This work presents a brief overview of Markov models in cancer screening evaluation and focuses on two specific models. A three-state model was first proposed to estimate jointly the sensitivity of the screening procedure and the average duration in the preclinical phase, i.e. the period when the cancer is asymptomatic but detectable by screening. A five-state model, incorporating lymph node involvement as a prognostic factor, was later proposed combined with a survival analysis to predict the mortality reduction associated with screening. The strengths and limitations of these two models are illustrated using data from French breast cancer service screening programmes. The three-state model is a useful frame but parameter estimates should be interpreted with caution. They are highly correlated and depend heavily on the parametric assumptions of the model. Our results pointed out a serious limitation to the five-state model, due to implicit assumptions which are not always verified. Although it may still be useful, there is a need for more flexible models. Over-diagnosis is an important issue for both models and induces bias in parameter estimates. It can be addressed by adding a non-progressive state, but this may provide an uncertain estimation of over-diagnosis. When the primary goal is to avoid bias, rather than to estimate over-diagnosis, it may be more appropriate to correct for over-diagnosis assuming different levels in a sensitivity analysis. This would be particularly relevant in a perspective of mortality reduction estimation.
This open, comparative, randomized, multicentre equivalence study compared cefepime 2 g bd and imipenem-cilastatin 1 g tds (50 mg/kg/day) as empirical monotherapy for febrile episodes in a homogeneous cohort of cancer patients with short duration neutropenia following chemotherapy for solid tumour, lymphoma or myeloma. The study was conducted in 17 French anti-cancer centres in 1995 and 1996. Response to monotherapy was assessed 7 days after treatment and was based on resolution of fever and signs and symptoms, eradication of pathogens, absence of new infection, relapse, and death of infectious origin, without addition of other antibiotics. Patients were treated for a minimum of 4 days. Of the 400 episodes randomized, 344 (86%) were evaluable for efficacy. Patient characteristics were comparable between treatment groups. Success of monotherapy was observed in 79% of episodes with cefepime and 72% with imipenem-cilastatin (equivalence, P <0.0001). The response rate for microbiologically documented infections was 66% with cefepime and 61% with imipenem-cilastatin (bacteraemic episodes: 63% for cefepime; 44% for imipenem-cilastatin). A second antibiotic (usually a glycopeptide) was added in 20% and 21% of the cases, respectively. Overall, the response to therapy, with or without an additional antibiotic, was 95% (cefepime) and 90% (imipenem-cilastatin). Survival was similar in both groups (95% and 98%, respectively). Cefepime treatment was better tolerated, with 9% of the patients experiencing related intercurrent events compared with 19% in the imipenem-cilastatin group (P = 0.003). Nausea/vomiting was significantly more frequent in the imipenem-cilastatin group (15%) than in the cefepime group (5%; P = 0.001). Cefepime monotherapy was as effective as, and better tolerated than, imipenem-cilastatin in the empirical treatment of fever during short duration neutropenia.
Objective Some patients (10 % – 32 %) with a positive guaiac fecal occult blood test (gFOBT) do not undergo the recommended colonoscopy. The aim of this study was to compare video capsule endoscopy (VCE) and computed tomography colonography (CTC) in terms of participation rate and detection outcomes when offered to patients with a positive gFOBT who did not undergo the recommended colonoscopy. Methods An invitation letter offering CTC or VCE was sent to selected patients after randomization. Acceptance of the proposed (or alternative) procedure and procedure results were recorded. Sample size was evaluated according to the hypothesis of a 13 % increase of participation with VCE. Results A total of 756 patients were targeted. Following the invitation letter, 5.0 % (19/378) of patients underwent the proposed VCE and 7.4 % (28/378) underwent CTC, (P = 0.18). Following the letter, 9.8 % (37/378) of patients in the VCE group underwent a diagnostic procedure (19 VCE, 1 CTC, 17 colonoscopy) vs. 10.8 % in the CTC group (41/378: 28 CTC, 13 colonoscopy; P = 0.55). There were more potentially neoplastic lesions diagnosed in the VCE group than in the CTC group (12/20 [60.0 %] vs. 8/28 [28.6 %]; P = 0.04). Thus, 15/20 noninvasive procedures in the VCE group (19 VCE, 1 CTC; 75.0 %) vs. 10/28 in the CTC group (35.7 %; P = 0.01) resulted in a recommendation of further colonoscopy, but only 10/25 patients actually underwent this proposed colonoscopy. Conclusion Patients with a positive gFOBT result who do not undergo the recommended colonoscopy are difficult to recruit to the screening program and simply proposing an additional, less-invasive procedure, such as VCE or CTC, is not an effective strategy.
Controversies regarding the benefits of breast cancer screening programs have led to the promotion of new strategies taking into account individual preferences, such as decision aid. The aim of this study was to assess the impact of a decision aid leaflet on the participation of women invited to participate in a national breast cancer screening program. This Randomized, multicentre, controlled trial. Women aged 50 to 74 years, were randomly assigned to receive either a decision aid or the usual invitation letter. Primary outcome was the participation rate 12 months after the invitation. 16 000 women were randomized and 15 844 included in the modified intention-to-treat analysis. The participation rate in the intervention group was 40.25% (3174/7885 women) compared with 42.13% (3353/7959) in the control group (p = 0.02). Previous attendance for screening (RR = 6.24; [95%IC: 5.75-6.77]; p < 0.0001) and medium household income (RR = 1.05; [95%IC: 1.01-1.09]; p = 0.0074) were independently associated with attendance for screening. This large-scale study demonstrates that the decision aid reduced the participation rate. The decision aid activate the decision making process of women toward non-attendance to screening. These results show the importance of promoting informed patient choices, especially when those choices cannot be anticipated.
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