Medicine of the Future in America

Category Archives: Radiation Therapy

Primary, Adjuvant, and Palliative Radiation Therapy (7)

Primary, Adjuvant, and Palliative Radiation Therapy (7)Five-year survivals in these groups were 16% and 26%, respectively. These studies suggest that there clearly is a subset of patients with lung cancer who can be cured with radiation therapy alone; thus, a watchful waiting policy is not the appropriate approach. Two recent reports of similar series of patients substantiated these findings.
Unresectable Lung Cancer
Similar to the group of patients with resectable but inoperable lung cancer, there is a subset of patients with unresectable nonmetastatic lung cancer who are cured by radiation therapy (60 Gy in 6 weeks). Published series of patients consistently report around a 6% 5-year survival rate. Higher doses (to 74 Gy) of conventionally fractionated radiation therapy may improve on these results. A recendy reported cooperative group study of hyperfractionated radiation therapy in patients with N2 lung cancer suggests that this technique with doses of 69.6 Gy in 6 weeks produces superior early (up to 3 years) results compared to conventional radiation therapy. This is now being tested in a phase III trial.
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Primary, Adjuvant, and Palliative Radiation Therapy (5)

Primary, Adjuvant, and Palliative Radiation Therapy (5)While clinical trials continue to search for the best chemotherapy regimen, the most standard therapy today is combined systemic chemotherapy and chest radiation therapy with prophylactic cranial irradiation given to complete responders. The added benefits of the chest radiation therapy appear greatest if it is given concurrent with chemotherapy early in the patients treatment course. The morbidity of the concurrent approach should decrease as newer chemotherapy regimens not containing Adriamycin replace the older regimens.

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Primary, Adjuvant, and Palliative Radiation Therapy (4)

However, there was a suggestion of improved disease-free survival in the N2 subgroup. This study has been criticized for including only patients with squamous cancer (adenocarcinoma and large cell carcinomas may be more radiocurable) and for a high rate (25%) of noncompliance with the radiation therapy dose protocol. In any case, regardless of the controversy over the overall survival data, postoperative radiation therapy does decrease the frequency of local regional recurrences and may prolong disease-free survival. This is a service to the patients as long as complications from radiation therapy can be minimized by careful selection of the patients and the radiotherapeutic techniques.

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Primary, Adjuvant, and Palliative Radiation Therapy (3)

Primary, Adjuvant, and Palliative Radiation Therapy (3)The intraoperative radiation therapy given in those studies was by either temporary or permanent radioactive implants (Table 4). The majority of the patients also received postoperative external-beam radiation therapy. The results (Table 5) are superior to those reported for high-dose external-beam radiation therapy alone, but these are selected uncontrolled series. A small study utilizing electron-beam intraoperative radiation therapy demonstrated high toxicity; this approach needs further refinement.
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Primary, Adjuvant, and Palliative Radiation Therapy (2)

For superior sulcus tumors, combined modest-dose preoperative radiation therapy (30 to 45 Gy) followed by radical surgical resection yields a 5-year survival of >30%* (Table 2). This survival may be improved by supplemental postoperative radiation therapy in selected patients at high risk for recurrence, namely, those with positive nodes or close or involved resection margins. The results of these combined-approach series for superior sulcus tumors are more favorable than those of radiation-only series (5-year survival, 22% to 23%), although the complication rate may be lower with the latter approach. For patients with marginally resectable disease (Table 3), modest doses of preoperative radiation therapy (30 to 40 Gy) convert a large proportion of patients to resectability and may improve the survival rate over that for radiation therapy alone (27% vs 8%). For patients with unresectable disease, 40 Gy of preoperative radiation therapy converts about one third to resectability, but the 5-year survival (6% to 8%) is not superior to that with radiation therapy alone. Preoperative radiation does not appear to offer any benefit to patients whose tumor is resectable at diagnosis.
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Primary, Adjuvant, and Palliative Radiation Therapy (1)

Primary, Adjuvant, and Palliative Radiation Therapy (1)The role of radiotherapy in the management of lung cancer is growing in magnitude and significance. Modem radiotherapy planning and delivery systems allow more precise delivery of higher doses of ionizing radiation to desired tumor volumes with preferential sparing of sensitive uninvolved tissues. This provides a hope of cure for the patient with non-resectable or inoperable nonmetastatic lung cancer, improves the thoracic control rate in nodepositive resected patients, and provides ever elongating high-quality palliation for the patient with a metastatic disease.
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