Postoperative outcomes of MR-invisible stage IB1 cervical cancer

OBJECTIVE: Tumor volume is a significant prognostic factor of cervical cancer. It is still unknown about outcome of biopsy-proven IB1 cervical cancer, which is invisible on preoperative magnetic resonance imaging (MRI). The aim was to evaluate retrospectively the postoperative outcomes of MR-invisible stage IB1 cervical cancers. STUDY DESIGN: Between January 2001 and December 2007, we reviewed the medical records of 86 patients with biopsy-proven IB1 cervical cancer that was invisible on MRI. During the same period, we also reviewed the medical records of 260 patients with biopsy-proven IB1 cervical cancer that was visible on MRI. Both of these cancer groups were treated with radical hysterectomy and lymph node dissection. MR-invisible and MR-visible IB1 cancers were compared in terms of pathologic parameters and long-term survival rate. RESULTS: The median sizes and depths of stromal invasion of MR-invisible vs MR-visible IB1 cancers were 4.5 +/- 7.1 mm and 33.3% +/- 20.1% vs 30 +/- 14 mm and 66.7% +/- 26.6%, respectively (P = .000). The incidences of lymph node metastasis, parametrial invasion, and lymphovascular invasion were 1.1% (1/86 cases) and 18.8% (49/260 cases; P = .000; odds ratio, 19.7), 0% (0/86 cases) and 6.5% (17/260 cases; P = .009; odds ratio, 12.4), and 4.7% (4/86 cases) and 26.9% (70/260 cases; P = .000; odds ratio, 7.6) in the MR-invisible and MR-visible IB1 cancers, respectively. Recurrence-free and overall 5-year survival rates of MR-invisible vs MR-visible IB1 cancers were 98.8% (85/86 cases) vs 91.2% (237/260 cases) and 100% (86/86 cases) vs 95.8% (249/260 cases), respectively (P = .011 and .045). CONCLUSION: MR-invisible IB1 cancer provides better postoperative outcomes than MR-visible IB1 cancer because of the much lower tumor burden.