RTOG 89-02

Background

Phase II trial (RTOG 89-02). 99 patients with T1 or T2 rectal adenocarcinoma within 8 cm of the anal verge. Evaluated preoperative CRT followed by local excision for sphincter preservation. Builds on CALGB 8984 framework.

Interventions and follow up

Arm A: Preoperative CRT: 45 Gy + 5-FU 1,000 mg/m²/day CI days 1–4 and 28–31 → local full-thickness excision 4–6 weeks later → adjuvant 5-FU × 4 cycle
Primary endpoint: Local control and sphincter preservatio
mFollow up: 5 year

Results

pCR: 37% (T1), 27% (T2)
5-yr local recurrence: 4% (T1), 16% (T2)
5-yr OS: 87% (T1), 72% (T2)
Sphincter preservation: 100%

Adverse events

Main adverse events: Grade ≥3 toxicity during CRT ~25%. Local wound complications 18%. Similar to CALGB 8984 rates.

Conclusions

Preoperative CRT followed by local excision achieves 100% sphincter preservation. T1 lesions fare well (4% local recurrence at 5 yr). T2 lesions have a substantially higher local recurrence rate (16%) — suggesting local excision after CRT for T2 disease carries meaningful oncologic risk. T1N0 is the optimal candidate for this approach.

Key Limitations

Key Limitations: Phase 2 study — no randomized comparison with radical resection (APR/LAR). T2 local recurrence (16%) exceeds what would be expected with TME. Patient selection critical: only T1-T2 N0 tumors with no lymphovascular invasion, well-differentiated, ≤4 cm, within 8 cm. Salvage surgery required in ~16% of T2 patients. Does not address modern organ preservation (watch-and-wait) strategies.

Clinical Context

RTOG 89-02 and CALGB 8984 together defined the outcomes of local excision after preoperative CRT for early rectal cancer. The acceptable T1 outcomes (4% local recurrence) and the higher T2 recurrence (16%) influenced the design of ACOSOG Z6041 and the growing emphasis on watch-and-wait for clinical complete responders rather than local excision as the gold standard organ-preserving approach.

References

References: Russell AH et al, Int J Radiat Oncol Biol Phys 2000 (RTOG 89-02)