7.1

Introduction

The prediction of tumor behavior and the process of neoplastic transformation

require a careful understanding of tumor biology, cellular metabolism, cell–cell

and cell–matrix interactions, and the interpretation of genotype–phenotype

alterations in the mutated cells (Vander Heiden and DeBerardinis 2017). Neoplastic

transformation leads to several changes in the cellular metabolism, with the more

common ones being an increased metabolic and nutrient demand, high turnover

(especially with aggressive tumors), and loss of regulatory signals restricting cell

growth and multiplication. Several of these metabolic changes can be used to image

these tumors, e.g., the use of ¹⁸F-FDG to target cells with high utilization of glucose,

and several agents targeting the differential receptor expression over neoplastic cells

(⁶⁸Ga-PSMA, ⁶⁸Ga-DOTATATE, 68Ga-DOTA-Exendin) (Parihar et al. 2018j, k).

Targeting these processes not only aids tumor detection but also helps in prognosti-

cation and prediction of response to specific treatments in a wide variety of

malignancies.

Currently, we live in a dichotomized world, one where the developed nations face

cancer and non-communicable diseases such as cardiovascular ailments as the

primary foe whereas the under-developed countries still face the highest morbidity

and mortality from infectious diseases. Indeed, as the countries’ transition from a

primarily infectious diseases afflicted population to one that is challenged by the

non-communicable diseases, access to affordable, accessible, and quality healthcare

becomes vital (Are et al. 2013).

The current challenges in oncologic practice can be broadly divided into three

planes—screening, diagnosis, and treatment. The diseases must be identified prefer-

ably in the pre-cancerous stage (dysplasia) or at least in early stages of

non-metastatic disease. This would necessitate development of suitable screening

techniques, which are already in place for several malignancies, such as colonoscopy

for colorectal cancers and breast self-exam and mammography for breast cancers.

Next comes the importance of diagnostic tests that can yield an accurate and

sufficiently detailed diagnosis as non-invasively as possible. Majority of the nuclear

medicine diagnostic armamentarium would fall into this category. Finally, the need

for precise, personalized, and evidence-based medicine that is affordable and has the

most favorable efficacy and safety profile cannot be overemphasized.

Nuclear medicine can address several of these challenges. Radiopharmaceuticals

offer the advantage of specific targeting of various bodily functions in a relatively

noninvasive way that often detects changes earlier than conventional anatomic

imaging. Further, the radiolabels can be altered to use the same targeting agents to

deliver a therapeutic dose of radiation, i.e., theranostics.

Going forwards, we discuss the avenues for diagnostic and therapeutic

applications of these radiopharmaceuticals in oncology.

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