Impact of T and N stage and treatment on survival and relapse in adjuvant rectal cancer: a pooled analysis.
OBJECTIVE
To determine survival and relapse rates by T and N stage and treatment method in five randomized phase III North American rectal adjuvant studies.


METHODS
Data were pooled from 3,791 eligible patients enrolled onto North Central Cancer Treatment Group (NCCTG) 79-47-51, NCCTG 86-47-51, US Gastrointestinal Intergroup 0114, National Surgical Adjuvant Breast and Bowel Project (NSABP) R01, and NSABP R02. Surgery alone (S) was the treatment arm in 179 patients. The remaining patients received adjuvant treatment as follows: irradiation (RT) alone (n = 281), RT + fluorouracil (FU) +/- semustine bolus chemotherapy (CT; n = 779), RT + protracted venous infusion CT (n = 325), RT + FU +/- leucovorin or levamisole bolus CT (n = 1,695), or CT alone (n = 532). Five-year follow-up was available in 94% of surviving patients, and 8-year follow-up, in 62%.


RESULTS
Overall (OS) and disease-free survival were dependent on TN stage, NT stage, and treatment method. Even among N2 patients, T substage influenced 5-year OS (T1-2, 67%; T3, 44%; T4, 37%; P <.001). Three risk groups of patients were defined: (1) intermediate (T1-2/N1, T3/N0), (2) moderately high (T1-2/N2, T3/N1, T4/N0), and (3) high (T3/N2, T4/N1, T4/N2). For intermediate-risk patients, those receiving S plus CT had 5-year OS rates of 85% (T1-2/N1) and 84% (T3/N0), which was similar to results with S plus RT plus CT (T1-2/N1, 78% to 83%; T3/N0, 74% to 80%). For moderately high-risk lesions, 5-year OS ranged from 43% to 70% with S plus CT, and 44% to 80% with S plus RT plus CT. For high-risk lesions, 5-year OS ranged from 25% to 45% with S plus CT, and 29% to 57% with S plus RT plus CT.


CONCLUSIONS
Different treatment strategies may be indicated for intermediate-risk versus moderately high- or high-risk patients based on differential survival rates and rates of relapse. Use of trimodality treatment for all patients with intermediate-risk lesions may be excessive, since S plus CT resulted in 5-year OS of approximately 85%; however, 5-year disease-free survival rates with S plus CT were 78% (T1-2/N1) and 69%(T3/N0), indicating room for improvement.
Gunderson
Leonard L
LL
Radiation Oncology Department, Mayo Clinic Cancer Center, Scottsdale, AZ 85259, USA. gunderson.leonard@mayo.edu
Sargent
Daniel J
DJ
Tepper
Joel E
JE
Wolmark
Norman
N
O'Connell
Michael J
MJ
Begovic
Mirsada
M
Allmer
Cristine
C
Colangelo
Linda
L
Smalley
Steven R
SR
Haller
Daniel G
DG
Martenson
James A
JA
Mayer
Robert J
RJ
Rich
Tyvin A
TA
Ajani
Jaffer A
JA
MacDonald
John S
JS
Willett
Christopher G
CG
Goldberg
Richard M
RM
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