Improving the accuracy and consistency of clinical target volume delineation for rectal cancer by an education program

BACKGROUND Accurate target volume delineation is the premise for the implementation of precise radiotherapy.Inadequate target volume delineation may diminish tumor control or increase toxicity.Although several clinical target volume(CTV)delineation guidelines for rectal cancer have been published in recent years,significant interobserver variation(IOV)in CTV delineation still exists among radiation oncologists.However,proper education may serve as a bridge that connects complex guidelines with clinical practice.AIM To examine whether an education program could improve the accuracy and consistency of preoperative radiotherapy CTV delineation for rectal cancer.METHODS The study consisted of a baseline target volume delineation,a 150-min education intervention,and a follow-up evaluation.A 42-year-old man diagnosed with stage IIIC(T3N2bM0)rectal adenocarcinoma was selected for target volume delineation.CTVs obtained before and after the program were compared.Dice similarity coefficient(DSC),inclusiveness index(IncI),conformal index(CI),and relative volume difference[ΔV(%)]were analyzed to quantitatively evaluate the disparities between the participants’delineation and the standard CTV.Maximum volume ratio(MVR)and coefficient of variation(CV)were calculated to assess the IOV.Qualitative analysis included four common controversies in CTV delineation concerning the upper boundary of the target volume,external iliac area,groin area,and ischiorectal fossa.RESULTS Of the 18 radiation oncologists from 10 provinces in China,13 completed two sets of CTVs.In quantitative analysis,the average CTV volume decreased from 809.82 cm3 to 705.21 cm3(P=0.001)after the education program.Regarding the indices for geometric comparison,the mean DSC,IncI,and CI increased significantly,whileΔV(%)decreased remarkably,indicating improved agreement between participants’delineation and the standard CTV.Moreover,an 11.80%reduction in MVR and 18.19%reduction in CV were noted,demonstrating a smaller IOV in delineation after the education program.Regarding qualitative analysis,the greatest variations in baseline were observed at the external iliac area and ischiorectal fossa;61.54%(8/13)and 53.85%(7/13)of the participants unnecessarily delineated the external iliac area and the ischiorectal fossa,respectively.However,the education program reduced these variations.CONCLUSION Wide variations in CTV delineation for rectal cancer are present among radiation oncologists in China's Mainland.A well-structured education program could improve delineation accuracy and reduce IOVs.

Reducing intrathecal pressure after traumatic spinal cord injury: a potential clinical target to promote tissue survival

Spinal cord injury （SCI） is an unexpected event that is both devastating and debilitating, resulting in not just motor and sensory loss, but also autonomic dysfunction of the bladder, bowel and sexual organs. Currently, there are no treatments available to improve outcome follow- ing SCI, leaving individuals with permanent and lifelong physical disability. Worldwide it is estimated that more than 500,000 people sustain a SCI each year, with average lifetime cost of paraplegia and quadriplegia estimated at $5 million and $9.5 million respectively. We therefore urgently need effective therapies to improve quality of life following SCI, and this requires a greater understanding of how cell and axonal injury develops after the traumatic event.

Delineation of clinical target volume in nasopharyngeal carcinoma

Radiotherapy is the mainstay treatment modality for nasopharyngeal carcinoma(NPC).Intensity-modulated radiation therapy(IMRT),as the standard technique,achieves the purpose of improving target coverage and better sparing of normal tissue.Increased attention has been given to explore various strategies for deescalating treatment intensity.The optimization of clinical target volume(CTV)is one of the most active research areas being widely discussed.Although the International Guidelines for the delineating of CTV in NPC had provided important references for clinicians,there are marked variations in practice among different institutions.This article reviews the development of CTV delineation in non-metastatic NPC patients among centers,and compares the similarities and differences in CTV delineation of various current guidelines in the hope of providing insights for future investigation.This review aims to provide a comprehensive summary of the development and evolution of CTV delineation on primary tumor and lymph nodes for definitive radiotherapy in non-metastatic NPC through historical lens.We also compare the differences of CTV delineation ways.In addition,we look into the clinical and practical challenges of CTV delineation,hoping to provide direction for future research.