Computed tomography chest imaging offers no advantage over chest X-ray in the initial assessment of gestational trophoblastic neoplasia

Abstract

BackgroundThe International Federation of Gynaecology and Obstetrics (FIGO) score identifies gestational trophoblastic neoplasia (GTN) patients as low-or high-risk of single-agent chemotherapy resistance (SACR). Computed tomography (CT) has greater sensitivity than chest X-ray (CXR) in detecting pulmonary metastases but effects upon outcomes remain unclear. Methods589 patients underwent both CXR and CT during GTN assessment. Treatment decisions were CXR-based. Number of metastases, risk scores and risk-category using CXR versus CT were compared. CT-derived chest assessment was evaluated as impact upon treatment-decision compared to patient outcome, incidence of SACR, time-to-normal-hCG (TNhCG) and primary chemotherapy resistance (PCR). ResultsMetastasis detection (p<0.0001) and FIGO score (p=0.001) were higher using CT versus CXR. CT would have increased FIGO score in 188 (31.9%), with 43 reclassified from low-to high-risk, of whom 23 (53.5%) received curative single-agent chemotherapy. SACR was higher when score (p=0.044) or risk-group (p<0.0001) changed. Metastases on CXR (p=0.019) but not CT (p=0.088) lengthened TNhCG.Logistic regression analysis found no difference between CXR (AUC=0.63) versus CT (AUC=0.64) in predicting PCR. Conclusion 4CT chest would improve the prediction of SACR, but does not influence overall treatment outcome, TNhCG or prediction of PCR. Lower radiation doses and cost mean ongoing CXR-based assessment is recommended.

The pregnancy that wasn’t: challenges of gestational trophoblastic neoplasia management in low- and middle-income countries

“…Approximately 40% of patients with a negative chest x-ray will have micro-metastases detected by a chest CT scan 6 . A chest CT scan improves prediction of single-agent chemotherapy resistance but does not influence overall treatment outcome or the time to human chorionic gonadotropin normalization 7…”

Challenges in the Treatment of Low-risk Gestational Trophoblastic Neoplasia

“…Although CT improves prediction of single-agent chemotherapy resistance, it does not influence overall treatment outcome or the time to hCG normalization. 7 On the contrary, because it has higher sensitivity in detecting micrometastases, which may be seen in 40% of patients, chest CT can distort the FIGO score, leading patients with low-risk GTN, who would be largely cured with single-agent regimens, to receive multiagent chemotherapy. 9 Thus, we emphasize the importance of basing the scoring of metastases according to the FIGO recommendations, which consists of a pelvic exam to assess genital metastases, Doppler pelvic ultrasound, and chest X-ray.…”

“…The most common site of GTN metastasis is the lung, 6 7 and, as such, the size and number of lung metastases is fundamental for a correct assessment of the WHO/FIGO prognostic score. Although FIGO expressly recommends using chest X-ray for screening for GTN lung metastases, 5 8 the use of chest computed tomography (CT) has become increasingly common in cancer staging, not only because of its higher sensitivity for detecting metastatic nodules, but also for the more accurate measurement of tumor size.…”

“…Although CT improves prediction of single-agent chemotherapy resistance, it does not influence overall treatment outcome or the time to hCG normalization. 7 On the contrary, because it has higher sensitivity in detecting micrometastases, which may be seen in ∼ 40% of patients, chest CT can distort the FIGO score, leading patients with low-risk GTN, who would be largely cured with single-agent regimens, to receive multiagent chemotherapy. 9 …”