Journal of Thoracic Oncology:
Letters to the Editor
Clinical Operational Research Unit (CORU); Department of Mathematics; University College London; London, United Kingdom (Treasure)
National Institute for Health and Clinical Excellence (NICE); London, United Kingdom (Macbeth)
Disclosure: The authors declare no conflicts of interest.
Address for correspondence: Tom Treasure, MD, Clinical Operational Research Unit (CORU), Department of Mathematics, University College London, London, United Kingdom. E-mail: email@example.com
To the Editor:
Searching the literature, Kemp et al.1 found clinical reports on only 43 individuals who had surgical excision of one or more pulmonary metastasis for gastric cancer. On the basis of the data extracted, the authors suggest that this surgery should be considered for future patients. A cautionary note is that 12 of 21 publications included in the review were of single case reports; the median number of cases per report is thus 1. Case reports appear in journals primarily because they are outside the norm and unrepresentative of the usual course of events.
The vital question is how would patients such as these have fared were it not for the metastasectomy; the authors implicitly offer 2% survival as the comparator. Their source2 applies to patients who had distant metastases at the time of entry to the National Cancer Database and are quite unlike those in Kemp's report where 33 of 34 patients were free of any metastases at the time of gastrectomy. Apparently 79% of patients with metastatic disease from gastric cancer present within 2 years of gastric resection, but the interval between gastrectomy and metastasectomy was nearly 3 years in Kemp's report. Of the 42 individuals where the pulmonary metastasis count is provided, 34 (81%) had a single metastasis, which is not the typical pattern of metastatic disease. Is it likely that these very few atypical cases reported over more than 30 years, 41 of 43 from Japan, inform practice in a disease that kills 10,000 a year in the United States?
Parallels are drawn with pulmonary metastasectomy for colorectal cancer.1 The conclusion of a 2010 systematic review reads “outcomes exceed those normally associated with metastatic colorectal cancer. It is this perception that has encouraged surgeons and caused the practice to grow.”3 This is a more tentative conclusion than Kemp et al. suggest. Five-year survival after pulmonary metastasectomy in colorectal cancer has been consistently of the order of 40% over 40 years.4 Is this a consequence of surgery or selection? The proposition put in 1980 is unresolved after 30 years.5 To test the hypothesis, data on Dukes stage and “disease-free interval” from American and Japanese reports of 144 and 159 patients6,7 were used to construct a model among patients matched for these factors in the Thames Cancer Registry. The model predicted similar survival to that observed, making selection the likely determinant.8 (A more readily accessible summary account is in the article by Utley and Treasure in the journal.)9
The practice of metastasectomy is extremely variable and increasing10 and is without a secure evidence base.11 There is sufficient doubt about the value of pulmonary metastasectomy for colorectal cancer for a multicenter, randomized, controlled trial to have been set up.12,13 What is seen in colorectal cancer might also apply in gastric cancer, but given the doubts about the present evidence, it would be prudent to not extrapolate to gastric carcinoma but to seek better evidence.
Tom Treasure, MD
Clinical Operational Research Unit (CORU)
Department of Mathematics
University College London
London, United Kingdom
Fergus Macbeth, FRCP
National Institute for Health and Clinical Excellence (NICE)
London, United Kingdom
1. Kemp CD, Kitano M, Kerkar S, et al. Pulmonary resection for metastatic gastric cancer. J Thorac Oncol 2010;5:1796–1805.
2. Hundahl SA, Phillips JL, Menck HR. The National Cancer Data Base Report on poor survival of U.S. gastric carcinoma patients treated with gastrectomy: Fifth Edition American Joint Committee on Cancer staging, proximal disease, and the “different disease” hypothesis. Cancer 2000;88:921–932.
3. Pfannschmidt J, Hoffmann H, Dienemann H. Reported outcome factors for pulmonary resection in metastatic colorectal cancer. J Thorac Oncol 2010;5(6 Suppl 2):S172–S178.
4. Fiorentino F, Hunt I, Teoh K, et al. Pulmonary metastasectomy in colorectal cancer: a systematic review and quantitative synthesis. J R Soc Med 2010;103:60–66.
5. Aberg T, Malmberg KA, Nilsson B, et al. The effect of metastasectomy: fact or fiction? Ann Thorac Surg 1980;30:378–384.
6. McCormack PM, Burt ME, Bains MS, et al. Lung resection for colorectal metastases. 10-year results. Arch Surg 1992;127:1403–1406.
7. Okumura S, Kondo H, Tsuboi M, et al. Pulmonary resection for metastatic colorectal cancer: experiences with 159 patients. J Thorac Cardiovasc Surg 1996;112:867–874.
8. Utley M, Treasure T, Linklater K, et al. Better out than in? The resection of pulmonary metastases from colorectal tumours. In X Xie, F Lorca, E Marcon (Eds.), Operations Research for Health Care Engineering: Proceedings of the 33rd International Conference on Operational Research Applied to Health Services. Saint-Etienne: Publications de l'Universitaire de Saint-Etienne, 2008. Pp. 493–500.
9. Utley M, Treasure T. Interpreting data from surgical follow-up studies: the role of modeling. J Thorac Oncol 2010;5(6 Suppl 2):S200–S202.
10. Internullo E, Cassivi SD, Van Raemdonck D, et al. Pulmonary metastasectomy: a survey of current practice amongst members of the European Society of Thoracic Surgeons. J Thorac Oncol 2008;3:1257–1266.
11. Van Raemdonck D, Friedel G. The European Society of Thoracic Surgeons lung metastasectomy project. J Thorac Oncol 2010;5(6 Suppl 2):S127–S129.
12. Treasure T, Fallowfield L, Farewell V, et al. Pulmonary metastasectomy in colorectal cancer: time for a trial. Eur J Surg Oncol 2009;35:686–689.
13. Treasure T, Fallowfield L, Lees B. Pulmonary metastasectomy in colorectal cancer: the PulMiCC trial. J Thorac Oncol 2010;5(6 Suppl 2):S203–S206.