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Low-Dose Chemo May Improve Survival in Advanced Cancer

The study covered in this summary was published on ssrn.com as a preprint and has not yet been peer reviewed.

Key Takeaway

  • Patients with certain common types of advanced cancer may live longer with low-dose palliative chemotherapy than with standard-dose chemotherapy.

Why This Matters

  • Patients with advanced cancer often select a “more is better” standard-dose palliative chemotherapy approach instead of a low-dose therapy option.

  • The current study found that a low-dose strategy may improve survival for patients with advanced ovarian, pancreatic, and lung cancers, with less toxicity and lower costs.

Study Design

  • The study involved patients who were diagnosed with stage III or IV ovarian, stage III or IV lung, stage IV colorectal, or any stage pancreatic cancer between 2004 and 2009 who were treated at Ballarat Oncology and Haematology Services outside of Melbourne, Australia.

  • Investigators compared survival outcomes between the 97 patients who received standard-dose chemotherapy and the 69 who received low-dose chemotherapy, defined as ≤50% of the standard dosing for their malignancy.

  • Hazard ratios (HRs) were adjusted for patient age and cancer stage.

Key Results

  • Overall, among patients who received the low-dose option, median survival was 1.7 years, the 5-year survival rate was 20%, and the 10-year survival rate was 7%. With standard dosing, median survival was half that (0.8 years), and the 5-year survival rate was 1%. There were no 10-year survivors.

  • Among 75 patients with lung cancer, median survival was 1.7 years with low-dose chemotherapy, vs 0.55 years with standard dosing (HR, 0.3 favoring low-dose). The 5-year survival rate was 12%, and the 10-year survival rate was 6% in the low-dose group; no standard-dose patients were alive at 5 years.

  • Among 27 patients with pancreatic cancer who received low-dose chemotherapy, median survival was 3.9 years, vs 0.5 years with standard dosing (HR, 0.2). The 5-year survival rate was 43%, and the 10-year survival rate was 14% in the low-dose group. No patients were alive at 5 years with standard dosing.

  • Among 18 patients with ovarian cancer, median survival was 7.9 years with low-dose chemotherapy, vs 1.58 years with standard dosing (HR, 0.15). The 10-year survival rate was 14% in the low-dose group. No patients who received standard doses were alive at 10 years.

  • Among 46 patients with colorectal cancer, median survival was slightly shorter with low-dose chemotherapy (1.3 vs 1.76 years), but the 5-year survival rate was 14%, and the 10-year survival rate was 9%, vs a 5-year survival of 4% with standard dosing. No patients were alive at 10 years. The colorectal cancer differences were not statistically significant.

  • A possible explanation for the findings is that lower toxicity may have led to longer treatment among low-dose patients.

Limitations

  • The study did not adjust for substantial confounders, including tumor subtypes, treatment duration, agents used, and differences in the use of surgery and radiation between the groups.

  • The fact that low-dose chemotherapy was defined as being ≤50% of the standard dose meant that doses close to the 50% mark in either direction were placed in separate groups for the analysis.

Disclosures

  • No external funding for the study was reported, and the investigators reported no conflicts of interest.

This is a summary of a preprint research study, “Low-Dose Palliative Chemotherapy Compared to Standard-Dose Chemotherapy for Poor-Prognosis Cancers Improves Overall Survival – A Single Institution Retrospective Study,” led by Andrew Dind of the University of Notre Dame, Sydney, Australia, provided to you by Medscape. The study has not been peer reviewed. The full text can be found at ssrn.com.

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who has worked for several major news outlets before joining Medscape and also an MIT Knight Science Journalism fellow. Email: [email protected].

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