What do systematic reviews say?

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

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 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 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 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

Concomitant (concurrent) chemoradiotherapy vs Radiotherapy alone

Concomitant (concurrent) chemoradiotherapy probably leads to lower overall survival, concurrent chemoradiotherapy vs radiotherapy alone… compared with radiotherapy alone (non-resectable tumours) (moderate certainty).

• Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy 2021 · Cochrane All outcomes
  HR 0.74 [0.67, 0.83]
  24 studies · 2852 participants
  Moderate

Pre-radiotherapy extraction of healthy molar teeth vs Conservative treatment (leaving the teeth in place during radiotherapy, with oral health education and disease prevention: oral hygiene, fluoride, diet advice)

The review found no eligible studies for this question.

• Dental extractions prior to radiotherapy to the jaws for reducing post‐radiotherapy dental complications 2013 · Cochrane All outcomes
  no estimate extracted
  0 studies
  No studies found

Pre-radiotherapy extraction of diseased molar teeth vs Conservative treatment (restoration of the teeth and leaving them in place during radiotherapy, with oral health education and disease prevention: oral hygiene, fluoride, diet advice)

The review found no eligible studies for this question.

• Dental extractions prior to radiotherapy to the jaws for reducing post‐radiotherapy dental complications 2013 · Cochrane All outcomes
  no estimate extracted
  0 studies
  No studies found

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

Surgery +/- radiotherapy + (adjuvant) chemotherapy probably leads to lower overall survival, adjuvant concurrent chemoradiation vs adjuvant… 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 0.84 [0.72, 0.98]
  4 studies · 1097 participants
  Moderate

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

Induction chemotherapy plus locoregional treatment (radiotherapy and/or surgery) vs Locoregional treatment (radiotherapy and/or surgery) alone

Induction chemotherapy plus locoregional treatment (radiotherapy… showed no clear difference in overall survival, induction platinum + 5-fluorouracil prior to… compared with locoregional treatment (radiotherapy and/or surgery) alone (moderate certainty).

• Interventions for the treatment of oral cavity and oropharyngeal cancer: chemotherapy 2021 · Cochrane All outcomes
  HR 0.85 [0.70, 1.04]
  5 studies · 7427 participants
  Moderate

Concomitant (concurrent) chemoradiotherapy vs chemoradiotherapy plus surgery

Chemoradiotherapy showed no clear difference in overall survival compared with chemoradiotherapy plus surgery (high certainty).

• Chemoradiotherapy versus chemoradiotherapy plus surgery for esophageal cancer 2017 · Cochrane Headline outcomes only
  HR 0.99 [0.79, 1.24]
  2 studies · 431 participants
  High

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

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

Perioperative chemotherapy vs primary surgery

Perioperative chemotherapy probably leads to lower overall survival by chemo‐/radiotherapy ‐ Chemoradiotherapy compared with primary surgery (moderate certainty).

• Perioperative chemo(radio)therapy versus primary surgery for resectable adenocarcinoma of the stomach,… 2013 · Cochrane Headline outcomes only
  HR 0.7 [0.5, 0.99]
  4 studies · 389 participants
  Moderate

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

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

Extended‐field radiotherapy vs pelvic radiotherapy

Extended‐field radiotherapy probably leads to lower overall survival compared with pelvic radiotherapy (moderate certainty).

• Extended‐field radiotherapy for locally advanced cervical cancer 2018 · Cochrane Headline outcomes only
  HR 0.67 [0.48, 0.94]
  1 study · 337 participants
  Moderate

Extended‐field radiotherapy vs pelvic chemoradiotherapy

Extended‐field radiotherapy probably leads to lower overall survival compared with pelvic chemoradiotherapy (moderate certainty).

• Extended‐field radiotherapy for locally advanced cervical cancer 2018 · Cochrane Headline outcomes only
  HR 0.5 [0.39, 0.64]
  1 study · 389 participants
  Moderate

Anti‐angiogenic therapy vs no anti‐angiogenic therapy

Anti‐angiogenic therapy showed no clear difference in overall survival ( compared with no anti‐angiogenic therapy (high certainty).

• Anti‐angiogenic therapy for high‐grade glioma 2018 · Cochrane Headline outcomes only
  HR 0.95 [0.88, 1.02]
  11 studies · 3743 participants
  High
• Anti‐angiogenic therapy for high‐grade glioma 2018 · Cochrane Headline outcomes only
  HR 0.93 [0.86, 1.02]
  8 studies · 2833 participants
  High
• Anti‐angiogenic therapy for high‐grade glioma 2018 · Cochrane Headline outcomes only
  HR 0.99 [0.85, 1.16]
  3 studies · 910 participants
  Moderate