Asymptomatic primary tumour in incurable metastatic colorectal cancer: is there a role for surgical resection prior to systematic therapy or not?

The impact of primary tumor resection for asymptomatic colorectal cancer patients with unresectable metastases: a systematic review and meta-analysis

BACKGROUND

Whether patients with asymptomatic primary tumors and unresectable metastases of colorectal cancer (CRC) should undergo primary tumor resection (PTR) remains controversial. This study aims to determine the appropriateness of PTR for these individuals by evaluating a number of outcome measures.

METHODS

A systematic literature search was performed. Outcome measures included overall survival, emergency surgery rates, incidence of postoperative complications, time to initiate chemotherapy, conversion rates, and chemotherapy-related toxicities.

RESULTS

Patients who received PTR in addition to chemotherapy had a better overall survival rate than those who only received chemotherapy (HR = 0.62, 95%CI, 0.50-0.78, I2 = 84%, p < 0.00001). In the RCT subgroup, there were no significant differences with a HR of 0.72 (95%CI, 0.45-1.13, I2 = 17%, p = 0.15). More patients in the chemotherapy alone group could be converted to resectable status (OR = 0.47, 95%CI, 0.27-0.82, I2 = 0%, p = 0.008), but the incidence of emergency surgery was 23% (95%CI, 17-29%, I2 = 14%). The risk of chemotherapy-related toxicity was not significantly higher in the PTR group (OR = 1.5, 95%CI, 0.94-2.43, p = 0.09, I2 = 0%), with a 7% incidence of postoperative complications (95%CI, 0-14%, p = 0.05, I2 = 0%). The time to initiate chemotherapy after PTR was approximately 33.06 days (95%CI, 25.55-40.58, I2 = 0%).

CONCLUSION

PTR plus chemotherapy may be associated with improved survival in asymptomatic CRC patients with unresectable metastases. However, PTR did not provide a significant survival benefit in the subgroup of RCTs. Additionally, PTR did not result in a significantly increased risk of chemotherapy-related toxicity, with a postoperative complication rate of approximately 7%, and chemotherapy could be initiated at approximately 33.06 days after PTR. Compared with the PTR plus chemotherapy, chemotherapy alone could result in a significantly higher conversion rate. However, about 23% of patients receiving chemotherapy alone required emergency surgery for primary tumor-related symptoms. The above results needed to be validated in future larger prospective randomized trials.

Effect of primary tumor resection on survival in patients with asymptomatic unresectable metastatic colorectal cancer: a systematic review and meta-analysis

OBJECTIVE

It remains controversial whether primary tumor resection (PTR) improves survival in patients with asymptomatic, unresectable metastatic colorectal cancer (mCRC). Therefore, we conducted a meta-analysis to assess the latest evidence on clinical outcomes.

MATERIALS AND METHODS

We systematically searched PubMed, Web of Science, Cochrane Library, and Embase databases for eligible studies published between database inception and May 2022. RevMan 5.4 and Stata 16.0 were used for the meta-analysis.

RESULTS

A total of nine studies were included, including four randomized controlled trials (RCTs) and five retrospective cohort studies. Meta-analysis showed that overall survival (OS) [HR = 0.89, 95%CI (0.74, 1.06), P = 0.19] and progression-free survival (PFS) [HR = 0.87, 95%CI (0.71, 1.06), P = 0.17] were not significantly different between the PTR and non-PTR groups. In the subgroup analysis, all subgroups showed no significant difference in OS between the two groups.

CONCLUSION

PTR may not provide additional survival benefits over chemotherapy in asymptomatic, unresectable mCRC patients. However, in view of the limitations of this study, more well-designed RCTs are needed to validate our conclusions.

The role of upfront primary tumor resection in asymptomatic patients with unresectable stage IV colorectal cancer: A systematic review and meta-analysis

BACKGROUND

Controversy exists over the role of upfront primary tumor resection (PTR) in asymptomatic patients with unresectable stage IV colorectal cancer (CRC). The purpose of this study was to evaluate the effect of upfront PTR on survival outcomes and adverse outcomes.

METHODS

Searches were conducted on PubMed, EMBASE, Web of Science, and Cochrane Library from inception to August 2021. Studies comparing survival outcomes with or without adverse outcomes between PTR and non-PTR treatments were included. Review Manager 5.3 was applied for meta-analyses with a random-effects model whenever possible.

RESULTS

Overall, 20 studies with 3,088 patients were finally included in this systematic review. Compared with non-PTR, upfront PTR was associated with better 3-year (HR: 0.69, 95% CI, 0.57-0.83, P = 0.0001) and 5-year overall survival (OS) (HR: 0.77, 95% CI, 0.62-0.95, P = 0.01), while subgroup analysis indicated that there was no significant difference between upfront PTR and upfront chemotherapy (CT) group. In addition, grade 3 or higher adverse effects due to CT were more frequent in the PTR group with marginal significance (OR: 1.74, 95% CI, 0.99-3.06, P = 0.05), and other adverse outcomes were comparable.

CONCLUSIONS

PTR might be related to improved OS for asymptomatic patients with unresectable stage IV CRC, whereas receiving upfront CT is a rational alternative without detrimental influence on survival or adverse outcomes compared with upfront PTR.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=272675.

How asymptomatic are early cancer patients of five organs based on registry data in Japan

BACKGROUND

One reason for the low cancer screening rate in Japan is that people are not concerned about cancer if they do not have symptoms.

METHODS

The authors retrospectively analyzed 18,405 cancer patients using hospital-based cancer registry data collected between 2007 and 2013 at the 13 hospitals of Shimane Prefecture, Japan. The symptomatic rates of five cancers (stomach, colorectal, lung, breast, and cervix) at each stage and the time of early diagnosis were investigated. The early detection rates of symptomatic and asymptomatic individuals were investigated.

RESULTS

The percentages of symptomatic cases tended to increase with progressive stages. The odds ratio (OR) of stage IV compared with that of stage I was 12.23 for stomach, 7.21 for colorectal, 16.91 for lung, 10.30 for breast, and 51.62 for cervical cancer. The proportions of early symptomatic cases at the time of diagnosis were low. Compared with the percentage of early symptomatic cases of stomach cancer of 25.5%, the percentage of lung cancer was the lowest, at 8.2% (OR 0.26), and the percentage of breast cancer was the highest, at 30.2% (OR 1.26). The percentages of early symptomatic cases of colorectal and cervical cancer were 18.9% (OR 0.68) and 19.9% (OR 0.73), respectively. The early detection rates of the asymptomatic and symptomatic groups were 77.6 and 36.1%, respectively.

CONCLUSION

Cancer registry data indicate that early cancers are asymptomatic, and once symptoms appear, treatment may not be effective. Policy makers should inform people of the necessity of cancer screening before they have symptoms.

Primary tumor sidedness is an independent prognostic marker for survival in metastatic colorectal cancer: Results from a large retrospective cohort with mutational analysis

Recent reports demonstrate inferior outcomes associated with primary right‐sided vs left‐sided colorectal tumors in patients with metastatic colorectal cancer (mCRC). We sought to describe our experience with mCRC patients on whom we have molecular data to determine whether primary tumor sidedness was an independent prognostic marker for overall survival (OS). mCRC patients with documented primary tumor sidedness who received mutational profiling between 2009 and 2014 were identified (n = 367, median follow‐up 30.4 months). Mutational profiling for >150 mutations across commonly mutated cancer genes including RAS, PIK3CA, BRAF, and PTEN as well as treatment data, including receipt of a biologic agent, were collected. Univariable/multivariable models were used to analyze relationships between collected data and OS. Among 367 patients, sidedness breakdown was as follows: 234 left (64%), 133 right (36%). 56% were male, with a median age at diagnosis of 57 (range 24‐89). A total of 143 patients had RAS mutations. Five‐year OS was 41%, median OS was 54 months (range 1‐149). Five‐year OS for left‐ vs right‐sided tumors was 46% vs 24% (P < .0001). On univariable analysis, among both RAS wildtype and mutant tumors, left‐sided tumors continued to have improved OS vs right‐sided tumors (HR: 0.49, 95% CI: 0.34‐0.69 RAS wildtype; HR: 0.61, 95% CI: 0.40‐0.95 RAS mutant). Left‐sidedness was an important prognostic factor for OS among RAS wildtype patients despite treatment with or without a biologic agent (P < .05). Left‐sidedness remained significant for improved OS on multivariable analysis (P < .0001). Left‐sided primary tumor remained most important prognostic factor for OS, even when adjusting for mutational status and receipt of biologic agent.