What do systematic reviews say?

Chemotherapy regimen A (+/- locoregional treatment) vs Chemotherapy regimen B (+/- locoregional treatment)

• Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy 2021 · Cochrane All outcomes
  Eight of 11 induction-before-radiotherapy studies reported overall survival; not pooled (heterogeneity). Only Vermorken 2007 significant: cisplatin+5-FU+docetaxel induction HR 0.73 (95% CI 0.57 to 0.93, P = 0.01).…
  8 studies
  GRADE not reported

Chemotherapy vs best supportive care

Chemotherapy probably leads to lower overall survival compared with best supportive care (moderate certainty).

• Chemotherapy for advanced gastric cancer 2017 · Cochrane Headline outcomes only
  HR 0.37 [0.24, 0.55]
  3 studies · 184 participants
  Moderate

Delayed chemotherapy vs immediate chemotherapy

Delayed chemotherapy showed no clear difference in overall survival compared with immediate chemotherapy (low certainty).

• Survival differences with immediate versus delayed chemotherapy for asymptomatic incurable metastatic colorectal cancer 2018 · Cochrane Headline outcomes only
  HR 1.17 [0.93, 1.46]
  3 studies · 351 participants
  Low

Biochemotherapy vs chemotherapy alone

Biochemotherapy showed no clear difference in overall survival† compared with chemotherapy (high certainty).

• Systemic treatments for metastatic cutaneous melanoma 2018 · Cochrane Headline outcomes only
  HR 0.94 [0.84, 1.06]
  1317 participants
  High

Polychemotherapy vs chemotherapy alone

Polychemotherapy showed no clear difference in overall survival† compared with chemotherapy (high certainty).

• Systemic treatments for metastatic cutaneous melanoma 2018 · Cochrane Headline outcomes only
  HR 0.99 [0.85, 1.16]
  594 participants
  High

High‐dose chemotherapy vs chemotherapy without bone marrow transplant or stem cell rescue

High‐dose chemotherapy showed no clear difference in overall survival at 5‐year compared with chemotherapy without bone marrow transplant or stem cell rescue (high certainty).

• High‐dose chemotherapy and autologous bone marrow or stem cell transplantation versus conventional chemotherapy for… 2016 · Cochrane Headline outcomes only
  RR 1 [0.96, 1.04]
  8 studies · 3566 participants
  High

Chemotherapy vs chemotherapy alone

Chemotherapy showed no clear difference in overall survival (non‐taxane monotherapy vs taxane monotherapy) compared with chemotherapy (low certainty).

• Salvage systemic therapy for advanced gastric and oesophago‐gastric junction adenocarcinoma 2020 · Cochrane Headline outcomes only
  HR 1.13 [0.86, 1.48]
  1 study · 219 participants
  Low

Combination chemotherapy vs single‐agent chemotherapy

It is very uncertain whether combination chemotherapy changes overall survival (3 years) compared with single‐agent chemotherapy (very low certainty).

• Combination chemotherapy versus single‐agent chemotherapy during preoperative chemoradiation for resectable rectal… 2015 · Cochrane Headline outcomes only
  HR 0.94 [0.59, 1.48]
  1 study · 598 participants
  Very low

Chemotherapy vs chemotherapy alone

Chemotherapy showed no clear difference in overall survival (taxane‐containing doublet therapy vs taxane… compared with chemotherapy (low certainty).

• Salvage systemic therapy for advanced gastric and oesophago‐gastric junction adenocarcinoma 2020 · Cochrane Headline outcomes only
  HR 1.05 [0.72, 1.54]
  2 studies · 121 participants
  Low

Chemotherapy vs placebo, best supportive care (BSC) or no treatment

Chemotherapy probably leads to lower overall survival compared with placebo, best supportive care (BSC) or no treatment (moderate certainty).

• Salvage systemic therapy for advanced gastric and oesophago‐gastric junction adenocarcinoma 2020 · Cochrane Headline outcomes only
  HR 0.66 [0.52, 0.83]
  2 studies · 547 participants
  Moderate

Chemotherapy vs biological therapy

Chemotherapy showed no clear difference in overall survival compared with biological therapy (moderate certainty).

• Salvage systemic therapy for advanced gastric and oesophago‐gastric junction adenocarcinoma 2020 · Cochrane Headline outcomes only
  HR 0.82 [0.66, 1.02]
  1 study · 395 participants
  Moderate

Chemotherapy vs best supportive care

Chemotherapy probably leads to lower overall survival compared with best supportive care (moderate certainty).

• Second‐line systemic therapy for metastatic colorectal cancer 2017 · Cochrane Headline outcomes only
  HR 0.58 [0.43, 0.8]
  1 study · 279 participants
  Moderate

Chemotherapy vs chemotherapy alone

• Salvage systemic therapy for advanced gastric and oesophago‐gastric junction adenocarcinoma 2020 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 107 participants
  High

Chemotherapy with TKI vs chemotherapy alone

Chemotherapy with TKI showed no clear difference in overall survival (OS) compared with chemotherapy alone (moderate certainty).

• Angiogenesis inhibitors for the treatment of epithelial ovarian cancer 2023 · Cochrane Headline outcomes only
  HR 0.85 [0.68, 1.08]
  8 studies · 940 participants
  Moderate

Perioperative chemotherapy vs primary surgery

Perioperative chemotherapy leads to lower overall survival by chemo‐/radiotherapy ‐ Chemotherapy only compared with primary surgery (high certainty).

• Perioperative chemo(radio)therapy versus primary surgery for resectable adenocarcinoma of the stomach,… 2013 · Cochrane Headline outcomes only
  HR 0.83 [0.75, 0.91]
  10 studies · 2033 participants
  High

Surgery +/- radiotherapy + (adjuvant) chemotherapy vs Surgery +/- radiotherapy alone (observation or adjuvant radiotherapy only)

Surgery +/- radiotherapy + (adjuvant) chemotherapy showed no clear difference in overall survival, adjuvant chemotherapy vs observation alone… compared with surgery +/- radiotherapy alone (observation or adjuvant radiotherapy… (moderate certainty).

• Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy 2021 · Cochrane All outcomes
  HR 0.95 [0.73, 1.22]
  5 studies · 353 participants
  Moderate

Interferon + chemotherapy vs chemotherapy alone

Interferon + chemotherapy may leads to higher overall survival compared with chemotherapy alone (low certainty).

• Interferon after surgery for women with advanced (Stage II‐IV) epithelial ovarian cancer 2013 · Cochrane Headline outcomes only
  HR 1.14
  2 studies · 244 participants
  Low

Bevacizumab plus chemotherapy vs chemotherapy alone

Chemotherapy + bevacizumab leads to lower overall survival compared with chemotherapy (high certainty).

• Second‐line systemic therapy for metastatic colorectal cancer 2017 · Cochrane Headline outcomes only
  HR 0.79 [0.7, 0.88]
  4 studies · 1723 participants
  High

Neoadjuvant chemotherapy prior to interval surgery (NACT) vs surgery followed by chemotherapy (PDS)

Neoadjuvant chemotherapy prior to interval surgery (NACT) showed no clear difference in overall survival ( compared with surgery followed by chemotherapy (PDS) (high certainty).

• Neoadjuvant chemotherapy before surgery versus surgery followed by chemotherapy for initial treatment in advanced… 2021 · Cochrane Headline outcomes only
  HR 0.96 [0.86, 1.08]
  4 studies · 2000 participants
  High

Cediranib plus chemotherapy vs placebo plus chemotherapy

Cediranib plus chemotherapy showed no clear difference in overall survival compared with placebo plus chemotherapy (low certainty).

• Vascular endothelial growth factor (VEGF) targeting therapy for persistent, recurrent, or metastatic cervical cancer 2021 · Cochrane Headline outcomes only
  HR 0.94 [0.53, 1.65]
  1 study · 69 participants
  Low