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Feb 25, 2021 10:04PM
If I may ask, what was the grade of your DCIS, and how large was it? My diagnosis was back in the days before the Oncotype test for DCIS was available, and back then what we used a lot when deciding between lumpectomy alone, lumpectomy + rads, or mastectomy, was the Van Nuys Prognostic Index. This index assigned points to age, tumor grade, tumor size and margin size and based on the point total, recommended the surgical plan. Here is a chart of the model:
I'm not understanding your comment about considering rads if it turns out that your cancer is genetic. Can you explain this more? To my understanding, an inherited genetic mutation increases your risk to be diagnosed, either this first time, or possibly again. Once you are diagnosed, if the cancer has been found while it is still DCIS, I don't believe that there is any difference in prognosis between those who have an inherited cancer vs. those who have a random diagnosis. It is the pathology of the DCIS and the surgical margins that determines recurrence risk. Your Oncotype recurrence risk estimates wouldn't change if your cancer is inherited or not.
What I'm not sure about about however is whether your Oncotype risk estimates are reliable with surgical margins of only 1mm. I recall that when the Oncotype test for DCIS came out in 2011, it was based on the E5194 study, which did not include any DCIS patients with margins less than 3mm in size. Other criteria for the trial were that all patients had low or intermediate grade DCIS that was ≤2.5 cm in size or high-grade DCIS that was ≤1 cm. Those criteria were transferred over to the Oncotype test, so for many years the Oncotype DCIS test was not run on patients who did not meet that criteria. This changed a couple of years ago when a second study was used to validate the Oncotype results, the Ontario DCIS Cohort Study. This study excluded only those with positive margins, so there where patients in the study who had more narrow margins. In fact the study notes that their patient base was broader than the E5194 study, and mentions that 45% of the patients in their study had margins of 1mm - 3mm (i.e. smaller than anyone included in E5194). But of that 45%, how many only had 1mm margins? That data does not appear to be available in the public domain. What we know is that in total 773 patients were used to validate the Oncotype for DCIS scores/recurrence risks. Of these 773 patients, 327 patients from E5194 and 245 (55%) of the 446 patients from the Ontario DCIS Cohort Study had 3mm+ margins. In total then, 572 (74%) of the 773 patients had 3mm+ margins. Of the remaining 201 patients who had margins between 1mm and 3mm, how many just had 1mm?
I admit to some bias here. I've been hanging around the DCIS forum for years, and surgical margin has always been considered critical. This is confirmed by the NCCN Treatment Guidelines (the gold standard used by most doctors in North America) which specify minimum 2mm margins for DCIS for patients having radiation, and say that for those who have a lumpectomy alone, the optimal margin width is unknown, but should be at least 2mm.
I understand your desire to pass on more surgery, rads and anti-hormone therapy. If your DCIS was very small and low grade, then as per the VNPI, even with the 1mm margin, your recurrence risk might be quite low. But if your area of DCIS was larger or higher grade, your risk of recurrence might be much higher than your Oncotype test result suggests, because of the narrow margin. Just something for you to consider.
Dx 9/15/2005 Right, 7cm+, DCIS-Mi, Stage IA, Gr 3, 0/3 nodes, ER+/PR- ** Dx 01/16/2019 Left, 8mm, IDC, Stage IA, Gr 2, 0/3 nodes, ER+/PR-, HER2- (FISH) ** Surgery 11/30/2005 MX Right, 03/06/2019 MX Left ** Hormonal Therapy 05/2019 Letrozole