The state of affairs in the development of chemo-radiotherapy is summarized at the end of 2007 by Professors Marcel Verheij and Harry Bartelink  in a contribution to a compendium to be published.
Since the early eighties, when Harry Bartelink was experimenting with cisplatinum at Stanford University, the use of chemotherapeutics combined with radiotherapy has undergone great development. In particular in an extensive European study in 1992, led by Dr Caro Koning and Dr Harry Bartelink, it was demonstrated that the combination of irradiation and a Cisplatinum treatment increases the chance of cure for non-small cell lung tumours. Patients live longer and less metastases occur than after radiotherapy only.
There are several reasons to expect an advantage from the combination of radiotherapy and chemotherapy. Radiotherapy is applied to eradicate larger, often primary tumours, while chemotherapy is aimed at microscopic small metastases which cannot be irradiated. In this way these therapies supplement each other in spatial coverage. Besides this, some tumour cell populations are more sensitive to chemotherapy and others more sensitive to radiotherapy. Furthermore, tumour cells can be weakened by chemotherapy, which enhances the effect of radiotherapy.
Concurrent chemo-radiation is more effective. Research shows that the combination therapy is most effective when chemotherapy and irradiation are administered over the same period. The effect of irradiation is then maximally enhanced and repair of the tumour is prevented. This is demonstrated for example in a trial in 1997, in which anal carcinoma is irradiated and simultaneously treated with the agents MMC (Mitomycine C) and 5FU (Fluorouracil): Bartelink et al. JCO 1997. A description of these cytostatic agents can be found in Wikipedia by clicking on: http://en.wikipedia.org/wiki/Mitomycin_C and http://en.wikipedia.org/wiki/Fluorouracil
In the trial, 52 patients have only had irradiation and 51 patients received concurrent chemo-radiation. Five years after treatment it is established that 70% of the patients that received chemo-radiation did not develop metastases, compared to 50% of the patients that were treated with only radiation. For the quality of life it is important that 80% of the "chemorad" patients do not require colostomy, while this is 40% for the patients who only had irradiation.
Verheij and Bartelink describe the situation in chemo-radiotherapy for a number of types of compact tumours. From various clinical research they conclude that concurrent chemo-radiotherapy results in an important improvement in the combat of large tumours. In most cases cisplatin is given, sometimes combined with another agent. The result is an improvement in the survival of cancer of head and neck, lungs and the uterine cervix. The concurrent chemo-radiotherapy is also given to make tumours shrink as a preparatory treatment for surgery.
It is expected that new biologically active agents will become available that could make chemo-radiotherapy even more effective. The new agents are targeted at the mechanism of uncontrolled growth of tumour cells.