Principles of Cancer Detection and Treatment

Various methods of cancer detection and treatment are discussed in oncology textbooks (for example, Holland et al., 1993 DeVita et al., 1993). In what follows, we will outline these methods with emphasis on approaches based on mass and heat transfer. 

Currently, there are six major methods available for cancer treatment surgery, radiotherapy, chemotherapy, immunotherapy, hyperthermia, and photodynamic therapy. The first three are the most widely used, and the last three are under development. Surgery, radiotherapy, hyperthermia, and photodynamic therapy are primarily local, while chemotherapy and immunotherapy are primarily systemic methods. In most cases a combination of methods is used for cancer treatment. Except for surgery, the application of the remaining five methods can be improved considerably by developing quantitative understanding of mass and/or heat transfer in tumors and normal tissues. In what follows, we will discuss the problems and promises of each of these five techniques from the point of view of mass and heat transfer, and mention anti-angiogenic approaches. 

The purpose of radiotherapy is to deliver a large radiation dose to the tumor and a minimal dose to the surrounding normal tissues. Depending upon the location and volume of the tumor, the radiation can be a photon source (e.g., x-ray tubes, cobalt teletherapy unit, linear accelerator, Betatrons) or a source for a high-energy particle (e.g., electrons, protons). 

When the radiation is absorbed by cells, a few of the atoms and molecules of the cells are ionized. The ionization leads, either directly or via the formation of free radicals, to chemical reactions in the cells and ultimately to cellular damage. Despite the significant use of radiotherapy, the chemical and physical mechanisms of this damage are not completely understood (Hall, 1988). 

The cellular damage depends primarily upon the dose of radiation. A low radiation dose can cause cancer a high dose can kill cancer. When healthy tissue receives a low to moderate dose, cell genes may undergo mutations leading to cancer. At a higher dose, the cells may die because of irreparable damage. 

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In the first part of this article (Section II), principles of cancer detection and treatment are discussed briefly. Emphasis is placed on methods relying on mass or heat transfer. A quantitative understanding of transport in tissues may be useful in improving these methods. 

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