Several practice-changing developments in the treatment of ovarian cancer were seen in 2019, including the results of the pivotal trial Gynecologic Oncology Group (GOG)-213, which were published in November in the New England Journal of Medicine.1 This trial randomly assigned women with ovarian cancer who had achieved a remission of more than 6 months after primary therapy (“platinum sensitive”) to either a repeat surgical cytoreduction followed by chemotherapy versus chemotherapy alone. It found that the addition of surgery provided no benefit in overall survival, challenging the notion that repeat surgical “debulking” should be routinely considered for the treatment of women with platinum-sensitive ovarian cancer.
Alexander Raths/Fotolia
The primary treatment of ovarian cancer includes a combination of surgery and chemotherapy, after which the vast majority of patients will experience a complete clinical response, a so-called “remission.” At that time patients enter surveillance care, in which their providers evaluate them, typically every 3 months in the first 2-3 years. These visits are designed to address ongoing toxicities of therapy in addition to evaluation for recurrence. At these visits, it is common for providers to assess tumor markers, such as CA 125 (cancer antigen 125), if they had been elevated at original diagnosis. As a gynecologic oncologist, I can vouch for the fact that patients “sweat” on this lab result the most. No matter how reassuring my physical exams or their symptom profiles are, there is nothing more comforting as a normal, stable CA 125 value in black and white. However, and may, in fact, be harmful.
Providers have drawn tumor markers at surveillance exams under the working premise that abnormal or rising values signal the onset of asymptomatic recurrence, and that earlier treatment will be associated with better responses to salvage therapy. However, this has not been shown to be the case in randomized, controlled trials. In a large European cooperative-group trial, more than 500 patients with a history of completely treated ovarian cancer were randomized to either reinitiation of chemotherapy (salvage therapy) when CA 125 values first doubled or to reinitiation of therapy when they became symptomatic without knowledge of their CA 125 values.2 In this trial the mean survival of both groups was the same (26 months for the early initiation of chemotherapy vs. 27 for late initiation). However, what did differ were the quality of life scores, which were lower for the group who initiated chemotherapy earlier, likely because they received toxic therapies for longer periods of time.
The results of this trial were challenged by those who felt that this study did not evaluate the role that surgery might play. Their argument was that surgery in the recurrent setting would improve the outcomes from chemotherapy for certain patients with long platinum-free intervals (duration of remission since last receiving a platinum-containing drug), oligometastatic disease, and good performance status, just as it had in the primary setting. Retrospective series seemed to confirm this phenomenon, particularly if surgeons were able to achieve a complete resection (no residual measurable disease).3,4 By detecting asymptomatic patients with early elevations in CA 125, they proposed they might identify patients with lower disease burden in whom complete debulking would be more feasible. Whereas, in waiting for symptoms alone, they might “miss the boat,” and discover recurrence when it was too advanced to be completely resected.
Dr. Emma C. Rossi
The results of the GOG-213 study significantly challenge this line of thought, although with some caveats. Because this new trial showed no survival benefit for women with secondary debulking prior to chemotherapy, one could question whether there is any benefit in screening for asymptomatic, early recurrence. The authors of the study looked in subgroup analyses to attempt to identify groups who might benefit over others, such as women who had complete surgical cytoreduction (no residual disease) but still did not find a benefit to surgery. The trial population as a whole included women who had very favorable prognostic factors, including very long disease-free intervals (median, 20.4 months), and most women had only one or two sites of measurable recurrence. Yet it is remarkable that, in this group of patients who were predisposed to optimal outcomes, no benefit from surgery was observed.
However, it is important to recognize that the equivalent results of single-modality chemotherapy were achieved with the majority of women receiving bevacizumab with their chemotherapy regimen. An additional consideration is that the chemotherapy for platinum-sensitive, recurrent ovarian cancer has changed in recent years as we have learned the benefit of poly (ADP-ribose) polymerase (PARP) inhibitor drugs as maintenance therapy following complete or partial response to chemotherapy.5 It is unclear how the addition of PARP inhibitor maintenance therapy might have influenced the results of GOG-213. Further advancements in targeted therapies and consideration of hyperthermic intraperitoneal chemotherapy at the time of surgery also are being developed, and so, the answer of optimal therapy for platinum-sensitive ovarian cancer is a fluid one and might include a role for surgery for some of these patients.
However, in the meantime, before routinely ordering that tumor marker assessment in the surveillance period, it is important to remember that, if secondary cytoreduction is not beneficial and early initiation of chemotherapy is not helpful either, then these tumor marker results might provide more hindrance than help. Why search for recurrence at an earlier time point with CA 125 elevations if there isn’t a benefit to the patient in doing so? There certainly appears to be worse quality of life in doing so, and most likely also additional cost. Perhaps we should wait for clinical symptoms to confirm recurrence?
In the meantime, we will continue to have discussions with patients after primary therapy regarding how to best monitor them in the surveillance period. We will educate them about the limitations of early initiation of chemotherapy and the potentially limited role for surgery. Hopefully with individualized care and shared decision making, patients can guide us as to how they best be evaluated. While receiving a normal CA 125 result is powerfully reassuring, it is just as powerfully confusing and difficult for a patient to receive an abnormal one followed by a period of “doing nothing,” otherwise known as expectant management, if immediate treatment is not beneficial.
Dr. Rossi is assistant professor in the division of gynecologic oncology at the University of North Carolina at Chapel Hill. She had no relevant financial disclosures. Email her at obnews@mdedge.com.
References
1. N Engl J Med. 2019 Nov 14;381(20):1929-39.
2. Lancet. 2010 Oct 2;376(9747):1155-63.
3. Gynecol Oncol. 2009 Jan;112(1):265-74.