MRI accurately diagnoses lymph-node metastases

Newsdesk Racial differences in prostate cancer confirmed by genetic study

Courtesy of Kari Gravem Kvakestad

A rare missense mutation in the macro- often under-represented in cancer “In the military, we get excellent trial phage receptor 1 (MSR1) gene is nearly studies. participation”, he says. But issues such twice as common in African-American “It is difficult to assess the overall as lack of insurance or potential for men with prostate cancer than in magnitude of [this] under-representat- discrimination may prevent particihealthy men, report Kathleen Cooney ion”, says Vickie Shavers (National pation in screening and in clinical trials (University of Michigan, MI, USA) and Cancer Institute, MD, USA), “or to in the real world. co-workers. Furthermore, the accurately measure overall progress in Under-representation of minority researchers found that heterozygosity of this area.” The NCI has had some groups in cancer trials is not unique to one common sequence variant in this success in increasing accessibility to the USA. In the UK, Janet Dunn gene is also more common in (Cancer Research UK Clinical affected men (Cancer Res 2003; 63: Trials Unit, Birmingham, UK) 3486–89). According to Judd believes that language difficulties Moul (US Department of Defence are a barrier to participation. “It Center for Prostate Disease can take considerable time to get Research, MD, USA), this study consent from a patient whose “goes some way to finding a native language is not English, and biological basis for the increased there can be ethical concerns if prostate cancer risk in black men”. patient information sheets are not African-Americans have the provided in their native langhighest overall rates of cancer uage”, says Dunn. Both Shavers incidence and death of any US Racial groups are often under-represented in clinical trials. and Dunn suggest that the key to ethnic or racial group. For improved minority participation prostate cancer, death rates in this clinical trials for minority groups, she in clinical research may be better edupopulation were more than double that explains, but participation rates still cation about trials. And, says Cooney, in white people between 1996 and 2000. differ between trials. “Impediments to better participation is essential. “Only Yet, despite this burden of illness, research participation vary”, says by paying attention to the ethnic or Cooney’s study—part of the Flint Shavers, “but lack of trust is a likely racial mix in our studies can we make Men’s Health Study—is unusual in common contributor.” sure our outcomes are applicable to real enrolling only African-Americans. Moul highlights other factors populations”, she concludes. Ethnic or racial minorities are more contributing to under-representation. Jane Bradbury

MRI accurately diagnoses lymph-node metastases Lymph-node metastases can be accurately detected in patients with prostate cancer by use of lymphotropic nanoparticles in combination with high-resolution MRI (N Engl J Med 2003; 348: 2491–99). “We can now accurately image and characterise lymph nodes independent of size”, lead-author Mukesh Harisinghani (Massachusetts General Hospital, MA, USA) told TLO. Currently the only way of assessing malignancy in lymph nodes is by looking at size, which is very inaccurate. Harisinghani and colleagues used a contrast agent called monocrystalline iron oxide which alters the magnetic properties of the lymph nodes detected by MRI. In the study, nanoparticles of this agent were given intravenously to 80 patients with prostate cancer, who underwent MRI just before, and 24 h after, administration of the contrast compound. Harisinghani’s team found that their agent helped detect metastases in all 33 patients in whom nodal metastases had been histopathologically confirmed. Comparing the results to use of MRI alone on a node-by-node basis, the new approach was more sensitive than conventional MRI for detecting metastases (90·5% vs 35·4%). “We have tested other types of cancer,

THE LANCET Oncology Vol 4 August 2003

including breast and bladder, and our results are very encouraging”, Harisinghani adds. Co-author Shahin Tabatabaei, also from Massachusetts General Hospital, believes the accuracy and minimally invasive nature of this technique could revolutionise diagnosis and treatment of prostate cancer. These findings, Harisinghani says, will enable researchers to better stage patients and avoid unnecessary nodal dissection, thereby reducing morbidity and cost. “This will lead to improved outcome”, he notes and speculatively suggests that this approach could be used to attack metastases themselves. Daniel Sullivan (Cancer Imaging Program, National Cancer Institute, MD, USA) agrees that the findings are very important in relation to morbidity, if not mortality. He cautions that it is not yet clear if this diagnostic test will translate into improved survival benefit. However, he concludes: “The findings should certainly lead to patients receiving more appropriate treatment for their particular stage of disease, and will also avoid unnecessary surgery or nodal resection.” Khabir Ahmad

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