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Journal of Clinical Oncology, Vol 24, No 15 (May 20), 2006: pp. 2398-2399 © 2006 American Society of Clinical Oncology. DOI: 10.1200/JCO.2006.06.3297
In Reply:Department of Gynaecological-Oncology, Southampton University Hospitals Trust, Southampton, United Kingdom
Cancer Research UK Department of Medical Oncology, Glasgow, United Kingdom
Royal Marsden Hospital, London, United Kingdom
Division of Oncology, Royal Brisbane and Womens' Hospital, Brisbane, Australia
Department of Gynaecological-Oncology, North Glasgow University Hospitals Trust, Glasgow, United Kingdom
Cancer Research UK Department of Medical Oncology, Glasgow, United Kingdom We thank Drs Aletti and Cliby for their comments and welcome the opportunity to reply to their specific points. There was a uniform rate of return of surgical data across country groups as well as for International Federation of Gynecology and Obstetrics stage. The return rates were similar for the United Kingdom patients (84%) versus non-United Kingdom patients (82%) and across the tumors stages: IC (80%), II (83%), III (82%), and IV (86%).1 We fully acknowledge that progression-free survival for FIGO stages IC, II, IIIA, and IIIB is more optimal than for stages IIIC and IV. It is for this reason that a systematic approach towards defining and then stratifying the prognostic score was undertaken. It is entirely reasonable therefore for the conclusions on more advanced ovarian cancer to be made. The comparison is not between the various prognostic groups but whether effective debulking surgery in each of these groups made a meaningful difference to survival. We have repeated the analysis of surgical effect restricting this to stage IIIC and IV patients only. In this reduced population we still observe the same pattern with the effect of debulking decreasing markedly across four equally sized prognostic groups (P = .020). There is not a universally defined cutoff in the literature and 2 cm is commonly used. The way our data is categorized makes it difficult to give a percentage for the patients with residual disease less than 1 cm, however the percentage with no residual disease was 33%. The rate of debulking to no residual disease was 29% for United Kingdom patients and 40% for non-United Kingdom patients. Only diaphragm involvement adds to the prognostic ability of the variables identified in the multivariate prognostic model in our article (all the existing identified variables retain their prognostic ability). The examination of a revised prognostic score, including the diaphragm variable, shows the same dependence of surgical affect on disease prognosis (split into four equally sized groups based on the prognostic score) although this does not quite reach statistical significance (P = .081). The lack of statistical significance might partially be explained by reduced numbers (diaphragm involvement was not available for 144 patients). An alternate, more powerful analysis, which uses the new prognostic score as a continuous variable still demonstrates a statistically significant dependence of the effect of debulking on patient prognosis (P = .007). We agree that residual disease is not a surrogate of aggressive surgery and it was for this reason that the comparison between the United Kingdom and non-United Kingdom was performed, as there is a clear difference in the radicality of surgery as well as the operating times between these country groups. We did examine the effect of various surgical techniques as part of our analysis, although this was not presented in our article. We could find no specific procedure that had any effect on progression-free survival after adjustment for background biology. While we agree that residual disease is not a complete surrogate for aggressive surgery, the ultimate aim of surgery, aggressive or not, is to minimize the amount of residual disease. If minimizing the amount of residual disease does not improve outcome extra surgical effort to achieve this is not worthwhile. The study by Eisenkop et al2 cited by the correspondents only examines the results for optimally cytoreduced patients, and it is difficult to conclude anything about the effect of surgery in different prognostic groups from these data. The correspondents’ own article3 does not control for the same background biologic variables as we have and it may well be if they had categorised their patients in the same way they would have seem the same variation in debulking effect with prognosis (discussed previously). Our conclusion regarding the effect of lymphadenectomy is supported from the randomized trial of Pacini et al.4 Moreover if we adjust the Cox analysis for whether patients have stage IIIC disease, we find this makes almost no difference to the estimated hazard ratios presented in our article. While lymphadenectomy might have a contributing role in improved progression-free survival, we were explicit that the Scottish Randomized Trial in Ovarian Cancer cannot confirm that lymphadenectomy was the cause of the survival difference. Finally, we would contend that our study has carefully stratified for the initial volume of disease (via stratifying most important biologic background variables identified via Cox multiple regression), residual disease, and patient comorbidities (performance status was not a statistically significant prognostic factor in our patient group; perhaps unsurprisingly given the eligibility criteria for the clinical trial). These are complex data sets to analyze and interpret. We thank the correspondents for their views and suggestions. Author’ Disclosures of Potential Conflicts of Interest
Although all authors completed the disclosure declaration, the following author or immediate family members indicated a financial interest. No conflict exists for drugs or devices used in a study if they are not being evaluated as part of the investigation. For a detailed description of the disclosure categories, or for more information about ASCO's conflict of interest policy, please refer to the Author Disclosure Declaration and the Disclosures of Potential Conflicts of Interest section in Information for Contributors.
Dollar Amount Codes (A) < $10,000 (B) $10,000-99,999 (C)
REFERENCES
1. Crawford SC, Vasey PA, Paul J, et al: Does aggressive surgery only benefit patients with less advanced ovarian cancer? Results from an international comparison within the SCOTROC-1 Trial. J Clin Oncol 23:8802-8811, 2005 2. Eisenkop SM, Spirtos NM: Procedures required to accomplish complete cytoreduction of ovarian cancer: Is there a correlation with "biological aggressiveness" and survival? Gynecol Oncol 82:435-441, 2001[Medline] 3. Aletti GD, Dowdy SC, Gostout BS, et al: Aggressive surgical effort and improved survival in advanced stage ovarian cancer. Obstet Gynecol 107:77-85, 2006 4. Pacini PB, Maggioni A, Hacker N, et al: Systematic aortic and pelvic lymphadenectomy versus resection of bulky nodes only in optimally debulked advanced ovarian cancer: A randomized clinical trial. J Natl Cancer Inst 97:560-566, 2005 Related Correspondence
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Copyright © 2006 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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$100,000 (N/R) Not Required
