[2024-06-11] Ovarian cancer follow-up June 2024

This morning, I met with Dr. Cooke, a Gynecologic Oncology Fellow at The Ottawa Hospital's Cancer Centre, for my quarterly ovarian cancer follow-up.

Dr. Cooke, a very pleasant and thorough doctor whom I met for the first time today, noted that I continue to do extremely well.
  • My CA125 remains low and stable. In fact, in her post-visit report, Dr. Cooke included my CA125 results, showing the long line of 7s, 8s and 9s I've received on monthly tests since February 2021.
  • My blood results—to ensure that the maintenance drug I am on (a PARP inhibitor named olaparib) is not becoming toxic—are acceptable.
  • And my lymph nodes and vagina appear normal. Dr. Cooke wrote in her post-visit report: "No palpable peripheral adenopathy. Abdomen is soft, non-tender and non-distended. Speculum, bimanual exams are normal with no evidence of disease."
I love "no evidence of disease."

Dr. Cooke noted a study that found that the majority of ovarian cancer patients with a mutation in their BRCA1 or BRCA2 gene who had been on olaparib for up to two years enjoyed a residual benefit for the next five years. Known as the SOLO-1 Trial, this study randomly assigned patients with newly diagnosed advanced ovarian cancer and a BRCA mutation who had responded to platinum-based chemotherapy to maintenance olaparib or placebo for up to two years. A 2023 update of the trial in the Journal of Clinical Oncology (Overall Survival With Maintenance Olaparib at a 7-Year Follow-Up in Patients With Newly Diagnosed Advanced Ovarian Cancer and a BRCA Mutation: The SOLO1/GOG 3004 Trial) noted that new data from 2022 had confirmed earlier findings from 2020 and 2018 that "the benefit of maintenance olaparib extends well beyond its 2-year treatment cap in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation." The benefits were these: 67.0% of the patients who had received olaparib for up to 2 years were still alive after 7 years, compared to 46.5% who had received a placebo. As well, 45.3% of the patients who had received olaparib for up to 2 years had not had a cancer recurrence after 7 years, compared to 20.6% who had received a placebo.

Given these data, Dr. Cooke stated that I could choose to come off the drug. However, in my previous discussions with Dr. Faught (including my most recent one in March 2024 when I had already been on olaparib for a full three years), the recommendation has been to stay on olaparib—a let's-not-rock-the-boat strategy. My sense from prior talks with Dr. Faught is that the decision to come off olaparib is often made for the doctor and patient: if cancer recurs or the drug becomes toxic to the patient, its use is discontinued. But I appear to be one of the rare patients with high-grade serous carcinoma and a BRCA mutation whose cancer has not recurred and whose body is tolerating the drug. I indicated to Dr. Cooke that if the gynecologic oncology team, including Dr. Faught, recommends a change in strategy, I am open to that.

Dr. Cooke summarized her assessment and plan thus:

BRCA 2 + high grade serous ovarian cancer, on Olaparib since Feb 2021. No clinical or serologic evidence of disease recurrence today. I initiated discussion regarding coming off olaparib, considering SOLO1 trial whereby patients with BRCA 1/2 mutation on olaparib with no residual disease completed treatment after 2 years. Prior discussions with Dr. Faught have mainly been around plan to continue on olaparib until toxicity reached or obvious signs of recurrence which we discussed is also not unreasonable and hence she will continue on olaparib for the time being. Follow up in 4 months.

While reading the update on the SOLO-1 trial, I came across an interesting statistic pertaining to ovarian cancer survivorship in the Journal of Clinical Oncology article: "Seven years is considered a clinically relevant time point for survivorship, as modeling indicates that most ovarian cancer–related deaths occur within 7 years of diagnosis, with mortality approaching that of women in the general population after a 9-year follow-up."

I followed the footnote from this statement to the article Defining Survivorship Trajectories Across Patients With Solid Tumors (JAMA Oncology, 2018). This paper noted that the risk of mortality was greatest immediately after ovarian cancer diagnosis "then rapidly decreased over 9 years until it reached stability, defining a 9-year high-risk period." An ovarian cancer patient who survives the 9-year high-risk period would enter a stable period, where their risk of death would remain just 1.2% above people of the same age and sex.

Clearly, I'm not yet beyond the 9-year high-risk period. However, it's been 3.8 years since my surgery for ovarian cancer and 3.3 years since I started taking olaparib, so I'm at least part way along the line of declining risk of recurrence. I hope to continue following that line into a stable period.