Lasers In The Treatment Of Cancer

ABSTRACT The advent of the C02 laser in 1964 aroused hope that the "silver bullet" in cancer therapy had arrived. Experiments were designed on laboratory animals and patients with varying results. Certainly, many of the requirements of adequate excisional surgery for cancer are obtained with the laser. The treatment of recurrent and particularly, metastatic cancer, seems to be possible. Palliation of cancer is possible in many cases. Relief of pain seems enhanced by the soft laser. All of these, with our aspirations for the near future will be discussed.Lasers are rapidly taking their position in the treatment of tumors. From the inception of the Carbon Dioxide laser, it was felt that it might be the final modality to accomplish tumor destruction. Certainly, many tumors can be treated for cure and many others for palliation and a better quality of life for the patient. New lasers and delivery systems are being tested and show great promise.Laser is an achronym for Light Amplification of Stimulated Emissions of Radiation. We find that there are three groups of lasers if one considers wavelenghts: Infra-red exem­ plified by Carbon Dioxide laser, the Nd:YAG and new Fluoride laser (experimental). Visible light includes the Argon, Ruby, and Helium Neon lasers. Ultraviolet is exemplified by the Nitrogen laser. The modes include CW or continuous beams, pulsed, which would include a stream of impulses separated by intervals of time, and super pulsed lasers which have short impulses with high peak powers of energy.Laser power varies with the type of treatment to be given. In some cases, we use the heat from the laser to accomplish the goal, others want a rapid high amount of energy rapidly dissipated. There is a lot of new material on soft (lower powered) lasers in the treatment of a large variety of diseases.There is a necessity that before you use the laser, you should have instruction on the basic physics, tissue interaction, safety, clinical indications and hands on experience. One should have a period of preceptorship until he feels adequate in the handling of the machine and the instructor or preceptor agrees. He should still be observed for several cases to be sure that the instrument is being used correctly.Continuing education is mandatory in laser surgery and medicine. The journal, "Lasers in Surgery and Medicine" prints articles on application and research. It will help each individual to keep up on the rapidly changing science of laser therapy. Attendance at the meeting of the "American Society of Laser Medicine and Surgery" and the "International Society of Laser Surgery and Medicine" will certainly help an individual to keep up. The many opportunities for new applications of these instruments should push interested indivi­ duals into the laboratory. They might be able to make good contributions and to check the new ideas of others.The Carbon Dioxide laser is the work horse of general surgery and surgical oncology. It may be used to make incisions into skin and for the dissection of various organs or^tissues. The laser cuts with an average width of 0.3 mm. but other models are available with beam width of 0.01 mm. The amount of tissue injury on either side of the incision is minimal and healing is adequate, but probably delayed. In the defocused mode, the laser will vaporize tissue but only to a very superficial degree. This beam is delivered through a series of mirrors. It also can be delivered through hollow wave guides with a minimal amount of flexibility. It may also be delivered through the microscope. The next commonly used laser is the NdiYAG. It's wavelength is in the near infra-red. It is primarily used for coagulation of tissue. The Nd:YAG and Argon lasers are delivered through a fiber optic. This makes it possible to deliver laser power through various endoscopes and cystoscopes. The loss of power passing fairly long distances is minimal. The Nd:YAG will coagulate an area approximately 5 mm. in diameter and will coagulate blood vessels to approximately the same size. It's various applications will be discussed. A sapphire tip has been developed which makes fine cutting and precise dissection possible. It eliminates the problem of coagulation necrosis and allows liver resection and precision surgery of other intraperito-