In vitro efficacy of five essential oils against Pediculus humanus capitis.

Treatment of head lice has relied mainly on the use of topical insecticides. Today, conventional topical pediculicides have suffered considerable loss of activity worldwide. There is increasing interest in the use of natural products such as essential oils for head louse control, and many of them are now incorporated into various over-the-counter products presented as pediculicides, often without proper evaluation. The aim of the present study was to assess the in vitro efficacy of five essential oils against adults of Pediculus humanus capitis using a contact filter paper toxicity bioassay. The chemical composition of the essential oils from wild bergamot, clove, lavender, tea tree, and Yunnan verbena was analyzed by gas chromatography-mass spectrometry. All treatments and controls were replicated three times on separate occasions over a period of 11 months. In all, 1239 living lice were collected from the scalp of 51 subjects, aged from 1 to 69 years. Clove oil, diluted either in coco oil or sunflower oil, demonstrated the best adulticidal activity, reaching > 90% mortality within 2 h in lice submitted to a 30-min contact. Yunnan verbena oil diluted in coco oil showed also a significant efficacy. Other essential oils showed a lower efficacy. The oil's major component(s) differed according to the tested oils and appeared chemically diverse. In the case of clove oil, the eugenol appeared as the main component. This study confirmed the potential interest of some of the essential oils tested, but not all, as products to include possibly in a pediculicidal formulation.

Duration of adjuvant chemotherapy for patients with non-metastatic colorectal cancer.

BACKGROUND: Surgery of primary tumour is the backbone of colorectal cancer treatment (CRC). But in stage III cancer, metastatic or local relapse is often observed (50%). So, adjuvant treatment is always considered in this setting. The best treatment duration of hypothetic disease is not easy to define. Adjuvant chemotherapy for CRC actually lasts 6 months. The choice of optimal duration is based upon old studies using 5-fluorouracil (5FU). During the last ten years, results of major randomized controlled studies (RCTs) comparing different durations of treatments and different schedules in adjuvant setting were published. Several studies compared a 6-month chemotherapy with a longer treatment. Conversely, a single study by Chau et al compared a 6 month chemotherapy with continuous treatment lasting 3 months. But the optimal duration of these chemotherapies could be challenged. Even though the optimal duration of chemotherapy in CRC is a major issue, it has never been answered adequately. OBJECTIVES: To evaluate the optimal duration of adjuvant treatment, we performed a meta-analysis of all RCTs comparing two durations of adjuvant treatment, 6 months versus 9 to 12 months. SEARCH STRATEGY: Publications were identified from PubMed (February 28th, 2009), Embase, and the Cochrane Database of Clinical Controlled Trials (CENTRAL) in the Cochrane Library 2009 issue 1. Reviews and books were also scrutinized. Abstracts were reviewed from ASCO annual meetings proceedings from 1998 to 2009. SELECTION CRITERIA: Patients with surgically resected colorectal cancer with high risk of recurrence. DATA COLLECTION AND ANALYSIS: Several RCTs compared shorter versus longer durations of chemotherapy, 6 studies for overall survival (OS) and 7 studies for relapse free survival (RFS), for a total of 10326 patients, mean age 63.1 years, including 9826 colon and 500 rectum cancers. MAIN RESULTS: Treatments were always based on 5-FU. Two studies were excluded, an epidemiological study and a study comparing continuous treatment during 3 months with conventional chemotherapy during 6 months. The later because it compared 2 durations less than or equal to 6 months. Shorter duration of chemotherapy (3-6 months) compared with longer duration (9-12 months) was not associated to poorer RFS (RR =0.96, 95% CI : 0.90-1.02) and OS (RR = 0.96 ; 95% CI : 0.91-1.02). AUTHORS' CONCLUSIONS: The present meta-analysis confirmed that adjuvant chemotherapy of CRC should not last for more than 6 months. Prolonged duration would result in lower benefit to risk ratio. However, the results do not make it possible to favour either 3 or 6 month durations. They should help design a future RCT comparing different durations of continuous treatment.

Microsatellite instability: a predictive marker in metastatic colorectal cancer?

Microsatellite instability (MSI) status is a good prognostic factor for colorectal cancer (CRC), but its predictive value for chemosensitivity remains controversial. We recently performed a meta-analysis (MA) in adjuvant setting showing that MSI high (MSI-H) status did not predict the efficacy of chemotherapy. Studies were identified by electronic search through PubMed, Embase and ASCO proceedings online databases, using several keywords (colorectal cancer, chemotherapy, microsatellite instability). For each study, we calculated the ratio of response rate, complete and partial responses divided by stable disease and progression. Our MA dealt with the predictive value of MSI status on the effect of metastatic chemotherapy using various combinations of 5FU, oxaliplatin or CPT11. From 159 articles and 76 abstracts, we selected only seven independent studies. Data were analysed with a random-effect model (due to heterogeneity between studies) using EasyMA software. Statistical calculations were performed on five studies representing 860 patients (mean age 63 years; 87 MSI-H; 733 microsatellite stable [MSS] tumors). A total of 287 patients received 5FU-based chemotherapy, whereas 574 patients received combinations of 5FU or capecitabine with oxaliplatin and/or irinotecan. Our MA found no benefit of metastatic chemotherapy in terms of response rate for MSI-H patients compared with MSS patients. The global hazard ratio for response rate was 0.83 (95% confidence interval: 0.95; 0.65-1.05; p = 0.11). In conclusion, MSI status did not predict the effect of chemotherapy for metastatic CRC. Metastatic chemotherapy had a similar effect on both MSI-H or on MSS tumors.