Appraisal of Systemic Treatment Strategies in Early HER2-Positive Breast Cancer-A Literature Review

BACKGROUND

The overexpression of the human epidermal growth factor receptor 2 (HER2+) accounts for 15-20% of all breast cancer phenotypes. Even after the completion of the standard combination of chemotherapy and trastuzumab, relapse events occur in approximately 15% of cases. The neoadjuvant approach has multiple benefits that include the potential to downgrade staging and convert previously unresectable tumors to operable tumors. In addition, achieving a pathologic complete response (pCR) following preoperative systemic treatment is prognostic of enhanced survival outcomes. Thus, optimal evaluation among the suitable strategies is crucial in deciding which patients should be selected for the neoadjuvant approach.

METHODS

A literature search was conducted in the Embase, Medline, and Cochrane electronic libraries.

CONCLUSION

The evaluation of tumor and LN staging and, hence, stratifying BC recurrence risk are decisive factors in guiding clinicians to optimize treatment decisions between the neoadjuvant versus adjuvant approaches. For each individual case, it is important to consider the most likely postsurgical outcome, since, if the patient does not obtain pCR following neoadjuvant treatment, they are eligible for adjuvant T-DM1 in the case of residual disease. This review of HER2-positive female BC outlines suitable neoadjuvant and adjuvant systemic treatment strategies for guiding clinical decision making around the selection of an appropriate therapy.

A Population-Based Study to Evaluate the Associations of Nodal Stage, Lymph Node Ratio and Log Odds of Positive Lymph Nodes with Survival in Patients with Small Bowel Adenocarcinoma

Purpose: This study aimed to determine the real-world prognostic significance of lymph node ratio (LNR) and log odds of positive lymph nodes (LOPLN) in patients with non-metastatic small bowel adenocarcinoma. Methods: Patients diagnosed with early-stage small bowel adenocarcinoma between January 2007 and December 2018 from a large Canadian province were identified. We calculated the LNR by dividing positive over total lymph nodes examined and the LOPLN as log ([positive lymph nodes + 0.5]/[negative lymph nodes + 0.5]). The LNR and LOPLN were categorized at cut-offs of 0.4 and −1.1, respectively. Multivariable Cox proportional hazards models were constructed for each nodal stage, LNR and LOPLN, adjusting for measured confounding factors. Harrell’s C-index and Akaike’s Information Criterion (AIC) were used to calculate the prognostic discriminatory abilities of the different models. Results: We identified 141 patients. The median age was 67 years and 54.6% were men. The 5-year overall survival rates for patients with stage I, II and III small bowel adenocarcinoma were 50.0%, 56.6% and 47.5%, respectively. The discriminatory ability was generally comparable for LOPLN, LNR and nodal stage in the prognostication of all patients. However, LOPLN had higher discriminatory ability among patients with at least one lymph node involvement (Harrell’s C-index, 0.75, 0.77 and 0.82, and AIC, 122.91, 119.68 and 110.69 for nodal stage, LNR and LOPLN, respectively). Conclusion: The LOPLN may provide better prognostic information when compared to LNR and nodal stage in specific patients.

Real-world Safety and Efficacy of Raltitrexed in Patients With Metastatic Colorectal Cancer

BACKGROUND

Use of fluoropyrimidine-based therapy in patients with metastatic colorectal cancer is associated with significant toxicities. This study aimed to assess the safety and efficacy of raltitrexed use in patients with metastatic colorectal cancer who developed significant toxicities after fluoropyrimidine-based treatment.

PATIENTS AND METHODS

We identified patients with metastatic colorectal cancer who were treated with raltitrexed-based systemic therapy after developing serious adverse events with fluoropyrimidine-based treatment in a large Canadian province from 2004 to 2018. Demographic, tumor, and treatment characteristics were retrieved from the electronic medical records. Progression-free and overall survival were assessed from the start of raltitrexed-based therapy.

RESULTS

A total of 86 patients were identified for the study. The median age was 66.5 years, and 58.1% of patients were men. The primary cancer site was right, left, and transverse colon in 38.4%, 27.9%, and 9.3%, respectively. The remaining 24.4% had rectal cancer. Among all patients, 43.0% had received more than 2 prior systemic therapies, and 37.6% had developed previous cardiotoxicity to fluoropyrimidine-based treatment. The median progression-free and overall survival were 8.5 and 10.2 months, respectively. On multivariable Cox regression model, patients with left-sided colon cancer (hazard ratio [HR], 0.33; 95% confidence interval [CI], 0.12-0.97; P = .044) and the Eastern Cooperative Oncology Group performance status of 0/1 (HR, 0.10; 95% CI, 0.01-0.82; P = .032) had a longer progression-free survival, whereas left-sidedness of colon cancer was the only factor that predicted overall survival (HR, 0.30; 95% CI, 0.10-0.88; P = .029). Raltitrexed was well-tolerated with common adverse events that included anemia in 41.7% of patients and chemotherapy-induced nausea and vomiting in 27.4%. Most toxicities were grade 1/2, but 16.7% of patients experienced grade 3. There were no cardiac events and treatment-related deaths.

CONCLUSIONS

Raltitrexed in patients with colorectal cancer who were previously treated with fluoropyrimidine-based systemic therapy is effective and well-tolerated.

Four cycles of docetaxel and cyclophosphamide as adjuvant chemotherapy in node negative breast cancer: A real-world study

Introduction

The optimal number of cycles of adjuvant docetaxel and cyclophosphamide (DC) in patients with node negative breast cancer is not known. We aimed to analyse the survival outcomes of patients with node negative and human epidermal growth factor receptor (HER2)-negative breast cancer treated with four cycles of DC.

Methods

Patients with node negative and HER2-negative breast cancer treated with four cycles of DC after surgery in a large Canadian province from 2008 to 2012 were identified. We analysed the 4-year and 9-year invasive disease free survival (iDFS) and overall survival (OS). Cox regression models were constructed to examine the associations of clinical characteristics with survival outcomes.

Results

A total of 657 patients were eligible for the current analysis. The median age was 53 years and 71.2% of patients had hormone receptor-positive breast cancer. Approximately three-fourths of patients had grade III tumours. At a median follow-up of nine years, the 4-year iDFS and OS were 91.0% and 95.5% and the corresponding 9-year rates were 80.5% and 88.0%, respectively. On multivariable Cox regression analysis, grade III tumour predicted worse iDFS (hazard ratio [HR], 2.15; 95% confidence interval [CI], 1.09–4.21; P = 0.026) and OS (HR, 3.15; 95% CI, 1.18–8.45; P = 0.022).

Conclusions

Adjuvant chemotherapy with four cycles of DC in a select population of node negative breast cancer was associated with encouraging long-term survival. In the absence of a randomized comparison between four and six cycles of DC, this study presents real-world evidence to consider four cycles of DC as a reasonable option.

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Non-anthracycline adjuvant chemotherapy administered in node negative breast cancer.

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Not known if four or six cycles of docetaxel and cyclophosphamide is optimal.

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Long-term survival rates in this real-world study using four cycles are encouraging.

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In absence of randomized comparison, four cycles is a reasonable option.

Cost-effectiveness analysis of multigene expression profiling assays to guide adjuvant therapy decisions in women with invasive early-stage breast cancer

Gene expression profiling (GEP) testing using 12-gene recurrence score (RS) assay (EndoPredict®), 58-gene RS assay (Prosigna®), and 21-gene RS assay (Oncotype DX®) is available to aid in chemotherapy decision-making when traditional clinicopathological predictors are insufficient to accurately determine recurrence risk in women with axillary lymph node-negative, hormone receptor-positive, and human epidermal growth factor-receptor 2-negative early-stage breast cancer. We examined the cost-effectiveness of incorporating these assays into standard practice. A decision model was built to project lifetime clinical and economic consequences of different adjuvant treatment-guiding strategies. The model was parameterized using follow-up data from a secondary analysis of the Anastrozole or Tamoxifen Alone or Combined randomized trial, cost data (2017 Canadian dollars) from the London Regional Cancer Program (Canada) and secondary Canadian sources. The 12-gene, 58-gene, and 21-gene RS assays were associated with cost-effectiveness ratios of $36,274, $48,525, and $74,911/quality-adjusted life year (QALY) gained and resulted in total gains of 379, 284.3, and 189.5 QALYs/year and total budgets of $12.9, $14.2, and $16.6 million/year, respectively. The total expected-value of perfect information about GEP assays' utility was $10.4 million/year. GEP testing using any of these assays is likely clinically and economically attractive. The 12-gene and 58-gene RS assays may improve the cost-effectiveness of GEP testing and offer higher value for money, although prospective evidence is still needed. Comparative field evaluations of GEP assays in real-world practice are associated with a large societal benefit and warranted to determine the optimal and most cost-effective assay for routine use.

Abstract PD6-09: Cost effectiveness of bilateral prophylactic mastectomy with and without different breast reconstruction techniques versus screening in women with high risk of breast cancer in the Canadian Province of Ontario

Purpose: We aimed to investigate the cost-effectiveness of mastectomy with and without different reconstruction for the purpose of determining which strategies represent value for money and identify the most cost-effective technique from the perspective of Ontario's health care system.

Methods: We developed a decision analytic model to project the lifetime clinical and economic consequences of different strategies .The decision model was parameterized using 10-year follow up and cost data from Ontario administrative health databases and Ontario Cancer registry and utility data from secondary Canadian sources. Costs are presented in 2018 Canadian dollars. Future costs and benefits were discounted at 5%.

Results: Compared to organized screening-based strategy, surgical strategies ranged from being more effective and cost-saving and up to being associated with an incremental cost effectiveness ratio (ICER) of $63,010 per quality-adjusted life year (QALY) gained, with BPM with immediate one-stage acellular dermal matrix (ADM)-assisted implant breast reconstruction having the greatest incremental QALY of 1.157 and lowest ICER of $9,615. Incorporating the PBM with one-stage ADM-assisted implant immediate breast reconstruction as the standard surgical strategy in Ontario would result in the largest total annual net gains of 20 QALYs and $ 1.7 million.

Table 1Baseline life-time outcomes of the decision model.   Extensive breast cancer screening alone vs. surgical interventionsStrategyOverall QALYsOverall costInc. QALYInc. costICER per QALY gainedExtensive breast cancer screening18.549$90,231Ref.Ref.Ref.Prophylactic bilateral mastectomy without breast reconstruction19.057$82,011+0.508−$8,220Cost-savingProphylactic bilateral mastectomy with two-stage traditional TE-implant immediate breast reconstruction19.364$111,319+0.815+$21,088$25,868 (dominated)Prophylactic bilateral mastectomy with one-stage ADM-assisted implant immediate breast reconstruction19.706$101,359+1.157+$11,128$9,615Prophylactic bilateral mastectomy with two-stage ADM-assisted TE-implant immediate breast reconstruction19.065$122,757+0.516+$32,526$63,010 (dominated)Prophylactic bilateral mastectomy with any type of autologous immediate breast reconstruction (with or without TE or breast implant)19.501$114,014+0.951+$23,784$24,988 (dominated)Prophylactic bilateral mastectomy with one-stage non-ADM immediate breast reconstruction19.408$103,512+0.859+$13,282$15,457 (dominated)Prophylactic bilateral mastectomy with delayed breast reconstruction19.241$107,582+0.691+$17,351$25,087 (dominated)ADM;acellular dermal matrix ; TE=Tissue Expander; ICER=Incremental cost-effectiveness ratio; QALY=Quality adjusted life year

Conclusion: The choice of breast reconstruction needs to be decided based on the patient body habitus, general condition and goals . BPM with and without reconstruction is likely both clinically and economically attractive. However ,all other things being equal , BPM with immediate one-stage ADM-assisted implant breast reconstruction is the most cost effective strategy and appears to offer the highest value for money.

Citation Format: Aljohani BE, Hannouf MB, Grant A, Doherty C, Zaric GS, Brackstone M. Cost effectiveness of bilateral prophylactic mastectomy with and without different breast reconstruction techniques versus screening in women with high risk of breast cancer in the Canadian Province of Ontario [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD6-09.

Survival outcome differences based on treatments used and knowledge of the primary tumour site for patients with cancer of unknown and known primary in Ontario

Introduction

Patients with cancer of unknown primary (cup) have pathologically confirmed metastatic tumours with unidentifiable primary tumours. Currently, very little is known about the relationship between the treatment of patients with cup and their survival outcomes. Thus, we compared oncologic treatment and survival outcomes for patients in Ontario with cup against those for a cohort of patients with metastatic cancer of known primary site.

Methods

Using the Ontario Cancer Registry and the Same-Day Surgery and Discharge Abstract databases maintained by the Canadian Institute for Health Information, we identified all Ontario patients diagnosed with metastatic cancer between 1 January 2000 and 31 December 2005. Ontario Health Insurance Plan treatment records were linked to identify codes for surgery, chemotherapy, or therapeutic radiation related to oncology. Multivariable Cox regression models were constructed, adjusting for histology, age, sex, and comorbidities.

Results

In 45,347 patients (96.3%), the primary tumour site was identifiable, and in 1743 patients (3.7%), cup was diagnosed. Among the main tumour sites, cup ranked as the 6th largest. The mean Charlson score was significantly higher (p < 0.0001) in patients with cup (1.88) than in those with a known primary (1.42). Overall median survival was 1.9 months for patients with cup compared with 11.9 months for all patients with a known-primary cancer. Receipt of treatment was more likely for patients with a known primary site (n= 35,012, 77.2%) than for those with cup (n = 891, 51.1%). Among patients with a known primary site, median survival was significantly higher for treated than for untreated patients (19.0 months vs. 2.2 months, p < 0.0001). Among patients with cup, median survival was also higher for treated than for untreated patients (3.6 months vs. 1.1 months, p < 0.0001).

Conclusions

In Ontario, patients with cup experience significantly lower survival than do patients with metastatic cancer of a known primary site. Treatment is associated with significantly increased survival both for patients with cup and for those with metastatic cancer of a known primary site.

The Potential Clinical and Economic Value of Primary Tumour Identification in Metastatic Cancer of Unknown Primary Tumour: A Population-Based Retrospective Matched Cohort Study

PURPOSE

Several genomic tests have recently been developed to identify the primary tumour in cancer of unknown primary tumour (CUP). However, the value of identifying the primary tumour in clinical practice for CUP patients remains questionable and difficult to prove in randomized trials.

OBJECTIVE

We aimed to assess the clinical and economic value of primary tumour identification in CUP using a retrospective matched cohort study.

METHODS

We used the Manitoba Cancer Registry to identify all patients initially diagnosed with metastatic cancer between 2002 and 2011. We defined patients as having CUP if their primary tumour was found 6 months or more after initial diagnosis or never found during the course of disease. Otherwise, we considered patients to have metastatic cancer from a known primary tumour (CKP). We linked all patients with Manitoba Health databases to estimate their direct healthcare costs using a phase-of-care approach. We used the propensity score matching technique to match each CUP patient with a CKP patient on clinicopathologic characteristics. We compared treatment patterns, overall survival (OS) and phase-specific healthcare costs between the two patient groups and assessed association with OS using Cox regression adjustment.

RESULTS

Of 5839 patients diagnosed with metastatic cancer, 395 had CUP (6.8%); 1:1 matching created a matched group of 395 CKP patients. CUP patients were less likely to receive surgery, radiation, hormonal and targeted therapy and more likely to receive cytotoxic empiric chemotherapeutic agents. Having CUP was associated with reduced OS (hazard ratio [HR] 1.31; 95% confidence interval 1.1-1.58), but this lost statistical significance with adjustment for treatment differences. CUP patients had a significant increase in the mean net cost of initial diagnostic workup before diagnosis and a significant reduction in the mean net cost of continuing cancer care.

CONCLUSION

Identifying the primary tumour in CUP patients might enable the use of more effective therapies, improve OS and allow more efficient allocation of healthcare resources.

The evolution of biosimilars in oncology, with a focus on trastuzumab

Cancer therapy has evolved significantly with increased adoption of biologic agents ("biologics"). That evolution is especially true for her2 (human epidermal growth factor receptor-2)-positive breast cancer with the introduction of trastuzumab, a monoclonal antibody against the her2 receptor, which, in combination with chemotherapy, significantly improves survival in both metastatic and early disease. Although the efficacy of biologics is undeniable, their expense is a significant contributor to the increasing cost of cancer care. Across disease sites and indications, biosimilar agents are rapidly being developed with the goal of offering cost-effective alternatives to biologics. Biosimilars are pharmaceuticals whose molecular shape, efficacy, and safety are similar, but not identical, to those of the original product. Although these agents hold the potential to improve patient access, complexities in their production, evaluation, cost, and clinical application have raised questions among experts. Here, we review the landscape of biosimilar agents in oncology, with a focus on trastuzumab biosimilars. We discuss important considerations that must be made as these agents are introduced into routine cancer care.

Abstract P4-12-05: Cost-effectiveness analysis of second-generation multi-gene expression prognostic assays compared with the standard 21-gene recurrence score assay to guide adjuvant therapy decisions in women with early stage breast cancer

Second-generation multi-gene expression assays can generate comprehensive molecular risk scores which may inform adjuvant chemotherapy decisions in women with early breast cancer. The 12-gene EPclin score assay (EndoPredict®) and 50-gene PAM50-risk of recurrence (ROR) score assay (Prosigna®) appeared to have better prognostic value when compared to the current north American standard 21-gene recurrence score (RS) assay (Oncotype DX®). We sought to investigate the cost-effectiveness of using EPclin and ROR score assays versus RS assay in women with axillary lymph node-negative (LN−), hormone receptor–positive (HR+), and human epidermal growth factor receptor 2–negative (HER2−) early-stage operable breast cancer (ESBC) from the perspective of the Canadian public healthcare system.

We developed a Markov model to project the lifetime clinical and economic consequences of operable LN- HR+ HER2− ESBC. We assumed that women within each risk category by RS assay (low, intermediate and high) would be reclassified to binary risk categories (low and high) by EPclin score assay and to three risk categories (low, intermediate and high) by ROR score assay. The decision model was parameterized using 10-year follow up data from retrospective analyses of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial, cost data from the London Regional Cancer Program (Ontario, Canada) and secondary sources. Costs are presented in 2017 Canadian dollars. Future costs and benefits were discounted at 5%.

EPclin and ROR score-based strategies led to an increase of 0.04 and 0.02 quality adjusted life years (QALY)/person and a decrease in cost of $917 and $600/person respectively, resulting in both strategies being cost-saving compared to RS-based strategy. Incorporating the EPclin and ROR score assays in place of the current standard RS-assay for operable LN- HR+ HER2− ESBC patients in Canada would result in total gains of 469 and 250 QALYs/year and total savings of $11.5 and $7.5 million/year, respectively. EPclin compared to ROR score-based strategy led to an increase of 0.02 QALY/person and a decrease in cost of $317/person, resulting in EPclin score-based strategy being dominant. Our results were most sensitive to the proportion of women classified by EPclin and ROR score assays to different risk categories and who received adjuvant chemotherapy. A value-of-information analysis revealed that the total expected value of perfect information about the EPclin and ROR score assays' clinical impact was $95 and $55 million/year, respectively.

Our results indicate that the EPclin and ROR score assays are both clinically and economically attractive for patients with operable LN- HR+ HER2− ESBC in the Canadian healthcare setting. Both assays should be considered for adoption in place of the current standard RS-assay for this patient population. The EPclin compared to the ROR score assay appears to be clinically more promising and provides greater value for money in the Canadian healthcare system. Field evaluations of the EPclin and ROR score assays in real-world Canadian clinical practice are associated with a large societal benefit and warranted.

Citation Format: Hannouf MB, Zaric GS, Brackstone M. Cost-effectiveness analysis of second-generation multi-gene expression prognostic assays compared with the standard 21-gene recurrence score assay to guide adjuvant therapy decisions in women with early stage breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-12-05.

The clinical significance of occult gynecologic primary tumours in metastatic cancer

OBJECTIVE

We estimated the frequency of occult gynecologic primary tumours (gpts) in patients with metastatic cancer from an uncertain primary and evaluated the effect on disease management and overall survival (os).

METHODS

We used Manitoba administrative health databases to identify all patients initially diagnosed with metastatic cancer during 2002-2011. We defined patients as having an "occult" primary tumour if the primary was classified at least 6 months after the initial diagnosis. Otherwise, we considered patients to have "obvious" primaries. We then compared clinicopathologic and treatment characteristics and 2-year os for women with occult and with obvious gpts. We used Cox regression adjustment and propensity score methods to assess the effect on os of having an occult gpt.

RESULTS

Among the 5953 patients diagnosed with metastatic cancer, occult primary tumours were more common in women (n = 285 of 2552, 11.2%) than in men (n = 244 of 3401, 7.2%). In women, gpts were the most frequent occult primary tumours (n = 55 of 285, 19.3%). Compared with their counterparts having obvious gpts, women with occult gpts (n = 55) presented with similar histologic and metastatic patterns but received fewer gynecologic diagnostic examinations during diagnostic work-up. Women with occult gpts were less likely to undergo surgery, waited longer for radiotherapy, and received a lesser variety of chemotherapeutic agents. Having an occult compared with an obvious gpt was associated with decreased os (hazard ratio: 1.62; 95% confidence interval: 1.2 to 2.35). Similar results were observed in adjusted analyses.

CONCLUSIONS

In women with metastatic cancer from an uncertain primary, gpts constitute the largest clinical entity. Accurate diagnosis of occult gpts early in the course of metastatic cancer might lead to more effective treatment decisions and improved survival outcomes.

The Clinical Significance of Occult Gastrointestinal Primary Tumours in Metastatic Cancer: A Population Retrospective Cohort Study

Purpose

The purpose of this study was to estimate the incidence of occult gastrointestinal (GI) primary tumours in patients with metastatic cancer of uncertain primary origin and evaluate their influence on treatments and overall survival (OS).

Materials and Methods

We used population heath data from Manitoba, Canada to identify all patients initially diagnosed with metastatic cancer between 2002 and 2011. We defined patients to have “occult” primary tumour if the primary was found at least 6 months after initial diagnosis. Otherwise, we considered primary tumours as “obvious.” We used propensity-score methods to match each patient with occult GI tumour to four patients with obvious GI tumour on all known clinicopathologic features. We compared treatments and 2-year survival data between the two patient groups and assessed treatment effect on OS using Cox regression adjustment.

Results

Eighty-three patients had occult GI primary tumours, accounting for 17.6% of men and 14% of women with metastatic cancer of uncertain primary. A 1:4 matching created a matched group of 332 patients with obvious GI primary tumour. Occult cases compared to the matched group were less likely to receive surgical interventions and targeted biological therapy, and more likely to receive cytotoxic empiric chemotherapeutic agents. Having an occult GI tumour was associated with reduced OS and appeared to be a nonsignificant independent predictor of OS when adjusting for treatment differences.

Conclusion

GI tumours are the most common occult primary tumours in men and the second most common in women. Patients with occult GI primary tumours are potentially being undertreated with available GI site-specific and targeted therapies.

Identification and survival outcomes of a cohort of patients with cancer of unknown primary in Ontario, Canada

BACKGROUND

Cancer of unknown primary origin (CUP) is defined by the presence of pathologically identified metastatic disease without clinical or radiological evidence of a primary tumour. Our objective was to identify incident cases of CUP in Ontario, Canada, and determine the influence of histology and sites of metastases on overall survival (OS).

MATERIAL AND METHODS

We used the Ontario Cancer Registry (OCR) and the Same-Day Surgery and Discharge Abstract Database (SDS/DAD) to identify patients diagnosed with CUP in Ontario between 1 January 2000, and 31 December 2005. Patient diagnostic information, including histology and survival data, was obtained from the OCR. We cross-validated CUP diagnosis and obtained additional information about metastasis through data linkage with the SDS/DAD database. OS was assessed using Cox regression models adjusting for histology and sites of metastases.

RESULTS

We identified 3564 patients diagnosed with CUP. Patients without histologically confirmed disease (n = 1821) had a one-year OS of 10.9%, whereas patients with confirmed histology (n = 1743) had a one-year OS of 15.6%. The most common metastatic sites were in the respiratory or digestive systems (n = 1603), and the most common histology was adenocarcinoma (n = 939). Three-year survival rates were 3.5%, 5.3%, 41.6% and 3.6% among adenocarcinoma, unspecified carcinoma, squamous cell carcinoma and undifferentiated histology, respectively. Three-year survival rates were 40%, 2.4%, 8.0% and 4.6% among patients with metastases localised to lymph nodes, the respiratory or digestive systems, other specified sites, and unspecified sites, respectively.

CONCLUSION

CUP patients in Ontario have a poor prognosis. Some subgroups may have better survival rates, such as patients with metastases localised to lymph nodes and patients with squamous cell histology.

Cost effectiveness of a 21-gene recurrence score assay versus Canadian clinical practice in post-menopausal women with early-stage estrogen or progesterone-receptor-positive, axillary lymph-node positive breast cancer

BACKGROUND

A 21-gene recurrence score (RS) assay provides a method of guiding treatment decisions in women with early-stage breast cancer (ESBC). We investigated the cost effectiveness of using the RS assay versus current clinical practice (CCP) in post-menopausal women with estrogen- or progesterone-receptor-positive, one to three positive axillary lymph-node ESBC from the perspective of the Canadian public healthcare system.

METHODS

We developed a decision analytic model to project the lifetime clinical and economic consequences of ESBC. We assumed that the RS assay would classify patients among risk levels (low, intermediate and high) and corresponding adjuvant treatment regimens. The model was parameterized using 7-year follow-up data from the Manitoba Cancer Registry, cost data from Manitoba Health administrative databases and secondary sources. Costs are presented in 2012 Canadian dollars, and future costs and benefits were discounted at 5 %.

RESULTS

In the base case analysis, the RS assay compared with CCP led to an increase of 0.08 quality-adjusted life-year (QALY) and an increase in cost of Can$36.2 per person, resulting in an incremental cost-effectiveness ratio (ICER) of Can$464/QALY gained. The ICER was most sensitive to the proportion of women classified to intermediate risk by the RS assay who received adjuvant chemotherapy, and absolute risk of relapse among patients receiving the RS assay.

CONCLUSIONS

The RS assay is likely to be cost effective in the Canadian healthcare system. Field evaluations of the assay in this patient population will help reduce uncertainty in clinical guidelines for intermediate-range RS-assay values and specific disease outcomes by the RS assay, which are important drivers of ICER.

Evaluating the efficacy of current clinical practice of adjuvant chemotherapy in postmenopausal women with early-stage, estrogen or progesterone receptor-positive, one-to-three positive axillary lymph node, breast cancer

PURPOSE

We evaluated the benefit of the current clinical practice of adjuvant chemotherapy for postmenopausal women with early-stage, estrogen- or progesterone-receptor-positive (er/pr+), one-to-three positive axillary lymph node (1-3 ln+), breast cancer (esbc).

METHODS

Using the Manitoba Cancer Registry, we identified all postmenopausal women diagnosed with er/pr+ 1-3 ln+ esbc during the periods 1995-1997, 2000-2002, and 2003-2005 (n = 156, 161, and 171 respectively). Treatment data were obtained from the Manitoba Cancer Registry and by linkage with Manitoba administrative databases. Seven-year survival data were available for the 1995-1997 and 2000-2002 populations. Using Cox regression, we assessed the independent effect of the clinical practice of adjuvant chemotherapy on disease-free (dfs) and overall survival (os).

RESULTS

Clinical breast cancer treatments did not differ significantly between the 2000-2002 and 2003-2005 populations. Adjuvant chemotherapy was administered in 103 patients in the 2000-2002 population (64%) and in 44 patients in the 1995-1997 population [28.2%; mean difference: 36%; 95% confidence interval (ci): 31% to 40%; p < 0.0001]. Compared with 1995-1997, 2000-2002 was not significantly associated with an incremental dfs benefit for patients over a period of 7 years (2000-2002 vs. 1995-1997; adjusted hazard ratio: 0.98; 95% ci: 0.64 to 1.4).

CONCLUSIONS

The treatment standard of adjuvant chemotherapy in addition to endocrine therapy may not be effective for all women with er/pr+ 1-3 ln+ esbc. There could be a subgroup of those women who do not benefit from adjuvant chemotherapy as expected and who are therefore being overtreated. Further studies with a larger sample size are warranted to confirm our results.

Cost-effectiveness of a 21-gene recurrence score assay versus Canadian clinical practice in women with early-stage estrogen- or progesterone-receptor-positive, axillary lymph-node negative breast cancer

BACKGROUND

A 21-gene recurrence score (RS) assay may inform adjuvant systematic treatment decisions in women with early stage breast cancer. We sought to investigate the cost effectiveness of using the RS-assay versus current clinical practice (CCP) in women with early-stage estrogen- or progesterone-receptor-positive, axilliary lymph-node negative breast cancer (ER+/ PR + LN- ESBC) from the perspective of the Canadian public healthcare system.

METHODS

We developed a Markov model to project the lifetime clinical and economic consequences of ESBC. We evaluated adjuvant therapy separately in post- and pre-menopausal women with ER+/ PR + LN- ESBC. We assumed that the RS-assay would reclassify pre- and post-menopausal women among risk levels (low, intermediate and high) and guide adjuvant systematic treatment decisions. The model was parameterized using 7 year follow up data from the Manitoba Cancer Registry, cost data from Manitoba administrative databases, and secondary sources. Costs are presented in 2010 CAD. Future costs and benefits were discounted at 5%.

RESULTS

The RS-assay compared to CCP generated cost-savings in pre-menopausal women and had an ICER of $60,000 per QALY gained in post-menopausal women. The cost effectiveness was most sensitive to the proportion of women classified as intermediate risk by the RS-assay who receive adjuvant chemotherapy and the risk of relapse in the RS-assay model.

CONCLUSIONS

The RS-assay is likely to be cost effective in the Canadian healthcare system and should be considered for adoption in women with ER+/ PR + LN- ESBC. However, ongoing assessment and validation of the assay in real-world clinical practice is warranted.

Cost-effectiveness of adding cetuximab to platinum-based chemotherapy for first-line treatment of recurrent or metastatic head and neck cancer

PURPOSE

To assess the cost effectiveness of adding cetuximab to platinum-based chemotherapy in first-line treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) from the perspective of the Canadian public healthcare system.

METHODS

We developed a Markov state transition model to project the lifetime clinical and economic consequences of recurrent or metastatic HNSCC. Transition probabilities were derived from a phase III trial of cetuximab in patients with recurrent or metastatic HNSCC. Cost estimates were obtained from London Health Sciences Centre and the Ontario Case Costing Initiative, and expressed in 2011 CAD. A three year time horizon was used. Future costs and health benefits were discounted at 5%.

RESULTS

In the base case, cetuximab plus platinum-based chemotherapy compared to platinum-based chemotherapy alone led to an increase of 0.093 QALY and an increase in cost of $36,000 per person, resulting in an incremental cost effectiveness ratio (ICER) of $386,000 per QALY gained. The cost effectiveness ratio was most sensitive to the cost per mg of cetuximab and the absolute risk of progression among patients receiving cetuximab.

CONCLUSION

The addition of cetuximab to standard platinum-based chemotherapy in first-line treatment of patients with recurrent or metastatic HNSCC has an ICER that exceeds $100,000 per QALY gained. Cetuximab can only be economically attractive in this patient population if the cost of cetuximab is substantially reduced or if future research can identify predictive markers to select patients most likely to benefit from the addition of cetuximab to chemotherapy.

Abstract P5-10-23: Frequency and Cost of Chemotherapy-Related Serious Adverse Effects in a Canadian Population Sample of Women with Estrogen and/or Progesterone Receptor Positive Early Stage Breast Cancer

Background: Chemotherapy-related serious adverse effects (CSAE) reported by clinical trials of chemotherapy and by population-based assessments of CSAE in breast cancer populations with different clinicopathological characteristics may not reflect the experiences of women with estrogen and/or progesterone receptor positive (ER+/PR+) early stage breast cancer (ESBC). We aimed to characterize the risks and economic impact of CSAE among women in the Canadian general population treated with chemotherapy for ER+/PR+ ESBC. Methods: We used the Manitoba Cancer Registry to identify all women (n=665) diagnosed with ER+/PR+ ESBC during the period from January 1, 2000 to December 31, 2002. One-year of follow-up information from diagnosis, including hospitalizations and emergency room visits for all adverse effects that are typically related to chemotherapy, were identified by linking with Manitoba Administrative Databases including the Hospital Discharge Database and the Physician Claims Database. 251 women received chemotherapy during the 12 months after the initial diagnosis with ESBC. Hospitalizations or emergency room visits for CSAE and health care expenditures were compared between women who did and did not receive chemotherapy. We assessed the effect of chemotherapy on rate of CSAE using logistic regression, adjusting for menopausal status, lymph node status, anthracycline-containing chemotherapy agents, and comorbid indices. All statistical tests were two-sided.

Results: Women who received chemotherapy were more likely than those who did not to be hospitalized or visit an emergency room for CSAE (2.6% versus 9%, mean difference =6.4%, 95% CI=3.5% to 10%, p=0.01). In a logistic regression analysis, the rate of CSAE was found to be significantly greater for women with post-menopausal status (post-versus pre-menopausal, odds ratio 2.4; CI= 1.7 to 2.8) and 1-3 lymph node positive (LN+) (0 versus 1-3 LN+, odds ratio, 3.1; CI= 2.5 to 3.6). Chemotherapy recipients incurred large incremental expenditures for CSAE (pre-menopausal LN-: $1100 per person per year; post-menopausal LN-: $1600 per person per year; post-menopausal 1-3 LN+: $2200 per person per year).

Conclusions: The impact and costs of CSAE among ER+/PR+ ESBC are larger than predicted from clinical data and vary significantly by lymph node and menopausal status. Our findings, when combined with recent population-based data suggesting that women with ER+/PR+ ESBC may not gain benefit from chemotherapy as much as reported in clinical trials, have important implications for quality of life and could affect decisions regarding the use of chemotherapy in these patients.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-10-23.

Abstract P5-10-08: Evaluating the Efficacy of Current Clinical Practice of Adjuvant Chemotherapy in Post-Menopausal Women with One to Three Positive Auxiliary Nodes and Estrogen and/or Progesterone Positive Early Stage Breast Cancer

Background: Within the last decade, adjuvant chemotherapy has become the treatment standard for post-menopausal women with one to three positive auxiliary lymph nodes (LN+) and estrogen and/or progesterone positive (ER+/PR+) early stage breast cancer (ESBC). Recent data suggest that many of these women do not benefit from chemotherapy. We aimed to evaluate whether the current clinical practice of adjuvant chemotherapy in post-menopausal women with 1-3 LN+ and ER+/PR+ ESBC is associated with incremental survival benefit versus previous standard treatment of adjuvant hormone therapy alone for the majority of these women. Methods: We used the Manitoba Cancer Registry to identify all post-menopausal women diagnosed with LN+ and ER+/PR+ ESBC during the periods of January 1995 to December 1997, January 2000 to December 2002, and January 2003 to December 2005 (n= 156, 163 and 171, respectively). Treatment data including surgery and adjuvant therapy for all women were obtained from the Manitoba Cancer Registry and by linking with the Manitoba Administrative Databases. Five-year survival data were available for those who were diagnosed during the periods of 1995 to 1997 and 2000 to 2002 and were also obtained from the Manitoba Cancer Registry. Clinical practice of adjuvant chemotherapy was not found to differ during the time period of 2000 to 2005. Therefore, the earlier two cohorts diagnosed during the time period of 2000 to 2002 and 1995 to 1997 were only included in this analysis to reflect the current versus the previous clinical practice of adjuvant chemotherapy. In this retrospective analysis, we assessed the independent effect of the clinical practice of adjuvant chemotherapy on disease-free survival (DFS) and overall survival (OS) using Cox regression, adjusting for comorbid indices and receipt of radiotherapy.

Results: Age, clinical tumour size, tumour grade, and receipt of breast cancer surgery and endocrine therapy did not differ significantly between the two cohorts. There were 104 patients (64%) of those who were diagnosed later (2000-2002) versus 44 patients (28%) of those who were diagnosed earlier (1995-1997) who received chemotherapy (mean difference= 36%, 95% CI= 25% to 35%, p = 0.01). The 5-year Kaplan-Meier estimate of DFS of patients diagnosed later did not differ significantly than those diagnosed earlier (DFS= 78% versus 73%, respectively, log-rank test p =0.57). The multivariate Cox Regression analysis demonstrated that patients in the later versus the earlier cohort were not significantly associated with incremental DFS benefit over 5 years (2000-2002 vs. 1995-1997, hazard ratio: 1.04; p = 0.7). Similar results were seen for OS over 5 years (2000-2002 vs. 1995-1997, hazard ratio: 1.06; p = 0.65).

Conclusion: The treatment standard of adjuvant chemotherapy in addition to endocrine therapy for the majority of women with 1-3 LN+ and ER+/PR+ ESBC was not found to be associated with incremental survival benefit in comparison with previous standards. Our results suggest that a large number of patients with 1-3 LN+ and ER+/PR+ ESBC may not gain benefit from adding chemotherapy to endocrine therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-10-08.