Atlas chapter 13 · Oncology (adjunctive)

Split-gill fungus / Sizofiran

Schizophyllum commune

E4-H++ — Supports the tested propositionR3 — two randomized cervical-cancer radiotherapy programmes were identified, but independence is limited by shared investigators, country, era and programme context, and the programmes emphasized partly different outcomes. Follow-up publications and secondary restatements are not counted as additional replications. R3 therefore represents meaningful repeated clinical investigation with limited independence and limited geographical/programme breadth.

Proposition / claim: Historical adjunctive clinical benefit from sizofiran in defined cervical-cancer radiotherapy programmes. The claim is historical and adjunctive; it is not that Schizophyllum commune treats cancer, nor that beta-glucans treat cancer.
Evidence owner: Sizofiran / SPG / schizophyllan, with the clinically studied preparation, dose and route retained as part of intervention identity. The evidence does not belong generically to Schizophyllum commune as food, mushroom powder, oral supplements, generic extracts, or to beta-glucans as a class. The grade-determining cervical-cancer programmes involved defined clinical administration, including intramuscular SPG.
Dominant uncertainty: Two layers. (1) Historical programme reconstruction: which publications represent genuinely independent trials and which are follow-ups; what preparation and route were used; how patients were selected; what background treatment was used; and which outcomes actually drive the positive signal. (2) Contemporary incremental benefit: only after the historical genealogy is reconstructed should we ask whether a clinically equivalent sizofiran adds meaningful benefit to contemporary oncology. The immediate uncertainty is therefore not “Does sizofiran work?” but “What exactly was independently demonstrated by the historical clinical programme?”

Organism: Schizophyllum commune
Tested intervention: Sizofiran / SPG / schizophyllan
Evidence target: Standardized preparation
Intervention description: Sizofiran (SPG, schizophyllan) is a defined beta-glucan produced from cultures of Schizophyllum commune. The grade-determining clinical evidence involved a defined preparation, dose and route, including intramuscular administration of SPG. It is not equivalent to oral Schizophyllum commune products, mushroom powder, generic extracts, or to beta-glucans as a class.
Population: Patients with cervical cancer in historical randomized clinical programmes, including stage II/III and locally advanced disease. The chapter does not define a single pooled population.
Comparator: Historical radiotherapy / conventional treatment without adjunctive sizofiran, as described in the programme reports. No placebo comparator is claimed.
Outcome: Recurrence, response and survival, with stage- and programme-dependent differences. The findings are heterogeneous and are not a uniform positive result across all settings.
Evidence maturity (E): E4-H+
Direction: + — Supports the tested proposition
Historical flag (H): H — grade-determining evidence belongs primarily to historical oncology environments; the historical flag is explicit in the source grade.
Replication (R): R3 — two randomized cervical-cancer radiotherapy programmes were identified, but independence is limited by shared investigators, country, era and programme context, and the programmes emphasized partly different outcomes. Follow-up publications and secondary restatements are not counted as additional replications. R3 therefore represents meaningful repeated clinical investigation with limited independence and limited geographical/programme breadth.
Claim Gap (CG): CG0-1: Historical randomized programmes investigated sizofiran as an adjunct in cervical-cancer treatment and reported favourable outcomes in some settings. CG1: Sizofiran has historical adjunctive oncology evidence. CG1-2: A polysaccharide derived from S. commune demonstrated clinical activity in historical cancer-treatment programmes. CG3-4: Schizophyllum commune fights cancer. CG4: Medicinal-mushroom beta-glucans are clinically proven cancer treatments. Claim ceiling: CG1 for sizofiran-specific historical wording. At the broadest claim, organism, compound, route, indication and treatment context have all expanded.
Evidence Transfer Vector: For the transferred proposition “Oral Schizophyllum supplements improve cancer survival.” ETV: I / D / C / P / R I — Intervention: sizofiran → generic fungal product D — Dose/route: historical clinical administration → oral supplement C — Clinical context: historical adjunctive oncology → modern treatment P — Population: defined cancer programmes → cancer generally R — Replication: intervention-specific historical evidence → generic modern certainty
Taxonomic Transfer Confidence: HIGH — organism identity is not the principal transfer problem in this chapter. High TTC must not be interpreted as high intervention equivalence.
Intervention Transfer Confidence: Sizofiran → generic Schizophyllum commune product: LOW. Preparation, dose and route are part of intervention identity; biological origin does not establish pharmacological equivalence.
Safety: S2
Conservation: C0/C+
Resolution zone: RZ-2 → RZ-3
Next best experiment: Historical evidence reconstruction first. Reconstruct the original programme at trial/family level: identify genuinely independent controlled programmes; separate follow-up publications from independent trials; establish preparation identity, dose, route, population, comparator/background therapy and outcomes; and determine which programmes actually generate the favourable signal. Only after this reconstruction should a contemporary randomized programme be proposed, if justified.
Primary references: Okamura K, Suzuki M, Chihara T, Fujiwara A, Fukuda T, Goto S, et al. Clinical evaluation of schizophyllan combined with irradiation in patients with cervical cancer. A randomized controlled study. Cancer. 1986;58(4):865-872. PMID: 2941141. — GRADE-OWNING / PRIMARY. Randomized controlled programme of sizofiran / SPG (schizophyllan) given intramuscularly alongside radiotherapy in cervical cancer; one of the two randomized programmes on which E4-H+ and Direction + rest.
Noda K, Takeuchi S, Yajima A, Akiya K, Kasamatsu T, Tomoda Y, et al. Clinical effect of sizofiran combined with irradiation in cervical cancer patients: a randomized controlled study. Cooperative Study Group on SPG for Gynecological Cancer. Jpn J Clin Oncol. 1992;22(1):17-25. PMID: 1573785. — GRADE-OWNING / PRIMARY. Second randomized controlled programme of intramuscular sizofiran with radiotherapy in cervical cancer; independence from the earlier programme is limited by shared investigators, country, era and programme context.
Okamura K, Suzuki M, Chihara T, Fujiwara A, Fukuda T, Goto S, et al. Clinical evaluation of sizofiran combined with irradiation in patients with cervical cancer. A randomized controlled study; a five-year survival rate. Biotherapy. 1989;1(2):103-107. PMID: 2534912. — FOLLOW-UP of the earlier randomized programme (extended survival reporting). Not an independent replication and not counted towards R.
Okamura K, Suzuki M, Chihara T, Fujiwara A, Fukuda T, Goto S, et al. Adjuvant immunotherapy: two randomized controlled studies of patients with cervical cancer. Biomed Pharmacother. 1989;43(3):177-181. PMID: 2528386. — SECONDARY SYNTHESIS / restatement of previously reported randomized programmes. Not an independent replication and not counted towards R.
Okamura K, Suzuki M, Chihara T, Fujiwara A, Fukuda T, Goto S, et al. Adjuvant immunotherapy for cervical cancer. Two randomized controlled studies using OK-432 or sizofiran. J Chemother. 1989;1(4 Suppl):1222-1224. PMID: 16312843. — SECONDARY RESTATEMENT of the same randomized programmes. Not an independent replication and not counted towards R.
Hamazaki Y. [Studies on immunotherapy of uterine cervical cancer by administration of schizophyllan (SPG)]. Nihon Sanka Fujinka Gakkai Zasshi. 1980;32(7):929-935. PMID: 6453913. Japanese. — CORROBORATIVE historical-control evidence predating the randomized programmes. Supports the clinical line of investigation but is not randomized replication.
Nakano T, Oka K, Hanba K, Morita S. Intratumoral administration of sizofiran activates Langerhans cell and T-cell infiltration in cervical cancer. Clin Immunol Immunopathol. 1996;79(1):79-86. PMID: 8612354. — MECHANISTIC / identity evidence. Immunological effect of sizofiran in cervical cancer; intratumoral route, so it does not own the grade and does not extend the intramuscular clinical proposition.
Source chapter: Chapter 13, The Fungal Evidence Atlas