Differential Perspectives by Specialty on Oligometastatic Colorectal Cancer: A Korean Oligometastasis Working Group’s Comparative Survey Study

Abstract

Purpose Despite numerous studies on the optimal treatments for oligometastatic disease (OMD), there is no established interdisciplinary consensus on its diagnosis or classification. This survey-based study aimed to analyze the differential opinions of colorectal surgeons and radiation oncologists regarding the definition and treatment of OMD from the colorectal primary.Materials and Methods A total of 141 participants were included in this study, consisting of 63 radiation oncologists (44.7%) and 78 colorectal surgeons (55.3%). The survey consisted of 19 questions related to OMD, and the responses were analyzed using the chi-square test to determine statistical differences between the specialties.Results The radiation oncologists chose “bone” more frequently compared to the colorectal surgeons (19.2% vs. 36.5%, p=0.022), while colorectal surgeons favored “peritoneal seeding” (26.9% vs. 9.5%, p=0.009). Regarding the number of metastatic tumors, 48.3% of colorectal surgeons responded that “irrelevant, if all metastatic lesions are amendable to local therapy”, while only 21.8% of radiation oncologist chose same answer. When asked about molecular diagnosis, most surgeons (74.8%) said it was important, but only 35.8% of radiation oncologists agreed.Conclusion This study demonstrates that although radiation oncologists and colorectal surgeons agreed on a majority of aspects such as diagnostic imaging, biomarker, systemic therapy, and optimal timing of OMD, they also had quite different perspectives on several aspects of OMD. Understanding these differences is crucial to achieving multidisciplinary consensus on the definition and optimal management of OMD.

Optimizing Treatment Strategy for Oligometastases/Oligo-Recurrence of Colorectal Cancer

“…Therefore, the reasonable definition and classification of oligometastatic CRC are highly important to determine the optimal treatment strategy, but the diagnosis is based solely on imaging findings and no biomarker for the identification is clinically available. Although there is consensus on many aspects of oligometastatic CRC, the detailed criteria and treatment strategies have not yet been completely established and are different among studies, specialties, and clinicians [ 21 ]. Furthermore, only a few comprehensive reviews on the definition and treatment of oligometastatic CRC have been reported [ 22 ].…”

Barriers in Oligometastasis Care in Korea: Radiation Oncologists’ Perspectives

“…Further studies focused on more specific case-based topics on lung, prostate, and colorectal primaries. Another study expanded the survey to the colorectal surgeons, the members of the Korean Society of Coloprotology [ 2 ]. Though failed to reach the statistical significance, awareness on and application of European Society for Radiotherapy and Oncology (ESTRO)/European Organisation for the Research and Treatment of Cancer (EORTC) classification [ 3 ] differed based on the patient volume cared by the respondents (less than 30 vs. more than 30 new patients per month).…”

“…Among the radiation oncologist specializing in genitourinary cancer, higher level of consensus was reached on synchronous oligometastasis compared to metachronous metastasis, who tended to offer stereotactic ablative dose radiotherapy more frequently for visceral metastasis than for bony metastasis [ 1 ]. In a survey on oligometastasis from colorectal primary, there were statistically significant disagreements between the radiation oncologists and the surgeons on the requirement of molecular diagnosis, role of local treatment for repeated and induced oligometastasis, and the valuable end-points (progression-free survival or local control) [ 2 ]. These inconsistencies in defining and categorizing oligometastatic disease may serve as a practical barrier in care of the oligometastatic patients.…”