A precise and simple isodose-volume-based verification method for HDR and LDR brachytherapy plans.

PURPOSE: The American Association of Physicists in Medicine (AAPM) code of practice for brachytherapy physics recommends performing an independent treatment time calculation. For this we implemented an easy to use isodose-based verification method for HDR (high-dose-rate) and LDR (low-dose-rate) brachytherapy plans. MATERIAL AND METHODS: Dose-volume-based methods have been developed for Ir-192-based high-dose-rate (HDR) and I-125 prostate low-dose-rate (LDR) brachytherapy. They allow checking the integral dwell time or activity when the volume of a suitable isodose is known. The verification method was validated for 55 clinical HDR and 243 clinical LDR plans. RESULTS: For HDR brachytherapy, the mean absolute difference between the estimated and calculated integral dwell time was 0.8% ± 1.0% (n = 30) with a single-source path and 2.7% ± 1.1% (n = 25) for multiple source paths. The corresponding value for LDR brachytherapy was 1.8% ± 2.0% (n = 243). In HDR brachytherapy, the verification method depends slightly on the plan class when considering one or more than one source paths. Good agreement between the estimated and calculated integral dwell times was obtained based on the 2 Gy isodose. Unlike HDR brachytherapy, the parameters used in the verification method for LDR brachytherapy plan verification strongly depend on the type of seed distribution. So, we recommend using an isodose at the prescribed dose for prostate HDR therapy. CONCLUSIONS: Isodose-based verification methods are precise, do not presuppose dedicated tools, and are simple to implement in clinical practice.

Choice of first line systemic treatment in pancreatic cancer among national experts.

BACKGROUND: Treatment options for patients with metastatic pancreatic cancer depend on various factors, including performance status, tumor burden and patient preferences. Metastatic pancreatic cancer is incurable and many systemic treatment options have been investigated over the past decades. This analysis of patterns of practice was performed to identify decision criteria and their impact on the choice of first-line management of metastatic pancreatic cancer. MATERIALS AND METHODS: Members of the Swiss Group for Clinical Cancer Research (SAKK) Gastrointestinal Cancer Group were contacted and agreed to participate in this analysis. Decision trees for the first line treatment of metastatic pancreatic cancer from 9 centers in Switzerland were collected and analyzed based on the objective consensus methodology to identify consensus and discrepancies in clinical decision-making. RESULTS: The final treatment algorithms included 3 decision criteria (comorbidities, performance status and age) and 5 treatment options: FOLFIRINOX, FOLFOX, gemcitabine + nab-paclitaxel, gemcitabine mono and best supportive care. CONCLUSION: We identified multiple decision criteria relevant to all participating centers. We found consensus for the treatment of young (age below 65) patients with good performance status with FOLFIRINOX. For patients with increasing age and reducing performance status there was a decreasing trend to use gemcitabine + nab-paclitaxel. Gemcitabine monotherapy was typically offered to patients in the presence of comorbidities. For patients with ECOG 3-4, most of the experts recommended BSC.

Molecular confirmation of oysters as the vector for hepatitis A in a 2005 multistate outbreak.

Numerous hepatitis A outbreaks were linked to the consumption of raw molluscan shellfish in the United States between 1960 and 1989. However, there had been no major molluscan shellfish-associated hepatitis A outbreaks reported in the United States for more than a decade (1989 to 2004). Beginning in late August 2005, at least 10 clusters of hepatitis A illnesses, totaling 39 persons, occurred in four states among restaurant patrons who ate oysters. Epidemiologic data indicated that oysters were the source of the outbreak. Traceback information showed that the implicated oysters were harvested from specific Gulf Coast areas. A voluntary recall of oysters was initiated in September. Hepatitis A virus (HAV) was detected in multiple 25-g portions in one of two recalled samples, indicating that as many as 1 of every 15 oysters from this source was contaminated. Comparing 315 nucleotides within the HAV VPl-2B region, 100% homology was found among four amplicons recovered from a total of six independent experiments of the implicated oysters, and an identical HAV sequence was detected in sera from all 28 patient serum specimens tested. Ten percent heterogeneity over 315 nucleotides (31 variants) was observed between the outbreak strain (subgenotype 1A) and an HM-175 strain (subgenotype 1B) used in the laboratory where the oysters were processed. To our knowledge, this investigation is the first in the United States to identify an HAV-identical strain in persons with hepatitis A as well as in the food that was implicated as the source of their infections.

The third molar question: to extract or not to extract.

Self-interest, moralists suggest, strongly influences people's behavior. To test the possible effect on dentists, we asked four groups--oral surgeons, periodontists, general practitioners, and orthodontists--to evaluate the need for removal of third molars in three cases. As expected, oral surgeons, who had the most to gain, recommended extraction at a significantly higher rate than the other groups. We found a direct hierarchical relationship between the degree of surgical orientation of a group and its likelihood to see a need for extraction.