Kawasaki Masayasu, Kameyama Masao, Kobayashi Hirotoshi, Kotake Kenjiro, Sugihara Kenichi
Department of Surgery, Bell Land General Hospital, Osaka, Japan.
Study Group for Peritoneal Metastasis from Colorectal Cancer by the Japanese Society for Cancer of the Colon and Rectum.
J Anus Rectum Colon. 2020 Oct 29;4(4):157-164. doi: 10.23922/jarc.2020-033. eCollection 2020.
In Japan, there are three grades of peritoneal metastasis from colorectal cancer. The grade depends on the extent and number of lesions (P classification). The P classification is useful for its simplicity but lacks objectivity. On the other hand, the peritoneal cancer index (PCI) objectively indicates the peritoneal metastasis grade. However, the evaluation process is complicated clinically. In this study, we compared these two methods and investigated how to improve the P classification's objectivity by referring to PCI.
We investigated 150 cases of synchronous peritoneal metastasis from colorectal cancer. We inspected the correlation between the P classification and the PCI and pointed out the problems which prevented objective evaluation when using the P classification. We also estimated new criteria for extent and number in the P classification.
We found the ideal definition for the best alignment between the P classification and the PCI was: ・P1 is metastases confined to one peritoneal region, ・P2 is 19 or fewer peritoneal metastases in two or more regions, and ・P3 is 20 or more metastases in two or more regions. This revision improved the P classification's objectivity and correlated with the PCI.
Grading using the P classification was both imprecise and subjective. We propose a new standard value of extent and number in the P classification based on the PCI. This improvement would provide an objective, simple method of grading for peritoneal metastasis from colorectal cancer.
在日本，结直肠癌的腹膜转移有三个等级。该等级取决于病变的范围和数量（P分类）。P分类因其简单性而有用，但缺乏客观性。另一方面，腹膜癌指数（PCI）客观地表明了腹膜转移等级。然而，其评估过程在临床上较为复杂。在本研究中，我们比较了这两种方法，并研究了如何通过参考PCI来提高P分类的客观性。
我们调查了150例结直肠癌同步腹膜转移病例。我们检查了P分类与PCI之间的相关性，并指出了使用P分类时妨碍客观评估的问题。我们还估计了P分类中范围和数量的新标准。
我们发现P分类与PCI之间最佳匹配的理想定义为：・P1为转移局限于一个腹膜区域，・P2为两个或更多区域有19个或更少的腹膜转移，・P3为两个或更多区域有20个或更多转移。这一修订提高了P分类的客观性，并与PCI相关。
使用P分类进行分级既不精确也不主观。我们基于PCI提出了P分类中范围和数量的新标准值。这一改进将为结直肠癌腹膜转移提供一种客观、简单的分级方法。
