Elective Nodal Irradiation in the Treatment of Non-Small Cell Lung Cancer

Reviewer: Christopher Dolinsky, MD
University of Pennsylvania School of Medicine
Last Modified: November 9, 2006

Presenter: K.E. Rosenzweig
Presenter's Affiliation: Memorial Sloan Kettering Cancer Center, NY, NY
Type of Session: Scientific

Background

It is difficult to know which nodal regions need irradiation when treating lung cancer with radiotherapy.
At the Memorial Sloan Kettering Cancer Center, physicians decided to omit treating clinically uninvolved nodal stations after a protocol for dose escalation that employed elective nodal irradiation was found to cause too may cases of severe and/or fatal radiation pneumonitis.
This review was undertaken to see if the omission of elective nodal irradiation increases the likelihood that patients will experience a local failure following radiation.

Materials and Methods

Between 1990 and 2005, a total of 510 patients were treated at the Memorial Sloan Kettering Cancer Center with radiation therapy as primary treatment for lung cancer.
20% were stage I/II, 24% were stage IIIA, 42% were stage IIIB, and 14% had recurrent disease.
Radiation alone was employed in 44% of patients, sequential chemotherapy then radiation was used in 41% of patients, and concurrent chemoradiotherapy was used in 19% of patients.
60% of patients had pre-treatment PET scanning.
Only lymph node regions directly involved with tumor based on CT and or PET imaging were included in the clinical target volume.
Elective nodal recurrence was defined as recurrence in an initially uninvolved lymph node in the absence of local failure (although it could exist in combination with a distant failure).

Results

The 2-year elective nodal failure rate was 7.2% (9% in the presence of a local failure).
The median time to elective nodal failure was 4 months.
Median follow-up was 16 months.
Overall local control was 48%.
There was no difference in the elective nodal failure rate between patients who did or didn't have a pre-treatment PET scan.

Author's Conclusions

The omission of elective nodal radiation in non-small-cell lung cancer patients leads to a 7-9% nodal failure rate.
The authors continue to treat patients to only the gross tumor volume plus an appropriate margin at MSKCC.

Clinical/Scientific Implications

The authors present an interesting analysis of a single institution’s treatment experience. The use of elective nodal radiation in lung cancer is certainly controversial. We have a difficult time managing this cancer, and even high doses of radiation often will not prevent a local failure. It would be useful to know whether the nodal failures were seen primarily in higher stage patients. It may be safe to omit nodal radiation in early stage patients, as has been previously suggested from other studies. However, patients with bulky bilateral adenopathy probably carry a significant risk of subclinical nodal disease in the draining lymph node regions. Sometimes, we may have to eliminate nodal radiation in patients with poor lung function due to years of heavy cigarette smoking, yet it may be safe to treat large radiation volumes in patients with healthy lungs. These are all difficult questions to answer. For now, elective nodal radiation can either be defended or argued against depending on the literature one reads. The decision to use elective nodal irradiation will continue to lie independently with the managing physician.