Three-dimensional conformal radiotherapy. Precision treatment of lung cancer

Three-dimensional conformal radiotherapy is a mode of precision radiation treatment that currently is being integrated into the multidisciplinary management of lung cancer. 3-DCRT represents a technical improvement in comparison with conventional treatment. This has been achieved without the use of innovations in accelerator hardware that are currently being developed and tested. When these technical advances are widely available for clinical use, they will be integrated with the current 3-DCRT systems, which are for the most part composed of improvements in software. Thus, 3-DCRT is a modality in a state of flux that should have great clinical potential in the future. The accurate dose volume histogram data available with current 3-DCRT systems will facilitate strategies to predict and prevent radiation pneumonitis.

Quantitative effect of combined chemotherapy and fractionated radiotherapy on the incidence of radiation-induced lung damage: a prospective clinical study

PURPOSE

The objective of this work was to assess the incidence of radiological changes compatible with radiation-induced lung damage as determined by computed tomography (CT), and subsequently calculate the dose effect factors (DEF) for specified chemotherapeutic regimens.

METHODS AND MATERIALS

A prospective, clinical study was conducted to determine the response of normal lung tissue to combined chemotherapy and radiotherapy. Radiation treatments were administered once daily, 5 days-per-week. Six clinical protocols were evaluated: ABVD (adriamycin, bleomycin, vincristine, and DTIC) followed by 35 Gy in 20 fractions; MOPP (nitrogen mustard, vincristine, procarbazine, and prednisone) followed by 35 Gy in 20; MOPP/ABVD followed by 35 Gy in 20; CAV (cyclophosphamide, adriamycin, and vincristine) followed by 25 Gy in 10; and 5-FU (5-fluorouracil) concurrent with either 50-52 Gy in 20-21 or 30-36 Gy in 10-15 fractions. CT examinations were taken before and at predetermined intervals following radiotherapy. CT evidence for the development of radiation-induced damage was defined as an increase in lung density within the irradiated volume. The radiation dose to lung was calculated using a CT-based algorithm to account for tissue inhomogeneities. Different fractionation schedules were converted using two isoeffect models, the estimated single dose (ED) and the normalized total dose (NTD).

RESULTS

A total of 102 patients were entered and 70 completed the study. Forty-two patients developed CT changes compatible with lung damage. The actuarial incidence of radiological pneumonitis was 71% for the ABVD, 49% for MOPP, 52% for MOPP/ABVD, 67% for CAV, 73% for 5-FU radical, and 58% for 5-FU palliative protocols. Depending on the isoeffect model selected and the method of analysis, the DEF was 1.11-1.14 for the ABVD, 0.96-0.97 for the MOPP, 0.96-1.02 for the MOPP/ABVD, 1.03-1.10 for the CAV, 0.74-0.79 for the 5-FU radical, and 0.94 for the 5-FU palliative protocols.

CONCLUSION

Quantitative dose effect factors (DEF) were measured by comparing the incidences of CT-observed lung damage in patients receiving chemotherapy and radiotherapy to those receiving radiotherapy alone. The addition of ABVD or CAV appeared to reduce the tolerance of lung to radiation.

Acute and delayed effects of radiotherapy in patients with oesophageal squamous cell carcinoma treated with chemotherapy, surgery and pre- and postoperative radiotherapy

Among 73 patients with oesophageal squamous cell carcinoma treated with chemotherapy (cisplatin + 5-fluorouracil), surgery and pre- and postoperative radiotherapy, the 1-year survival rate was 68% and the 5-year rate 26%. The treatment was well tolerated, though there were 11 cases of pericardial or pleural effusion, in all of which the effusion was benign and could be successfully treated with pleural aspiration and/or pleurodesis, pericardiocentesis, or in one case pericardectomy.

Intraoperative radiotherapy for esophageal carcinoma--significance of IORT dose for the incidence of fatal tracheal complication

PURPOSE

The feasibility of intraoperative radiotherapy (IORT) combined with modified regional lymphatic dissection (plus esophagectomy) for advanced esophageal carcinoma was tested. The quality of life in the patients was expected to improve by modified surgery, securing a good local control by additional IORT.

METHODS AND MATERIALS

Total esophagectomy plus modified three-regional lymphatic dissection with upper mediastinal IORT followed by postoperative external beam irradiation was systematically given to 62 patients between August 1989 and June 1992. Sixty-five percent of the patients were age over 60, and 76% (47/62) of the patients were Stage III or IV by pTNM. Several techniques for the IORT were developed and used throughout this period, including a temporary collapse of the right lung by unilateral tracheal incubation (for the insertion of IORT applicator) and an in vivo dosimetry to know the appropriate range (energy) of electron beam. The method of surgical treatment, the dose of external beam irradiation were kept standardized, and only the dose of IORT was randomized either to 20 or 25 Gy. IORT-related complications and the pattern of failures were carefully monitored.

RESULTS

(a) Most prominent IORT-related complication was the late tracheal damage, which occurred 6 of 44 patients who were at risk for more than a year. (b) The incidence of IORT-induced tracheal damage was sharply dependent on the dose of IORT; 6 out of 21 patients who received single dose of 25 Gy, and none out of 33 who were given 20 Gy or less. (c) 2-year cause-specific survival and actuarial 2-year survival were 75.0 +/- 14.5% and 62.5 +/- 13.2%, respectively. No loco-regional recurrence has been detected at the time of analysis.

CONCLUSION

IORT in combination with modified total esophagectomy is an effective and safe method to obtain a local control in advanced esophageal carcinomas, if the dose of IORT does not exceed 20 Gy.

[A case of radiation pneumonitis caused by treatment of lung cancer which revealed marked hypervasculality on bronchial arteriography]

A 44-year-old man was admitted to our hospital because of hemoptysis. He had been admitted to our ward in June 1991, after resection of a brain tumor at another hospital due to cerebral metastasis of lung cancer (adenocarcinoma). Systemic chemotherapy and pulmonary irradiation therapy were performed during the first hospitalization. Radiation pneumonitis occurred 1 month after the completion of radiotherapy, which responded to administration of corticosteroids. One year and 4 months later after the completion of radiotherapy, he was readmitted to our hospital because of hemoptysis. Chest computed tomogram and bronchoscopy showed no recurrence of lung cancer, so pulmonary arteriography and bronchial arteriography were performed to investigate the cause of hemoptysis. Pulmonary arteriograms showed diminished vascularity in the area of radiation fibrosis, but a bronchial arteriogram showed inflammatory hypervascularization in the same field. We considered that the bronchial arterial angiogenesis induced by radiation pneumonitis was the cause of hemoptysis. Bronchial arteriography is necessary in cases of radiation pulmonary fibrosis with hemoptysis without obvious recurrence of tumor. If the growth of new blood vessels in the bronchial artery can be induced by radiation therapy, the administration of anti-cancer agents to the bronchial artery should be considered in the treatment of recurrent lung cancer after radiation therapy.

The role of free radicals in the development of radiation interstitial pneumonitis

We examined the morphologic changes in the lung tissue of Wistar rats after chest irradiation and determined sequentially the content of free radicals (FR) using electron spin resonance. The activity of superoxide dismutase (SOD) was also assessed using the chemical glow method of xanthine oxidase. After chest irradiation, the content of FR in the lung progressively increased and the activity of SOD progressively decreased. We discuss here the role of the FR in the developing process of radiation interstitial pneumonitis.

Double hemibody irradiation (DHBI) in the management of relapsed and primary chemoresistant multiple myeloma

In view of increasing controversy regarding the role of double hemibody irradiation (DHBI) in the treatment of multiple myeloma, we have analysed the use of this technique at our institution over a 6-year period. Fifty-five patients with multiple myeloma were treated with both upper and lower hemibody irradiation between January 1985 and January 1991; 42 had relapsed post-plateau and 13 were chemoresistant to initial therapy. Fifteen patients received alpha IFN-2b maintenance therapy post-DHBI, at a dose of 3 Mu three times per week, as part of a randomized trial. Ninety-five per cent of patients experienced symptomatic improvement in bone pain post-DHBI, 21% of whom discontinued opiate analgesics altogether; 63% had a minor biochemical response and 38% had a partial biochemical response. The overall survival (OS) and progression free survivals (PFS) in all patients were 11 months and 8 months respectively. No significant difference was noted in either OS or PFS, according to whether patients were chemoresistant or had relapsed post-plateau. alpha IFN did not appear to prolong survival (OS or PFS) post-DHBI. Cytopenia was a significant problem, such that only 60% of patients had counts adequate enough to be eligible for alpha IFN. We conclude that DHBI is an effective treatment in patients with relapsed multiple myeloma and in those who are chemoresistant to initial therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Total body irradiation as preparation for bone marrow transplantation in treatment of acute leukemia and aplastic anemia

In an attempt to improve survival while minimizing toxicity, many bone marrow transplant centers are now studying the use of cytoreduction regimens with an increased amount of radiation in single-dose or fractionated-exposure schedules for patients with leukemia and aplastic anemia. In order to review the current results, the literature prior to September, 1982 was surveyed and data were tabulated for each transplant center regarding the number of patients receiving transplants, diagnoses, cytoreducation regimen, clinical status, revission duration, relapse rate, causes of death and incidence of interstitial pneumonia. The incidence and severity of cataracts, growth failure, hypothyroidism and second malignant neoplasms were noted, and the data obtained from the literature search were updated and expanded by telephone questionnaire when possible. Marked variation in the technique of transplantation was found among the participating institutions, making it difficult to determine the contribution of the various TBI doses, dose rates and fractionation schedules to the efficacy and toxicity of the combined regimen. In order to define the risk-benefit ratio of the various TBI regimens more clearly, prospective controlled, randomized studies will be required.

Acute and delayed toxicities of total body irradiation. Seattle Marrow Transplant Team

Total body irradiation is being used with increasing frequency for the treatment of lymphopoietic malignancies and in preparation for marrow transplantation. Acute toxicities include reversible gastroenteritis, mucositis, myelosuppression and alopecia. As the success of treatment improves and more patients become long-term survivors, manifestations of delayed and chronic toxicity become evident. These include impairment of growth and development, gonadal failure and sterility, cataract formation and possibly secondary malignancies. The contribution of total body irradition to the development of pneumonitis and pulmonary fibrosis is still poorly understood. Some of these changes are reversible or correctable, whereas others are permanent. Nevertheless, until equally effective but less toxic regimens become available, total body irradiation appears to be the treatment of choice to prepare patients with leukemia for marrow transplantation.

Magna-field irradiation: work in progress in bone marrow transplantation at The Princess Margaret Hospital, Toronto

Our work with total body irradiation (TBI) for acute leukemia in relapse dates from 1959. Following reports of the Seattle experience, we treated a small number of patients in remission--lowering the dose to 500 rad given at 50 rad/min, based in part on our experience with radiation pneumonitis complicating upper HBI. We have treated 51 patients since July 1979, with an actuarial survival of 65% overall, and 85% for patients 35 years-old or less. A specially designed cobalt-60 unit is used, which allows very large fields and high exposure rates. Dose is calculated at midplane and a homogeneity of +/- 5% obtained.

Radiobiological considerations in magna-field irradiation

Radiobiological considerations are described for total body irradiation (TBI) as given to patients undergoing bone marrow transplantation (BMT). Although much progress has been made in the use of BMT for refractory leukemias, many patients still die from interstitial pneumonia and relapse. Fractionated TBI has been introduced in order to improve leukemic cell kill, while increasing the degree of normal tissue tolerance. Traditionally, bone marrow stem cells, leukemic cells and immunocytes have been considered as having a limited ability to repair radiation damage while cells of lung tissue and intestinal epithelial cells have a greater capacity. During fractionated radiation therapy or continuous low-dose rate exposure, repair of sublethal damage between fractions allows greater recovery in the cell of lung tissue compared to those in the bone marrow. Clinically, the potential benefit of six fractions over one fraction or low dose-rate TBI has yet to be proved, although there is suggestive evidence for a reduced incidence of interstitial pneumonitis. However, other extraneous factors such as doses to the lung, differences in conditioning regimens, effect of increased delay in BMT for patients receiving fractionated TBI, and the unmeasurable differences between insitutions make definite conclusions impossible. Despite this, a consenus for dose fractionation has developed and most centers are moving away from the use of large single dose TBI.