Multiplet resonances in MRS data from normal and cancerous prostate - Signal Processing in MRS with Biomedical Applications - page 331

11

Multiplet resonances in MRS data from
normal and cancerous prostate

11.1 Dilemmas and di culties in prostate cancer diag-

nostics and screening

Prostate cancer is an exceedingly common malignancy. In the U.S. carcinoma
of the prostate is the most frequently diagnosed visceral cancer. Both in the
U.S. and in the European Union it is cited as the most common cancer among
men [401]-[403]. In the U.S. in 2006 the number of malignancyrelated deaths
due to prostate cancer exceeded those from colorectal cancer [403].
The number of detected cases has increased dramatically in the 1990s based
on the widespread testing with prostate specific antigen (PSA) [404]. The
highest rates are reported in the U.S. and Western Europe and lowest in the
Asian countries. However, these findings should be interpreted in the light
of diagnostic intensity and screening behavior. Namely, “incidence rates in
some countries, the United States being a prime example, reflect the sum of
clinical disease and latent disease, but in other countries only clinical disease”
(p. 401) [405]. Nevertheless, even before PSA became available, there were
marked geographic differences in incidence.
The death rate from prostate cancer has been declining in many countries
of Western Europe and North America since the mid 1990s. This is thought to
be related, to a substantial extent, to early detection [402, 406, 407], since the
5year survival rate of local disease is cited to be “effectively 100%”, whereas
with distant metastases this falls to 34% [402].
Screening with PSA is probably responsible, at least in part, for these
favorable developments. However, there are no specific cutpoints that si
multaneously yield optimal sensitivity and specificity [408]. Despite the lack
of prospective, randomized controlled evidence demonstrating the benefit,
screening with PSA plus digital rectal examination is recommended by, e.g.
the American Cancer Society and the American Urological Association, al
though not by the American College of Preventive Medicine [403]. This more
widespread screening has led to an increased detection of localized tumors,
decreased frequency of nodal spread and of late stage detection, all of which
improve survival dramatically. It should nevertheless also be pointed out that

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