Extensive-Stage SCLC Treatment
·
Standard Treatment Options for Patients With
Extensive-Stage SCLC
o
Combination chemotherapy
o
Radiation therapy
·
Treatment Options Under Clinical Evaluation
·
Current Clinical Trials
Standard Treatment Options for Patients With Extensive-Stage SCLC
Standard
treatment options for patients with extensive-stage small-cell
lung cancer (SCLC) include
the following:
- Combination
chemotherapy.
- Radiation
therapy.
- Thoracic
radiation therapy for patients who respond to chemotherapy.
- Prophylactic
cranial irradiation (PCI).
Combination chemotherapy
Chemotherapy
for patients with extensive-stage disease (ED) SCLC is commonly given as a
two-drug combination of platinum and etoposide in doses associated with at
least moderate toxic effects (as in limited-stage [LD] SCLC).[1] Cisplatin is associated with significant toxic
effects and requires fluid hydration, which can be problematic in patients with
cardiovascular disease. Carboplatin is active in SCLC, is dosed according to
renal function, and is associated with less nonhematological toxic effects.
Other
regimens appear to produce similar survival outcomes but have been studied less
extensively or are in less common use.
Table 2.
Combination Chemotherapy For Extensive-Stage SCLC
|
||
Standard treatment
|
Etoposide + cisplatin
|
|
Etoposide + carboplatin
|
||
Other regimens
|
Cisplatin + irinotecan
|
|
Ifosfamide + cisplatin +
etoposide
|
||
Cyclophosphamide +
doxorubicin + etoposide
|
||
Cyclophosphamide +
doxorubicin + etoposide + vincristine
|
||
Cyclophosphamide + etoposide
+ vincristine
|
||
Cyclophosphamide +
doxorubicin + vincristine
|
Doses and
schedules used in current programs yield overall response rates of 50% to 80%
and complete response rates of 0% to 30% in patients with ED.[2,3][Level of evidence: 1iiA]
Intracranial
metastases from small cell carcinoma may respond to chemotherapy as readily as
metastases in other organs.[4,5]
Evidence
(standard regimens):
- Two meta-analyses evaluating the role of
platinum combinations versus nonplatinum combinations have been published.
o
A
Cochrane analysis did not identify a difference in 6-, 12-, or 24-month
survival.[6]
o
A
meta-analysis of 19 trials published between 1981 and 1999 showed a significant
survival advantage for patients receiving platinum-based chemotherapy compared
with those not receiving a platinum agent.[3][Level of evidence: 1iiA]
- The Hellenic Oncology Group conducted a
phase III trial comparing cisplatin and etoposide with carboplatin plus
etoposide.[7] The median survival was 11.8 months in
the cisplatin arm and 12.5 months in carboplatin-treated patients.[7][Level of evidence: 1iiA] Although this
difference was not statistically significant, the trial was underpowered
to prove equivalence of the two treatment regimens in patients with either
LD or ED.
Evidence
(other combination chemotherapy regimens):
- Irinotecan. Five trials and two meta-analyses have
evaluated the combination of etoposide and cisplatin versus irinotecan and
cisplatin. Only one of the trials showed the superiority of the irinotecan
and cisplatin combination.[8][Level of evidence: 1iiA] Subsequent
trials and the meta-analyses support that the regimens provide equivalent
clinical benefit with differing toxicity profiles.[9-14][Level of evidence: 1iiA] Irinotecan and
cisplatin regimens led to less grade 3 to 4 anemia, neutropenia, and
thrombocytopenia but more grade 3 to 4 vomiting and diarrhea than
etoposide and cisplatin regimens. Treatment-related deaths were comparable
between the two groups.
- Topotecan. In a randomized trial of 784 patients, the
combination of oral topotecan given with cisplatin for 5 days was not
found to be superior to etoposide and cisplatin.[15] The 1-year survival rate was 31% (95%
confidence interval [CI], 27%–36%) and was deemed to be noninferior, as
the difference of -0.03 met the predefined criteria of no more than 10%
absolute difference in 1-year survival.[15][Level of evidence: 1iiA]
- Paclitaxel. No consistent survival benefit has resulted
from the addition of paclitaxel to etoposide and cisplatin.[16,17]
Evidence
(duration of treatment):
- The optimal duration of chemotherapy is not
clearly defined, but no obvious improvement in survival occurs when the
duration of drug administration exceeds 6 months.[7,18,19]
- No clear evidence is available from
reported data from randomized trials that maintenance chemotherapy will
improve survival duration.[20-22][Level of evidence: 1iiA] However, a
meta-analysis of 14 published, randomized trials assessing the benefit of
duration/maintenance therapy reported an odds ratio of 0.67 for both 1-
and 2-year overall survival (OS) of 0.67 (95% CI, 0.56–0.79; P <
.001 for 1-year OS and 0.53–0.86; P < .001 for 2-year OS). This
corresponded to an increase of 9% in 1-year OS and 4% in 2-year OS.[23][Level of evidence: 1iiA]
Evidence
(dose intensification):
- The role of dose intensification in
patients with SCLC remains unclear.[24-28] Early studies showed that
under-treatment compromised outcome and suggested that early dose
intensification may improve survival.[24,25] A number of clinical trials have
examined the use of colony-stimulating factors to support dose-intensified
chemotherapy in SCLC.[26-34] These studies have yielded
conflicting results.
o
Four
studies have shown that a modest increase in dose intensity (25%–34%) was
associated with a significant improvement in survival with no compromise in
quality of life (QOL).[26-29][Level of evidence: 1iiA]
o
Two
of three studies that examined combinations of the variables of interval, dose
per cycle, and number of cycles showed no advantage.[29-32][Level of evidence: 1iiA]
o
The
European Organization for Research and Treatment of Cancer trial (EORTC-08923) reported a randomized comparison
of standard-dose cyclophosphamide, doxorubicin, and etoposide given every 3
weeks for five cycles versus intensified treatment given at 125% of the dose
every 2 weeks for four cycles with granulocyte colony-stimulating factor
(G-CSF) support.[32] The median dose intensity delivered was
70% higher in the experimental arm; the median cumulative dose was similar in
both arms. There was no difference between treatment groups in median or 2-year
survival.
o
A
randomized, phase III trial compared ifosfamide, cisplatin, and etoposide (ICE),
which was given every 4 weeks, with twice weekly ICE with G-CSF and autologous
blood support.[33] Despite achieving a relative dose
intensity of 1.84 in the dose-accelerated arm, there was no difference in
response rate (88% vs. 80%, respectively), median survival (14.4 vs. 13.9
months, respectively), or 2-year survival (19% vs. 22%, respectively) for
dose-dense treatment compared with standard treatment.[33][Level of evidence: 1iiA] Patients who received
dose-dense treatment spent less time on treatment and had fewer episodes of
infection.
o
A
randomized, phase II study of identical design reported a significantly better
median survival for the dose-dense arm (29.8 vs. 17.4 months, respectively; P = .02) and 2-year survival (62% vs.
36%, respectively; P = .05).[34] However, given the small study size (only
70 patients), these results should be viewed with caution.
Factors influencing treatment with chemotherapy
Performance status
More
patients with ED SCLC have greatly impaired performance status at the time of
diagnosis than patients with LD. Such patients have a poor prognosis and
tolerate aggressive chemotherapy or combined-modality therapy poorly.
Single-agent intravenous, oral, and low-dose biweekly regimens have been
developed for these patients.[30,35-41]
Prospective,
randomized studies have shown that patients with a poor prognosis who are
treated with conventional regimens live longer than those treated with the
single-agent, low-dose regimens or abbreviated courses of therapy. A study
comparing chemotherapy every 3 weeks with treatment given as required for
symptom control showed an improvement in QOL in those patients receiving
regular treatment.[38][Level of evidence: 1iiDii]
Other
studies have tested intensive one-drug or two-drug regimens. A study conducted
by the Medical Research Council demonstrated similar efficacy for an etoposide
plus vincristine regimen and a four-drug regimen.[39] The latter regimen was associated with a greater
risk of toxic effects and early death but was superior with respect to
palliation of symptoms and psychological distress.[39][Level of evidence: 1iiC] Studies comparing a
convenient oral treatment with single-agent oral etoposide versus combination
therapy showed that the overall response rate and OS were significantly worse
in the oral etoposide arm.[35,40][Level of evidence: 1iiA]
Age
Subgroup
analyses of phase II and phase III trials of SCLC patients by age showed that
myelosuppression and doxorubicin-induced cardiac toxic effects were more severe
in older patients than in younger patients and that the incidence of
treatment-related death tended to be higher in older patients.[41] About 80% of older patients, however, received
optimal treatment, and their survival was comparable to that of younger
patients. The standard chemotherapy regimens for the general population could
be applied to older patients in good general condition (i.e., performance
status of 0–1, normal organ function, and no comorbidity). There is no evidence
of a difference in response rate, disease-free survival (DFS), or OS in older
patients compared with younger patients.
Radiation therapy
Radiation
therapy to sites of metastatic disease unlikely to be immediately palliated by
chemotherapy, especially brain, epidural, and bone metastases, is a standard
treatment option for patients with ED SCLC. Brain metastases are treated with
whole-brain radiation therapy.
Chest
radiation therapy is sometimes given for superior vena cava syndrome, but
chemotherapy alone, with radiation reserved for nonresponding patients, is
appropriate initial treatment. (Refer to the PDQ summary on Cardiopulmonary Syndromes for more information.)
Thoracic radiation therapy for patients who
respond to chemotherapy
Patients
with ED treated with chemotherapy who have achieved a response can be
considered for thoracic radiation therapy.
Evidence
(thoracic radiation therapy):
- A randomized trial of 498 patients who
responded after receiving four to six cycles of chemotherapy compared
thoracic radiation therapy with 30 Gy in 10 fractions versus no radiation
therapy. All patients received PCI.[42][Level of evidence: 1iiA]
o
OS
was the primary study endpoint and not statistically different between the two
groups at 1 year (33% for the thoracic radiation therapy group vs. 28% for the
control group, P = .066).
o
However,
in a secondary analysis, 2-year OS was 13% in the thoracic radiation group (95%
CI, 9–19) versus 3% in the control group (95% CI, 2–8; P = .004). The OS during the entire
course of follow-up was not reported.
o
Thoracic
radiation therapy resulted in 6-month progression-free survival of 24% in the
thoracic radiation group (95% CI, 19–30) versus 7% in the control group (95%
CI, 4–11; P= .001).
o
Intrathoracic
recurrences, both isolated (19.8% vs. 46.0%) and in combination with
recurrences at other sites (43.7% vs. 79.8%), were reduced by approximately
50%.
o
Thoracic
radiation therapy was well tolerated.
PCI
Patients
with ED treated with chemotherapy who have achieved a response can be
considered for administration of PCI.
Evidence
(PCI):
- A randomized trial of 286 patients who
responded following four to six cycles of chemotherapy compared PCI versus
no further therapy.[43][Level of evidence: 1iiD
o
The
cumulative risk of brain metastases within 1 year was 14.6% in the radiation
group (95% CI, 8.3–20.9) and 40.4% in the control group (95% CI, 32.1– 48.6).
o
Radiation
was associated with an increase in median DFS from 12.0 weeks to 14.7 weeks and
in median OS from 5.4 months to 6.7 months after randomization.
o
The
1-year survival rate was 27.1% (95% CI, 19.4–35.5) in the radiation group and
13.3% (95% CI, 8.1–19.9) in the control group.[43]
o
Radiation
had side effects but did not have a clinically significant effect on global
health status.[43]
o
Only
29% of the randomly assigned patients had brain imaging at diagnosis.[44]
Combination chemotherapy and radiation therapy
Combination
chemotherapy plus chest radiation therapy does not appear to improve survival
compared with chemotherapy alone in patients with ED SCLC.
Treatment Options Under Clinical Evaluation
Treatment
options under clinical evaluation for patients with ED SCLC include the
following:
·
New
drug regimens.
·
Alternative
drug doses and schedules.
Current Clinical Trials
Check
for U.S. clinical trials from NCI's list of cancer clinical trials that are now
accepting patients withextensive stage small cell lung cancer. The list of
clinical trials can be further narrowed by location, drug, intervention, and
other criteria.
General
information about clinical trials is also available from the NCI Web
site.
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