The KRAS-Variant and Cetuximab in HPV-Positive Oropharyngeal Cancer in NRG/RTOG 1016

PURPOSE/OBJECTIVE(S)

NRG/RTOG 1016 was a non-inferiority phase III trial comparing radiation with cisplatin versus cetuximab monotherapy for patients with HPV-positive oropharyngeal squamous cell carcinoma (SCC). The trial did not meet the non-inferiority criteria for overall survival (OS) and had significantly worse progression-free survival (PFS) and locoregional failure (LRF) in patients treated with cetuximab. Based on prior evidence that HNSCC patients with a germ-line mutation in KRAS (the KRAS-variant) had a positive response to radiation with cisplatin plus cetuximab without increased toxicity, samples from RTOG 1016 were used to test the protocol-specified hypothesis that KRAS-variant patients will have better outcomes when receiving IMRT + cetuximab monotherapy compared to IMRT + cisplatin.

MATERIALS/METHODS

The KRAS-variant was tested in 562 samples at MiraDx, a CLIA-certified laboratory. OS, PFS, LRF, and distant metastases (DM) were as defined per the RTOG 1016 protocol, and hazard ratios (HRs) were estimated by (cause-specific) Cox models. Negative binomial regression was used to model the number of treatment-related acute and late (≤ and > 180 days from end of treatment, respectively) grade 3-5 adverse events. To assess the predictive role of the KRAS-variant, all models included KRAS, assigned treatment, and their interaction, with the interaction tested at two-sided 0.05. HRs and toxicity ratios are expressed as IMRT + cetuximab / IMRT + cisplatin.

RESULTS

The prevalence of the KRAS-variant was 16% with similar patient and tumor characteristics and well-balanced treatment arms for variant and non-variant patients. Median follow-up was 8.6 years. There was no significant interaction between KRAS and treatment for OS (p = 0.99), PFS (p = 0.56), LRF (p = 0.09), or DM (p = 0.19) (Table 1). In KRAS-variant patients the mean acute and late toxicity ratios were 0.53 (95% CI 0.36, 0.80) and 1.62 (95% CI 0.57, 4.62). In non-variant patients, the mean acute and late toxicity ratios were 0.80 (95% CI 0.67, 0.95) and 0.55 (95% CI 0.35, 0.87), respectively. The interaction of KRAS and treatment was not significant for acute (p = 0.07) or late toxicity (p = 0.07).

CONCLUSION

While this study does not directly refute prior evidence that KRAS-variant patients benefit from radiation + cisplatin and cetuximab, this study does not support the hypothesis that the KRAS-variant is a predictive biomarker of improved outcome in HPV+ oropharyngeal SCC patients treated with IMRT + cetuximab alone, and suggests that for KRAS-variant patients, potential benefits in LRF and acute toxicity with cetuximab may be offset by worse DM and worse late toxicity.

Newly Recognized CNS Tumors in the 2021 World Health Organization Classification: Imaging Overview with Histopathologic and Genetic Correlation

In 2021, the World Health Organization released an updated classification of CNS tumors. This update reflects the growing understanding of the importance of genetic alterations related to tumor pathogenesis, prognosis, and potential targeted treatments and introduces 22 newly recognized tumor types. Herein, we review these 22 newly recognized entities and emphasize their imaging appearance with correlation to histologic and genetic features.

Are we giving General Practitioners what they want from Psychiatric out-patient review letters?

We aimed to assess the quality of out-patient clinic letters in relation to GPs expectations. A questionnaire was devised and sent to 65 GPs to ascertain what they felt to be important in a psychiatric out-patient clinic letter. We examined 250 out-patient clinic letters comprising both a formatted and unformatted pattern. We compared whether one particular type of letter was more successful at providing the information specifically requested by GPs. Fifty seven per cent of GPs responded to the questionnaire. Letters following a pre-determined formatted template, although slightly longer, consistently conveyed more relevant information. Conclusion: The use of formatted letters is a means of enhancing communication between psychiatrists and GPs and within secondary psychiatry services.

A STRATEGY FOR RAPID IDENTIFICATION OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS NASAL CARRIER STATUS

Methicillin Resistant Staphylococcus aureus (MRSA) is a multi drug resistant organism responsible for severe outbreaks of life threatening infections in hospitals which are difficult to treat They are spread by nasal carriage among the hospitalised patients, staff and visitors. Mannitol cloxacillin salt agar (MCSA) is a single tube method to identify MRSA. However, tubes showing growth and change in colour on biochemical characterisation often do not prove to be MRSA. In this study we have combined two strategies for the rapid identification and isolation of MRSA by culture in MCSA and multiplex PCR for mecA and femB genes. Anterior nasal swabs obtained from nursing staff and patients admitted to a large referral hospital, were inoculated into MCSA. Of the 100 tubes inoculated, 8 tubes showed change in colour and growth. On conventional testing 4 were MRSA, 3 were methicillin sensitive S aureus (MSSA) and 1 was Methicillin Sensitive Coagulase Negative S aureus (MSCNS). Genotyping by multiplex PCR revealed 5 MRSA, 2 MSSA and 1 MRCNS. The Multiplex PCR technique to rapidly identify presence of mecA and femB genes showed presence of both mecA and femB bands in all MRSA. The methicillin sensitive organisms showed absence of mecA gene while coagulase negative organisms showed absence of the fern B gene. Combining MSCA with multiplex PCR for mec A and fem B genes made the test both rapid and specific. Use of this strategy would enable rapid screening of nasal carriers and early implementation of hospital infection control measures.

Real time observation of anaphase in vitro

We used digital fluorescence microscopy to make real-time observations of anaphase chromosome movement and changes in microtubule organization in spindles assembled in Xenopus egg extracts. Anaphase chromosome movement in these extracts resembled that seen in living vertebrate cells. During anaphase chromosomes moved toward the spindle poles (anaphase A) and the majority reached positions very close to the spindle poles. The average rate of chromosome to pole movement (2.4 microns/min) was similar to earlier measurements of poleward microtubule flux during metaphase. An increase in pole-to-pole distance (anaphase B) occurred in some spindles. The polyploidy of the spindles we examined allowed us to observe two novel features of mitosis. First, during anaphase, multiple microtubule organizing centers migrated 40 microns or more away from the spindle poles. Second, in telophase, decondensing chromosomes often moved rapidly (7-23 microns/min) away from the spindle poles toward the centers of these asters. This telophase chromosome movement suggests that the surface of decondensing chromosomes, and by extension those of intact nuclei, bear minus-end-directed microtubule motors. Preventing the inactivation of Cdc2/cyclin B complexes by adding nondegradable cyclin B allowed anaphase A to occur at normal velocities, but reduced the ejection of asters from the spindles, blocked chromosome decondensation, and inhibited telophase chromosome movement. In the presence of nondegradable cyclin B, chromosome movement to the poles converted bipolar spindles into pairs of independent monopolar spindles, demonstrating the role of sister chromatid linkage in maintaining spindle bipolarity.

DNA bending by the a1 and alpha 2 homeodomain proteins from yeast

Structural and biochemical studies of monomer homeodomain-DNA complexes have not so far revealed any cases of pronounced DNA distortion. In this paper we show that multimeric complexes of the yeast homeodomain proteins a1 and alpha 2 induced significant bends in their operators upon binding. Based on a series of circular permutation experiments, we found that a dimer of alpha 2 bound to operator DNA produced a mild bend in the DNA, whereas the alpha 2-MCM1-DNA and the a1-alpha 2-DNA complexes exhibited much sharper bends. As these latter two complexes represent the in vivo form of DNA-bound a1 and alpha 2, we conclude that, in the cell, these homeodomain proteins are associated with pronounced bends in DNA. We discuss possible roles for these bends in transcriptional repression.

Footlength measurement in the neonate

In 353 neonates, foot length were recorded along with birth weight, crown heel length and head circumference. Foot length correlated well with all three indices (p less than .01). Highest correlation in preterm babies was with crown heel length and weight, and in term babies with head circumference. The formula, length = footlength x 6.5 +/- 20 mm could be correctly used in 95% of babies. When it is difficult to weigh or measure the length accurately, foot length can serve as a useful measurement to assess a baby quickly.

Centbutindole vs trifluoperazine: a double-blind controlled clinical study in acute schizophrenia

Twenty-nine acute schizophrenic patients were treated under double-blind conditions for six weeks with either centbutindole in a dose range of 3 mg/day to 4.5 mg/day or trifluoperazine in the dose range of 15 mg/day to 22.5 mg/day. Both drugs produced a significant improvement in initial psychopathology. No significant differences were demonstrated between the two treatment conditions.

Effects of intravenous metoclopramide in 81 patients with tardive dyskinesia

We compared acute effects of single intravenous administrations of metoclopramide (40 mg) and placebo in a double-blind crossover study involving 81 patients with tardive dyskinesia. Metoclopramide produced significantly greater reduction in mean total Abnormal Involuntary Movement Scale score as well as in ratings for six of the seven body areas, when compared with placebo. On adjusting each patient's metoclopramide response for his or her placebo response, we found that 35 of the 81 patients had 50% or greater placebo-corrected improvement. There were no apparent clinical differences between metoclopramide responders and nonresponders. Administration of 60 mg of metoclopramide to 15 patients produced greater improvement in tardive dyskinesia as compared with 40 mg; the incidence of acute dystonia, however, jumped from 10% with 40 mg to 33% with 60 mg.

Tardive dyskinesia in India: a prevalence study

We screened the entire inpatient population (N = 1963) of a state hospital near Bombay, India, for tardive dyskinesia (TD) using specific diagnostic criteria. Prevalence of TD was found to be 9.6%, which was much lower than that reported from the Western countries. Percent prevalence of TD was greatest in the age group 41 to 50, after which it seemed to decline. TD patients had received neuroleptic treatment for significantly longer periods and in significantly greater amounts than non-TD patients. The principal reason for the relatively low prevalence of TD in India is probably the practice of using neuroleptics in comparatively small doses (mean daily dose is about 200 mg of chlorpromazine equivalents). A possible contribution of racial-genetic factors cannot be excluded.