Preferential use of imaging modalities in staging newly diagnosed rectal cancer: a survey of US radiation oncologists.

BACKGROUND: Accurate staging is crucial for management of patients with newly diagnosed rectal cancer. Endorectal ultrasound (EUS) has been the standard modality in the United States for decades, with magnetic resonance imaging (MRI) now preferred by national guidelines. Positron emission tomography (PET), conversely, is not recommended. The current utilization of imaging modalities by American radiation oncologists in staging newly diagnosed rectal cancer is unknown. METHODS: American radiation oncologists completed an anonymous institutional review board-approved online survey probing their imaging preferences for initial staging of rectal cancer patients. RESULTS: We received 220 responses from American radiation oncologists, with 39% in academic centers and with 45% seeing more than 10 rectal cancer patients per year. Most respondents utilize all three imaging modalities for rectal cancer staging-EUS, MRI and positron emission tomography/computed tomography (PET/CT). Fifty-two percent and 38% of respondents are high utilizers of EUS and MRI, respectively, defined as ordering these tests at least 75% of the time. Forty seven percent were high PET utilizers. The latter was associated with practice in a private setting (P=0.015) and being within 10 years from residency training completion (P<0.01). CONCLUSIONS: Our analysis reveals a dramatic discordance among national guidelines and the practice patterns among American radiation oncologists. More rely on PET for initial staging of rectal cancer patients than on pelvic MRI. Further research needs to determine the most effective imaging work-up of patients with an initial diagnosis of rectal cancer.

Does a fine line exist between regional and metastatic pelvic lymph nodes in rectal cancer-striking discordance between national guidelines and treatment recommendations by US radiation oncologists.

BACKGROUND: Management of rectal cancer with involved lateral pelvic lymph nodes (LPLNs) at the time of diagnosis-the stage we refer institutionally to as Stage 3.5-is controversial. The American Joint Committee on Cancer's 7th edition classifies internal iliac lymph nodes (LNs) as regional (Stage III), but both external and common iliac LNs as metastatic (Stage IV). However, in many Asian countries all LPLNs are considered regional and patients are treated with curative intent, with literature supporting improved outcomes with LPLN dissection. Management patterns of these patients by US radiation oncologists (ROs) are unknown. METHODS: American ROs completed an anonymous institutional review board-approved online questionnaire regarding rectal cancer management. RESULTS: Among the 220 completed responses, 45% treat more than 10 patients annually and 39% work in academia. We found 10.5% and 34.2% recommend biopsy of clinically involved internal and common iliac LNs, respectively. The vast majority of responders-98.6% and 94.5%-treat involved internal and common iliac LNs with curative intent, respectively. Respondents recommend treatment intensification to involved internal iliac LNs by dissection of the nodal basin (88.2%) and radiation therapy (RT) boost (59.1%), and treatment intensification to involved common iliac LNs by LN dissection (76.4%) and RT boost (63.6%). CONCLUSIONS: Our analysis reveals that the vast majority of US ROs approach patients with involved LPLNs, both regional (internal iliac) and metastatic (common iliac), with curative intent. They recommend treatment intensification with surgical resection and/or RT boost to involved nodes. Prospective clinical trials need to determine the appropriate management of patients with Stage 3.5 rectal cancer.