subsequent nonresponders and switch to salvage procedures is a critical step in this
concept. It is also possible to modify the therapy in responders during the applica-
tion of specific treatment. Early response of lymphoma after one cycle of chemo-
therapy can be obtained on fluorodeoxyglucose (FDG)-PET.^18 Identification of
nonresponders is particularly important in the neoadjuvant setting where ineffective
therapy should be stopped earlier and the patient can undergo immediate surgery.^19
Studies have shown that early detection of esophageal cancer response to
neoadjuvant chemotherapy by PET-CT can be used to modify patient management
and influence the patient prognosis as well.^20 PET imaging may contribute to the
detection or exclusion of a residual disease in esophageal cancer patients following
chemoradiotherapy.^21 Volumetric measurement is a promising tool in monitoring
tumor response, providing different quantitative assessments in comparison to
standard Response Evaluation Criteria in Solid Tumours (RECIST) guideline
established to standardize and simplify response criteria for solid tumors in adult
and pediatric cancer clinical trials. The terms complete response, partial response,
stable disease, and progression are defined in RECIST criteria. Major changes in the
revised RECIST guideline include the number of lesions to be assessed and the
assessment of pathological lymph nodes (nodes with short axis of15 mm are
considered measurable and assessable as target lesions).^22 The question of disease
progression is clarified in some aspects. Furthermore, in the revised RECIST
guideline, “unequivocal progression” of a nonmeasurable/nontarget disease is
explained in more detail and the imaging guidance is incorporated, including the
interpretation of FDG-PET scan assessment.^23 RECIST-based assessment of tumor
response does not take into consideration nonuniform, eccentric proliferation or
retraction of lung neoplasms. Volumetric measurement of the entire tumor offers
potentially earlier detection of therapy response and could modify treatment deci-
sions.^24 Preliminary results are encouraging but have to be validated in randomized
clinical trials.^25 Volumetric imaging has also a promising role in the follow-up of
nodules detected within screening programs or incidentally obtained on imaging
performed for other indication. CT screening for lung cancer is a good example of
the use of volumetric imaging to reduce recall rates without reducing the sensitivity
of cancer detection.^26 Accurate assessment of therapy response is not only impor-
tant for decision making in oncology. Molecular imaging with fluorescent anti-
bodies created to detect tumor necrosis factor (TNF) responsible for the suppression
(^18) Basu ( 2010 ).
(^19) Crommelin et al. ( 2011 ).
(^20) Kostakoglu et al. ( 2002 ).
(^21) Bombardieri ( 2006 ).
(^22) Klayton et al. ( 2012 ).
(^23) Klayton et al. ( 2012 ).
(^24) Eisenhauer et al. ( 2009 ).
(^25) Mozley et al. ( 2010 ).
(^26) Buckler et al. ( 2010 ).
The Role of Radiology in Personalized Medicine 223