Combination of paclitaxel and radiation: genotoxicity in vitro in four mammalian cell lines.

Paclitaxel is an antimicrotubular agent that blocks the cells in the G2/M phase of the cell cycle. Due to this action, it is presumed that this drug could function as a radiation sensitizer. We studied the genotoxic effects of a combination of paclitaxel and radiation in four mammalian cell lines in the micronucleus assay. The results do not show a clear radiation-sensitizing effect. In the three cell lines, L5178Y, V79 and HeLa, the micronucleus frequencies varied around a theoretical additive effect of the single treatments (paclitaxel or radiation alone). Only the human breast cancer cell line MCF-7 showed consistently lower than additive micronucleus frequencies, although the deviation was not significant. Overall, it remains inconclusive whether paclitaxel exerts a radiosensitizing effect and, if so, whether this effect depends on the cell type or other characteristics of tumor biology.

Cytotoxic and genotoxic effects of paclitaxel (Taxol) and radiation in a squamous cell carcinoma cell line of the larynx.

Paclitaxel (Taxol) is an antimicrotubular agent which blocks the cells in the G2/M phase of the cell cycle. Because of this mechanism it is presumed that this drug could function as a radiation sensitizer. The cytotoxic and genotoxic effects of paclitaxel and a combination of paclitaxel and radiation were studied in the human laryngeal carcinoma cell line HLac 79. The growth of the cells was significantly reduced at concentrations of paclitaxel as low as 10 nM. Flow cytometry data showed a G2/M block after exposure to paclitaxel. Radiation at 12 and 24 h after drug treatment exerted an additive but no radiation sensitizing effect. As genotoxic effect paclitaxel induced multinucleated cells, possibly in a synergistic manner, at low concentrations (10 nM) and radiation doses up to 3 Gy.

[Indications and risks of manual lymph drainage in head-neck tumors]. / Nutzen und Risiken der manuellen Lymphdrainage bei Kopf-Hals-Tumoren.

BACKGROUND: Secondary lymphedema of the head and neck can develop as a result of obstruction of lymphatic channels following the surgical removal of lymph nodes and fibrosis due to irradiation. This can be treated with manual lymphatic drainage. An increase of tumor recurrence due to this therapy is at controversial discussion. PATIENTS: In a retrospective study 191 patients treated for head and neck cancer were questioned on occurrence of lymphedema and therapy with manual lymphatic drainage. RESULTS: 100 patients had received lymphatic drainage, whereas 91 patients belonged to the group without lymphatic drainage therapy. In 37 cases a tumor recurrence or local metastases were reported, 18 of whom had received lymphatic drainage and 19 belonged to the control group. Among these 37 patients neither the group with lymphatic drainage nor the control group differed significantly concerning stage of cancer, histopathological grading, the in sano/non in sano resection of the primary tumor and a lymphangiosis carcinomatosa. An increased recurrence rate among patients who underwent a lymphatic drainage therapy could not be found. CONCLUSION: A lymphatic drainage therapy for patients presenting with lymphedema after the oncological therapy does not increase the rate of local recurrencies. Moreover it improves the quality of life after the cancer therapy. As only few data are available for cases with non in sano surgery and tumors with lymphangiosis carcinomatosa these cases should be excluded from a lymphatic drainage therapy. A spreading of occult tumor cells in these patients might be possible.