© 2004 Blackwell Publishing Ltd European Journal of Cancer Care, 2004, 13, 193 Letters to the Editor Study of white coat effect on the prognosis of women with breast cancer TO THE EDITOR: We were fascinated to read the study of white coat effect on the prognosis of women with breast cancer (Costa et al. 2003). However there are several unanswered questions: Methodology Most studies quantify white coat effect (WCE) by the dif- ference between office and home ambulatory blood pres- sure values (Pickering et al. 2002), with home seen as the more tranquil environment. In this study WCE was quan- tified as the difference between blood pressure measured by the doctor and the nurse, in a clinic environment. This design was a record-based, retrospective study. It is important to know whether an attempt was made to control for variables that may be associated with blood pressure measurement (Reeves 1995). For example: doctor and nurse interpersonal variations in measurement tech- niques, training, equipment, timing of measurements during the consultation and the chemotherapeutic regimes the women were having. It is also likely that the nature of the initial doctor consultation and the subse- quent nurse encounters differed with respect to the goals and activities of the appointments. Such variations could easily result in significant variations in blood pressure, particularly within the stressful environment of the oncology clinic. We also found no mention of patients who did not have three blood pressure measurements and were therefore excluded from the analysis. Analysis We wonder whether the analysis controlled for baseline characteristics? Can the authors speculate as to why dias- tolic WCE was higher than systolic? It is important to note that diastolic blood pressure is technically more dif- ficult to measure and hence an inherent risk of inaccuracy could well account for these results. Conclusions For the above reasons, we contest whether this study shows WCE to be more common in women with breast cancer, than the general female population. The question as to whether quantifying the WCE would be useful in the oncology setting, other than to highlight the women’s potential increased risk of a cardiovascular event (Mancia 2000), we believe requires more research, particularly through prospective multivariate analysis. REFERENCES Costa L.J.M., Varella P.C.S. & del Giglio A. (2003) White coat effect in breast cancer patients undergoing chemotherapy. European Journal of Cancer Care 12, 372–373. Mancia G. (2000) White coat effect. Innocuous or adverse phe- nomenon? European Heart Journal 21, 1647–1648. Pickering T., Gerin W. & Schwartz A. (2002) What is white-coat effect and how should it be measured? Blood pressure moni- toring, Vol. 7, 293–300. Reeves R. (1995) Does this patient have hypertension? How to measure blood pressure. JAMA 273, 1211–1218. LARA ALLOWAY, JENNI BURT, RICHARD HARDING & IRENE J HIGGINSON Department of Palliative Care and Policy, Guy’s, King’s and St Thomas’ School of Medicine, London, UK. Correspondence: Dr Lara Alloway, Department of Pallia- tive Care and Policy, Guy’s, King’s and St Thomas’ School of Medicine, King’s College London, and Weston Educa- tion Centre, Cutcombe Road, Denmark Hill, London SE5 9RJ, UK (e-mail: lara.alloway@kcl.ac.uk) REPLY We appreciate the questions regarding our article on the white coat effect (WCE) in patients with breast cancer. In fact, we collected our data retrospective so that we could not include home blood pressure readings because most of the patients did not measure blood pressure at home. Since the blood pressure measurements were always done either at the doctor’s office or by the oncology nurse in the same chemotherapy suite (always in the afternoon and by the same doctors and nurses), probably most of the vari- ations that can influence blood pressure evaluation that were mentioned might have been constant throghout the study. We do not know why diastolic WCE was more pro- nounced than the systolic one, but we feel that it may be a real phenomenon since blood pressure measurements were taken always by the same team of nurses and doctors. The significant prognostic impact of diastolic WCE was independent by multivariate analysis of base- line prognostic characteristics such as clinical stage, axil- lary lymph node involvement and hormone receptor positivity. Finally, we did not present any data to suggest that breast cancer patients have WCE more frequently than normal women because no control population was included in this study. What we believe is that women with breast cancer and WCE may behave clinically differ- ently than women without WCE and we agree that further studies are needed to confirm our findings. REFERENCE Costa L.J.M., Varella P.C.S. & del Giglio A. (2003) White Coat effect in breast cancer patients undergoing chemotherapy. European Journal of Cancer Care 12, 372–373. AURO DEL GIGLIO Avenida Reboucas 3387, Sao Paulo 05410-040, Brazil. Correspondence: Auro del Giglio, MD FACP (e-mail: sandrabr@netpoint.com.br)