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* From the Thoracic Oncology Program and Experimental Therapeutics Program (Dr. Simon), H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL; and Chief, Radiation Oncology (Dr. Turrisi), Wayne State University School of Medicine, Detroit, MI.
Correspondence to: George R. Simon, MD, H. Lee Moffitt Cancer Center and Research Institute, 12902 Magnolia Dr, MRC-4W, Tampa, FL 33612; e-mail: simongr{at}moffitt.usf.edu
| Abstract |
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Methods: We conducted a comprehensive review of the available literature and the previous American College of Chest Physicians guidelines of SCLC. Controversial and less understood areas of the management of SCLC were then subject to an exhaustive review of the literature and detail analyses. Experts in evidence-based analyses compiled the accompanying systematic review titled "Evidence for Management of SCLC." The evidence was then assessed by a panel of experts to incorporate "clinical relevance." The resultant guidelines were then scored according to the grading system outlined by the American College of Chest Physicians grading system task force.
Results: SCLC accounts for 13 to 20% of all lung cancers. Highly smoking related and initially responsive to treatment, it leads to death rapidly in 2 to 4 months without treatment. SCLC is staged as limited-stage and extensive-stage disease. Limited-stage disease is treated with curative intent with chemotherapy and radiation therapy, with approximately 20% of patients achieving a cure. For all patients with limited-stage disease, median survival is 16 to 22 months. Extensive-stage disease is primarily treated with chemotherapy with a high initial response rate of 60 to 70% but with a median survival of 10 months. All patients achieving a complete remission should be offered prophylactic cranial irradiation. Relapsed or refractory SCLC has a uniformly poor prognosis.
Conclusion: In this section, evidence-based guidelines for the staging and treatment of SCLC are outlined. Limited-stage SCLC is treated with curative intent. Extensive-stage SCLC has high initial responses to chemotherapy but with an ultimately dismal prognosis with few survivors beyond 2 years.
Key Words: chemotherapy guideline radiation therapy review small cell lung cancer staging
| Introduction |
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| Key Questions |
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2. Does early vs late administration of TRTx influence outcome?
3. Does the duration of administration of TRTx affect survival or toxicity?
4. In responding patients with extensive disease, does the administration of consolidative TRTx affect outcome?
5. What is the role of prophylactic cranial irradiation (PCI) in the treatment of SCLC?
6. Is there a role for positron emission tomography (PET) scanning in SCLC staging?
7. Do the pathologic subtypes of SCLC influence treatment outcome?
8. What is the role of surgery in the management of patients with SCLC, and how are patients selected for surgery?
9. What is the role and what are the relative benefits of second-line/salvage therapy?
Clinical research has slowed in this disease, and there are few contemporary studies that directly address many of these questions. Evidence-based guidelines rely on timely, contemporary, pertinent evidence that is largely lacking in many of these areas. Decreased disease frequency and difficulty in conducting large trials are oft-cited reasons for this lack of activity. With the exception of question 7 regarding pathology subtypes, all of these questions posed to the systematic review are discussed in the context of these guidelines.
| Materials and Methods |
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Accompanying this guideline is an "Evidence for Management of SCLC chapter, comprehensive research of some of the most controversial but not infrequently encountered questions in SCLC. In relevant sections of this guideline, the reader will be referred to this evidence report (see "SCLC Evidence" chapter).
| Guideline |
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| Staging of SCLC |
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Complete evaluation of a patient with newly diagnosed SCLC consists of a history and physical examination, pathology confirmation or review, CT of the chest and abdomen to include the whole liver and adrenal glands, bone scan, and a CT with contrast or MRI examination of the brain. While the prevalence of brain metastases at diagnosis varies, the brain is a common site of treatment failure; therefore, evaluation of the brain prior to treatment remains mandatory. Scanning the asymptomatic brain is likely to lead to the diagnosis of more previously unsuspected brain metastases, but there is no evidence yet that it improves survival.3 However, because it has a direct impact on the correct staging of the disease and consequently on developing a treatment plan, it is the opinion of the authors of this guideline that brain imaging should be performed for all patients currently undergoing staging for SCLC. Additionally, CBCs, electrolytes, BUN, creatinine, and liver function tests should be performed in all patients at baseline. The utility of PET in SCLC has been reported in several small prospective studies.245678910 These studies are small, with varying reference standards and with uncertainty about the execution and interpretation of the results. Even though the cumulative evidence suggests that PET added to conventional staging improves the sensitivity in detecting extracranial disease, the frequency of changes in stage attributable to PET are still unknown and is plagued by wide confidence intervals (CIs) in the estimates of diagnostic and staging accuracy. Randomized prospective studies need to be conducted before the routine use of PET scan for staging SCLC can be recommended. Therefore, outside of a clinical trial, the routine use of PET in SCLC cannot be recommended. (Please refer to question 6 of the evidence report. (See "Evidence for Management of Small Cell Lung Cancer" chapter)
The routine use of bone marrow aspiration has been abandoned because it was rare to have disease detected in the bone marrow in the absence of obvious bony disease in the bone scan. In one study,11 of 403 patients with SCLC, only 7 patients (1.7%) had extensive disease based on marrow involvement alone. Because bone marrow examination rarely changes the stage of cancer in noninvasively assessed patients, and because all patients with SCLC receive chemotherapy as part of their overall treatment strategy, routine use of this procedure is not recommend in the staging of SCLC. Other investigators1213 have also reached similar conclusions. Therefore, bone marrow examination, formerly standard, is rarely indicated and has been abandoned as a routine procedure for the staging of SCLC.
| Recommendations |
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2. PET is not recommended in the routine staging of SCLC. Grade of recommendation, 2B
| Treatment for Extensive-Stage SCLC |
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A metaanalysis performed by Chute et al16 evaluated 21 cooperative group trials performed in North America from 1972 to 1993. Patients with extensive-stage SCLC treated during a similar time interval listed in the Surveillance, Epidemiology, and End Results database were also examined. Trends were tested in the number of trials and the survival time of patients over time. In this analysis, a 2-month prolongation in median survival was demonstrated in extensive-stage SCLC. This improvement in survival was independently associated with both cisplatin-based therapy and in the improvement of best supportive care (BSC) and general medical management. This metaanalysis further strengthens the evidence in favor of cisplatin-based chemotherapy for the first-line treatment of extensive stage SCLC.
The issue of carboplatin vs cisplatin was reviewed by Brahmer et al,17 who concluded that carboplatin plus etoposide seems to be as effective but less toxic (except for increased myelosuppression) than cisplatin plus etoposide. The Hellenic Oncology Group conducted a randomized phase II trial18 comparing cisplatin and etoposide with carboplatin and etoposide. In this study, consisting of patients with limited-stage and extensive-stage disease, median survival times were 11.8 months for the cisplatin group and 12.5 months for the carboplatin group. The difference was not statistically significant, although the study did not have enough power to show a survival difference.
A Japanese trial19 compared cisplatin and irinotecan (camptothecin-11 [CPT-11]) with cisplatin and etoposide. Patients randomized to the cisplatin/CPT-11 arm fared statistically significantly better than the patient cohort randomized to the cisplatin/etoposide arm (median survival, 420 days vs 300 days). Confirmatory trials were then launched in the United States. One of these trials using a different dosing schedule for cisplatin/irinotecan failed to show a survival advantage over cisplatin/etoposide. Fewer patients receiving cisplatin/irinotecan had hematologic toxicities (ie, grade 3/4 anemia, thrombocytopenia, neutropenia, and febrile neutropenia) compared with patients receiving cisplatin/etoposide. However, more patients receiving cisplatin/CPT-11 had nonhematologic toxicities in the form of grade 3/4 diarrhea and vomiting.20 Several phase II trials with irinotecan, topotecan, paclitaxel, in combination with either cisplatin or etoposide, have been reported. These have been summarized in Table 1 .2122232425262728293031323334353637
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Pemetrexed/platinum combinations have been investigated in extensive-stage SCLC. A randomized phase II trial39 evaluated the use of cisplatin or carboplatin plus pemetrexed in previously untreated patients. Patients were randomly assigned to receive pemetrexed at 500 mg/m2 plus cisplatin at 75 mg/m2 or carboplatin (area under the concentration curve of 5). Treatment was administered once every 21 days for a maximum of six cycles. Seventy-eight patients were enrolled into this multicenter trial. Median survival time for cisplatin/pemetrexed was 7.6 months, with a 1-year survivorship of 33.4% and a response rate of 35% (95% CI, 20.6 to 51.7%). Median survival time for carboplatin/pemetrexed was 10.4 months, with a 1-year survivorship of 39.0% and a response rate of 39.5% (95% CI, 24.0 to 56.6%). Median time to progression for cisplatin/pemetrexed was 4.9 months and for carboplatin/pemetrexed was 4.5 months. Grade 3/4 hematologic toxicities included neutropenia (15.8% vs 20.0%) and thrombocytopenia (13.2% vs 22.9%) in the cisplatin/pemetrexed and carboplatin/pemetrexed treatment groups, respectively. Pemetrexed/platinum doublets had activity and appeared to be well tolerated in first-line extensive-stage SCLC. This randomized phase II trial suggests that pemetrexed/platinum combinations may be comparable in efficacy in extensive-stage SCLC to the more traditional cisplatin-etoposide or cisplatin-irinotecan regimens.39
The issue of adding a third drug to cisplatin and etoposide has been investigated. The Hoosier Oncology Group40 evaluated the addition of ifosfamide to cisplatin and etoposide in a phase III trial of 171 extensive-disease patients. At the expense of increased toxicity, 2-year survival increased from 5 to 13% with addition of ifosfamide. Mavroudis et al41 compared paclitaxel, etoposide, and platinum with etoposide and platinum. The study was terminated early secondary to higher number of toxic deaths in the paclitaxel, etoposide, and platinum arm. Despite a statistically significant improvement in the time to progression for paclitaxel, etoposide, and platinum, there was no difference in overall survival.
The issue of adding TRTx to chemotherapy in the treatment of extensive-stage SCLC has also been evaluated. This has been discussed in the accompanying evidence report and technological assessment and to which the reader is referred to for a more detailed analysis. One randomized controlled trial42 (n = 99) suggests that adding concurrent TRTx improves survival of patients with extensive-stage disease that responds to an initial three cycles of platinum/etoposide chemotherapy with a complete response (CR) outside the thorax and at least a partial response in the thorax. Uncontrolled data from the same trial42 suggest little to no benefit for other patients. Grades 3/4 esophagitis was more common with TRTx.
In summary, for extensive-stage SCLC, a combination of cisplatin combined with either etoposide or CPT-11 or carboplatin combined with etoposide are currently considered standard regimens. The standard treatment arm for a comparative prospective study remains cisplatin (60 to 80 mg/m2), and etoposide delivered in three to five divided doses between 250 and 360 mg/m2. There is no evidence to support continuing treatment beyond six cycles. It is reasonable to administer consolidative TRTx in patients achieving a CR outside the chest and at least a CR or partial response in the chest, although the evidence for this is weak. This issue needs to be further addressed in phase III randomized trials.
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4. After chemotherapy, patients achieving a CR outside the chest and complete or partial response in the chest can be offered consolidative TRTx in the chest. Grade of recommendation, 2C
| Maintenance Treatment |
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Treatments other than chemotherapy for maintenance were also tested in randomized clinical trials. A phase III randomized trial45 evaluated the efficacy of anti-GD3 immunization as maintenance treatment. There was no benefit in overall survival. Metalloproteinase inhibitors and inhibitors of angiogenesis including thalidomide are currently being investigated in the maintenance setting.
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| Treatment of Relapsed or Refractory SCLC (Systematic Review Question 9) |
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In a randomized multicenter study, von Pawel et al46 compared cyclophosphamide, adriamycin, and vincristine (CAV) with topotecan as a single agent in patients who had relapse at least 60 days after completion of initial therapy. Patients received either topotecan as a 30-min/d infusion for 5 days every 21 days, or CAV infused on day 1 every 21 days. A total of 211 patients were enrolled. The response rates were 24.3% in patients treated with topotecan and 18.3% in patients treated with CAV (p = 0.285). Median times to progression were 13.3 weeks for the topotecan arm and 12.3 weeks for the CAV arm. Median survival times were 25 weeks for topotecan and 24.7 weeks for CAV. The proportion of patients with symptom improvement was greater in the topotecan arm than in the CAV group for four of the eight symptoms evaluated. The authors46 concluded that topotecan was at least as effective as CAV in the treatment of patients with recurrent SCLC and resulted in improved symptom control. However, toxicity rates were high in both arms and alternative dose schedules of topotecan are currently favored.
Another study47 randomly assigned patients with relapsed SCLC not considered as candidates for standard IV therapy to BSC alone (n = 70) or oral topotecan (2.3 mg/m/d, days 1 through 5, every 21 days) plus BSC (topotecan; n = 71). In an intent-to-treat analysis, survival (primary end point) was prolonged in the topotecan group (log rank p = 0.0104). Median survival time with BSC was 13.9 weeks (95% CI, 11.1 to 18.6), and with topotecan it was 25.9 weeks (95% CI, 18.3 to 31.6). Partial responses were seen in 7% of patients receiving topotecan, with an additional 44% of patients achieving stable disease. Patients receiving topotecan had slower quality of life deterioration and greater symptom control. Principal toxicities with topotecan were hematologic: grade 4 neutropenia, 33%; grade 4 thrombocytopenia, 7%; and grade 3/4 anemia, 25%. Toxic deaths occurred in four patients (6%) in the topotecan arm. All-cause mortality rates within 30 days of random assignment were 13% with BSC and 7% with topotecan. Hence, in patients unable to tolerate IV chemotherapy, treatment with oral topotecan is an option.47 Several reported phase II trials in relapsed/refractory SCLC are summarized in Table 2 .3148495051
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| Treatment of Elderly (or Poor Performance Status) Patients With SCLC |
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Elderly patients with poor PS or with compromised organ function may be offered single-agent chemotherapy or polychemotherapy in attenuated doses. However, several randomized studies5556 have indicated that such "gentler" chemotherapy is inferior to optimal combination chemotherapy. Options available to these patients include oral etoposide for 14 days combined with carboplatin on day 1 every 28 days57; abbreviated chemotherapy with CAV in full doses followed up 3 weeks later by cisplatin and etoposide in optimal doses58; or chemotherapy with platinum, adriamycin, vincristine, and etoposide, with all four drugs in reduced doses.59 A phase III trial60 compared carboplatin/gemcitabine with cisplatin/etoposide in patients with poor-prognosis SCLC, with carboplatin and gemcitabine exhibiting a more favorable overall toxicity profile at the expense of increased myelotoxicity but with equivalent efficacy. Another phase III trial61 compared single-agent carboplatin with CAV, with carboplatin producing response rates, relief of tumor-related symptoms, and survival similar to that seen with CAV. There was a lower risk of life-threatening sepsis and less need for hospitalization in the group that received carboplatin.
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8. Elderly patients with poor prognostic factors such as poor PS or medically significant concomitant comorbid disease may still be considered for chemotherapy. Grade of recommendation, 2C
Studies with SCLC cell lines have shown that they have greater radiosensitivity than human adenocarcinomas or squamous cell lung cancer cell lines. Because of these observations, many early trials of combining radiation with chemotherapy in SCLC used lower total radiation doses. It has become increasingly clear that higher doses than those of the old regimens of 30 Gy in 10 fractions or 45 Gy in 25 fractions are needed to provide durable local control because lower doses are associated with local relapse rates in excess of 50%.
A number of trials conducted in the 1970s and 1980s compared chemotherapy alone to chemotherapy plus TRTx in patients with limited SCLC. There were differences in radiation dose, timing, and choice of chemotherapeutic agents, but most were performed with alkylating agent and doxorubicin-based therapy rather than cisplatin and etoposide. The analysis by Warde and Payne62 showed improved local control and survival with the addition of TRTx, particularly in patients
60 years old. Pignon et al63 obtained individual patient data from these trials and was able to update analyses from the time of original publication. They found that the addition of TRTx resulted in an increase in 3-year survival from 8.9 to 14.3%, an absolute improvement of 5%, and a relative improvement of nearly 50%. With the publication of these two metaanalyses, the debate shifted from whether to use TRTx to how best to integrate it with chemotherapy.
In limited disease, the ability to use concurrent therapy is predicated on avoiding drugs with intrathoracic organ toxicity that compound with radiotherapy. The optimal chemotherapy to utilize with radiation therapy has been a subject of investigation as well. A prospective randomized trial64 comparing cisplatin and etoposide (PE) to cyclophosphamide, etoposide and vincristine (CEV) was reported by Sundstrom et al. A total of 436 eligible patients were randomized to chemotherapy with PE (n = 218) or CEV (n = 218). Patients were stratified according to extent of disease (limited disease, n = 214; extensive disease, n = 222). The PE group received five courses of etoposide at 100 mg/m2 IV and cisplatin at 75 mg/m2 IV on day 1, followed up by oral etoposide 200 mg/m2/d on days 2 to 4. The CEV group received five courses of epirubicin at 50 mg/m2, cyclophosphamide at 1,000 mg/m2, and vincristine at 2 mg, all IV, on day 1. In addition, patients with limited disease received TRTx concurrent with chemotherapy cycle 3, and those achieving CR during the treatment period received PCI. The 2-year and 5-year survival rates in the PE arm (14% and 5%; p = 0.0004) were significantly higher compared with those in the CEV arm (6% and 2%). Among patients with limited disease, median survival time was 14.5 months vs 9.7 months in the PE and CEV arms, respectively (p = 0.001). The 2-year and 5-year survival rates of 25% and 10% in the PE arm compared with 8% and 3% in the CEV arm (p = 0.0001). Quality-of-life assessments revealed no major differences between the randomized groups. The authors concluded that PE is superior to CEV in patients with limited-disease SCLC. Therefore, PE is the recommended chemotherapy regimen to combine with TRTx in the treatment of limited-stage SCLC.
| Sequencing and Timing of Radiation and Chemotherapy |
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Murray et al65 performed a metaanalysis of trials that combined chemotherapy and TRTx, using progression-free survival at 3 years as a surrogate end point for long-term survival, and favored the earlier initiation of concurrent TRTx with chemotherapy. If initiation of radiation was delayed beyond 5 weeks of initiation of chemotherapy, the benefit decreased and survival approached that seen with chemotherapy alone. However, this analysis did not separate issues of timing from those of concurrency.
There have been at least nine randomized trials that have addressed the issue of the timing of radiation in limited SCLC (Table 2 in the evidence report and technical assessment; see chapter "SCLC Evidence"). There are major differences in trial design, choice of chemotherapeutic agents, and radiation dose and fractionation schedules.
De Ruysscher et al66 undertook a systematic review and literature-based metaanalysis to determine whether the timing of chest radiotherapy may influence the survival of patients with limited-stage SCLC. Eligible randomized controlled clinical trials were identified according to the Cochrane Collaboration Guidelines, comparing different timing of chest radiotherapy. Early chest irradiation was defined as beginning within 30 days after the start of chemotherapy. Considering all seven eligible trials, the overall survival at 2 years or 5 years was not significantly different between early or late chest radiotherapy. When only trials were considered that used platinum chemotherapy concurrent with chest radiotherapy, a significantly higher 5-year survival was observed when chest radiotherapy was started within 30 days after the start of chemotherapy (2-year survival: odds ratio, 0.73; 95% CI, 0.51 to 1.03; p = 0.07; 5-year survival: OR, 0.64; 95% CI, 0.44 to 0.92; p = 0.02). This was even more pronounced when the overall treatment time of chest radiotherapy was < 30 days. These data seem to indicate that 5-year survival rates of patients with limited-stage SCLC are in favor of early chest radiotherapy, with a significant difference if the overall treatment time of chest radiation is < 30 days and if a platinum-based chemotherapy is used concurrently.
In another report, Spiro et al67 examined the effect on survival of the timing of TRTx in patients with limited-disease SCLC. Patients received three cycles of cyclophosphamide, doxorubicin, and vincristine, alternating with three cycles of EP. Three hundred twenty-five chemotherapy- and radiotherapy-naive patients were randomly assigned to either early TRTx administered concurrently in the second cycle or late TRTx administered concurrently with the sixth cycle. The dose was 40 Gy in 15 fractions over 3 weeks.