Pelvic Fracture as a Consequence of Radiation for Cervical Cancer

By William B. Ershler, MD

ABSTRACT & COMMENTARY

SYNOPSIS: Among 300 women treated at MD Anderson with radiation therapy for cervical cancer, pelvic fracture occurred in 29, with 83% diagnosed within two years of completing therapy. Older age and lower BMI were found to be significant risk factors.

Source: Schmeler KM, et al. Pelvic fractures after radiotherapy for cervical cancer. Implications for survivors. Cancer. 2010;116:625–630.

Curative treatment for cervical cancer often calls for radiation therapy, either delivered primarily or as an adjunct to surgical excision and chemotherapy.1,2 With the improvement in survival that such therapies have provided, there are now concerns over the long-term consequences of such approaches. Among these is the occurrence of pelvic fractures in those patients who had received radiotherapy. To address the incidence and risk of pelvic fracture among treated cervical-cancer patients, Schmeler et al at MD Anderson performed a retrospective review of the case histories of women treated there in the years 2001 through 2006.

Of the 516 women treated with curative-intent radiotherapy, 300 patients had at least one post-treatment computed tomography scan or magnetic resonance imaging study available for review, and they comprised the study population. All imaging studies were reviewed by a single radiologist to evaluate for fractures.

Pelvic fractures were noted in 29 of 300 patients (9.7%). Fracture sites included sacrum (n = 24; 83%), sacrum and pubis (n = 3; 10%), iliac crest (n = 1; 3%), and sacrum and acetabulum (n = 1; 3%). Only thirteen of the thirty patients (45%) were symptomatic, with pain being the most common presenting symptom. The median time from the completion of radiotherapy to the detection of fractures on imaging studies was 14.1 months (range, 2.1-63.1 months), with 38% of patients diagnosed within one year and 83% diagnosed within two years of completing therapy. The median age of the patients at diagnosis was higher in the women who developed a fracture compared with the women who did not (56.5 years vs. 46.7 years; p = .04). A higher number of women with a fracture were postmenopausal (62% vs. 37%; p = .03). The median body mass index was lower in the women who had a fracture (26.0 kg/m2 vs. 28.0 kg/m2; p = .03).

Commentary

Thus, pelvic fractures were detected in approximately 10% of women after radiotherapy for cervical cancer. This, itself, is not a new finding, as there have been reports of an increased risk of increased pelvic fracture among women who received radiation for gynecological malignancy.3-5 However, unlike prior reports, this review included primarily American women and is large enough to establish risk factors. Thus, it was found that older patients and those with larger BMI were statistically more likely to sustain pelvic fracture. There were no statistically significant differences found with regard to ethnicity, smoking history, stage of disease, tumor grade, radiation dose, or use of concomitant chemotherapy between those who did or did not sustain fracture.

Among this cohort, the majority of fractures were diagnosed within two years of completion of treatment, although the median follow-up was only 20, and there were fractures observed in some after 60 months.

Although by no means established, it appears that radiation negatively affects the bone remodeling process, resulting in osteopenia and fracture risk. With an apparent risk of fracture not long after the completion of therapy, it is reasonable to develop strategies to enhance bone health for these patients. Certainly, bone mineral density screening and pharmacologic intervention are reasonable precautions and should be the subject of future investigation.

References

1. Stehman FB, et al. Carcinoma of the cervix treated with radiation therapy. I. A multi-variate analysis of prognostic variables in the Gynecologic Oncology Group. Cancer. 1991;67:2776-2785.

2. Morris M, et al. Pelvic radiation with concurrent chemotherapy compared with pelvic and para-aortic radiation for high-risk cervical cancer. N Engl J Med. 1999;340:1137-1143.

3. Abe H, et al. Radiation-induced insufficiency fractures of the pelvis: evaluation with 99mTc-methylene diphosphonate scintigraphy. AJR Am J Roentgenol. 1992;158:599-602.

4. Blomlie V, et al. Incidence of radiation-induced insufficiency fractures of the female pelvis: Evaluation with MR imaging. AJR Am J Roentgenol. 1996;167:1205-1210.

5. Oh D, et al. Pelvic insufficiency fracture after pelvic radiotherapy for cervical cancer: analysis of risk factors. Int J Radiat Oncol Biol Phys. 2008;70:1183-1188.