The myth of measurable disease in ovarian cancer

Interobserver and intraobserver variability of RECIST assessment in ovarian cancer

OBJECTIVES

Measurement of Response Evaluation Criteria In Solid Tumors (RECIST) relies on reproducible unidimensional tumor measurements. This study assessed intraobserver and interobserver variability of target lesion selection and measurement, according to RECIST version 1.1 in patients with ovarian cancer.

METHODS

Eight international radiologists independently viewed 47 images demonstrating malignant lesions in patients with ovarian cancer and selected and measured lesions according to RECIST V.1.1 criteria. Thirteen images were viewed twice. Interobserver variability of selection and measurement were calculated for all images. Intraobserver variability of selection and measurement were calculated for images viewed twice. Lesions were classified according to their anatomical site as pulmonary, hepatic, pelvic mass, peritoneal, lymph nodal, or other. Lesion selection variability was assessed by calculating the reproducibility rate. Lesion measurement variability was assessed with the intra-class correlation coefficient.

RESULTS

From 47 images, 82 distinct lesions were identified. For lesion selection, the interobserver and intraobserver reproducibility rates were high, at 0.91 and 0.93, respectively. Interobserver selection reproducibility was highest (reproducibility rate 1) for pelvic mass and other lesions. Intraobserver selection reproducibility was highest (reproducibility rate 1) for pelvic mass, hepatic, nodal, and other lesions. Selection reproducibility was lowest for peritoneal lesions (interobserver reproducibility rate 0.76 and intraobserver reproducibility rate 0.69). For lesion measurement, the overall interobserver and intraobserver intraclass correlation coefficients showed very good concordance of 0.84 and 0.94, respectively. Interobserver intraclass correlation coefficient showed very good concordance for hepatic, pulmonary, peritoneal, and other lesions, and ranged from 0.84 to 0.97, but only moderate concordance for lymph node lesions (0.58). Intraobserver intraclass correlation coefficient showed very good concordance for all lesions, ranging from 0.82 to 0.99. In total, 85% of total measurement variability resulted from interobserver measurement difference.

CONCLUSIONS

Our study showed that while selection and measurement concordance were high, there was significant interobserver and intraobserver variability. Most resulted from interobserver variability. Compared with other lesions, peritoneal lesions had the lowest selection reproducibility, and lymph node lesions had the lowest measurement concordance. These factors need consideration to improve response assessment, especially as progression free survival remains the most common endpoint in phase III trials.

Resisting RECIST-Uniformity Versus Clinical Validity

OBJECTIVES

The Response Evaluation Criteria in Solid Tumors (RECIST) International Working Group developed criteria for tumor response and progression to standardize radiological assessment in patients receiving chemotherapy in phase 2 trials. However, it is unclear whether the defined percentage change in tumor size and volume reflects true clinical benefit for the patient. The RECIST criteria were designed to improve objectivity in trials, but not to replace clinical decision making. The aim of this study was to understand clinicians' opinions about RECIST in current oncology practice.

METHODS

Using Web-based questionnaires, we investigated attitudes to the use of RECIST at a large comprehensive cancer center and in an international group of gynecologic cancer specialists through the Gynecologic Cancer InterGroup. The results reported here relate to the survey focusing on gynecologic cancer.

RESULTS

Sixty medical professionals from 13 countries responded to the survey. The majority of respondents worked at a tertiary or specialist cancer center (51; 86%). Overall, 66% of respondents felt RECIST increased trial objectivity and was a good measure of response. The majority of respondents (81%) reported that they infrequently challenged RECIST evaluation. Overall, 60% felt more than 10% of patients came off trial for clinical rather than radiological progression. In the context of a new small lesion, only 35% felt that should always be considered disease progression. The importance of both clinician and radiologist input was highlighted with nontarget progression. Nontarget progression and target progression were recognized as equally important for clinical decision making (72%).

CONCLUSIONS

RECIST is a key criterion for endpoint assessment in clinical trials with its value recognized by clinicians. However, this survey also highlights the practical limitations of RECIST. Disconnect can be seen between the radiological result and the clinical picture-learning from these patients is critical. Continued efforts to improve metrics assessing patient benefit in trials remains a priority.

CA125-related tumor cell kinetics variables after chemotherapy in advanced ovarian cancer: a systematic review

Various kinetic parameters, based on a minimum of two time points, have been built with CA125 determinations. The aim of this study is to review studies about the clinical application of CA125-related tumor cell kinetics variables in patients with advanced ovarian cancer (AOC) receiving chemotherapy. A literature search for studies about CA125-related variables in patients with AOC was undertaken on three databases, by predefined search criteria, and a selection of studies was performed. Sixty-two studies were selected. CA125-related variables were summarized in three groups: response-related, time-to-event, and other CA125-related tumor cell kinetics variables. Even though CA125 changes and half-life after chemotherapy were the most studied, other variables and two models have been well defined, and often showed an interesting power to predict survival. These kinetics variables are related to the CA125 regression curve, pre- and post-chemotherapy kinetics, or are variables inferred from a population model of CA125 kinetics.

Current approaches and challenges in managing and monitoring treatment response in ovarian cancer

Epithelial ovarian cancer is the leading cause of death among gynecologic malignancies. Treatment of recurrent ovarian cancer remains a challenge despite advances in surgical and chemotherapeutic options. A goal of many providers is to detect recurrences as early as possible and initiate treatment though there is controversy as to whether this impacts outcome. Elevations in CA125 and radiological findings may precede symptoms of recurrence by several months. While detection of recurrences by physical exam alone is unusual, a thorough exam in conjunction with reported symptoms and elevated CA125 is sufficient to detect 80-90% of recurrences. A spiral CT scan may be used to confirm recurrence in the setting of asymptomatic CA125 elevation and a PET/CT can yield additional insight if the CT is inconclusive. Initiating chemotherapy prior to the development of symptoms, even in the setting of elevated CA125, does not impact overall survival primarily because the efficacy of available treatments in the recurrent setting is poor. More information about tumor biology and ways to predict which patients will benefit from available treatment options is required. Consequently, the approach to post-treatment surveillance should be individualized taking into account the clinical benefit of the second-line therapy, versus the costs and morbidity of the surveillance method.

RECIST: no longer the sharpest tool in the oncology clinical trials toolbox---point

Although "response" has been an attractive term for oncologists and patients, oncologists really want to know which therapy to start for a given patient and when to discontinue that therapy in favor of an alternative. In efficacy trials, cancer therapeutics have conventionally been assessed by endpoints that are based on the categorical Response Evaluation Criteria In Solid Tumors (RECIST) system. In this article, we make the case for a new paradigm in which therapeutics are assessed on a continuous scale by evidence of efficacy, using a variety of quantitative tools that take advantage of technologic innovations and increasing understanding of cancer biology. The new paradigm relies on randomized comparisons between investigational arms and control arms, as historical controls are unavailable or unreliable for these quantitative measures. We discuss multiple limitations of RECIST, including its overemphasis on tumor regression, concerns about the accuracy of tumor measurements and the validity of comparisons with historical controls, and its inadequacy in disease settings in which tumor measurements on cross-sectional imaging are difficult or uninformative. We discuss how the new paradigm overcomes these limitations and provides a framework for answering the key questions of the oncologist and improving patient outcomes.

Independent radiologic review in metastatic colorectal cancer: systematic review and meta-analysis

PURPOSE

To perform a meta-analysis addressing evaluation bias in local radiologic assessment (LRA) of lesions when compared with independent radiologic review (IRR) in randomized controlled trials (RCTs) testing chemotherapy for metastatic colorectal cancer (CRC).

MATERIALS AND METHODS

MEDLINE, EMBASE, ClinicalTrials.gov, the Cochrane Library, and Web sites for major medical meetings were searched for RCTs of chemotherapy for metastatic CRC that reported response evaluation by both LRA and IRR. The risk ratios (RRs) of response in the experimental (RR(exp)) and control (RR(cont)) arms were calculated (response rate in LRA divided by response rate in IRR) for each selected study. The ratio of RR of response was calculated (RR of response of LRA divided by RR of response of IRR). The random-effects model was applied. Meta-regression was used to examine the effect of study characteristics on outcomes.

RESULTS

LRA and IRR results were concordant (13 studies; 7742 patients; ratio of RR of response = 0.97; 95% confidence interval [95% CI]: 0.90, 1.04; P = .35). However, LRA overestimated tumor response independently of therapy allocation (interaction test, P = .81) both in control (RR(cont), 1.163; 95% CI: 1.086, 1.246; P < .001) and experimental (RR(exp), 1.156; 95% CI: 1.093, 1.222; P < .001) therapies. Meta-regression did not show any effect of trial characteristics on effects.

CONCLUSION

LRA yields higher response rates in RCTs testing chemotherapy for metastatic CRC, although there was no sign of bias toward experimental therapy. The need for IRR to control evaluation bias must be reappraised.

Sorafenib in Combination With Gemcitabine in Recurrent Epithelial Ovarian Cancer: A Study of the Princess Margaret Hospital Phase II Consortium

Objectives:

Antiangiogenic strategies have demonstrated efficacy in epithelial ovarian cancer (EOC). Sorafenib is a novel multitargeted kinase inhibitor with antiangiogenic activity. Gemcitabine has known activity against EOC. A phase 1 clinical trial of this combination suggested activity in ovarian cancer with no dose-limiting toxicity. This phase 2 study was designed to examine the safety and efficacy of gemcitabine and sorafenib in patients with recurrent EOC.

Methods:

Patients with recurrent EOC after platinum-based chemotherapy and who had subsequently received up to 3 prior chemotherapy regimens were eligible. Gemcitabine (1000 mg/m2 intravenous [IV]) was administered weekly for 7 of 8 weeks in the first cycle, then weekly for 3 weeks of each subsequent 4-week cycle. Sorafenib (400 mg p.o. bid) was given continuously. The primary end point for this trial was objective response rate by the Response Evaluation Criteria in Solid Tumors. Secondary endpoints included Gynecologic Cancer Intergroup (GCIG) CA-125 response, time to progression, overall survival, and toxicity.

Results:

Forty-three patients were enrolled, and 33 completed at least 1 cycle. Two patients had a partial response (Response Evaluation Criteria in Solid Tumors objective response rate = 4.7%). Ten patients (23.3%) maintained response or stable disease for at least 6 months. GCIG CA-125 response was 27.9%. The median time to progression was 5.4 months, and the median overall survival was 13.0 months. Hematologic toxicity was common but manageable. The most common nonhematologic adverse events were hand-foot syndrome, fatigue, hypokalemia, and diarrhea.

Conclusion:

This trial of gemcitabine and sorafenib in recurrent EOC did not meet its primary efficacy end point, but the combination was associated with encouraging rates of prolonged stable disease and CA-125 response.

Assessment of tumor response as a surrogate endpoint of survival in recurrent/platinum-resistant ovarian carcinoma: a Gynecologic Oncology Group study

PURPOSE

We investigated whether tumor response rate (TRR), disease control rate (DCR), or progression-free survival (PFS) was a valid surrogate for overall survival (OS) in phase II trials of second-line therapies for patients with platinum-resistant ovarian carcinoma (PROC).

METHODS

We retrospectively evaluated data from 11 second-line phase II trials conducted for PROC by the Gynecologic Oncology Group (GOG). TRR included complete response and partial response (CR/PR) and DCR was defined as either tumor response or stable disease (CR/PR+SD). Survival by tumor response was analyzed using a landmark approach. Correlations of OS with TRR, DCR, and PFS were estimated.

RESULTS

Among 407 patients analyzed the TRR was 13.8% (56/407) and DCR was 38.8% (158/407). Median OS was 10.2 months while median PFS was only 2.4 months. Median OS among patients with a best response of CR/PR, SD, and progressive disease (PD) was 13.3, 12.1 and 5.7 months, respectively, showing no difference between CR/PR and SD. From a protocol level, DCR correlated better with OS (Pearson r=0.748; Tau-b r=0.514) compared to TRR (Pearson r=0.564; Tau-b r=0.404). PFS rate at 6 months (Pearson r=0.661; Tau-b r=0.514) also correlated strongly with OS.

CONCLUSIONS

This study demonstrates the limitations of the use of response rate alone in PROC. Clinical benefit, as defined by OS, appeared similar for patients with an objective response and those with SD. The DCR, by including tumor response and SD may have utility as a surrogate endpoint for survival in phase II therapeutic trials in PROC.

Secreted protein acidic and rich in cysteine as a regulator of murine ovarian cancer growth and chemosensitivity

OBJECTIVE

Secreted protein acidic and rich in cysteine (SPARC) influences the growth of several solid tumors. Our objectives were to determine the effect of SPARC on the growth and response to cisplatin therapy of platinum-resistant ovarian cancer.

STUDY DESIGN

SPARC expression was determined in 4 platinum-resistant ovarian cancer cell lines. The effect of increasing SPARC on cell proliferation was determined in vitro. The effect of host-derived SPARC on tumor growth and response to therapy was determined in vivo using the murine ovarian cancer cell line, OSEID8, which was injected into the peritoneum of wild-type (WT) and SPARC-null (SP-/-) mice.

RESULTS

Forced expression of SPARC decreased growth of platinum-resistant ovarian cancer cell lines in vitro. In vivo, tumor growth was more aggressive in the absence of host-derived SPARC resulting in decreased survival compared with WT mice (P = .005). Cisplatin did not improve survival of WT mice. In contrast, cisplatin therapy resulted in a significant survival advantage (P = .0048) and decreased tumor volume (P = .02) in SP-/- animals.

CONCLUSION

We conclude that SPARC is an important extracellular matrix protein that regulates the growth and chemosensitivity of ovarian cancer. In general, SPARC appears to control tumor cell growth but also impede the efficacy of cisplatin therapy. Therefore, selective inhibition of SPARC may provide an attractive strategy for increasing the efficacy of therapy in platinum-resistant ovarian tumors.

Pharmaceutical management of ovarian cancer : current status

Over recent decades, truly impressive progress has been made in the outcome associated with the pharmacological antineoplastic management of women with advanced ovarian cancer. Following initial surgery, the large majority of patients with this malignancy will receive a chemotherapy regimen that includes a platinum drug (carboplatin or cisplatin) and a taxane (paclitaxel or docetaxel). Currently, objective responses are observed in approximately 60-80% of patients treated in the front-line setting, with documented improvements in overall survival compared with prior non-platinum and taxane programmes. Unfortunately, despite the high response rate to initial chemotherapy, the majority of women with advanced disease will experience recurrence of the malignant process and be candidates for a variety of possible second-line therapeutic options. It is well recognized that ovarian cancer patients who are documented to experience an initial response to platinum-based chemotherapy but where the disease recurs approximately 6 or more months following the completion of primary therapy, may have another clinically meaningful response (both objective and subjective) to a second platinum-based strategy. However, an optimal management approach in this setting remains to be defined. Furthermore, the malignant cell populations in all ovarian cancer patients who experience an initial relapse of the disease process will eventually be resistant to the platinum agents. In this setting, multiple drugs have been shown to be biologically active. Again, an optimal strategy to be employed in the platinum-resistant setting has yet to be demonstrated through the conduct of evidence-based trials. Reasonable goals of therapy in women with recurrent or resistant ovarian cancer are to improve overall survival, reduce the severity (and delay the occurrence) of symptoms and optimize overall quality of life.

Phase II study of pegylated liposomal doxorubicin and oxaliplatin in relapsed advanced ovarian cancer

OBJECTIVE

This phase II study evaluated the efficacy and safety of pegylated liposomal doxorubicin (PLD) 30 to 35 mg/m(2) plus oxaliplatin 70 mg/m(2) every 28 days in women with advanced ovarian cancer that recurred or progressed after a platinum-based regimen.

METHODS

43 women received a median of 6 courses of treatment.

RESULTS

Objective response was 54% in the evaluable population and was higher in women with platinum-sensitive (67%) compared with platinum-resistant disease (29%). At a median duration of follow-up of 15.5 months, median overall survival was 15.8 months and time to tumor progression 7.3 months. Most toxicity was no greater than grade 1 or 2. There was no grade 3 or 4 palmar-plantar erythrodysesthesia. After 264 cycles administered, neutropenia was the most common cause of severe toxicity and required one patient to withdraw from the study. No cardiotoxicity was reported.

CONCLUSION

PLD plus oxaliplatin is active and well tolerated in women with relapsed advanced ovarian cancer, regardless of platinum sensitivity.

Comparison of Outcomes of Phase II Studies and Subsequent Randomized Control Studies Using Identical Chemotherapeutic Regimens

Purpose

To determine whether promising results from phase II studies could be reproduced in phase III studies, and to examine which characteristics of phase II studies might be of predictive value for subsequent phase III studies.

Methods

We searched for all phase III studies of chemotherapy in advanced solid malignancies, published in the English language literature from July 1998 to June 2003. Each phase III study was reviewed to identify preceding phase II studies. Phase II and phase III studies included in this analysis must have used identical regimens. Data were extracted from both phase II and phase III studies.

Results

Of 181 phase III studies identified, 43 used therapeutic regimens identical to those in 49 preceding phase II studies. Twelve phase III studies (28%) were “positive.” The vast majority (81%) of phase III studies have lower response rates than preceding phase II studies, with a mean difference of 12.9% among all studies analyzed. None of the phase II study characteristics evaluated significantly predicted for “positive” phase III studies, but the sample size of phase II studies demonstrated a trend toward being predictive (P = .083).

Conclusion

Promising results from phase II studies frequently do not translate into “positive” phase III studies. Response rates in most phase III studies are lower than those in preceding phase II studies.

Should CA-125 Response Criteria Be Preferred to Response Evaluation Criteria in Solid Tumors (RECIST) for Prognostication During Second-Line Chemotherapy of Ovarian Carcinoma?

Purpose

The aim of the study was to compare the prognostic value of a response by the Gynecologic Cancer Intergroup (GCIG) Cancer Antigen (CA) -125 response criteria and the Response Evaluation Criteria in Solid Tumors (RECIST) on survival in patients with ovarian carcinoma receiving second-line chemotherapy.

Patients and Methods

From a single-institution registry of 527 consecutive patients with primary ovarian carcinoma, 131 records satisfied the inclusion criteria: ovarian carcinoma of International Federation of Gynecology and Obstetrics stage IC to IV, first-line chemotherapy with paclitaxel and a platinum compound, refractory or recurrent disease, and second-line chemotherapy consisting of topotecan or paclitaxel plus carboplatin. Univariate and multivariate analyses of survival were performed using the landmark method.

Results

In patients with measurable disease by RECIST and with assessable disease by the CA-125 criteria (n = 68), the CA-125 criteria were 2.6 times better than the RECIST at disclosing survival. In a multivariate Cox analysis with inclusion of nine potential prognostic parameters, CA-125 response (responders v nonresponders; hazard ratio, 0.21; P < .001) and number of relapse sites (solitary v multiple; hazard ratio, 0.47; P = .020) were identified as contributory prognostic factors for survival, whereas the parameters of RECIST (responders v nonresponders), as well as the remaining variables, had nonsignificant prognostic impact.

Conclusion

The GCIG CA-125 response criteria are a better prognostic tool than RECIST in second-line treatment with topotecan or paclitaxel plus carboplatin in patients with ovarian carcinoma.