A phase II trial, feasibility of combination of daily cisplatinum and accelerated radiotherapy via concomitant boost in stage III non-small cell lung cancer

Hypo-fractionated boost in locally advanced non-small cell lung cancer: temporal distribution of boost fractions

To propose new schemas for radiation boosting of primary tumors, in locally advanced non-small cell lung cancers (NSCLC), in conjunction with standard chemoradiotherapy. To investigate the effect of temporal distributions of the boost fractions on tumor control. NSCLC cases, previously treated with 60 Gy in 30 fractions, were retrospectively planned by adding a radiation boost (25 Gy in 5 fractions) to the primary tumor. Several integrated and sequential boosting schedules were considered. Biological doses were calculated for targets and organs at risk (OAR). Tumor control probabilities (TCP) were calculated using an empirical model and a stochastic model that accounts more systematically for tumor growth kinetics and cell kill. For heterogeneous patient populations, the TCPs for different boost schedules ranged from 82% to 84% and from 73% to 74% for integrated and sequential boosting respectively. For individual tumors with specific growth parameters, the TCP varied by up to 19% between the different schedules. The TCP for sequential boosting was expected to be up to 67% lower than front integrated boosting. The gap in TCP between schedules was higher for tumors with higher clonogenic cell numbers, lower radio-sensitivity, shorter doubling times and lower cell loss. The proposed boosting schemas are dosimetrically feasible and biologically effective. We suggest that the boosts are most effective when given during the first week of treatment and least effective when given sequentially after the end of treatment. The effect of boost scheduling and the effectiveness of front boosting are expected to be most significant for tumors with high clonogenic cell numbers, fast growing rates, low cell loss and low radio-sensitivity. Ultimately, animal studies and clinical trials, guided by biology modeling as presented in the present work, will be needed to verify the effectiveness of fine tuning temporal distributions of radiotherapy fractions.

Randomized Phase 2 Study of Radiotherapy Alone versus Radiotherapy with Paclitaxel in Non-Small Cell Lung Cancer

This randomized phase 2 study aimed to assess and compare the toxicity and response rates in patients with unresectable non-small cell lung cancer treated with radiotherapy (1.8-2 Gray [Gy] daily, five fractions a week, total 63 Gy) or radiotherapy + paclitaxel administered weekly (1.8 Gy daily, five fractions a week, total 59.4 Gy). Twelve patients in the latter arm received 30 mg/m2 paclitaxel (median six cycles) over a 3-h infusion once weekly. After assessing toxicity, the remaining nine patients received 60 mg/m2 paclitaxel weekly (median six cycles). Response was evaluated radio-logically 1 month after treatment. Grade 3 toxicity was 20% and 38% in the radiotherapy and chemoradiotherapy groups, respectively. Overall survival rates in complete and objective (complete plus partial) responders and progression-free survival rate of the objective responders were significantly better in the chemoradiotherapy arm. We believe that using paclitaxel in concurrent chemoradiotherapy regimens may be effective in patients with unresectable, locoregionally advanced non-small cell lung cancer.

Radiosensitization with chemotherapeutic agents

The combination of low-dose chemotherapy and thoracic radiotherapy is one of the treatments proposed in an attempt to improve the prognosis of locally advanced non-small cell lung cancer. Chemotherapeutic drugs administered at subtoxic doses act by means of a radiosensitization mechanism. Platinum-derived drugs have been historically used as radiosensitizers, without cumulative unacceptable toxicity. Many new chemotherapeutic agents, which have shown promising results in terms of disease control in advanced non-small cell lung cancer, show also a radiosensitizing activity. However, the optimal dose and timing of such drugs when used concurrently to radiotherapy are unknown. This paper will review the results obtained using new chemotherapeutic drugs as radiosensitizers.