Effect of reoxygenation on the hypoxia-induced up-regulation of serine protease inhibitor PAI-1 in head and neck cancer cells

In squamous cell carcinoma of the head and neck (SCCHN), hypoxia is considered a crucial physiological modulator for malignant progression, wherebythe plasminogen activation system is involved in overlapping functions such as moulding of the extracellular matrix, cell proliferation and signal transduction. Little is known about the effects of reoxygenation on the plasminogen activation system in SCCHN cells. Three human SCCHN cell lines (BHY, CAL27, FaDu) and a non-transformed human fibroblast cell line (VH7) were exposed to hypoxic (<0.5% O(2)) conditions for up to 72 h and subsequently reoxygenated at normoxic conditions for 24 h. Urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) protein concentration and former protein activity were determined by ELISA and complex ELISA, respectively. Reoxygenation induced significant changes in cell-associated and secreted PAI-1 protein compared to the normoxic control. Significant increase in cell-associated and secreted uPA protein after reoxygenation was only observed for some of the cell lines. Determination of uPA-PAI-1 complex formation revealed the release of active protein into the cell supernatant. The beneficial role of reoxygenation during radiation therapy is widely accepted. However, reoxygenation does not seem to counteract the effects induced by hypoxia on the plasminogen activation system. Fatally irradiated reoxygenat- ed tumour cells might still produce sufficient amounts of 'harmful' protein and thus initiate a path for invasion and metastasis for surviving tumour cells.

Split course hyperfractionated accelerated radio-chemotherapy (SCHARC) for patients with advanced head and neck cancer: influence of protocol deviations and hemoglobin on overall survival, a retrospective analysis

Background

The advantage of hyperfractionated accelerated radiation therapy for advanced head and neck cancer has been reported. Furthermore, randomized trials and meta-analyses have confirmed the survival benefit of additional chemotherapy to radiotherapy. We retrospectively analyzed the efficiency and toxicity of the Regensburg standard therapy protocol "SCHARC" and the overall survival of our patients.

Methods

From 1997 to 2004, 64 patients suffering from advanced head and neck cancer (88 % stage IV, 12 % stage III) were assigned to receive the SCHARC protocol. Around half of the patients were diagnosed with oro-hypopharynx carcinoma (52 %), one third with tongue and floor of mouth tumors (29 %) and one fifth (19 %) suffered from H & N cancer at other sites. The schedule consisted of one therapy block with 30 Gy in 20 fractions over a two week period with concomitant chemotherapy (d 1–5: 20 mg/m²/d DDP + 750–1000 mg/m²/d 5FU (cont. infusion). This therapy block was repeated after a fortnight break up to a cumulative dose of 60 Gy and followed by a boost up to 70 Gy (69–70.5 Gy). All patients assigned to this scheme were included in the survival evaluation.

Results

Forty patients (63 %) received both radiation and chemotherapy according to the protocol. The mean follow up was 2.3 years (829 d) and the median follow up was 1.9 years (678 d), respectively. The analysis of survival revealed an estimated 3 year overall survival rate of 57 %. No patient died of complications, 52 patients (80 %) had acute grade 2–3 mucositis, and 33 patients (58 %) suffered from acute grade 3 skin toxicity. Leucopenia was no major problem (mean nadir 3.4 g/nl, no patient < 1.0 g/nl) and the mean hemoglobin value decreased from 13.2 to 10.5 g/dl. Univariate analysis of survival showed a better outcome for patients with a hemoglobin nadir >10.5 g/dl and for patients who completed the protocol.

Conclusion

The SCHARC protocol was effective in patients diagnosed with advanced head and neck cancer. It led to long-term disease control and survival in about 50 % of the patients with significant but acceptable toxicity. Most patients were not anemic at beginning of therapy. Therefore, we could assess the influence of pre-treatment hemoglobin on survival. However, a low hemoglobin nadir was associated with poor outcome. This result suggests an influence of anemia during therapy on prognosis.

Current and future use of hematopoietic growth factors in cancer medicine

Myelosuppression, in particular neutropenia and anemia are serious complications of malignancy and its treatment. Neutropenia can make patients vulnerable to potentially life-threatening infection. It often results in dose reductions and delay of planned chemotherapy, which can have a significant detrimental effect on tumour response and survival. Anemia can be associated with a range of debilitating effects, which can severely impair patients' QOL. In addition, there is some evidence recognizing anemia as a poor prognostic indicator, associated with reduced treatment efficacy. Reduction in the duration and severity of neutropenia and anemia is possible by initiation of appropriate growth factors during the first and subsequent cycles of chemotherapy. New and improved growth factor support with agents such as pegfilgrastim and darbepoetin alfa has the potential to improve the management of chemotherapy-induced neutropenia and anemia further. Thrombopoietin is currently in clinical trials to assess its potential role in the treatment of thrombocytopenia in patients with cancer.