Morbidity related to the lip-split mandibulotomy approach: a systematic and narrative review.

The lip-split mandibulotomy (LSMA) is an access procedure that has been used in head and neck (H&N) surgery as an aid to surgical resection of inaccessible tumours of the postertior oral cavity and oropharynx. Anecdotal evidence suggests that it has significant morbidity. Voices of concern within the H&N surgical community suggest that it has been abandoned in favour of technological advances such as robotic surgery. We report here the first (to our knowledge) registered systematic review of its kind, documenting the safety and efficiency of LSMA in H&N surgery. We performed a PRISMA-guided systematic review (PROSPERO-registered) and identified reports using a search algorithm in MEDLINE/EMBASE. LSMA-related surgical complications were recorded using the Clavien-Dindo classification. Secondary outcomes included swallowing dysfunction, facial cosmesis, and patient satisfaction recorded in health-related quality of life questionnaires (HRQoL). From 125 studies identified, 54 met the inclusion criteria (3872 patients). The LSMA mortality rate was 0%; we did not identify a single case of perioperative death. The median rate of osteoradionecrosis was 5.4%, whereas fistula formation was 5.7%. Malunion was noted in 4.9%. Other complications (surgical site infection, plate exposure) were around 5%. There was significant between-study variation with regards to swallowing assessment tools, but overall there was no significant difference in outcomes. This was also the case for the HRQoL questionairres. LSMA is a safe procedure with an acceptable rate of complications, and should definitely remain in the armamentarium of H&N surgery.

Head and neck sarcomas: A single institute series.

BACKGROUND: Sarcomas are tumours of mesenchymal origin, accounting for 1% of all malignancies. METHODS: This is a retrospective analysis of 107 head and neck sarcoma cases, treated over a period of thirteen years. RESULTS: Fifty-four patients had with craniofacial bone sarcomas (BSs) (male: 33; female: 21) with high grade osteosarcoma being the most predominant type. The soft tissue sarcomas (STS) (53 patients; male: 28, female: 25) were histologically diverse with rhabdomyosarcomas and myxofibrosarcomas being the predominant types. The majority of BSs were managed with neoadjuvant chemotherapy followed by surgery, whereas in STSs treatment included predominantly surgery followed by radiotherapy. Overall survival estimates were 79% at 2years and 64% at 5years (mean follow-up period was 48months). CONCLUSIONS: The mesenchymal origin of sarcomas, the pattern of disease spread and the different extent of cancellous bone infiltration in contrast to epithelial tumours, dictate distinct principles for surgical clearance.

Nevirapine induces growth arrest and premature senescence in human cervical carcinoma cells.

OBJECTIVE: The aim of this study was to assess the impact of nevirapine on a cervix carcinoma cell line. METHODS: HeLa cells were cultured in Dulbecco's modified Eagle medium supplemented with 20% fetal bovine serum at 37 degrees C and humidified 10% CO(2) in air. Nevirapine was purified from commercially available Viramune (Boehringer-Ingelheim), diluted in dimethyl sulfoxide (DMSO, Sigma-Aldrich) in 350 microMu final concentration and added to cell cultures 5 h after seeding. The same DMSO volume (0.2% final concentration) was added to controls. RESULTS: We found that nevirapine treatment induces reversible growth arrest and produces morphological changes in treated cells. In contrast with previous reports the observed effects of nevirapine did not correlate with promotion of differentiation, but with induction of premature senescence. Premature senescence as a response to anti-tumour treatment is a common effect of the most anti-cancer chemotherapeutics. Nevirapine treated cells strongly accumulated SA-b-Gal activity and also expressed increased levels of p53 and p21 when analyzed via RT-PCR. In order to further explore the potent mechanisms of premature senescence induction we performed pChk2-Thr68 immunofluorescence analysis and found that nevirapine treated cells exhibited increased number of nuclear foci, indicating activated DNA damage response. CONCLUSION: We propose that at least in HeLa cell line nevirapine treatment exerts an effect far from the differentiation process, by introducing the cells into premature senescence. Based on these data, the effects of RT inhibitors should be further investigated since they may represent an additional agent against human cancer.

Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints.

Recent studies have indicated the existence of tumorigenesis barriers that slow or inhibit the progression of preneoplastic lesions to neoplasia. One such barrier involves DNA replication stress, which leads to activation of the DNA damage checkpoint and thereby to apoptosis or cell cycle arrest, whereas a second barrier is mediated by oncogene-induced senescence. The relationship between these two barriers, if any, has not been elucidated. Here we show that oncogene-induced senescence is associated with signs of DNA replication stress, including prematurely terminated DNA replication forks and DNA double-strand breaks. Inhibiting the DNA double-strand break response kinase ataxia telangiectasia mutated (ATM) suppressed the induction of senescence and in a mouse model led to increased tumour size and invasiveness. Analysis of human precancerous lesions further indicated that DNA damage and senescence markers cosegregate closely. Thus, senescence in human preneoplastic lesions is a manifestation of oncogene-induced DNA replication stress and, together with apoptosis, provides a barrier to malignant progression.

Activation of the DNA damage checkpoint and genomic instability in human precancerous lesions.

DNA damage checkpoint genes, such as p53, are frequently mutated in human cancer, but the selective pressure for their inactivation remains elusive. We analysed a panel of human lung hyperplasias, all of which retained wild-type p53 genes and had no signs of gross chromosomal instability, and found signs of a DNA damage response, including histone H2AX and Chk2 phosphorylation, p53 accumulation, focal staining of p53 binding protein 1 (53BP1) and apoptosis. Progression to carcinoma was associated with p53 or 53BP1 inactivation and decreased apoptosis. A DNA damage response was also observed in dysplastic nevi and in human skin xenografts, in which hyperplasia was induced by overexpression of growth factors. Both lung and experimentally-induced skin hyperplasias showed allelic imbalance at loci that are prone to DNA double-strand break formation when DNA replication is compromised (common fragile sites). We propose that, from its earliest stages, cancer development is associated with DNA replication stress, which leads to DNA double-strand breaks, genomic instability and selective pressure for p53 mutations.