Hello everybody,
I am working on a clinical cancer registry data for neoadjuvant therapy of stage II/III rectal cancer patients. In this data, there are some cases with more than 5 months difference between starting the neoadjuvant chemo(radio)therapy and surgery. I was wondering whether I should include these cases in the survival analysis or exclude them as an error in the data. In the ESMO guideline, I could not find any precise time difference definition for neoadjuvant therapy setting in rectal cancer patients.
I would appreciate your comments.
Best regards,
Masoud
Dear Masoud
the optimal time between neoadjuvant conventional chemoradiotherapy to surgery is 6 to 8 weeks.In short course chemoradiotherapy this interval is decreased to 7 to 10 days.
i suppose the majority of your cases are in conventional groups, that is,6 to 8 weeks.
in my opinion it is better include all your patients in your study even for interval of 5 months.
Dear Masoud
I recommend to study this paper
Gastroenterol Res Pract. 2016;2016:6756859. doi: 10.1155/2016/6756859. Epub 2016 Mar 30.
Effect of Interval between Neoadjuvant Chemoradiotherapy and Surgery on Oncological Outcome for Rectal Cancer: A Systematic Review and Meta-Analysis.
Wang XJ1, Zheng ZR2, Chi P1, Lin HM1, Lu XR1, Huang Y1.
Author information
Abstract
Aim. To evaluate the influence of interval between neoadjuvant chemoradiotherapy (NCRT) and surgery on oncological outcome. Methods. A systematic search was conducted in PubMed, the Cochrane Library, and Embase databases for publications reporting oncological outcomes of patients following rectal cancer surgery performed at different NCRT-surgery intervals. Relative risk (RR) of pathological complete response (pCR) among different intervals was pooled. Results. Fifteen retrospective cohort studies representing 4431 patients met the inclusion criteria. There was a significantly increased rate of pCR in patients treated with surgery followed 7 or 8 weeks later (RR, 1.45; 95% CI, 1.18-1.78; and P < 0.01 and RR, 1.49; 95% CI, 1.15-1.92; and P = 0.002, resp.). There is no consistent evidence of improved local control or overall survival with longer or shorter intervals. Conclusion. Performing surgery 7-8 weeks after the end of NCRT results in the highest chance of achieving pCR. For candidates of abdominoperineal resection before NCRT, these data support implementation of prolonging the interval after NCRT to optimize the chances of pCR and perhaps add to the possibility of ultimate organ preservation.
The necessary or recommended time interval between the START of neoadjuvant therapy of rectal cancer and surgical operation is not precisely defined.
Your kind question also needs some adjustment, because in the neoadjuvant treatment of rectal cancer there are couple of modalities including chemotherapy, radiotherapy and chemoradiation. The waiting time from the END of neoadjuvant treatment until surgery is strongly dependent from the procedure applied, because rationales are different in every kind of therapeutic approach.
Dear Ladislaus,
Thanks for your excellent comments. To make my question clear, we have a dataset containing retrospective clinical info of rectal cancer patients. in this dataset, we have the detailed information on preoperative chemo and radiotherapies including starting date and the relevant chemo and radiotherapy regimens. We would like to examine outcomes of patients who received neoadjuvant therapy in term of overall survival. However, in order to define the neo-chemoradiotherapy group, we could not find a precise definition for the maximum time difference between starting radio and chemotherapy that fits the neoadjuvant therapy setting. We would like to exclude cases who received any other treatment modalities out of the neoadjuvant setting.
Regards,
Masoud
OK, let's focus on neoadjuvant regimens used in preoperative/neoadjuvant setting.
1.) Long course chemoradiation is the most frequently used approach, using 45 Gy cumulative dose delivered during a 5 weeks period concomitantly with the chemo of choice. Sometimes extra boost is also needed up to 50,4 Gy cumulative dose (3 extra days). The recommended time for surgery is minimum 6 weeks after the end of CRT, but it could be extended up to 8 weeks. If you put together these numbers, the time between the START of CRT and surgery is within 87 and 104 days.
2.) During the so called neoadjuvant short-course RT, 25 Gy delivered in five fractions in one week followed by surgery done within a week. So, it means that the time betreen the START of neoadjuvant treatment and surgery is within 6 to 13 days. This approach is not widely accepted.
3.) In very rare cases, only chemo are used as neoadjuvant treatment. The length of it is 12 weeks (4 cycles of CAPOX, or 6 cycles of FOLFOX). Tumor can be resected between 2 and 4 weeks. In this case the time period between the START of treatment and surgery is within 84 and 98 days.
I hope that these data could provide you some help to define your investigational window on your dataset.
Sincerely Yours: Leslie
Dear Masoud,
I could not add more accurate information than this shared by Ladislaus. But the modern approach in this field called "wait&watch" implies that postponing the time of surgery would give the chance to have more cases with complete tumour response. Which is important, especially for very low cancers, where no other operative option than abdominoperineal excision is possible. Accordingly, the main problem not having appropriate standard yet, in my opinion, is how to assess adequately a post-therapeutic tumour response.
I would suggest A.Habbr-Gamma article about this recent tendency: http://www.ncbi.nlm.nih.gov/pubmed/15383798.
Sincerely Yours: Svilen
Dear Svilen,
Thanks for your excellent comments which gave me a lot of new ideas regarding my approaches in the analysing data. Best regards, Masoud
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