Absence of thoracic radiation myelitis after hyperfractionated radiation therapy with and without concurrent chemotherapy for Stage III nonsmall-cell lung cancer

Physical models and simpler dosimetric descriptors of radiation late toxicity

Predicting radiation damage to specific organs is becoming ever more challenging with the use of intensity-modulated beams, nonuniform dose distributions, partial organ irradiation, and interpatient and even intraorgan variations in radiation sensitivity. Data-based physical models can be of use in summarizing complicated dose-volume data to help describe clinical outcomes and ultimately aid in the prediction of clinical toxicity. This article attempts to provide a brief overview of the use of normal tissue complication probability (NTCP) models and other simple dose/volume metrics to describe a few clinically significant complications (either frequent or serious) associated with radiation therapy of the head and neck, thorax, and abdominal-pelvic regions. Specifically, it reviews the application of these methods for late toxicities of the parotid, lung, heart, spinal cord, liver, and rectum. It focuses on organ-specific NTCP parameters as well as simple dosimetric descriptors that might be used to help treatment plan evaluation in clinical practice.

Interfraction interval in patients with stage III non-small-cell lung cancer treated with hyperfractionated radiation therapy with or without concurrent chemotherapy: final results in 536 patients

We investigated the influence of interfraction interval (IFI) on treatment outcome in patients with stage III non-small-cell lung cancer (NSCLC) treated with hyperfractionated radiation therapy (Hfx RT) with or without concurrent chemotherapy (CHT). During 3 randomized phase III and 1 phase II study, a total of 536 patients were treated with Hfx RT alone or with concurrent carboplatin/etoposide. Two hundred eighty-five patients were treated with IFI of 4.5-5.0 hours, while 251 patients were treated with IFI of 5.5-6.0 hours. "Shorter" (4.5-5.0 hours) IFI led to better overall survival (OS) (P = 0.0000) and local recurrence-free survival (LRFS) (P = 0.0000). Multivariate analyses showed IFI to be an independent prognosticator of both OS and LRFS. These results were confirmed when we separated all patients (n = 536) into those treated with Hfx RT only (n = 127) and those treated with concurrent RT/CHT (n = 409). Various RT-related high-grade acute toxicity was not different between the 2 IFI, but patients treated with shorter IFI had a significantly higher incidence of hematological toxicity (P = 0.002). None of the late high-grade toxicities were different between the 2 interfraction intervals. Using regression analysis, it was shown that IFI was not a significant predictor of any of acute or late high-grade (> or =3) toxicity. IFI is an important prognosticator of OS and LRFS in patients with stage III NSCLC treated with Hfx RT with or without concurrent carboplatin/etoposide. IFI led to higher incidence only of hematological toxicity, but was not predictive of any acute or late high-grade (> or =3) toxicity. A carefully designed randomized trial seems necessary to give better insight into the issue of optimal IFI in this disease.

Continuously infused carboplatin used as radiosensitizer in locally unresectable non-small-cell lung cancer: a multicenter phase III study

PURPOSE

To determine the radiosensitizing effect of prolonged exposure of carboplatin in patients with locally unresectable non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Patients with histologically proven NSCLC, performance score <2, weight loss <10%, and normal organ functions were randomized between carboplatin 840 mg/m2 administered continuously during 6 weeks of radiotherapy or thoracic radiotherapy alone (both 60 Gy). Toxicity was evaluated with National Cancer Institute Common Toxicity Criteria (NCI CTC) and the Radiation Therapy Oncology Group (RTOG) criteria. Quality of life was measured with European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30/LC13 questionnaires.

RESULTS

One-hundred and sixty patients were included. Pathologically confirmed persistent tumor was present in 53% of patients in the combination arm versus 58% in the radiotherapy alone arm (P=0.5). Median survival in the combination arm was 11.8 [95% confidence interval (CI) 9.3-14.2] months and in the radiotherapy alone arm 11.7 (95% CI 8.1-15.5) months; progression-free survival was not different between arms [6.8 and 7.5 months, respectively (P=0.28)]. Acute toxicity was mild, late toxicity was radiation-induced cardiomyopathy (three patients) and pulmonary fibrosis (five patients). Quality of life was not different between arms, but in all measured patients cough and dyspnea improved, pain became less, and slight paresthesia developed 3 months after treatment.

CONCLUSION

Addition of continuously administered carboplatin as radiosensitizer for locally unresectable NSCLC does not improve local tumor control or overall survival.

No thoracic radiation myelitis after spinal cord dose > or = 50.4 Gy using 1.2. Gy b.i.d. fractionation in patients with Stage III non-small cell lung cancer treated with hyperfractionated radiation therapy with and without concurrent chemotherapy

We investigated a risk of developing radiation myelitis during four prospective studies using hyperfractionated radiation therapy (HFX RT) with and without concurrent chemotherapy (CHT) during which a portion of thoracic spinal cord received a dose > or = 50.4 Gy given via 1.2 Gy b.i.d. fractionation. Of 536 patients with Stage III non-small cell lung cancer (NSCLC) which were treated on three prospective randomised Phase III studies and one Phase II study, 336 patients received irradiation dose > or = 50.4 Gy to a portion of their spinal cord and survived >1 year after the beginning of therapy. None of these 336 patients developed thoracic radiation myelitis. Therefore, the influence of potentially contributing factors on the occurrence of radiation myelitis, such as cord length, interfraction interval, or administration of concurrent CHT was not possible to investigate. These results give new insight about the influence of total dose/dose per fraction/interfraction interval with or without concurrent CHT on the thoracic spinal cord toxicity.

Hyperfractionated radiotherapy for clinical stage II non-small cell lung cancer

BACKGROUND AND PURPOSE

Patients with stage II non-small cell lung cancer who are not suitable for or refuse surgery are treated with radiotherapy, but the results reported so far are not satisfactory. To improve the prognosis of such patients, we have used hyperfractionated radiotherapy. In this paper, we retrospectively analyzed results of the treatment.

MATERIALS AND METHODS

Between 1988 and 1993, 67 patients were treated with hyperfractionated radiotherapy with 1.2 Gy twice daily to a total dose of 69.6 Gy. All patients were technically operable, but 43 had medical problems and 24 refused surgery. The median age and Karnofsky performance status score was 60 and 90 years, respectively. No patient received chemotherapy or immunotherapy. The median follow-up period was 61 months.

RESULTS

The median survival time and the 5-year survival rate were 27 months and 25% (standard error, SE, 6%), respectively. The 5-year local control rate was 44% (SE,7%). Univariate analysis of prognostic factors revealed that a higher Karnofsky performance status score, weight loss of < or =5% before treatment, and T1 stage were associated with better prognosis, and peripheral location was of borderline significance (P = 0.053). There were two bronchopulmonary and two esophageal acute grade 3 toxicities, and one bronchopulmonary and two esophageal late grade 3 toxicities. No grade 4 or 5 toxicity was observed.

CONCLUSION

These results are encouraging and further studies on the use of hyperfractionation seem to be warranted for stage II non-small cell lung cancer.

Radiation myelopathy

Radiation myelitis has long been recognised as a sinister consequence of spinal irradiation and has limited the acceptable dose of therapeutic radiation to the cord. Over the past 10 years, the pathogenesis has been increasingly understood through the use of animal models. The importance of 'dose per fraction' and 'inter-fraction interval' have been incorporated into new mathematical models which suggest that, for small fractions, the cord may tolerate higher doses of radiation than was previously thought. Clinical recognition of the condition has improved through the description of characteristic magnetic resonance imaging changes. However little advance has been made in its treatment.