Why the fallopian tube is most probably not the origin of serous carcinoma of the ovary-Part 4-STIC

In 2003, Pieck published a study suggesting that BRCA 1 and 2 related ovarian cancers were of tubal origin. Based on this publication around 2006, there were a myriad of papers expanding this idea to all serous carcinomas of the ovary. In order to adapt the tumor to the new theory it was proposed that the designation of the tumor be changed from serous carcinoma of the ovary to "pelvic serous carcinoma". The easy explanation for why we have not seen"the primary lesion in the tube before" was that the fallopian tube was not properly submitted. A SEE-FIM protocol was designed, and everyone was looking for the"origin of serous carcinoma of the ovary" in the fallopian tube epithelium. In 2008, several abstracts and papers reported that STIC was found in only 40% of the cases using the SEE-FIM protocol. In 2016, the percentage of STIC in high grade serous carcinoma of the ovary came down to 21%. Some authors thought that perhaps STIC was a very small lesion. So in the negative cases, serial sectioning of entire blocks was obtained. By doing this, the percentage went up to 30%. It is evident that even using a special protocol and obtaining microscopic sections of the entire fallopian tube, STIC is not found in 70% of ovarian serous carcinoma.

Furthermore, there are different publications from Dr Colin Stewart in 2012, Joseph Rabban in 2015, and Friedrich Kommoss in 2017 showing metastatic lesions in the epithelium of the fallopian tube. These studies make the theory of STIC as a primary lesion in cases of ovarian serous carcinoma very questionable. STIC could represent a metastasis or part of a multicentric disease.

There is no doubt that in cases of BRCA patients STIC is most probably is the primary lesion; however, extending this concept to all serous carcinomas of the ovary, in my opinion, has been a mistake.