Lay Summary: Adjuvant chemotherapy is now standard for lung cancer.
There is evidence to recommend platinum-based chemotherapy regimens as post-operative adjuvant therapy in the management of patients with completely resected stage II and IIIA NSCLC. Cisplatin-based treatment is preferred, although a carboplatin-based regimen can be used as an alternative if there is a contraindication to cisplatin. There is uncertainty about a benefit to patients with resected stage IB NSCLC, although adjuvant chemotherapy may still be considered in selected individuals.
A meta-analysis published in 1995 indicated that post-operative chemotherapy did not significantly reduce the risk of death in surgically resected, pathologic stage IB, II and IIIA NSCLC, although there was a trend in favour of adjuvant chemotherapy regimens that included the agent cisplatin.
ECOG 3590 and ALPI failed to demonstrate any benefit from adjuvant chemotherapy, either with or without post-operative radiotherapy. However, IALT study renewed interest in adjuvant therapy, as cisplatin-based combination chemotherapy was shown to improve relapse-free survival by 5.1%, and overall survival by 4.1% at five years.
The recent reports of NCIC CTG BR.10 and ANITA support a role for platinum-based combination chemotherapy as adjuvant therapy in resected NSCLC. Both trials demonstrated an improvement in overall survival: NCIC CTG BR.10 15% at 5 years, and ANITA 8.6% at 5 years.
A number of factors may account for the lack of benefit from adjuvant therapy in ECOG 3590 and ALPI, as compared to IALT, NCIC CTG BR.10, and ANITA. These include the potentially detrimental effect of post-operative radiotherapy, the impact of newer chemotherapy agents, and the total dose of chemotherapy delivered.
In conclusion: IALT, NCIC CTG BR.10, and ANITA provide compelling evidence in favour of adjuvant chemotherapy, although appropriate selection of patients for treatment is highlighted by the 0.8% risk in IALT of chemotherapy-related adverse events resulting in death. Both NCIC CTG BR.10 and ANITA also reported treatment-related deaths, accounting for 0.8% and 1.7% of those treated with chemotherapy, respectively.
The initial report of CALGB 9633 in 2004 indicated that adjuvant treatment with the combination of carboplatin and paclitaxel in resected stage IB NSCLC was associated with a 12% improvement in survival at 4 years. However, an update presented in 2006 demonstrated only a non-significant trend in favour of treatment at 5 years. While further analyses of CALGB 9633 are planned, the LACE meta-analysis also suggests a lack of benefit for adjuvant chemotherapy in resected stage IB NSCLC.
The Lung Tumour Group recommends routine consideration of adjuvant platinum-based combination chemotherapy in patients with fully resected stage II and IIIA NSCLC, but there is now uncertainty about its prescription in those with resected stage IB NSCLC. The magnitude of benefit of adjuvant therapy is likely proportional and dependent on the risk of relapse according to stage. There may be individuals with stage IB NSCLC with features associated with a risk of relapse similar to those with a higher stage of NSCLC. However, those high risk factors that might support selection for adjuvant chemotherapy are not defined. Adjuvant chemotherapy may still be offered to highly motivated individuals with resected stage IB NSCLC, but a discussion regarding the potential risks and harms of treatment is necessary.
Only chemotherapy regimens used in the most recent trials are evidence-based. These include the combination of cisplatin and vinorelbine as standard, as these two agents were employed in IALT, NCIC CTG BR.10 and ANITA. Cisplatin-based treatment is preferred, but in individuals with a contraindication to cisplatin, the combination of carboplatin and paclitaxel is an acceptable alternative.
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