evaluated.

Assessment of malnutrition parameters in head and neck cancer and their relation to postoperative complications.

Malnutrition is reported frequently in head and neck cancer patients. The impact of malnutrition on surgical outcome is not clearly understood. The purpose of this study was to define the usefulness of six different parameters in scoring malnutrition and to determine the nutritional parameter primarily related to postoperative complications.

p53 expression above the basal cell layer in oral mucosa is an early event of malignant transformation and has predictive value for developing oral squamous cell carcinoma

Epithelial dysplasia is usually used to establish the prognosis of oral premalignant lesions. Its assessment, however, is subjective and does not always correctly predict the outcome of the lesions in terms of malignant transformation. Early molecular alteration(s) that dictate the development of cancer should be identified and used to evaluate oral premalignant lesions. In this context, alterations in the expression of p53 were investigated. Thirty‐five oral premalignant lesions and 11 carcinomas that developed from them in a period of 16 years were investigated for p53 expression by immunohistochemistry. Normal oral mucosa from healthy individuals and oral benign lesions were used as controls. In benign lesions and normal mucosa, p53 staining, when present, was confined to the basal cell layer. Seven out of 35 (20 per cent) premalignant lesions showed p53 expression clearly above the basal cell layer and six of these (86 per cent) developed carcinomas. Suprabasal p53 expression was found in three lesions with no or mild dysplasia that developed carcinomas. All carcinomas derived from premalignant lesions with p53 suprabasal expression showed p53 expression in neoplastic cells. The combined use of histological parameters (presence of moderate or severe dysplasia) with p53 expression patterns (p53 staining above the basal cell layer) showed the highest sensitivity for the detection of lesions that progressed to carcinoma (91 per cent). When used individually, the p53 expression pattern showed higher specificity than assessment of dysplasia (96 per cent vs. 54 per cent) and higher positive predictive value (86 per cent vs. 44 per cent) for correct prediction of the malignant transformation of the lesions. The results suggest that clear expression of p53 above the basal cell layer is an early event in oral carcinogenesis and an indicator of a developing carcinoma, even preceding morphological tissue alterations. However, since immunohistochemistry cannot always detect changes in p53 expression in lesions preceding carcinoma, p53 immunohistochemical analysis is strongly recommended in conjunction with histological parameters, to increase the sensitivity of detection of cases that will progress to carcinoma.