Reviewing the role of parametrial boost in patients with cervical cancer with clinically involved parametria and staged with positron emission tomography.

Objective: Primary objective was to validate the practice of not treating clinically involved parametria by parametrial boost. Secondary objective was to validate the adequacy of nodal boost in node-positive patients regardless of parametrial status.
Material and Methods: A retrospective analysis of 193 patients with locoregionally advanced cervical cancer treated with curative intent using external beam radiotherapy and brachytherapy. All patients were staged clinically (International Federation of Gynecology and Obstetrics) and radiologically using magnetic resonance imaging and positron emission tomography. The positron emission tomography positive nodes were boosted to an additional dose of 6 to 10 Gy after 40 Gy to the whole pelvis. Parametrial boost was not used. Patients with stages IB to IIa and stages IIB to IIIB disease were allocated to groups A and B, respectively.
Results: The pelvic failure (P = 0.430) and extrapelvic failure (P = 0.437) did not differ significantly between groups A and B. In multifactor analysis, tumor volume was significantly associated with pelvic failure (P = 0.009) and node positivity was significantly associated with extrapelvic failure (P = 0.002). Clinical parametrial involvement in the absence of parametrial boost was not related to either pelvic or extrapelvic failure. None of the node-positive patients had isolated pelvic nodal failure.
Conclusion: Cervical cancer with clinically involved parametria can be adequately treated without parametrial boost. A dose of 46 to 50 Gy was adequate to avoid isolated pelvic nodal failure.