Role of radiotherapy in the treatment of small cell lung carcinoma

Radiotherapy is an important component in the treatment of limited stage small cell carcinoma of the lung. It improves both local control and survival. This article reviews the scientific and clinical data that have led to combined therapy being considered the current standard for care of limited stage disease. Questions of radiation dose, treatment volume, fractionation, and integration with chemotherapy are discussed. New avenues of investigation to reduce toxicity and optimize treatment efficacy are also discussed.

Analysis of localization errors in the definition of the mantle field using a beam's eye view treatment-planning system

PURPOSE

Reports of the treatment of Hodgkin's disease (HD) with radiotherapy using the mantle field technique have demonstrated that coverage of disease by the field blocks significantly compromises outcome. It is our hypothesis that the availability of computerized tomography images reduces the incidence of localization error, and that the use of beam's eye view treatment planning techniques may further improve localization. The purpose of this report is to assess the possible contribution of a three-dimensional treatment-planning system to tumor localization and mantle block drawing in patients with HD.

MATERIALS AND METHODS

We evaluated the localization error rate of four experienced radiation oncologists as they drew the lung blocks for the mantle field. The analysis included 16 patients treated with mantle fields in our department between 1989 and 1991. In each case our computerized three-dimensional treatment planning system was used to generate a beam's eye view display of tumor volumes. Simulation radiographs for all 16 patients were overlaid with acetate film, and lung blocks were drawn by clinicians using only the simulation radiographs for reference. The process was repeated with the thoracic CT scans available for reference. The mantle block contours for each trial were then superimposed upon the beam's eye view plots of tumor volumes. The beam's eye view plot was our benchmark for the evaluation of errors of tumor localization. Localization errors were defined as touching or overlap of the shielding blocks onto tumors.

RESULTS

There was a high degree (p < 0.0003) of consistency in scoring across all pairing of clinicians and the results from all four were polled for the analysis. The overall error rate using the simulation radiographs alone was 18%. The rate was significantly lower (13%) when the CT images were available (p = 0.038). The axillary region had the highest localization error rate (41.7% with CT available and 27.1% with CT available) and the superior mediastinum had the lowest error rate (10.7% without CT, 8.5% with CT). Compared with a system such as beam's eye view, which could reduce the localization error rate to zero, the error rate with CT scans available is still significant [95% confidence interval (CI = 10-17.1%)]. Localization errors were more likely with increasing tumor size when CT scans were not available (p = 0.029). A similar trend was not seen when CT scans were available (p = 0.2). In a multivariate analysis, the use of CT scans predicted for reduced localization error rate (p = 0.03). Tumors in the axilla and inferior mediastinum had a greater relative risk than those in the superior mediastinum (p = 0.0001)

CONCLUSION

The availability of CT imaging offers an advantage in the outlining of the mantle field in the treatment of Hodgkin's disease. When the error rate is evaluated using a beam's eye view treatment planning system, a significant proportion of tumors may be overlapped by the outlined mantle blocks even when CT images are available for reference. The use of beam's eye view treatment planning in mantle field definition, especially for tumors in the axillary region, may reduce the incidence of geographic misses.

Concurrent cisplatin/etoposide plus chest radiotherapy followed by surgery for stages IIIA (N2) and IIIB non-small-cell lung cancer: mature results of Southwest Oncology Group phase II study 8805

PURPOSE

To assess the feasibility of concurrent chemotherapy and irradiation (chemoRT) followed by surgery in locally advanced non-small-cell lung cancer (NSCLC) in a cooperative group setting, and to estimate response, resection rates, relapse patterns, and survival for stage subsets IIIA(N2) versus IIIB.

PATIENTS AND METHODS

Biopsy proof of either positive N2 nodes (IIIAN2) or of N3 nodes or T4 primary lesions (IIIB) was required. Induction was two cycles of cisplatin and etoposide plus concurrent chest RT to 45 Gy. Resection was attempted if response or stable disease occurred. A chemoRT boost was given if either unresectable disease or positive margins or nodes was found.

RESULTS

The median follow-up time for 126 eligible patients [75 stage IIIA(N2) and 51 IIIB] was 2.4 years. The objective response rate to induction was 59%, and 29% were stable. Resectability was 85% for the IIIA(N2) group eligible for surgery and 80% for the IIIB group. Reversible grade 4 toxicity occurred in 13% of patients. There were 13 treatment-related deaths (10%) and 19 others (15%) died of causes not related to toxicity or tumor. Of 65 relapses, 11% were only locoregional and 61% were only distant. There were 26 brain relapses, of which 19 were the sole site or cause of death. There was no survival difference (P = .81) between stage IIIA(N2) versus stage IIIB (median survivals, 13 and 17 months; 2-year survival rates, 37% and 39%; 3-year survival rates, 27% and 24%). The strongest predictor of long-term survival after thoracotomy was absence of tumor in the mediastinal nodes at surgery (median survivals, 30 v 10 months; 3-year survival rates, 44% v 18%; P = .0005).

CONCLUSION

This trimodality approach was feasible in this Southwest Oncology Group (SWOG) study, with an encouraging 26% 3-year survival rate. An Intergroup study is currently being conducted to determine whether surgery adds more to the risk or to the benefit of chemoRT.

Radiation Therapy Oncology Group (RTOG) 88-08 and Eastern Cooperative Oncology Group (ECOG) 4588: preliminary results of a phase III trial in regionally advanced, unresectable non-small-cell lung cancer

BACKGROUND

Regionally advanced, surgically unresectable non-small-cell lung cancer represents a disease with an extremely poor prognosis. External-beam irradiation to the primary tumor and regional lymphatics is generally accepted as standard therapy. The use of more aggressive radiation regimens and the addition of cytotoxic chemotherapy to radiotherapy have yielded conflicting results. Recently, however, results from clinical trials using innovative irradiation delivery techniques or chemotherapy before irradiation have indicated that patients treated with protocols that incorporate these modifications may have higher survival rates than patients receiving standard radiation therapy.

PURPOSE

On the basis of these results, the Radiation Therapy Oncology Group (RTOG)-Eastern Cooperative Oncology Group (ECOG) elected to conduct a phase III trial comparing the following regimens: 1) standard radiation therapy, 2) induction chemotherapy followed by standard radiation therapy, and 3) twice-daily radiation therapy.

METHODS

Patients with surgically unresectable stage II, IIIA, or IIIB non-small-cell lung cancer were potential candidates. Staging was nonsurgical. Patients were required to have a Karnofsky performance status of 70 or more and weight loss less than 5% for 3 months prior to entry into the trial, to be older than 18 years of age, and to have no metastatic disease. Of the 490 patients registered in the trial, 452 were eligible. The disease in 95% of the patients was stage IIIA or IIIB. More than two thirds of the patients had a Karnofsky performance status of more than 80. Patients were randomly assigned to receive either 60 Gy of radiation therapy delivered at 2 Gy per fraction, 5 days a week, over a 6-week period (standard radiation therapy); induction chemotherapy consisting of cisplatin (100 mg/m2) on days 1 and 29 and 5 mg/m2 vinblastine per week for 5 consecutive weeks beginning on day 1 with cisplatin, followed by standard radiation therapy starting on day 50; or 69.6 Gy delivered at 1.2 Gy per fraction twice daily (hyperfractionated radiation therapy).

RESULTS

Toxicity was acceptable, with four treatment-related deaths. Three patients subsequently died of chronic pulmonary complications. Compliance with protocol treatment was acceptable. One-year survival (%) and median survival (months) were as follows: standard radiation therapy--46%, 11.4 months; chemotherapy plus radiotherapy--60%, 13.8 months; and hyperfractionated radiation therapy--51%, 12.3 months. The chemotherapy plus radiotherapy arm was statistically superior to the other two treatment arms (logrank P = .03).

CONCLUSIONS

In "good-risk" patients with surgically unresectable non-small-cell lung cancer, induction chemotherapy followed by irradiation was superior to hyperfractionated radiation therapy or standard radiation therapy alone, yielding a statistically significant short-term survival advantage.

Split-course accelerated radiation therapy combined with carboplatin and 5-fluorouracil for palliation of metastatic or unresectable carcinoma of the esophagus

BACKGROUND

Patients with metastatic or unresectable carcinoma of the esophagus have poor survival, but often require palliation of dysphagia.

METHODS

Twenty-seven patients with unresectable carcinoma of the esophagus were treated with carboplatin, 5-fluorouracil, and split-course accelerated radiation therapy. Seventy-four percent of patients had adenocarcinoma, and 26% had squamous cell carcinoma.

RESULTS

The regimen was well tolerated; 25% of the patients had disease improvement after completing therapy, although the majority of these patients had all of their disease within the radiation field. Ninety-three percent (13/14) of the patients who experienced disease progression during therapy progressed in areas treated with chemotherapy alone. Median survival was 6 months. Fifty-nine percent of the 17 patients who presented with dysphagia achieved durable relief of that symptom.

CONCLUSIONS

Carboplatin and 5-fluorouracil have low activity in patients with metastatic esophageal cancer. However, in combination with radiation therapy, this regimen is tolerable when the primary goal is palliation of dysphagia near the end of life. Future studies should focus on identifying more active regimens with response and survival as endpoints.

Pediatric midbrain tumors: a benign subgroup of brainstem gliomas

The presentation, radiographic findings and course of 17 children with MRI-documented intrinsic midbrain lesions are reviewed. The anatomic centers of all the lesions were tectal, peritectal, or tegmental. Lesions centered at the pineal gland were excluded. Signs of increased intracranial pressure from hydrocephalus requiring shunt placement were present in 14 patients. Histopathological diagnosis was confirmed in three tumors; these were low grade astrocytomas and all received focal irradiation, as did one unbiopsied tumor. The remaining 13 patients with no histopathological diagnosis received no therapy other than shunt placement in 11. All but one of the lesions have remained clinically and radiographically stable, with a 4-year progression-free and total survival of 94 and 100%, respectively. We conclude that mass lesions originating in the upper midbrain are a subset of intrinsic brainstem tumors with a relatively benign course, usually presenting with hydrocephalus after infancy. They may remain stable for considerable periods and may require no further therapy after treatment of hydrocephalus. Surgical biopsy and/or resection can usually be reserved for progressive or atypical lesions which may also require further adjuvant therapy.

Platinum combined with radiation therapy in small cell lung cancer: focusing like a laser beam on crucial issues

The addition of radiotherapy to combination chemotherapy has been shown to improve survival for patients with limited small cell lung cancer (SCLC). Although SCLC is very sensitive to radiotherapy, the impact of radiation may be confounded by interaction among various radiotherapy factors or by the chemotherapeutic agents used in combination. The potential effects of such radiation factors as dose, volume, fractionation, sequence with chemotherapy, and timing (early v late), as well as choice of chemotherapy, therefore must be carefully considered when designing or comparing clinical trials of combined modality therapy for SCLC. The combination of thoracic radiotherapy plus platinum-based chemotherapy currently represents the cornerstone of such combination treatment for SCLC. Many questions remain, however, and it is hoped that new trials will be designed to focus more precisely on unsettled issues.

Results of primary and adjuvant CT-based 3-dimensional radiotherapy for malignant tumors of the paranasal sinuses

PURPOSE

This study reports our clinical experience supporting the normal tissue-sparing capability of 3-dimensional (3-D) treatment planning when applied to advanced neoplasms of the paranasal sinuses.

METHODS AND MATERIALS

Between 1986 and 1992, computed tomography (CT)-based 3-D radiotherapy was used to treat 39 patients with advanced stage malignant tumors of the paranasal sinuses as all or part of initial treatment. Fifteen unresectable patients were treated with primary radiotherapy to a median prescribed total dose of 68.4 Gy. Twenty-four patients were treated with postoperative adjuvant radiotherapy for close margins (< 5 mm), microscopic or gross residual disease. The median prescribed total doses were 55.8 Gy, 59.4 Gy and 67.8 Gy, respectively. Globe-sparing fields were used in the primary treatment plans of 37 patients (95%). The median follow-up is 4.5 years (range, 19-86 months).

RESULTS

For the unresectable patients who were treated with radiotherapy alone, the local control rate at 3 years is 32%. The actuarial overall survivals at 3 and 4 years are 32%. For the patients who received postoperative adjuvant radiotherapy, none of the five patients irradiated for close surgical margins recurred locally. Three of the 14 with microscopic residual (21%) recurred locally at 26, 63, and 74 months from the start of irradiation. Four of the five with gross residual (80%) recurred locally with a median time to recurrence of 2 years. The local control rates at 3 and 5 years for the adjuvant group are 75% and 65%, respectively. The actuarial overall survival at 3 and 5 years are 65% and 60%, respectively. None of the first sites of local disease progression were judged to have occurred outside the high-dose region. There was one case of mild osteoradionecrosis successfully treated with conservative treatment, one case of limited optic neuropathy and one case of possible radiation-induced cataract. There was no blindness related to irradiation.

CONCLUSION

This study indicates that computed tomography-based 3-D radiotherapy can preserve critical structures unaffected by tumor invasion and achieve the generally expected local control rates when it is used as all or part of initial treatment for extensive malignant tumors of the paranasal sinus. The presence of gross disease was a major adverse prognostic factor in this study. Additional therapeutic maneuvers are essential to improve the local control and survival rate in patients with advanced paranasal sinus carcinomas.

Considerations on radiotherapy dose intensity for limited small cell lung cancer

The factors of dose, volume, fractionation, and timing with chemotherapy undoubtedly influence outcomes in terms of treatment of limited small cell lung cancer with thoracic radiotherapy. The type and timing with chemotherapy may be very important. For integration of chemotherapy with radiation therapy, the measure of iso-effects, for tumor and acute tissue and late effects, may be hard to come by. This paper relates a variety of different total doses, according to the relative scales provided by nominal standard dose (NSD, NRET) and the biologic effective dose (Gy-10 and Gy-3), which employs the alphabeta linear quadratic model. A variety of different fraction schemes have been used clinically. These allow us to compare intensifying of the dose versus standard treatment versus relative prolongation of the dose. When defined as measure of 2-year survivals, there is not a tremendous difference in observed outcomes. However, there may be differences that are discerned later when the endpoint local control is examined. This paper reviews the current pilot studies using platinum-etoposide chemotherapy, at a variety of different dose-intensive regimens of thoracic radio-therapy and their relative effects. To prove benefit, randomized trials are needed.

Dose-volume histogram and 3-D treatment planning evaluation of patients with pneumonitis

PURPOSE

Tolerance of normal lung to inhomogeneous irradiation of partial volumes is not well understood. This retrospective study analyzes three-dimensional (3-D) dose distributions and dose-volume histograms for 63 patients who have had normal lung irradiated in two types of treatment situations.

METHODS AND MATERIALS

3-D treatment plans were examined for 21 patients with Hodgkin's disease and 42 patients with nonsmall-cell lung cancer. All patients were treated with conventional fractionation, with a dose of 67 Gy (corrected) or higher for the lung cancer patients. A normal tissue complication probability description and a dose-volume histogram reduction scheme were used to assess the data. Mean dose to lung was also calculated.

RESULTS

Five Hodgkin's disease patients and nine lung cancer patients developed pneumonitis. Data were analyzed for each individual independent lung and for the total lung tissue (lung as a paired organ). Comparisons of averages of mean lung dose and normal tissue complication probabilities show a difference between patients with and without complications. Averages of calculated normal tissue complication probabilities for groups of patients show that empirical model parameters correlate with actual complication rates for the Hodgkin's patients, but not as well for the individual lungs of the lung cancer patients treated to larger volumes of normal lung and high doses.

CONCLUSION

This retrospective study of the 3-D dose distributions for normal lung for two types of treatment situations for patients with irradiated normal lung gives useful data for the characterization of the dose-volume relationship and the development of pneumonitis. These data can be used to help set up a dose escalation protocol for the treatment of nonsmall-cell lung cancer.

Cisplatin-etoposide based chemoradiation treatment for limited small cell lung cancer: the current situation

Although the role of thoracic radiotherapy in limited small cell lung cancer has been established by two meta-analyses, optimization of radiotherapy with chemotherapy requires a full understanding of the chemotherapeutics used and the factors involved in administration of thoracic radiotherapy. The Cisplatin-Etoposide (PE) combination has replaced the cyclophosphamide or doxorubicin as the combination of choice, but it isn't clear whether the addition of the other agents add to benefit or toxicity. New agents continue to be sought to improve systemic failure. This paper focuses on the radiotherapy variables: dose, volume, fractionation, temporal sequencing, and variety of methods of combining the modalities are discussed. Results of a variety of pilot studies using thoracic radiotherapy and the PE combination are discussed. A randomized trial of accelerated radiotherapy versus standard fractionation has been completed within the past year, but results are not yet available. Further trials are warranted to improve integration of modalities in order to increase survival and reduce local and systemic failure without increasing untoward effects.

Radiation therapy as an alternative to surgery in the management of intracranial juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma is a benign, vascular tumor which typically presents in adolescent males. Although surgical resection is usually recommended for the management of this tumor, external beam radiation therapy has also been advocated in the literature. We report three cases of large juvenile nasopharyngeal angiofibromas with extensive intracranial extension primarily managed with external beam radiation therapy. Although there was not complete resolution of the tumors, there was significant alleviation of symptomatology with no serious side effects from the radiation therapy. Based on these cases, we feel that external beam radiation therapy in the management of extensive juvenile nasopharyngeal angiofibromas with intracranial extension is warranted in certain select cases.

Use of Veff and iso-NTCP in the implementation of dose escalation protocols

PURPOSE

This report investigates the use of a normal tissue complication probability (NTCP) model, 3-D dose distributions, and a dose volume histogram reduction scheme in the design and implementation of dose escalation protocols for irradiation of sites that are primarily limited by the dose to a normal tissue which exhibits a strong volume effect (e.g., lung, liver).

METHODS AND MATERIALS

Plots containing iso-NTCP contours are generated as a function of dose and partial volume using a parameterization of a NTCP description. Single step dose volume histograms are generated from 3-D dose distributions using the effective-volume (Veff) reduction scheme. In this scheme, the value of Veff for each dose volume histogram is independent of dose units (Gy, %). Thus, relative dose distributions (%) may be used to segregate patients by Veff into bins containing different ranges of Veff values before the assignment of prescription doses (Gy). The doses for each bin of Veff values can then be independently escalated between estimated complication levels (iso-NTCP contours).

RESULTS AND CONCLUSION

Given that for the site under study, an investigator believes that the NTCP parameterization and the Veff methodology at least describe the general trend of clinical expectations, the concepts discussed allow the use of patient specific 3-D dose/volume information in the design and implementation of dose escalation studies. The result is a scheme with which useful prospective tolerance data may be systematically obtained for testing the different NTCP parameterizations and models.

Results of high-dose thoracic irradiation incorporating beam's eye view display in non-small cell lung cancer: a retrospective multivariate analysis

PURPOSE

To review the University of Michigan clinical experience in nonsmall cell lung cancer using high-dose thoracic irradiation (> or = 60 Gy) so that a starting dose for our prospective dose-escalation study could be determined.

METHODS AND MATERIALS

Eighty-eight consecutive patients diagnosed with medically inoperable or locally advanced, unresectable nonsmall cell lung cancer were identified who were treated with thoracic irradiation alone to a minimum total dose of 60 Gy (uncorrected for lung density). All patients except four (95%) underwent computed tomography scanning for treatment planning that included beam's eye view display for tumor and critical structure localization. All patients were treated with standard fractionation in a continuous course to uncorrected total doses ranging from 60 to 74 Gy (median, 67.6 Gy).

RESULTS

The median follow-up exceeds 24 months for all surviving patients (range, 12 to 78 months). The median survival time was 15 months, and the 2- and 3-year overall actuarial survival rates were 37% and 15%, respectively. Survival was significantly different between stage of disease (p = .004) and N-stage (p = .002) by univariate analysis. In a multivariate analysis, stage becomes the only characteristic significantly associated with outcome. The median time to local progression for 86 evaluable patients was 29 months. Stage (p = .0003), T-stage (p = .0095) and N-stage (p = .027) were significantly different with respect to local progression-free survival by univariate analysis. However, only stage was prognostic for local progression-free survival by multivariate analysis. There was no difference between large volume treatment (inclusion of the contralateral hilar and supraclavicular lymph nodes) and small volume treatment (exclusion of these elective nodal sites) with respect to local progression-free survival (p = .507) or survival (p = .520). With regard to dose, there was no significant difference between patients who received > 67.6 Gy and patients who received < or = 67.6 Gy with respect to local progression-free survival (p = .094) or survival (p = .142). Within the Stage III subgroup, local progression-free survival (p = .018) and survival (p = .061) were longer favoring the high-dose group of patients. Despite these doses, disease progression within the irradiated field was the predominant first site of treatment failure.

CONCLUSION

This retrospective study has shown that it is feasible to deliver uncorrected tumor doses as high as 70 Gy using standard fractionation in NSCLC with acceptable morbidity. Local control remains a significant problem. These data indicate justification for a starting dose in a prospective radiation dose-escalation study.

Alternating chemotherapy and twice-daily thoracic radiotherapy in limited-stage small-cell lung cancer: a pilot study of the Eastern Cooperative Oncology Group

PURPOSE

This pilot study was undertaken to determine the efficacy and feasibility of alternating cisplatin and etoposide with multiple daily fractions of thoracic radiotherapy (TRT) in patients with limited-stage small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Thirty-four SCLC patients received four courses of cisplatin (30 mg/m2/d x 3) plus etoposide (120 mg/m2/d x 3) (PE) every 3 weeks. TRT was administered twice daily (1.5 Gy per fraction) for 5 consecutive days in the week after cycles 1, 2, and 3 of chemotherapy (total TRT dose, 45 Gy). Patients who achieved a complete response (CR) received one course of late-intensification (LI) treatment consisting of cyclophosphamide (4 g/m2) and etoposide (900 mg/m2). Prophylactic cranial irradiation (PCI) was optional.

RESULTS

Nineteen of 32 assessable patients achieved a CR (59%) and 12 had a partial response (38%), for an overall response rate of 97% (95% confidence interval [CI], 84% to 99%). Median survival was 18 months, while 2-year progression-free survival was 47%. Leukopenia < or = 1,000/microL occurred in 12% of induction treatment cycles. Severe esophagitis was uncommon. Pulmonary fibrosis that was asymptomatic or minimally symptomatic was observed in eight patients (25%). There was one episode of adult respiratory distress syndrome (ARDS) during LI chemotherapy. Life-threatening neutropenia (< or = 500/microL) developed in all patients who underwent LI chemotherapy, with a median duration of 10 days (range, 8 to 19). Two patients died of sepsis during LI chemotherapy.

CONCLUSION

Alternating PE and TRT as performed in this trial is an effective brief induction regimen for limited-stage SCLC. However, this particular regimen did not appear to be substantially different in terms of efficacy or toxicity compared with regimens using concurrent chemotherapy and standard-fraction TRT. LI chemotherapy was associated with unacceptable toxicity and did not appear to have a favorable impact on survival.

Incorporation of radiotherapy fractionation in the combined-modality treatment of limited small-cell lung cancer

Although systemic failure continues to plague patients receiving combined-modality treatment for limited small-cell lung cancer (SCLC), improvements in chemotherapy, including use of cisplatin/etoposide-based regimens, and radiotherapy have produced increases in median, 2-year, and 5-year survival over the last decade. Employing more conservative volumes of radiotherapy in more aggressive ways, today about 50% of SCLC patients will survive 2 years and 30%, 5 years. Moreover, integrating radiotherapy with chemotherapy early in the course of treatment can potentially eliminate resistant clones. The various factors in radiotherapy, including dose, volume, fractionation, and timing, therefore deserve scrutiny in the reporting and design of clinical trials.

The evolving role of radiation therapy in the treatment of locally advanced lung cancer

RT has been used routinely in the treatment of NSCLC and SCLC for the past several decades. Although largely considered a palliative treatment by most oncologists, there is increasing evidence that RT, when combined with cisplatin-based chemotherapy or given by altered fractionation, may improve the survival in NSCLC. Three large randomized trials have now shown that RT plus a cisplatin-based combination or cisplatin alone prolongs patient survival. Studies of hyperfractionation and accelerated hyperfractionation have also shown promise and are being tested in randomized trials worldwide. The results from these trials must be assessed against ongoing radiation dose escalation studies using new treatment planning technologies, albeit still in their infancy. These trials are discussed in this report. Systemic therapy is the cornerstone of treatment for SCLC. Although the value of RT was hotly debated during the 1970s and 1980s, it is now well established that RT improves survival when combined with chemotherapy in limited stage patients. Despite this advancement, other issues (such as timing or sequencing of modalities, radiation dose, fractionation, and treatment volume), remain unsettled. Randomized trials designed to address these important issues are in progress.

Innovations in multimodality therapy for lung cancer. Combined modality management of limited small-cell lung cancer

Recent approaches to the treatment of limited small-cell lung cancer have combined local radiotherapy and systemic chemotherapy in an attempt to improve local control and inhibit distant metastases. Local control is a key indicator of the efficacy of radiotherapy administration in combined-modality regimens. However, even in combined-modality trials using high total radiotherapy doses, local failure rates have ranged from 30 to 50 percent. The components of radiotherapy administration--including dose, volume, fractionation, integration with chemotherapy (concurrent, alternating, or sequential), and timing (early or late administration)--are also important considerations. Hyperfractionation, or the administration of small fractions of radiation more than once daily (usually twice), and accelerated hyperfactionation, or the administration of three fourths of the standard radiation dose two to three times daily, have emerged as important concepts in radiotherapy. Although the optimal chemotherapy regimen for combined-modality treatment has not yet been established, use of cisplatin and etoposide combinations, which do not promote pulmonary, cardiac, or esophageal toxicity, have been particularly appropriate in patients with small-cell lung cancer.

The integration of platinum and radiotherapy in the treatment of lung cancer

Combined-modality therapy in lung cancer is a common practice throughout the world. The use of radiochemotherapy appears to be firmly established in the treatment of small cell lung cancer, but the role of prophylactic cranial irradiation remains undecided. Many recommend its use in the treatment of non-small cell lung cancer as well, but no facts exist to support this position. Because of poor long-term outcome and high frequency of systemic relapse, integration of chemotherapy for the treatment of non-small cell lung cancer is becoming more prevalent. This article discusses methods of integration, the problems of combined- modality toxicity, recent trials, and reports of multimodal therapy in lung cancer. The advantages of certain regimens of chemotherapy and new methods of radiotherapy are also discussed.

Thoracic radiotherapy variables: influence on local control in small cell lung cancer limited disease

In limited small cell lung cancer (LSCLC), the high local failure rate of chemotherapy by itself (60-100%) and with the addition of external beam radiotherapy (approximately 30%) has led to investigation of methods to improve local control. To that end, we integrated Platinum 60 mg/m2, d. 1, 22 and Etoposide 120 mg/m2, d. 4, 6, & 8; 25, 27 & 29 with concurrent twice-daily 150 cGy (total dose: 4500 cGy). Of 32 consecutively referred patients, 4 with variant histology, 31 were evaluable for toxicity, response, and survival. Two of 4 variant histology patients responded, and 27 of 27 pure small cell responded, p = 0.005. CT scans were inaccurate at forecasting survival. Of 17/32 patients considered "positive," 59% of these were survivors; of those considered "negative," 47% were survivors, p = N.S. Radiation portals were volumetrically conservative; the supraclavicular fossa was included infrequently and the contralateral hilum not at all. Local failure occurred in only 1/27 patients (4%). All four variant patients failed locally, p = 0.001. With a median follow-up of 43 months, the actuarial disease-free survival remains nearly 50%. Variant histology is more predictive of local control than the physical factors of dose or volume.

The influence of tumor size and pre-treatment staging on outcome following radiation therapy alone for stage I non-small cell lung cancer

From 1970 through 1987, 77 patients with Stage I lung cancer were treated with definitive radiation therapy (RT) alone at the Fox Chase Cancer Center or the Hospital of The University of Pennsylvania. All patients had a pathologic diagnosis of non-small cell lung cancer and were not candidates for surgical resection because of premorbid medical problems or patient refusal. The median age was 72 years, although 10 patients were over 80. The histologic cell type was squamous in 44, adenocarcinoma in 15, large cell in 3, adenosquamous in 1, non-small cell in 11, and bronchioli-alveolar in 3. Tumor size was retrievable in 75 patients and 25 were less than or equal to 3 cm, 41 from 3-6 cm, and 9 greater than 6 cm. Diagnostic staging varied during the study period. Twelve patients, evaluated with a CT scan of the chest, including the liver, and a bone scan were classified as having "excellent" staging, 24 patients with conventional tomography, liver-spleen scan and a bone scan had "good" staging, and 41 patients were staged less rigorously. The RT was of megavoltage energy in all patients. The median dose was 60 Gy. The mediastinum was treated in all but eight patients who had poor pulmonary function. Survival was measured from the date of pathologic diagnosis. The actuarial 3-year survival rate of the entire group of patients is 17% with a median survival time of 20 months. Of the 61 deaths, 51 were due to disease and 10 were due to intercurrent disease without evidence of tumor recurrence. The actuarial 3-year disease-specific survival (DSS) was 22%. The 3-year disease-specific survival for patients with tumors less than 3 cm and from 3-6 cm was 30% and 17%, respectively. All nine patients with tumors greater than 6 cm were dead of disease. Local progression occurred in 33 patients, resulting in a 44%, 3-year actuarial freedom from local progression. The median time to local failure was 28 months and there were no local failures after 3 years in the 18 patients eligible for observation beyond this point. Of the patients with "excellent" staging, only 2 of 12 were dead of disease compared with 22 of 24 with "good" staging and 30 of 41 of the remainder. In this large group of Stage I non-small cell lung cancer, thorough pre-treatment staging and smaller tumor size are associated with a more favorable outcome.