Chrono-oncology

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The chrono Oncology ( gr. Χρόνος chronOS " Time "; Oncology . AltGr ὄγκος ONKOS "swelling" and -logie "science of the formation, development and treatment of tumor diseases") is the branch of Chronobiologie that the temporal dispositions and cyclic patterns of emergence , Development and treatment of tumor diseases .

Almost all living beings have endogenous cyclical processes that, often synchronized with exogenous cycles (e.g. day-night cycle), enable optimal vitality of the respective living being. Tumor cells , too , have clocks of this type, which as a result of evolutionary development are optimally matched to the survival success of the respective tumor. Chrono-oncology examines these processes and the resulting behavioral patterns and tries to improve the efficiency of tumor treatment while reducing undesirable side effects by means of therapeutic methods and active ingredients tailored to them.

history

Biological cycles have been observed since ancient times. Hippocrates and Galenus already described rhythms in the course of illnesses in which the number seven was assigned special importance.

A systematic study of chronocyclic phenomena began in the 20th century. Fundamental temporal behavior patterns and their causes are now known. As early as the late 19th century it was discovered that biological cycles existed, which in most cases are synchronized with exogenous cycles. In the middle of the 20th century, the gene expression of biological rhythms in plants was recognized and it was found that the endogenous cycles persist almost unchanged even in the absence of exogenous timers. However, after longer periods of time without synchronization, both the period duration and the phase position change in relation to the time of day. There is currently a consensus that endogenous oscillators are the cause of biological rhythms. In recent years, the chronocyclic behavior has been demonstrated down to the cell level.

Chrono-oncological diagnostics

The chrono oncological diagnostics includes in addition to the general methods of diagnosis, the determination of tumor activity phases. Here, the knowledge is used that the cells of a tumor have endogenous oscillators and show cyclical behavior patterns like any other living being. As a result, the pharmacological susceptibility of tumors is subject to obvious fluctuations with the time of day. Both the period duration and the phase position in relation to the time of day can deviate significantly from the values ​​of the host organism's cycles (e.g. the circadian sleep-wake cycle or the ultradian 90-minute sleep cycle in adults). To determine the tumor susceptibility cycle, both the period duration and the phase position in relation to the time of day must be determined. This requires data acquisition and evaluation of the measured values ​​obtained. While for circadian cycle periods at least four measured values ​​z. If, for example, the tumor activity distribution is sufficient in one day, infra- or ultradian cycle periods require a correspondingly higher number of measurements, possibly over several days ( Nyquist-Shannon sampling theorem ).

Chronomodulated Therapy

If, instead of permanent medication, the active ingredient is only administered in phases of high drug susceptibility ( chronopharmacology ), lower doses can achieve a comparable effect while at the same time reducing the risk of harmful side effects. Because the organism is only temporarily exposed to the active ingredients, it is also possible to use higher doses than with permanent drug administration without increasing side effects, but the probability of survival is significantly increased or success occurs after a shorter treatment time. If the period of the vital cycles of the host organism deviates appreciably from the corresponding values ​​for the cell growth cycle of the tumor, then tumor cell growth cycles and the cycles of the host organism are temporally decoupled (desynchronized). A time-controlled therapy can then be applied effectively with possibly only marginal influences on the life-sustaining processes of the host organism.

further reading

  • R. Kluge, H.-J. Forthund, W. Hofmann: Chronobiological aspects in the diagnosis of prostate diseases. In: J. Schuh (Hrsg.): Lectures of the German-Soviet Symposium Chronobiologie-Chronomedizin, Halle / Saale. 1st to 6th July 1986 ( beginning of article freely available)
  • M. Hallek, F. Levi, E. Haenc, B. Emmerich: Importance of chronopharmacology for oncology. In: Oncology. 12, 5, 1989, pp. 230-238.
  • B. Lemmer : Chronopharmacology. Daily rhythms and drug effects . Stuttgart 2004, ISBN 3-8047-1304-1 .

Individual evidence

  1. ↑ E. Bünning: On the knowledge of the hereditary daily periodicity in the primary leaves of Phaseolus multiflorus. In: Yearbook for Scientific Botany. Volume 81, 1935, pp. 411ff.
  2. ^ J. Aschoff , R. Wever: Spontanperiodik des Menschen with the exclusion of all timers. In: The natural sciences. Volume 49, 1962, p. 337f.
  3. ^ J. Aschoff: Zeitgeber der Tierischen Tagesperiodik. In: The natural sciences. Volume 41, 1954, p. 49f.
  4. ↑ SCN synchronization . Website of the University of Lübeck - AG Chronophysiology. Retrieved February 8, 2014.
  5. ↑ C. Borchard-Tuch: Therapy in the rhythm of the internal clock . In: Pharmaceutical newspaper. - online. Retrieved February 8, 2014.
  6. ↑ Precisely dose medication . Focus-Online. Retrieved February 8, 2014.