of immune response in patients with Crohn’s disease has potential to predict
therapeutic response to biological therapy.^27 Patients with low amounts of cells
with membrane TNF expression will not respond and should not be exposed to
serious side effects of this therapy. Conventional morphologic head and neck
cancer imaging by using MSCT and MR imaging, despite providing accurate
anatomical data, is not sufficient to determine cancer response to chemo-irradiation.
We need neuroimaging modalities that can provide biological information beyond
the size and enhancement of a tumor. Novel noninvasive functional imaging
methods are necessary to predict therapeutic outcome and thereby improve the
ability to properly select patients for the treatment with both conventional and
targeted therapies, to better evaluate therapeutic effectiveness during the early
phases of treatment, and to enhance a priori risk assessment for treatment-induced
toxicity. Knowing the molecular nature of cancer, potentially unresponsive tumors
can be treated by use of an alternative protocol. Tumor hypoxia is a common
phenomenon in head and neck cancers (HNC) reflecting cancer’s resistance to
chemotherapy and radiation.^28 Hypoxic cells are resistant to the cytotoxic effects
of chemotherapy and ionizing radiation and require radiation doses up to three
times higher than those in the same cells under normoxic condition to achieve the
same level of cell inactivation. There is a growing interest in diagnosing hypoxic
HNC before therapy in the hope of applying novel treatment strategies that may
overcome resistance to conventional chemo-irradiation.^29
Identifying imaging biomarkers in the preclinical stage followed by therapeutic
intervention prevents the development of a disease. Radiology has a long-time
experience with mammographic identification of preclinical breast cancers or
cancer precursors. Pleomorphic calcifications in segmental distribution without
soft tissue lesion are characteristic for ductal carcinoma in situ, but not all suspected
calcifications are malignant. Mammographic screening is a well-established proce-
dure for systematic detection of early breast cancers within defined age range based
on imaging biomarkers in asymptomatic women. Imaging biomarkers are exten-
sively used as surrogate end points in clinical drug trials, allowing for shortening of
trial time and reducing costs.^30 Due to tremendous improvements in radiologic and
nuclear medicine imaging in terms of spatial, contrast, and temporal resolution, as
well as functional information and increasing number of diagnostic procedures
worldwide, incidental findings of preclinical disorders or indolent lesions increase
the risk of overdiagnosis. Overdiagnosis refers to diagnosing an indolent disease in
an asymptomatic examinee without potential to influence the subject’s health
during his or her life. Cancer overdiagnosis can be explained by tumor stability
over time or very slow progression resulting in the death of a patient before
symptoms occur. Considering the individual approach to the patient, it is important
(^27) Van Klaveren et al. ( 2009 ).
(^28) Atreya et al. ( 2014 ).
(^29) Nordsmark et al. ( 2005 ).
(^30) Thrall ( 2004 ).
224 D. Miletic ́et al.