Chemotherapy and radiotherapy can cause second cancers (e.g., breast cancer after chest radiation for Hodgkin disease, therapy-related myeloid leukaemia) years after cure.
Original statement
سرطانات ثانوية (ثدي ولوكيميا ميلويدية) بعد سنوات من الشفاء
not verbatim – paraphrase. Translation by the project; the Arabic wording is authoritative.
Translation
Chemotherapy and radiotherapy can cause second cancers (e.g., breast cancer after chest radiation for Hodgkin disease, therapy-related myeloid leukaemia) years after cure.
Origin
- Source status
- Archive editors
- Attribution
- Archive editors (rule page summary/narrative)
- Origin
- https://eltayebat.com/rule/chemo-radiation/
- Attribution uncertainty
- Written by archive operators; not attributed to Elawady.
- Claimed mechanism
DNA damage from radiation and alkylating/topoisomerase agents
- Claimed health effect
Second malignancies
- Population concerned
Cancer survivors
- Geographic restriction by Elawady
none found
Scientific assessment
True – The statement is supported by robust evidence.
Certainty of evidence: high – Further research is very unlikely to change the assessment.
1. What was claimed?
Secondary breast cancers and myeloid leukaemia years after cure.
2. What is demonstrably correct?
Breast-cancer RR 3.2 with >=4 Gy and 8.0 with >40 Gy after Hodgkin radiotherapy (A-CHM-06); therapy-related MDS/AML has a median survival of 8 months (A-CHM-15); tamoxifen raises endometrial cancer risk (A-CHM-08).
3. What is wrong or exaggerated?
The 'heavy price' framing is not matched by absolute data: in 647,672 adult survivors, radiotherapy accounted for about 8% of second cancers in irradiated patients and 5 extra cancers per 1,000 treated by 15 years; the authors conclude most second cancers are due to other factors (A-CHM-07). Tamoxifen's benefit 'greatly outweighs' its risk (A-CHM-08).
4. What remains unclear?
Risk under modern reduced fields and doses.
5. Which studies support it?
A-CHM-06, A-CHM-15, A-CHM-08, I-CHM-06 (lung cancer RR 2.10 after RT); A-CHM-07 for the existence of the effect (radiotherapy-associated RR above 1 for every first-cancer site, with dose and latency gradients; 3,266 excess second solid cancers).
6. Which studies contradict it?
None against the existence of treatment-related second cancers. Limiting the magnitude: A-CHM-07 (about 8% of second solid cancers in irradiated adults attributable to radiotherapy; 5 excess cancers per 1,000 treated by 15 years); I-CHM-06 (absolute lung-cancer risk about 0.3% in non-smokers).
7. What applies to Germany and Europe?
Survivorship screening programmes (e.g., early breast screening after chest radiation) exist in Europe.
8. What is known about Egypt?
No Egyptian data reviewed.
9. What practical conclusion is appropriate?
Second cancers are a real, mostly uncommon late effect that justifies long-term follow-up.
Assessment details
- Rationale for certainty of evidence
Dose-response case-control data, large registry cohort and case series agree on existence; magnitude in adults is modest.
- Source quality
Correctly cited; magnitude context omitted.
- Regional transferability
High.
- Individual exceptions
Higher risk after childhood/young-adult chest radiation, high doses, smoking.
- Regional scope of the claim
- general (biological/medical)
- Last reviewed
- 26 October 2026 provisional
Scientific evidence in detail
Scientifically well supported – The claim agrees with consistent, high-quality evidence.
Research question: Do chemotherapy and radiotherapy cause second cancers years after treatment, and what is the absolute risk compared with the benefit?
Research question in detail (PECO)
- Population
- Cancer survivors treated with chemotherapy and/or radiotherapy
- Intervention or exposure
- Chemotherapy (alkylating agents, topoisomerase II inhibitors, anthracyclines), radiotherapy
- Comparison
- No such treatment
- Geographic scope
- universal biology
- Outcomes
- Therapy-related myeloid neoplasms
- Radiation-induced solid cancers
Study results as reported by the authors. Our assessment follows below.
What speaks for the claim?
Chemotherapy for early breast cancer: benefits and risks in 100,000 women
Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Lancet 2023 · PMID 37061269 · DOI 10.1016/S0140-6736(23)00285-4 Meta-analysisfull text checkednewly addedRandomised data: anthracycline caused extra acute myeloid leukaemia.
- Actual result
- AML 12/6768 (0.18%) vs 2/6783 (0.03%); about 1 extra case per 700 women
- Methodological quality
- high (IPD meta-analysis of RCTs)
- Relevance
- direct
- Limitations
- Short follow-up
Chest radiation for Hodgkin disease raises later breast-cancer risk in young women
Travis LB et al.. JAMA 2003 · PMID 12876089 · DOI 10.1001/jama.290.4.465 Case-control studyabstract checkedBreast cancer after chest radiotherapy for Hodgkin disease, rising with dose and persisting for decades.
- Actual result
- RR 3.2 (>=4 Gy) to 8.0 (>40 Gy)
- Methodological quality
- high (nested case-control)
- Relevance
- direct
- Limitations
- Old high-dose techniques
Leukaemia-type cancers after breast cancer treatment
Wolff AC et al.. J Clin Oncol 2015 · PMID 25534386 · DOI 10.1200/JCO.2013.54.6119 Cohort studyabstract checkednewly addedLarge cohort: marrow neoplasms after adjuvant breast cancer therapy are rare but rise after 5 years.
- Actual result
- 0.24% at 5 y, 0.48% at 10 y
- Methodological quality
- moderate (cohort)
- Relevance
- direct
- Limitations
- Few events
What speaks against the claim?
Only a small share of second cancers in adults is caused by radiotherapy
Berrington de Gonzalez A et al.. Lancet Oncol 2011 · PMID 21454129 · DOI 10.1016/S1470-2045(11)70061-4 Cohort studyfull text, structured risk-of-bias assessmentOnly a small share of second cancers in adults is attributable to radiotherapy.
- Actual result
- 8% of second solid cancers; about 5 excess per 1000 treated by 15 years
- Methodological quality
- high (SEER cohort, full text)
- Relevance
- direct (limits the size)
- Limitations
- Registry data
What does the overall evidence say?
Editorial assessment based on the studies above – not itself a study result.
Which position is better supported?
Treatment-related second cancers are real; in adults they are uncommon compared with the cancers treated.
Why some studies weigh more
Randomised IPD data give unbiased absolute harm; registries quantify population share.
Is a causal relationship established? Yes, established Dose-response, randomised comparison (AML), mechanism (DNA damage).
Remaining uncertainty
Risks beyond 15-20 years with current regimens.
Justified conclusion
Correct. Absolute risks: about 1-2 extra leukaemias per 1000 adjuvant breast cancer patients, and about 3-5 excess solid cancers per 1000 irradiated adults within 10-15 years; higher after childhood treatment.
Does this depend on the country?
- General biological effects
- Universal biology.
- Eating habits
- Not relevant.
- Origin of the food
- Not relevant.
- Contaminants
- Not relevant.
- National production conditions
- Not relevant.
- Legal rules
- Not relevant.
- Actual monitoring data
- No monitoring data relevant.
A regional difference that changes the conclusion is not supported by robust data.
Statistical re-check
- Recompute AML absolute risk and NNH; compare with NNT – 0.18% vs 0.03%; ARI 0.15%; NNH 677 (paper: about 700); NNT for recurrence 38; about 18 recurrences prevented per AML case recalculated
- Attributable share – 3266/42294 = 7.7% (reported 8%) recalculated
- HR precision – HR 6.8 (1.3-36.1) very imprecise; absolute rates per 1000 person-years (0.16-0.54) are more informative recalculated
Certainty of the overall evidence (GRADE, simplified)
- Main outcome
- Therapy-related second cancers
- Starting level
- high (randomised trials)
- Result
- high
Simplified assessment by a single reviewer, following the GRADE approach; not a formal GRADE panel. GRADE rates the body of evidence for one outcome, not individual studies.
Search strategy
Documented literature searches for this review (search strings in the original database syntax).
| Database | Date | Search | Looking for | Hits | Included |
|---|---|---|---|---|---|
| Europe PMC | 26 October 2026 | TITLE:"marrow neoplasms" AND TITLE:"adjuvant breast cancer" | supporting evidence | 1 | |
| Europe PMC | 26 October 2026 | (TITLE:"therapy-related" OR TITLE:"second malignan" OR TITLE:"second cancer" OR TITLE:"subsequent malignan") AND (TITLE:"chemotherapy" OR TITLE:"radiotherapy") AND (TITLE:"meta-analysis" OR TITLE:"cohort") AND (TITLE:"absolute" OR TITLE:"incidence") AND PUB_YEAR:[2014 TO 2026] | both directions | 1 | |
| PubMed | 26 October 2026 | "Early Breast Cancer Trialists Collaborative Group"[Corporate Author] AND Lancet[ta] AND 2012:2026[dp] | both directions | 12 |
Open questions
Second-cancer risk after modern radiotherapy techniques.
How deeply was this checked?
7 linked studies: 2 checked in full text (1 of them with a structured risk-of-bias assessment), 5 on the basis of the abstract, 0 bibliographically only. No formal assessment with two independent reviewers and no independent human expert review has taken place yet.
Last scientific review: 26 October 2026
History of the verdict
In plain language
Radiation and some chemotherapy drugs can, years later, cause a new cancer. Young women who had chest radiation for Hodgkin lymphoma have a clearly higher breast-cancer risk. In adults overall, only about 5 of every 1,000 irradiated patients develop an extra cancer within 15 years because of the radiation. Survivors should follow recommended screening.
Studies on this claim
Studies supporting the claim (4)
-
Chest radiation for Hodgkin disease raises later breast-cancer risk in young women
Travis LB et al.. JAMA 2003 · PMID 12876089 · DOI 10.1001/jama.290.4.465Case-control studycited by the Tayebat archiveabstract checked★ key studyRisk was about 3 times higher with >=4 Gy and 8 times higher with >40 Gy to the breast.
Second breast cancer after HD radiotherapy
Does the study support the specific claim? Yes · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Quantify radiation-related breast cancer.
- How was the study done?
Nested case-control.
- How many people, animals or samples were studied?
105 cases, 266 controls.
- What was actually found?
Dose-dependent RR 3.2-8.0.
- How large was the observed effect?
RR 8.0 above 40 Gy.
- What do the results mean in everyday life?
Women treated with chest radiation young need breast screening.
- What are the study's limitations?
Old techniques, wide CIs.
- What does it say about Elawady's specific claim?
Supports existence of second cancers.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
That Hodgkin treatment does net harm.
-
Leukaemia caused by earlier cancer treatment has a poor outlook
Smith SM et al.. Blood 2003 · PMID 12623843 · DOI 10.1182/blood-2002-11-3343Case series / case reportcited by the Tayebat archiveabstract checkedIn 306 patients, median survival after diagnosis was 8 months.
t-MDS/AML exists and is serious
Does the study support the specific claim? Yes · Methodological quality: low · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Describe t-MDS/AML.
- How was the study done?
Case series.
- How many people, animals or samples were studied?
306.
- What was actually found?
Typical chromosome changes; poor survival.
- How large was the observed effect?
Median survival 8 months.
- What do the results mean in everyday life?
Rare but serious complication.
- What are the study's limitations?
No incidence data.
- What does it say about Elawady's specific claim?
Supports existence.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
How often it happens.
-
Chemotherapy for early breast cancer: benefits and risks in 100,000 women
Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Lancet 2023 · PMID 37061269 · DOI 10.1016/S0140-6736(23)00285-4Meta-analysisindependent cross-checkfull text checked★ key studyAnthracycline-taxane chemotherapy lowered recurrence and breast-cancer death; it caused about one extra leukaemia per 700 women and no measurable excess heart deaths within about 5 years.
Quantifies therapy-related AML: about one extra case per 700 women treated.
Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Weigh benefits and risks of anthracycline-containing chemotherapy
- How was the study done?
Pooled individual data from randomised trials
- How many people, animals or samples were studied?
18,103 women in the main comparison; about 100,000 overall
- What was actually found?
Fewer recurrences (RR 0.86) and fewer breast-cancer deaths; AML 0.18% vs 0.03%
- How large was the observed effect?
10-year recurrence 16.4% vs 18.9%; up to 8.7 points fewer recurrences with concurrent anthracycline
- What do the results mean in everyday life?
For every leukaemia caused, roughly 18 recurrences are prevented in this data set
- What are the study's limitations?
Short follow-up for heart effects; high-risk heart patients often excluded
- What does it say about Elawady's specific claim?
Harms of chemotherapy are real (AML) but small compared with the benefit; this contradicts the idea that harms outweigh benefits
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Cannot quantify heart failure 15-20 years after treatment
-
Leukaemia-type cancers after breast cancer treatment
Wolff AC et al.. J Clin Oncol 2015 · PMID 25534386 · DOI 10.1200/JCO.2013.54.6119Cohort studyindependent cross-checkabstract checked★ key studyAbout 5 in 1000 treated women developed a marrow cancer within 10 years.
Confirms therapy-related marrow neoplasms; absolute risk about 0.5% at 10 years.
Does the study support the specific claim? Yes · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Measure risk of marrow cancers after treatment
- How was the study done?
Cohort of 20,063 patients
- How many people, animals or samples were studied?
US academic centres
- What was actually found?
Low but real risk that keeps rising after 5 years
- How large was the observed effect?
0.24% at 5 y, 0.48% at 10 y
- What do the results mean in everyday life?
Rare, but a reason for follow-up
- What are the study's limitations?
Few events
- What does it say about Elawady's specific claim?
Supports existence of second cancers; shows they are rare
- Do the results apply to Germany and Europe?
High
- What can explicitly not be concluded from this study?
Cannot show harm outweighs benefit
No study in this group is marked as key.
Studies contradicting or limiting the claim (0)
No studies in this group.
Studies with mixed or unclear results (3)
-
Only a small share of second cancers in adults is caused by radiotherapy
Berrington de Gonzalez A et al.. Lancet Oncol 2011 · PMID 21454129 · DOI 10.1016/S1470-2045(11)70061-4Cohort studycited by the Tayebat archivefull text, structured risk-of-bias assessment★ key studyAbout 5 extra cancers per 1,000 treated patients within 15 years; 8% of second cancers in irradiated patients.
Small attributable fraction (8%; 5/1000 at 15 y)
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Estimate radiotherapy-attributable second cancers.
- How was the study done?
SEER cohort.
- How many people, animals or samples were studied?
647,672 survivors.
- What was actually found?
8% attributable; 5/1000 by 15 years.
- How large was the observed effect?
RR 1.08-1.43.
- What do the results mean in everyday life?
The risk is real but small compared with the benefit of cure.
- What are the study's limitations?
No randomisation; no data on smoking, chemotherapy or doses; treatments before 2003.
- What does it say about Elawady's specific claim?
Limits the 'heavy price' framing.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Risk for an individual patient.
-
Tamoxifen raises the small risk of uterine cancer but prevents far more breast-cancer events
Fisher B et al.. J Natl Cancer Inst 1994 · PMID 8133536 · DOI 10.1093/jnci/86.7.527Randomised controlled trialcited by the Tayebat archiveabstract checkedUterine cancer about 1.6 vs 0.2 per 1,000 women per year; 38% fewer recurrence-type events.
Endometrial cancer excess; net benefit
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Assess second cancers under tamoxifen.
- How was the study done?
RCT vs placebo.
- How many people, animals or samples were studied?
2,843 + 1,220.
- What was actually found?
RR 7.5 endometrial cancer; benefit outweighs.
- How large was the observed effect?
1.6 vs 0.2/1000/year.
- What do the results mean in everyday life?
Report abnormal bleeding during tamoxifen; continue therapy.
- What are the study's limitations?
Few events; data-integrity issue.
- What does it say about Elawady's specific claim?
Mixed.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
That tamoxifen is net harmful.
-
With modern techniques, radiotherapy's heart and lung risks are small for non-smokers
Taylor C et al.. J Clin Oncol 2017 · PMID 28319436 · DOI 10.1200/JCO.2016.72.0722Meta-analysisindependent cross-checkabstract checked★ key studyAbout 0.3% risk of radiation-related heart death or lung cancer in non-smokers, higher in smokers.
Lung cancer risk small in non-smokers
Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Estimate absolute RT risks.
- How was the study done?
Dose review + IPD meta-analysis.
- How many people, animals or samples were studied?
40,781 women.
- What was actually found?
Small absolute risks; smoking key.
- How large was the observed effect?
Cardiac mortality RR 1.30.
- What do the results mean in everyday life?
Stop smoking before/after radiotherapy.
- What are the study's limitations?
Smoking modelled.
- What does it say about Elawady's specific claim?
Puts Darby in perspective.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Individual dose-specific risk.
No study in this group is marked as key.
Regional context
Germany / EU
Survivorship screening programmes (e.g., early breast screening after chest radiation) exist in Europe.
Egypt
No Egyptian data reviewed.
What applies in my country?
General scientific assessment
True Treatment-related second cancers exist; in adults they are uncommon relative to the cancers cured.
This statement concerns biological or medical relationships. The scientific assessment above applies regardless of the country; country-specific food data do not change it.
References
- Breast cancer following radiotherapy and chemotherapy among young women with Hodgkin disease.. Travis LB et al.. JAMA 2003 · PMID 12876089 · DOI 10.1001/jama.290.4.465
- Clinical-cytogenetic associations in 306 patients with therapy-related myelodysplasia and myeloid leukemia: the University of Chicago series.. Smith SM et al.. Blood 2003 · PMID 12623843 · DOI 10.1182/blood-2002-11-3343
- Anthracycline-containing and taxane-containing chemotherapy for early-stage operable breast cancer: a patient-level meta-analysis of 100 000 women from 86 randomised trials.. Early Breast Cancer Trialists' Collaborative Group (EBCTCG). Lancet 2023 · PMID 37061269 · DOI 10.1016/S0140-6736(23)00285-4
- Risk of marrow neoplasms after adjuvant breast cancer therapy: the national comprehensive cancer network experience.. Wolff AC et al.. J Clin Oncol 2015 · PMID 25534386 · DOI 10.1200/JCO.2013.54.6119
- Proportion of second cancers attributable to radiotherapy treatment in adults: a cohort study in the US SEER cancer registries.. Berrington de Gonzalez A et al.. Lancet Oncol 2011 · PMID 21454129 · DOI 10.1016/S1470-2045(11)70061-4
- Endometrial cancer in tamoxifen-treated breast cancer patients: findings from the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-14.. Fisher B et al.. J Natl Cancer Inst 1994 · PMID 8133536 · DOI 10.1093/jnci/86.7.527
- Estimating the Risks of Breast Cancer Radiotherapy: Evidence From Modern Radiation Doses to the Lungs and Heart and From Previous Randomized Trials.. Taylor C et al.. J Clin Oncol 2017 · PMID 28319436 · DOI 10.1200/JCO.2016.72.0722