How we treat metastatic colon cancer in older adults

Navigating through novelties concerning mCRC treatment-the role of immunotherapy, chemotherapy, and targeted therapy in mCRC

Over the course of nearly six decades since the inception of initial trials involving 5-FU in the treatment of mCRC (metastatic colorectal cancer), our progressive comprehension of the pathophysiology, genetics, and surgical techniques related to mCRC has paved the way for the introduction of novel therapeutic modalities. These advancements not only have augmented the overall survival but have also positively impacted the quality of life (QoL) for affected individuals. Despite the remarkable progress made in the last two decades in the development of chemotherapy, immunotherapy, and target therapies, mCRC remains an incurable disease, with a 5-year survival rate of 14%. In this comprehensive review, our primary goal is to present an overview of mCRC treatment methods following the latest guidelines provided by the National Comprehensive Cancer Network (NCCN), the American Society of Clinical Oncology (ASCO), and the American Society of Colon and Rectal Surgeons (ASCRS). Emphasis has been placed on outlining treatment approaches encompassing chemotherapy, immunotherapy, targeted therapy, and surgery's role in managing mCRC. Furthermore, our review delves into prospective avenues for developing new therapies, offering a glimpse into the future of alternative pathways that hold potential for advancing the field.

Clinical characteristics and treatment propensity in elderly patients aged over 80 years with colorectal cancer

BACKGROUND/AIMS

Elderly patients (≥ 80 years) with colorectal cancer (CRC) tend to avoid active treatment at the time of diagnosis despite of recent advances in treatment. The aim of this study was to determine treatment propensity of elderly patients aged ≥ 80 years with CRC in clinical practice and the impact of anticancer treatment on overall survival (OS).

METHODS

Medical charts of 152 elderly patients (aged ≥ 80 years) diagnosed with CRC between 1998 and 2012 were retrospectively reviewed. Patients' clinical characteristics, treatment modalities received, and clinical outcome were analyzed.

RESULTS

Their median age was 82 years (range, 80 to 98). Of 152 patients, 148 were assessable for the extent of the disease. Eighty-two of 98 patients with localized disease and 28 of 50 patients with metastatic disease had received surgery or chemotherapy or both. Surgery was performed in 79 of 98 patients with localized disease and 15 of 50 patients with metastatic disease. Chemotherapy was administered in only 24 of 50 patients with metastatic disease. Patients who received anticancer treatment according to disease extent showed significantly longer OS compared to untreated patients (localized disease, 76.2 months vs. 15.4 months, p = 0.000; metastatic disease, 9.9 months vs. 2.6 months, p = 0.001). Along with anticancer treatment, favorable performance status (PS) was associated with longer OS in multivariate analysis of clinical outcome.

CONCLUSION

Elderly patients aged ≥ 80 years with CRC tended to receive less treatment for metastatic disease. Nevertheless, anticancer treatment in patients with favorable PS was effective in prolonging OS regardless of disease extent.

Cost-Effectiveness of Treatment Sequences of Chemotherapies and Targeted Biologics for Elderly Metastatic Colorectal Cancer Patients

BACKGROUND

Treatment patterns for metastatic colorectal cancer (mCRC) patients have changed considerably over the last decade with the introduction of new chemotherapies and targeted biologics. These treatments are often administered in various sequences with limited evidence regarding their cost-effectiveness.

OBJECTIVE

To conduct a pharmacoeconomic evaluation of commonly administered treatment sequences among elderly mCRC patients.

METHODS

A probabilistic discrete event simulation model assuming Weibull distribution was developed to evaluate the cost-effectiveness of the following common treatment sequences: (a) first-line oxaliplatin/irinotecan followed by second-line oxaliplatin/irinotecan + bevacizumab (OI-OIB); (b) first-line oxaliplatin/irinotecan + bevacizumab followed by second-line oxaliplatin/irinotecan + bevacizumab (OIB-OIB); (c) OI-OIB followed by a third-line targeted biologic (OI-OIB-TB); and (d) OIB-OIB followed by a third-line targeted biologic (OIB-OIB-TB). Input parameters for the model were primarily obtained from the Surveillance, Epidemiology, and End Results-Medicare linked dataset for incident mCRC patients aged 65 years and older diagnosed from January 2004 through December 2009. A probabilistic sensitivity analysis was performed to account for parameter uncertainty. Costs (2014 U.S. dollars) and effectiveness were discounted at an annual rate of 3%.

RESULTS

In the base case analyses, at the willingness-to-pay (WTP) threshold of $100,000/quality-adjusted life-year (QALY) gained, the treatment sequence OIB-OIB (vs. OI-OIB) was not cost-effective with an incremental cost-effectiveness ratio (ICER) per patient of $119,007/QALY; OI-OIB-TB (vs. OIB-OIB) was dominated; and OIB-OIB-TB (vs. OIB-OIB) was not cost-effective with an ICER of $405,857/QALY. Results similar to the base case analysis were obtained assuming log-normal distribution. Cost-effectiveness acceptability curves derived from a probabilistic sensitivity analysis showed that at a WTP of $100,000/QALY gained, sequence OI-OIB was 34% cost-effective, followed by OIB-OIB (31%), OI-OIB-TB (20%), and OIB-OIB-TB (15%).

CONCLUSIONS

Overall, survival increases marginally with the addition of targeted biologics, such as bevacizumab, at first line and third line at substantial costs. Treatment sequences with bevacizumab at first line and targeted biologics at third line may not be cost-effective at the commonly used threshold of $100,000/QALY gained, but a marginal decrease in the cost of bevacizumab may make treatment sequences with first-line bevacizumab cost-effective. Future economic evaluations should validate the study results using parameters from ongoing clinical trials.

DISCLOSURES

This study was supported in part by a grant from the Agency for Healthcare Research and Quality (R01-HS018956) and in part by a grant from the Cancer Prevention and Research Institute of Texas (RP130051), which were obtained by Du. The authors report no conflicts of interest. Study concept and design were primarily contributed by Parikh, along with the other authors. All authors participated in data collection, and Parikh took the lead in data interpretation and analysis, along with Lairson and Morgan, with assistance from Du. The manuscript was written primarily by Parikh, along with Lairson, Morgan, and Du, and revised by Parikh.

Treatment of Metastatic Colorectal Cancer Patients ≥75 Years Old in Clinical Practice: A Multicenter Analysis

BACKGROUND

Colorectal cancer patients have a median age of incidence >65years although they are largely under-represented in phase-III trials. This large population contains patients unfit for treatment, those suitable for monotherapy or for doublets and the impact of chemotherapy outside clinical trial is unclear. The aim of the study was to retrospectively analyse Overall Survival(OS) of elderly metastatic colorectal cancer(mCRC) patients treated with chemotherapy in daily practice.

METHODS

Kaplan-Meir method was used for OS, the log-rank or Tarone-Ware test for differences between subgroups, Cox's proportional hazard model to assess the impact of known prognostic factors and treatment.

RESULTS

751 patients with mCRC observed between January 2000 and January 2013 were collected. Median age was 79 year(75-93); Male/Female 61/39%, ECOG-PS 0-1/2 85/15%; colon/rectum 74/26%; multiple metastatic sites 34%, only liver metastasis in 41% of patients. KRAS status was studied in 35% of patients: 44% of them showed gene mutation. 20.5% of patients did not received any kind of treatment including surgery. Comorbidities observed: cardiovascular 34%, diabetes 14%, hypertension 50%. Primary tumor was resected in 80.6%; surgery of liver metastasis was done in 19% of patients (2.3% of patients >80years). 78% of patients underwent chemotherapy. Median follow up was 12 months(range 1-124). Median OS was 17 months (CI 95%15-19);median OS in no-treated patients was 5 months (4-6); mOS of patients with at least one treatment was 20 months (18-22). In KRAS mutated group median OS was 19months (15-23) while in KRAS wild type patients median OS was 25 months (20-30). At multivariate analysis sex(Female), age(<80y), performance status(0-1), chemotherapy, Surgery of metastasis, Surgery of primary tumor and Site of metastasis(liver) were prognostic factors for OS.

CONCLUSION

The results of our study show that in clinical practice treatment has a positive impact on OS of elderly patients, confirmed at multivariate analysis, included patients with age >80 years old or with a poor performance status (respectively p<0.0001 and p<0.0001). KRAS analysis deserve further evaluation.

Patterns of Biologics Use Across Treatment Lines in Elderly (Age >65) Medicare Patients With Metastatic Colon Cancer

BACKGROUND

We explored biologics receipt in metastatic colon cancer.

METHODS

We used Surveillance, Epidemiology, and End Results-Medicare data of 4,545 elderly patients diagnosed with incident metastatic colon cancer from 2003 to 2009, treated with chemotherapy and/or biologics, and followed up through 2010.

RESULTS

A total of 2,504 (55%) patients received a biologics-containing regimen. Treatment with biologics fluctuated between 46% and 63% of first-line regimens and 67% and 73% of second-line regimens. Bevacizumab accounted for 95% of first-line and 68% of second-line biologics use. Cetuximab accounted for 33% of second-line and 48% of third-line use. Panitumumab accounted for 5% of second-line and 27% of third-line use. The adjusted odds of biologics receipt decreased rapidly with age, resulting in a threefold difference between the youngest and the oldest study participants in the sample (odds ratio [OR] 0.35, p < .01). African Americans (OR 0.77, p = .03) and patients with Charlson Comorbidity Index of 1 (OR 0.83, p = .02) or >1 (OR 0.75, p < .01) were considerably less likely to receive biologics therapy. Medicare state buy-in was associated with 2% lower odds of receiving biologics (OR 0.98, p = .04).

CONCLUSION

After controlling for sociodemographic and clinical differences, age, race, comorbidities, and low income had a statistically significantly negative effect on the likelihood of receiving biologics among treated patients. Use of biologics varied over time, across the treatment continuum, and by chemotherapy regimen. Bevacizumab was most frequently used in both first- and second-line treatment. Cetuximab was the second most prescribed biologic. Panitumumab use was mostly limited to third-line treatment.

IMPLICATIONS FOR PRACTICE

It is well-known that patients in the "real world" receive cancer treatments that do not reflect the strict treatment protocols of clinical trials. This is particularly true for complex and elderly patients with metastatic disease, who are frequently underrepresented in clinical trials. Although this article does not provide any additional evidence about the effectiveness of one treatment regimen or treatment sequence over another, it enhances our understanding of oncology practice outside of the clinical trial setting and provides useful information for future health services and health economics research in metastatic colon cancer.

Patterns of Treatment Sequences in Chemotherapy and Targeted Biologics for Metastatic Colorectal Cancer: Findings from a Large Community-Based Cohort of Elderly Patients

Background

Over the last decade, multiple chemotherapies/targeted biologics have been approved for metastatic colorectal cancer (mCRC). However, evidence is limited with regards to the array of treatments received by mCRC patients.

Objective

This study examines treatment sequences (first- to third-line chemotherapy/targeted biologics) and the factors associated with first-line targeted biologics and common treatment sequences for elderly mCRC patients treated in a community setting.

Methods

A retrospective cohort study was conducted in mCRC patients diagnosed from January 2004 through December 2009 using the Surveillance, Epidemiology and End Results Medicare-linked database. The treatment sequences administered to elderly mCRC patients were empirically identified.

Results

Of 4418 mCRC patients who received treatment, 1370 (31 %) received first, second, and third line; 1164 (26 %) received first and second line; and 1884 (43 %) received only first line. The most common first line of treatment for mCRC patients was 5-fluorouracil/leucovorin + oxaliplatin (FOLFOX) + bevacizumab (23 %) and FOLFOX (23 %). 5-fluorouracil/leucovorin + irinotecan (FOLFIRI)-based regimens were commonly (22 %) administered in second line. The most common treatment sequence was first-line oxaliplatin or irinotecan followed by second-line oxaliplatin or irinotecan + bevacizumab followed by a third-line targeted biologic. Of patients who received first-line therapy, 47 % also received a targeted biologic, and the factors associated were age, comorbidity score, cancer site, geographic location, and year of diagnosis.

Conclusion

Elderly mCRC patients receive a multitude of treatments in various sequences. Further exploration of the comparative effectiveness of treatment sequences may yield important information for improving mCRC survival.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-015-0059-9) contains supplementary material, which is available to authorized users.