Steriotactic Hypofractionated Radiotherapy Promising for

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Lung Cancer

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Researchers from Sweden have reported promising results of treating stage I non-small cell lung cancer (NSCLC) with three fractions of 15 Gy given over one week rather than smaller daily doses spread over a longer period of time. The details of this study appeared in the January 2006 issue of Lung Cancer .

Patients with early-stage I-II NSCLC are preferentially treated with surgery, and the value of adjuvant and neoadjuvant radiation and/ or chemotherapy is controversial. However, more recent trials suggest that adjuvant chemotherapy is effective in preventing recurrences. For clinically staged patients, the 5-year survival rates following surgery for stage I-II NSCLC range from 20% to 60% depending on size of the primary and nodal involvement. However, many patients with NSCLC are elderly or too debilitated, usually from cardiopulmonary disease, to undergo surgery. There is also a group of patients who refuse surgery due to the anticipated high risks of morbidity and mortality, especially form pneumonectomy. Such patients are offered definitive radiation therapy for treatment. Previous studies have suggested that survival rates approaching those achieved by surgery can be achieved with radiation therapy alone. Radiation therapy is usually administered in relatively small fractions over several weeks.

Researchers involved in the current study performed a phase II trial involving three 15 Gy fractions given over 1 week. The rationale for this approach is that larger doses of radiation given at shorter intervals may be more effective than smaller fractions given over a longer period of time. These authors suggest that 45 Gy of radiation given in this hypofractionated manner is biologically equivalent to over 100 Gy administered by conventional schedules. They treated 45 patients with an average age of 74 years with stage I NSCLC who were deemed medically inoperable. Toxicity was absent in half the patients with the remainder having tolerable toxicities. The median follow-up was 43 months. Nine of the 45 patients developed local recurrence, two had regional recurrence and 9 had distant metastases. The median survival was 39 months, the one year survival was 80% and the 5 year survival was 30%. These researchers are carrying out a randomized trial to determine if this radiation regimen is superior to conventional fractionated radiotherapy.

Comments: The ability to deliver precise radiation with stereotactic techniques appears to allow larger doses of radiation to be administered without prohibitive toxicity. It remains to be seen whether or not these results are superior to conventional scheduling of radiotherapy. Since adjuvant chemotherapy is effective for patients receiving surgery alone these results might be improved by adding chemotherapy after radiation therapy.

Reference: Nyman J, Johansson K-A. Hulten U. Stereotactic hypofractionated radiotherapy for stage I non-small cell lung cancer- mature results for medically inoperable patients. Lung Cancer . 2006;51:97-103.